Paper 2- Biopsychology

Question 1

Briefly outline the main functions of the brain

Answer 1

1. To collect, process and respond to information in the environment
2. To coordinate the working of different organs and cells in the body

Question 2

Outline the features to the Central Nervous system

Answer 2

• The Brian - The key information processor in our body. Responsible for conscious awareness and higher mental functions such as decision making as well as receiving sensory input and also sends messages to various parts of the body
• The spinal cord - Passes messages to and from the brain as well as the spinal nerves radiating from the spinal cord contain sensory and motor pathways that connect to the central nervous system to the peripheral nervous system

Question 3

Outline the features of the Peripheral nervous system

Answer 3

The PNS sends information from the outside world to the central nervous system, and transmits messages from the central nervous system to muscles and glands in the body. It transmits messages via millions of neurons nerve cells). These neurons can be sensory (afferent) and Motor (Efferent)

There are two sub sections
* The autonomic nervous system control centres are in the brain stem . The ANS contains only motor pathways and it governs vital internal systems, such as the heart, circulatory system, breathing rate and glands. It is important for maintain homeostasis and it has a sympathetic and parasympathetic branch
* The somatic nervous system is made up of sensory receptors/ pathways and motor pathways. It controls muscles (movement) and maintain communication between the CNS and the outside world(via the sense)- i.e. it connects the CNS with the outside world via senses and carriers commands from the motor cortex in the brain

Question 4

Outline the sympathetic nervous system branch

Answer 4

It is the flight or fight responses which lead to an increased heart rate and an increased blood pressure and sweat glands

Question 5

Outline the Parasympathetic nervous system branch

Answer 5

It conserves energy and helps to increase digestion. When there is a rest digestions responses the heart rate drops which leads to an increased salvation

Question 6

Outline the Glands and hormones in The Endocrine system

Answer 6

• Adrenalin is produced by the adrenal glands and is associated to fight or flight. It is linked to behaviour of increased heart rate, blood pressure and expanding the passages to the lungs.
• Oestrogen is produced by the ovaries and is associated with the female reproductive system. It is linked to the behaviour of nurturing and maternal caregiving, aggression and communication
• Thyroxin is produced by the thyroid gland and is associated with influencing the heart rate and metabolic rate. It links to behaviour such as panic attacks, short temper and mood swings

Question 7

Briefly outline the fight or flight response and the role of adrenalin

Answer 7

The endocrine system and the automatic nervous system often work in parallel. When a stressor (something in the environment that causes stress) is perceived, the ANS changes from its normal resting state (the Parasympathetic state) to a psychologically aroused state (the Sympathetic state)
Following this, the body goes through a complex process using the sympathomedullary system to allow you to deal with the stressor

Question 8

Outline how the body responds to a stressor

Answer 8

1. Situation is appraised and perceived as Stressful (e.g. using limbic system and past emotional memories
2. The Hypothalamus is alerted. This recognises the stress is acute so it activates the sympathomedullary (SAM) pathway
3. This activates the sympathetic branch of the ANS. ANS stands for Automatic Nervous System, and it is concerned with the regulation of internal structures of systems. Nerve pathways of the sympathetic nervous system originate in the Brain Stem and travel via the Spinal Cord and Spinal Nerves to various organs
4. When activated (e.g. when acute stress is perceived), the SNS stimulates the Adrenal Medulla which is a part of the Adrenal Gland. These are located just above the Kidneys
5. The Adrenal Medulla secretes the hormones Adrenalin and Noradrenalin into the Bloodstream
6. This prepares the body for fight or Flight and as such causes a number of psychical (bodily) changes, including, increased alertness, Increase in respiration rate, pupil dilate, etc.
7. After a few minutes… the parasympathetic rebound. However, the body cannot maintain this increased level of activity for long periods of time (as it takes too much energy.) So, after a few minutes the para sympathetic branch of the nervous system is activated. This is a countershock response and serves to return the body back to its natural reflexed resting stat. It’s actions are antagonist to the sympathetic system.

Question 9

Evaluate the flight or fight response in humans

Answer 9

The Fight or flight response may be an Overly simplistic explanation of how humans respond to stressors. Many researchers argue that the humans may not always to stressors with flight or flight. Gray (1998) suggested that there is a third possible response to a dangerous stressor - the freeze repsonse. It is the thought that the freeze response allows people to quickly assess a dangerous situation - it gives humans time to decide whether to fight or run away. Because of this, for a more complete explanations of human repsonse to stressors, we must take into account both fight or flight and freeze responses

In addition, the flight or fight response may be somewhat gender bias. Researcher has suggested that Males are much more likely to how a fight or flight repsonse, possible due to the higher levels of testosterone and adrenaline produced by males. However, Taylor (2000) argues that this ignores a somewhat unique repsonse shown by females when faced with a dangerous stressor - the Tend and Befriend response. Because success in Fight or flight is reduced in female due to biological and evolutionary differences, Taylor suggests that females are more likely to response to stressors with the tend-and befriend repsonse, this is characterized by tending ton young in times of stress and befriending those around in times of stress to increase the like hood of survival- a much more successful strategy for females. Therefore suggesting that humans only respond to stressors with Fight or Flight makes is potentially Gender Bias

Question 10

What are neurons

Answer 10

Neurons are the basic building blocks of the nervous system. They are nerve cells that process and transmit messages through electrical and chemical signals

By transmitting signals Electrically and chemically, neurons provide the nervous system with its primary means of communication

Question 11

What are the three main types of neurons

Answer 11

1. Motor neuron - a nerve cell forming part of a pathway along with impulses pass from the brain or spinal cord to a muscle or gland
2. Sensory neurone- peripheral nervous system- nerve cells that are activated by sensory input form the environment
3. Relay neurons - central nervous system area - carry nerve impulses within the central nervous system

Question 12

Outline the structure of neurons

Answer 12

Neurons vary in size, from less a millimetre to up to a meter, but all share the basic structure. The cell body (or soma) includes a nucleus which contains the cell body, and these carry nerves impulses from neighbouring neurons towards the cell body. The axon carriers the impulses away from the cell body down the length of the neuron. The axon is covered in a fatty layer of myelin sheath- this protects the axon and speeds up electrical transmission of the impulse.

If the myelin sheath was continuous, this would have the revers effects and would slow down the electrical impulse. Thus, the myelin sheath is segmented by gaps called nodes of Ranvier. These speed up transmission of the impulse by forcing the impulse to Jump across the gaps along the axon

Finally, at the end of the axon are terminal buttons that communicate with the next neuron in the chain across a gap known as a synapse

Question 13

Outline the function of electrical transmission

Answer 13

When a neuron is in a resting state the inside of the cell is negatively charged compared to the outside. When a neuron is activated by a stimulus ( a nerve impulse) the inside of the cell becomes positively charged for a split second causing an action potential to occur. This creates an electrical impulse that travels down the axon towards the end of the neuron.

Messages then need to be transmitted across synapses.

Question 14

Briefly Outline neurotransmitters and the process of (chemical) synaptic transmission

Answer 14

Neurotransmitters are chemicals that diffuse across the synapse to the next neuron in the chain.

When a pre-synaptic neuron is stimulated by nerve impulses (creating an action potential), neurotransmitters are released into the synaptic cleft (synapse) from the vesicles in the pre-synaptic neuron membrane (actually, the membrane of the vesicles fuses with the membrane of the pre-synaptic neuron axon terminal, which allows the neurotransmitters to be released and enter the synapse).

The neurotransmitter diffuses across the synapse. It binds to postsynaptic receptor sites (the dendrites of the next, post-synaptic neuron).

Binding of the neurotransmitters to the receptor triggers a postsynaptic response specific for the receptor. The effects of the neurotransmitter on the post-synaptic neuron are either excitatory or inhibitory. The chemical message converted back to an electrical impulse.

Once the message has been transmitted, the neurotransmitters are broken down by an enzyme and excess neurotransmitters are taken back up by the pre-synaptic neuron (known as the reuptake).

Question 15

Outline Excitation and inhibiton in the synaptic transmission

Answer 15

Excitation (depolarisation) is when a NT (e.g. adrenalin) increases the positive charge of the postsynaptic neuron. This increases the likelihood that the neuron will fire and pass on the electrical impulse

Inhibition (hyperpolarisation) is when a NT (e.g. serotonin) increases the negative charge of the postsynaptic neuron. This decreases the like hood that the neuron will fire and pass on the electrical impulse

Question 16

Outline summation in the synaptic transmission

Answer 16

Summation is the addition of positive an negative post-synaptic potentials A nerve cells can receive both positive and negative potentials simultaneously
The potentials received are summed and if the net effect on the postsynaptic neuron is inhibitory, the neuron will be less likely to fire, and if the net effect is excitatory, the neuron will be more likely to fire

Question 17

Outline the difference between electrical and chemical transmission

Answer 17

At electrical synapse, two neuron and psychically connected to one another through gap junctions. This is rare in vertebrates, but does occur occasionally. Gap junctions permit changes in the electrical properties of one neurone to effect the other, and vice versa, so the two neurone essentially behave as one.
Chemical neurotransmission occurs at chemical synapses. In chemical neurotransmission, the presynaptic neuron and the postsynaptic neuron are separated by a small gap- the synapse- and neurotransmitters are needed in order to allow message to cross

Question 18

Outline and evaluate FMRI as a way to studying the brain

Answer 18

It uses magnetic fields and radio waves to detect the changes in both blood oxygenation and flow that occurs as a result of neural activity in specific parts of the brain. It measures to change in the energy released by haemoglobin, reflecting activity of the brain to give a moving picture of the brain

• One key strength of FMRI is, unlike other scanning techniques such as PET, it does not rely not the use of radiation. If administered correctly it is virtually risk-free, non-invasive and straightforward to use. It also produces images that have very high spatial resolution, depicting detail by the millimetre, and providing a clear picture of how brain activity is localised. This means that fMRI can safely provide a clear picture of brain activity.
• FMRI is expensive compared to other neuroimaging techniques. It has poor temporal resolution because there is around 5-second time-lag behind the image on screen and the initial firing of neuronal activity. This means FMRI may not truly represent moment-to-moment brain activity

Question 19

Outline and evaluate EEG as a way to studying the brain

Answer 19

It measures electrical activity within the brain via electrodes that are fixed to an individuals scalp using a skull cap. The scan recording represents the brainwave patterners that are generated from the action of thousands of neurons providing an overall account of brain activity

• EEG has been useful in studying the stages of sleep and in the diagnosis of conditions such as epilepsy, a disorder characterised by random bursts of activity in the brain that can easily be detected on screen. Unlike FMRI, EEG technology has extremely high temporal resolution as it measures the exact neural activity in real time.
• The main drawback of EEG lies in the generalised nature of the information received. The EEG signal is also not useful for pinpointing the exact source of neural activity. Therefore it does not allow researchers to distinguish between activities originating and different but adjacent locations

Question 20

Outline and evaluate Event Related Potentials (ERPs) as a way to study the brain

Answer 20

ERPs uses statistical averages to indicate neurological functioning associated with specific behaviours / activities. As such researchers have devised a way of teasing out and isolating these responses using a statistical averaging technique, all extraneous brain activity from the original EEG is filtered out leaving only the responses that relate to the presentation of a specific stimulus or performance of a specific task. Electrodes are put on the scalp and detect neuronal activity (directly below where they are placed) in response to a stimulus introduced by the researcher. Statistical averages are used to indicate specific neurological functioning in response to specific behaviours / stimuli.

• The limitation of EEG are partly addressed through the use of ERPs. These bring much more specificity to the measurement of neural processes than could ever be achieved using raw EEG data. As ERPs are derived form EEG measurement, they have excellent temporal resolution, especially when compared to neuroimaging techniques such as FMRI. This means that ERPs are frequently used to measure cognitive functions and deficits such as allocation of attention resources and the maintenace of working memory
• Critics have pointed to a lack of standardisation in ERPs methodology between different researches studies which makes it difficult to confirm findings. A further issue is that, in order to establish pure data and ERP studies, background ‘noise’ and extraneous material must be completely eliminated

Question 21

Outline and evaluate Post Mortem Studies as a way to study the brain

Answer 21

These are a technique involving the analysis of a persons brain following their death. They are used to establish the underlying neurobiology of a particular behaviour (i.e. to try and correlate structural abnormalities/damage to behaviour).

Informed consent is an issue- some patients lose the ability to consent during their life time due to the issues that make them of interest to psychologists (e.g memory problems); however, these patients are often still investigated using this method (e.g. HM’s brain was still studied after he died!). If consent can be gained from the individuals family, this has to be done quickly as the brain will start to decay, reducing the validity of conclusions following this method

Question 22

Briefly outline Localisation of function in the brain

Answer 22

As Sperry’s research demonstrated, the brain is one of the most complex and fascinating systems. Advances in the methods of investigating the brain have allowed psychologists to investigate the idea that different functions and behaviours are Localised in specific areas

Question 23

Outline the Localisation vs holistic theory in the localisation of function in the brain

Answer 23

During the 19th century, scientist such as Paul Broca and Karl Wernicke discovered that specific areas of the brain are associated with particular physical and psychological functions.

Before the investigations, scientists generally took a holistic view and thought all parts of the brain were involved in the processing of thought and action.

This is the idea that different parts of the brain perform different tasks and are involved with different parts of the body

Question 24

Outline the theory of Hemispheres of the brain in the localisation of function in the brain

Answer 24

The brain is divided into two symmetrical halves called the left and the right hemispheres. The outer layer of each of the hemispheres is called the cerebral cortex. It covers the inside of the brain. The cortex appears grey due to the location of cell bodies

Question 25

Outline the functions of the Right Hemisphere

Answer 25

• Spatial Ability
• Facial Recognition
• Creativity
• Imagination
• Processing of information by the left eye
• Left side movement

Question 26

Outline the functions of the Left Hemisphere

Answer 26

• Language (speech production and understanding)
• Mathematical skills
• Logic
• Analytical thought
• Processing of information received by right eye
• Right side movement

Question 27

Outline what ‘The Back of the frontal lobe’ is and its function?

Answer 27

The Back of the frontal lobe, in both hemispheres, is the motor area. This deals with movement on the in the opposite side of the body. Damage here would lead to a possible loss of fine motor movement

Question 28

Outline what ‘The Front of Both Parietal Lobes’ is and its function?

Answer 28

The front of both parietal lobes is the somatosensory area, this is separated from the motor by a ‘valley’ called the central sulcus. The Somatosensory area deals with sensory information form the skin is represented

Question 29

Outline what the ‘Occipital Lobe’ is and its function?

Answer 29

The Occipital lobe deals visual information, so is known as the visual area or visual cortex. Information from the right visual field sends information to the right visual fields sends information to the left visual cortex and the left visual field to the right visual cortex. This means that damage to the right visual cortex can cause blindness in parts of the left visual field

Question 30

Outline the motor, somatosensory, visual and auditory centres

Answer 30

Motor - The top of the frontal lobe is the motor area. It is responsible for the movement on the opposite side of the body. Damage would lead to possible loss of the motor movement

Somatosensory - It is found in Parietal lobe. It is responsible for sensory information from the skin. Damage would lead to numbness or tingling

Visual - It is found in the Occipital lobe and it is responsible for visual information. Damage would lead to blindness in part of the left visual field

Auditory - It is found at the bottom of the Temporal Lobe and it is responsible for speech-based information. Damage would lead to hearing loss

Question 31

Outline the langauge areas of the brain

Answer 31

Wernicke’s area - It is found in the top of the Temporal Lobe and it is responsible for understanding language. Damage would lead to Wernicke’s aphasia being damaged

Broca’s area - It is at the bottom of the Frontal Lobe and it is responsible for speech production. Damage would lead to slow speech and also lacks of fluency

Question 32

Evaluation of the Localisation of function in the brain

Answer 32

There is evidence from Brain scans and research involving transcranial magnetic stimulation to support localization of function in the brain. There is a wealth of evidence providing support for idea that many neurological functions are localized. For example Transcranial magnetic stimulation can be used to alter the electrical activity in different parts of the brain, and this leads to specific behavioural disruption. As brain scanning techniques have a high degree a scientific rigor and objectivity, this adds a very convincing’ scientific element to the idea of localization of function

There is evidence from Case Studies that also support localization of function in the brain. Perhaps the most interesting case studies to support localization of function in the brain was the most infamous case of Phineas Cage. Gage was a rail world worker aged 25 years, he suffered a severe accident. While working, Gage caused an explosion, which resulted in a metre long temping iron to be blasted through Gage left check. The accident destroyed virtually all of Gage’s left frontal lobe. Reports from family and friends reported that his behaviour turned from calm and reserved individuals, to one who was quick tempered, rude and aggressive. This left psychologists to conclude that the frontal lobes are associated with personality elements, including behaviour and risk taking function’s. This therefore supports the case for localization of function. However they are problems with the case studies as it is difficult to make a meaningful generalisation from the findings of a single individuals

Further we have to consider that damage to more than one area can ahve very specific effects. For example, research has shown that damage to both Broca’s and Wernicke’s areas can lead to Global Aphasia (the inability to produce and understand speech) alongside right side paralysis. Once again, we therefore have to be careful not to make overly general (nomothetic) conclusions when considering localisation of function and damage to areas of the brain

Question 33

What is hemispheric lateralisation

Answer 33

It is the idea that the two halves of the brain are functionally different and that certain mental processes and behaviours are mainly controlled by one hemisphere rather than the other. For example, we have already seen that the ability to produce and understand language is usually controlled by the left hemisphere of the brain

Question 34

What is the Split brain studies

Answer 34

Split brain studies are a series of studies that started in the 1960’s involving epileptic patients who had experienced a surgical separation of the hemispheres of the brain (an operation called a commissurotomy in which the Corpus callosum and other tissues that connect the two hemispheres are cut down the middle)

Question 35

Outline the Sperry’s Split Brian Studies

Answer 35

Aim- To study how two separated hemispheres deal with, for example, speech and vision

Participants and sample
1. All the participants were epileptics had previously undergone commissions to deal with their severe elliptic conversions
2. The first patient ( a man) had his surgery over 5 1/2 years before the study was started
3. The second patient, a housewives and mother in her 30s had her surgery more than 4 years before the study had started

Research methods- Quasi/ lab experiment design : repeated measures - difference in the IV is an existing difference

Experimental design - 11 patients whom had an operation to sever that corpus callosum in an attempt to reduce the severity of their epileptic seizures

Procedure
* Ps had to be silent during, unless a Q by the experimenter
* The experimenter controlled which visual field received the info
* Eleven people who had a split- brain operation were studied using a special set up in which an image could be projected to a participants and the same image be projected to the left. In the normal brain the corpus callosum would immediately have the information between both hemispheres of giving a complete picture of the visual world

Question 36

What are the key findings and conclusions from the Sperry’s Split brain studies

Answer 36

Describing what you can see- When a picture of an object was shown to a patient’s right visual field, the patient could easily describe what was seen. If, however, the same object was shown to the left visual field, the patient could not describe what was seen, and typically reported that there was nothing there because they were unable to describe the object.

Composite words- If two words were presented simultaneously, one on either side of the visual field (for example, a ‘key’ on the left and ‘ring’ on the right as in the picture on the previous page), the patient would write with their left hand the word ‘key’ (left hand goes to the right hemisphere linked to left visual field) and say the word ‘ring’.

Matching faces- right hemisphere also appeared dominant in terms of recognising faces. When asked to match a face from a series of other faces, the picture processed by the right hemisphere (left visual field) was consistently selected; whilst the picture presented to the left hemisphere was consistently ignored. When a composite picture made up of two different halves of a face was presented - one half to each hemisphere - the left hemisphere dominated in terms of verbal description whereas the right hemisphere dominated in terms of selecting a matching picture.

The findings of Sperry’s research highlights a number of key differences between the two hemispheres. Left hemispheres is dominant in terms of speech and language. Secondly, the right hemispheres is dominant in terms of visual- motor loss

Question 37

Evaluate Sperry’s Split brain studies

Answer 37

Sperry’s findings have been replicated by other research. A further strength that Sperry’s original findings have been replicated in subsequent research. For example, Gazzaniga repeated Sperry’s research using a sample of split-brain patients and concentrating on the facial and shape recognition and matching elements. He found found similar results to Sperry with regards hemispheric lateralisation and facial matching. This validates the conclusions about hemispheric lateralization

In addition, some elements of Sperry’s methodology can be praised, which adds a good level of scientific rigour to the research and conclusions. One strength to Sperry’s procedure that using a mixture of quasi- experiments and clinical case studies, he was able to combine qualitative and quantitative approaches and compare results from a different methods. The quasi- experiments is a qualitative method of a data collection, it provides information in the form of numbers and frequencies. As mentions, these positives add a degree a scientific rigor to Sperry’s research and conclusions

However, Sperry’s research has been criticised as lacking ecological validity and mundane realism. This is because Sperry’s research was conducted in a laboratory, the procedure lacks ecological validity. In real life hemisphere would not be isolated in real life and the visual field would not be split. Because of these issues, we have to be careful when generalizing Sperry’s conclusions about lateralization of function beyond his experimental group to everyone and everyday situations

Question 38

Define Plasticity

Answer 38

Plasticity describes the brains tendency to change and adapt as a result of experience and new learning.

Question 39

Outline the Research into Plasticity

Answer 39

Maguire et al. (2000) studied the brains of London taxi drivers. They found more grey matter in the posterior hippocampus than in a matched control group. This part of the brain is associated with the spatial and navigational skills in humans. As part of their training London Taxi drivers take a test called ‘the knowledge’. Maguire concluded that learning the knowledge altered the structure of the brain in the taxi drivers. This study supports the notion of plasticity as it shows that the human brain changes in repsonse to new learning

Draganski et al (2006) found similar results to Maguire when using medical students. They tested them 3 months before and after their exams. Learning-included changes were seen in the posterior hippocampus, again arguably because of the learning of the new information for the exams. Mechelli (2004) found that people who are bi-lingual had a larger parietal cortex compared to matched controls. These studies once again support the notion of plasticity by highlighting that the brain changes in repsonse to new learning.

Taijiri (2013) He monitored via brain scans the stem cells provided to rats following brain trauma. It was found that there was clear development of neuron like cells in the area of injury. This demonstrates the ability of the brain to create new connections following trauma and thus supports the notion of functional recovery.

Question 40

Outline Functional recovery of the brain after trauma

Answer 40

The functional recovery is another example of neural plasticity. Neuroscientists suggests this can happen quickly after trauma and then slow down, where a person may have to undergo rehabilitation to help further their recovery.

It is thought that young children, whose brain are still maturing, are more likely to recover from trauma; their brain appears to have greater plasticity and recover as it still developing and maturing. Functional recovery therefore appears to deteriorate with age and neural recognition is less effective in older brains (Elbert, et all)

The brain is able to rewire itself by forming new synaptic connections. Secondary neural pathways, that wouldn’t normally carry out those functions are activated to enable functioning to continue, often like before (DOIDGE, 2007). This is supported by some structural changes on the brain

Question 41

Evaluate the role of plasticity and functional recovery of the brain

Answer 41

Although there is evidence to support the notions of plasticity and functional recovery there are a number of methodological issues that we have to consider. Although some research uses admirable scientific measures (e.g. the use of a matched control in Mechelli’s study which allows clear valid conclusions about plasticity to be drawn), there are a number of issues we have to consider. Some research does not have a clear matched control, making it difficult to develop valid conclusions about plasticity. Further, research often uses limited samples (e.g. MacGuire used only taxi drivers and Draganski used medical students), focusing on limited experiences. We have to be careful therefore not to make overly nomethic and generalised about plasticity and functional recovery.

In addition, the notion of Plasticity and Functional recovery has had some fantastic pratical applicaitons. Understanding the process of plasticity has helped in our understanding and application of neurorehabilitation. Research that has shown us that spontaneous recovery slows down after a few weeks has led us to identify and develop appropriate treatments to aid the recovery process, introducing them at the correct time to maintain recovery. Techniques may include movement therapy and also electrical stimulation of the brain for some stroke sufferers to help improve cognitive function and physical movement. This shows the brain can fix itself to a point but will need extra intervention to help further, and research into plasticity and functional recovery has therefore helped develop techniques that significantly improve the lives of people who have suffered trauma.

However, we have to be aware of the negative implicaitons when it comes to plasticity. Sometimes the brains ability to rewire itself can be maladaptive. For example, Prolonged drug use has been shown to lead to poorer cognitive ability as well as an increased risk of dementia in later life. This results in pain and unpleasant feelings. This is thought to be due to cortical reorganisation in the somatosensory cortex following limb loss (Ramachandran and Hirstein, 1998). We therefore have to be cautious when making conclusions and predicitons about plasticity and functional recovery, and we must appreciate the possible negative affects as well as the positive ones.

Question 42

What is a Biological rhythm?

Answer 42

A biological rhythm can be defined as any change in a biological activity (such as sleep and waking) that repeats periodically. These rhythms are most often synchronised with daily, monthly or annual cyclical changes in the environment

Question 43

What are Biological rhythm controlled by

Answer 43

Biological rhythms are controlled by two things - exogenous zeitgebers (external changes to the environment) and endogenous pacemakers (internal biological structures- sometimes known as biological ‘clock’)

Question 44

What are the different types of biological rhythm

Answer 44

Biological rhythms are defined by the length of time once cycle takes.

There are three main types of biological rhythm
1. ultradian
2. circadian
3. infradian

Question 45

What are the Ultradian biological rhythm and give an example

Answer 45

These are cycles which last less than a day and often occur multiple-times during the day. For example the feeding patterns of animals and humans, alternes, and the stages of sleep (5 stages, repeat every 90 mins when asleep

The rhythm are patterns of activity that have many cycles during a day. One of the main examples is the different stages of sleep

Question 46

Outline the Research into the stages of sleep

Answer 46

Rechtshaffen and kales (1968) monitored a rang of participants in a ‘sleep laboratory’ and found that when a person is asleep, the electrical activity in their brain changes. Recent research has concluded that sleep is much more complex than this and that each sleep stages is identified by specific patterns of brain activity and bodily functions

The fact that we have multiple (normally 4 to 5) cycles of the stages of sleep, makes the stages of sleep an example of an ultradian rhythm!

Question 47

Outline the Stages of Sleep

Answer 47

A complete sleep cycle goes through the four stages of NREM sleep before entering REM (Stage 5) and then repeating. Research using EEG has highlighted distinct brain waves patterns during the different stages of sleep.

1. Stages 1 and 2 are ‘light sleep’ stages. During these stages brainwave patterns become slower and more rhythmic, starting with alpha waves progress to theta waves.
2. Stages 3 and 4 are ‘deep sleep’ or slow wave sleep stages, where it is difficult to wake someone up. This stage is associated with slower delta waves.
3. Finally, Stage 5 is REM (or dream) sleep. Here is the body is paralysed (to stop the person acting out their dream) and brain activity resembles that of an awake person.

On average, the entire cycle repeats every 90 minutes and a person can experience up to five full cycles in a night.

Question 48

What is the role of EPs and EZs on the Ultradian Sleep Cycle (stages of sleep)

Answer 48

Research has shown that the stages of sleep are heavily controlled by endogenous pacemakers. The critical endogenous structures for the control of REM and NREM stages lay in the Ascending reticular formation (RF)

Question 49

What are the key psychical structures in the Ultradian rhythms

Answer 49

• The Raphe nuclei- this is essential for NREM sleep- destruction of the raphe nuclei will lead to abnormal NREM (stages 1-4) sleep
• NREM is also thought to be dependent on the Neurotransmitter serotonin as abnormal production of this can lead to a disrupted sleep cycle
• The locus coeruleus is essential or REM sleep. Destruction of the locus coeruleus will lead to abnormal REM sleep
• The REM stage is also thought to be dependent on the neurotransmitter noradrenalin and acetylcholine (levels of these are also controlled by the locus coeruleus): abnormal production of these can lead to disrupted REM cycles

Question 50

What could also factor to Ultradian rhythms

Answer 50

Although they are largely controlled by EP’s, EZ’s do have some effect. For example, aspects such as sudden rises or fall of temperature am sunlight can disrupt can disrupt the sleep cycle and each stage

Question 51

Evaluate the research into ultradian rhythms

Answer 51

One strength of menstrual synchrony research is that it may be explained by natural selection. Synchronisaiton of the menstrual cycle, of the kind observed in the Stern and McClintock study, is thought by some to have evolutionary value. For our distant ancestors it may have been advantageous for women to menstruate together and become pregnant at the same time. In a soical group, this would allow babies who had lost their mothers during or after childbirth to have access to breast milk, therby improving their chances of survival. This suggests that synchronisaiton is an adaptive strategy

A major advantage of research in this area is that it is scientific as it is based largely on the biological approach. Most studies in this area employ empirical methods with have a high degree of objectivity. This removes the influence of individual subjectivity and bias, which is desirable in science. For example, the brain wave activity of each stage is investigated using EEGs (e.g. Rechtshaffen and Kales, Ohayon) with other changes established using other scientific apparatus such as EOGs and EMGs

However, the fact that many sleep studies are conducted in sleep lavatories may also be a disadvantage as results may lack ecological validity. Sleep laboratories are often extremely artificial and unlike a persons normal sleeping environment. In real life we are exposed to exogenous zeitgebers such as light and alarm clocks. Conclusions about the nature of sleep based on these methods may therefore lack ecological validity and may not generalise beyond the sleep lab and offer a true picture about the nature of ‘real world’ sleep

Question 52

What are Infradian biological rhythms and give and example

Answer 52

These are cycles that take periods longer than a day
For example human 28 days menstrual cycle or hibernating or migrating behaviour

Question 53

Outline the menstrual cycle as an infradian rhythm

Answer 53

The cycle refers to the line between the first day of women’s period, when the womb lining is shed, to the day of a women’s period, when the womb lining is shed, to the day before next period. The cycle takes approximately 28 days to complete.

• The endogenous pacemaker associated with the menstrual cycle is the ovarian cycle. The ovarian cycle is regulated by a series of hormonal changes and feedback mechanisms involving the hypothalamus, pituitary gland, and ovaries.
• The exogenous zeitgebers associated with the menstrual cycle has suggested that seasonal change in daylight duration may impact the menstrual cycle

Question 54

Outline and evaluate a study into the menstrual cycle as a infradian rhythm

Answer 54

Stern and McClintock studied 29 women with a history of irregular periods. Samples of pheromones were gathered from nine of the women at different stages of their menstrual cycles, via a cotton pad placed in their armpit. Stern and McClintock found that 68% of women experienced changes to their cycle which brought them closer to the cycle of their ‘odour donor’

One strength of menstrual synchrony research is that it may be explained by natural selection. Synchronisation of the menstrual cycle, of the kind observed in the study, is thought be some to have evolutionarily value. In a social group, this would allow babies who had lost their mothers during or after childbirth to have access to breast milk, thereby improving their chances of survival. This suggests that synchronisation is an adaptive strategy.

One limitation of synchronisation studies is their methodological shortcomings. There are many factors that may effect change to the menstrual cycle, including stress. These may act as confounding variables, which means that any supposed pattern of synchronisation is no more than would have been expected to occur by change. This may explain why other studies have findings to replicated the findings

Question 55

Outline Seasonal affective disorder as an infradian rhythm

Answer 55

Seasonal affective disorder is a depressive disorder which has a seasonal pattern on onset. The main symptoms of SAD and persistent low mood alongside a general lack of activity and interest in life. The endogenous pacemaker associated with SAD is Hormone melatonin is implicated in the cause of SAD. The Exogenous zeitgebers associated are during the night, pineal gland secrets melatonin until there is an increase in light

Question 56

Outline and evaluate study into Seasonal affective disorder

Answer 56

Studies show light therapy helps to reduce the effects of SAD in about 80% of people (Stanassi 2009)

One of those effective treatments however light therapy can produce headaches and eye strain. perhaps more tellingly Kelly Rohan et al (2009) recorded a relapse rate of 46% over successful, compared to 27% in a comparison group

Question 57

Evaluate the research into infradian rhythms

Answer 57

We have to be cautious as a lot of research into the influence of pheromones on infradian rhythms are conducted on animals. Due to ethical issues, much of the information about the role of pheromones on infradian rhythms is derived from animal studies. While there is a body of evidence that suggest animal infradian rhythms are influenced by pheromones we have to be cautious when generalising these conclusions to humans , due to the vast psychological and psychological differences between species

That being said, research into infradian rhythms has major theoretical applications. Benefits of the menstrual cycle and menstrual synchrony. McClintock argues that if our ancestors all menstruated together then they would fall pregnant at similar times, therefore when they had children they would be cared for selectivity, increasing chances of survival. It is certainly the case that research into infradian rhythms has had a significant impact on the psychological community and has stimulated much subsequent research and theory

We have to be careful not to make overly nomothetic assumptions about infradian rhythms such as the menstrual cycle and SAD. It is too general to assumer that everybody’s infradian rhythms function in the same way. Research has shown that infradian rhythms can be influenced by a variety of factors, including lifestyle and age. (for example, research has shown that the family support or the use of drugs and/ or alcohol can significantly influence (SAD). Therefore we must ensure that we take an idiographic approach when considering the nature of infradian rhythms as individual differences are likely them greatly

Question 58

What are the Circadian biological rhythm and give an example

Answer 58

These are cycles that last approximately 24 hours. For example It is our sleep-wake routine (awake for 16 hours, asleep for 8 hours)

Question 59

Outline Core body temperature as a circadian rhythm

Answer 59

Core body temperature varies by about 2 degrees across the course of a day. it is the lowest around 4am and peaks at around 6pm. However, body temperature operates on a cycle of approximately 24 hours, making it a circadian rhythm. It is believed that body temeprature may have an effect on our mental abilities, in that the warmer we are the better our cogntive performance. This was shown by Folkard (1977) who found that children who had stories read to them at 3pm showed superior recall of the story compared to children who had the story read at 9 a.

Question 60

Outline the sleep wake cycle as a circidan rhythm

Answer 60

We sleep for around 8 hours per night and are awake for approximately 16 hours; the fact that his pattern repeats itself every 24 hours makes the sleep wake cycle an example of a circadian rhythm

The fact that we feel drowsy when its night-time and alert during the day seems to indicate the effect of daylight (an important exogenous zeitgeber) on our sleep/wake cycle. However if our body clock was left to ‘free-run’, without the influence of light and other external cues, would we be able to fall asleep and wake up at regular intervals?

Question 61

Outline a case study into the sleep wake cycle

Answer 61

He stayed underground for extended periods of time with no external cues to guide his rhythms (e.g. no clocks or daylight), so only his internal clock influenced his behaviour
After spending six months in a cave, his circadian rhythm settled to just over 24 hours
This indicates the role of an endogenous pacemaker in control of circadian rhythms

Question 62

What are some other research into circadian rhythm

Answer 62

Similar results were recorded by Jürgen Aschoff and Rütger Wever (1976) who convinced a group of participants to spend four weeks in a World War 2 bunker deprived of natural light. All but one of the participants (whose sleep/wake cycle extended to 29 hours) displayed a circadian rhythm between 24 and 25 hours. Both Siffre’s experience and the bunker study suggest that the ‘natural’ sleep/wake cycle may be slightly longer than 24 hours but that it is entrained by exogenous zeitgebers associated with our 24-hour day (such as the number of daylight hours, typical mealtimes, etc.).

Despite this, we should not overestimate the influence of exogenous zeitgebers on our internal biological clock. Simon Folkard et al. (1985) studied a group of 12 people who agreed to live in a dark cave for three weeks, retiring to bed when the clock said 11.45 pm and rising when it said 7.45 am. Over the course of the study, the researchers gradually speeded up the clock (unbeknown to the participants) so an apparent 24-hour day eventually lasted only 22 hours! It was revealed that only one of the participants was able to comfortably adjust to the new regime. This would suggest the existence of a strong free-running circadian rhythm that cannot easily be overridden by exogenous zeitgebers.

Question 63

Outline some of the disruption of Circadian rhythms

Answer 63

They are disturbed for example as a result of shift work or jet lag . This causes desynchronisation of the circadian sleep week cycle with exogenous zeitgebers.

The desynchronisation can ahve a major negative effects, such as tiredness, nausea, depression, reduced alertness and cogntive functioning can also have long term effects, such as an increased risk of cancer (e.g. Kubo, observed a sample of Japanese men who worked shifts and found that even when lifestyle factors were controlled (smoking, stress, etc), people who worked shifts had an increase risk of cancer. Kubo concluded that this was due to desynchronization caused by working shifts)

Question 64

Why does desynchronization have negative effects?

Answer 64

When a persons biological rhythms are disrupted and their endogenous pacemakers are out of synch with the new exogenous zeitgebers, the body will try and adjust and re-synchronise the biological rhythms. This takes a great deal of energy which may explain some of the negative effects.

There is some research which suggests the energy needed to resynchronise biological rhythms is taken from other psychological systems, such as the immune system and digestive systems; this can explain why people who are constantly experiencing disruption ahve an increased susceptibility to illness and experience feelings of nausea

Question 65

Evaluate research into circadian rhythms

Answer 65

One strength of research into circadian rhythms is that it provides an understanding of the adverse consequences that occur when they are disrupted (desynchronisation).
For example, night workers engaged in shift work experience a period of reduced concentration around 6 in the morning (a circadian trough) meaning mistakes and accidents are more likely (Boivin et al. 1996). Research has also pointed to a relationship between shift work and poor health - shift workers are three times more likely to develop heart disease than people who work more typical work patterns (Knutson 2003). This shows that research into the sleep/wake cycle may have real-world economic implications in terms of how best to manage worker productivity.

However, studies investigating the effects of shift work tend to use correlational methods. This means it is difficult to establish whether desynchronisation of the sleep/wake cycle is actually a cause of negative effects. There may be other factors. For example, Charlene Solomon (1993) concluded that high divorce rates in shift workers might be due to the strain of deprived sleep and other influences such as missing out on important family events.
This suggests that it may not be biological factors that create the adverse consequences associated with shift work

Another strength of research into circadian rhythms is that it has been used to improve medical treatments. Circadian rhythms co-ordinate a number of the body’s basic processes such as heart rate, digestion and hormone levels. These rise and fall during the course of a day has led to the field of chronotherapeutics - how medical treatment can be administered in a way that corresponds to a person’s biological rhythms. For example aspirin as a treatment for heart attacks is most effective if taken last night. Aspirin reduces blood platelet activity and this can reduce the risk of heart attack. Heart attacks are most likely to occur early in the morning, so the timing of taking aspirin matters. Research has supported this (e.g. Bonten et al. 2015). This shows that circadian rhythm research can help increase the effectiveness of drug treatments.

One limitation of research into circadian rhythms is that generalisations are difficult to make.
The studies described on the facing page (Aschoff and Wever, and Siffre) are based on very small samples of participants (just one in the case of Siffre). It seems that sleep/wake cycles may vary widely from person to person. Research by Charles Czeisler et al. (1999) found individual differences in sleep/wake cycles varying from 13 to 65 hours. In addition, a study by Jeanne Duffy et al. (2001) revealed that some people have a natural preference for going to bed early and rising early (knowns larks) whereas others prefer the opposite (owls]. Even Siffre, in a later 1999 study, observed that his own sleep/wake cycle had slowed down since he was a young man. This means that it is difficult to use the research data to discuss anything more than averages, which may be meaningless.

Question 66

Outline the role of endogenous pacemakers in the sleep wake cycle

Answer 66

Endogenous pacemakers, led by the suprachiasmatic nucleus (SCN) in the hypothalamus, are internal biological clocks that regulate the sleep-wake cycle. They generate 24-hour circadian rhythms, influencing physiological processes and neurotransmitter release. The SCN uses light input to synchronize these rhythms with the external day-night cycle. Disruptions, like shift work or jet lag, can lead to a misalignment with health consequences. In essence, endogenous pacemakers are essential for maintaining a consistent sleep-wake pattern and overall well-being.

Question 67

Outline SCN and the sleep wake cycle

Answer 67

The SCN is a tiny bundle nerve cells located in the hypothalamus. The SCN has been found to be the key endogenous pacemaker that influences our circadian sleep wake cycle. Nerve fibres connected to the RETINA of the eye cross in an area called the optic chiasma on their way to the visual area of the cerebral cortex. The SCN lies just above the optic chiasm and it receives information about light levels in the external environment. This happens even when the eyes are closed. Depending on the light levels, the SCN relays one of the two messages to the Pineal gland- it wither tells it to start producing melatonin or to stop the production of melatonin

Question 68

Outline animal research into the SCN

Answer 68

The influence of the SCN has been demonstrated in studies involving animals. Patricia DeCoursey et al. (2000) destroyed the SCN connections in the brains of 30 chipmunks who were then returned to their natural habitat and observed for 80 days. The sleep/wake cycle of the chipmunks disappeared and by the end of the study a significant proportion of them had been killed by predators (presumably because they were awake, active and vulnerable to attack when they should have been asleep).
In another study, Martin Ralph et al. (1990) bred mutant hamsters with a 20-hour sleep/wake cycle. When SC cells from the foetal tissue of mutant hamsters were transplanted into the brains of normal hamsters, the cycles of the second group defaulted to 20 hours.

Question 69

Describe the the pineal gland and its affect on melatonin

Answer 69

The SCN passes the information on day length and light that it receives to the pineal gland (a pea-like structure in the brain just behind the hypothalamus). This is another endogenous mechanism guiding the sleep/wake cycle. During the night, the pineal gland increases production of melatonin - a chemical that induces sleep and is inhibited during periods of wakefulness. Melatonin has also been suggested as a causal factor in seasonal affective disorder (see previous spread).

Question 70

Outline the role of exogenous zeitgebers in the sleep waken cycle

Answer 70

Light is a key zeitgeber in humans. It can reset the body’s main endogenous pacemaker, the SC, and thus plays a role in the maintenance of the sleep/wake cycle. Light also has an indirect influence on key processes in the body that control such functions as hormone secretion and blood circulation. In an innovative study, Scott Campbell and Patricia Murphy (1998) demonstrated that light may be detected by skin receptor sites on the body even when the same information is not received by the eyes. Fifteen participants were woken at various times and a light pad was shone on the back of their knees. The researchers managed to produce a deviation in the participants’ usual sleep/wake cycle of up to three hours in some cases! This suggests that light is a powerful exogenous zeitgeber that need not necessarily rely on the eyes to exert its influence on the brain.

As every parent knows, babies are seldom on the same sleep/wake cycle as the rest of the family, in fact new born babies’ initial sleep/wake cycle is pretty much random. At about 6 weeks of age, the circadian rhythms begin and, by about 16 weeks, babies” rhythms have been entrained by the schedules imposed by parents, including adult-determined mealtimes and bedtimes.
Research on jet lag suggests that adapting to local times for eating and sleeping (rather than responding to one’s own feelings of hunger and fatigue) is an effective way of entraining circadian rhythms and beating jet lag when travelling long distances

Question 71

Evaluate the role of EPs and EZs in the sleep wake cycle

Answer 71

One limitation is that exogenous zeitgebers do not have the same effect in all environments.
The experiences of people who live in places where there is very little darkness in summer and very little light in winter tell a different story from the usual narrative. For instance, people who live within the Arctic Circle (e.g. the Inuits of Greenland) have similar sleep patterns all-year round, despite spending around six months in almost total darkness.
This suggests the sleep/wake cycle is primarily controlled by endogenous pacemakers that can override environmental changes in light. Another limitation is evidence that challenges the role of exogenous zeitgebers. Laughton Miles et al. (1977) recount the study of a young man, blind from birth, who had an abnormal circadian rhythm of 24.9 hours. Despite exposure to social cues, such as regular mealtimes, his sleep/wake cycle could not be adjusted. This suggests that social cues alone are not effective in resetting the biological rhythm.

However, there are a number of ISSUES with the research in this area, especially if we consider that many of the studies are conducted on ANIMALS. In addition to the obvious extrapolation issues, some psychologists question the ETHICS of animal studies in this area. For example, In the DeCoursey et al and Ralph studies the animals were exposed to considerable harm, invasive surgical procedures and therefore risk when they were returned to their natural environment. Whether what we learn from these studies about the circadian sleep wake cycle in humans justifies the harsh treatment of the animals is a matter of debate. However, we have to assume that a full COST BENEFIT analysis was conducted prior to the research and that an Ethical committee agreed that these studies should go ahead.

In addition, there are some issues with the levels of CONTROL and VALIDITY in some of the research in this area that uses HUMAN PARTICIPANTS. For example, psychologists are critical of the LACK OF CONTROL over confounding variables in Campbell and Murphey’s study; they point to the fact that there may have been SOME light exposure to the participants eyes. This is a major confounding variable that REDUCES THE VALIDITY of their conclusions. In addition, the fact that later studies have NOT REPLICATED Campbell and Murphey’s findings further allows us to question both the VALIDITY and RELIABILITY of their conclusions. We can also consider case studies such as SIFFRE to provide support for the conclusions about endogenous pacemakers and exogenous zeitgebers However, these case studies of total isolation are EXTREMELY RARE and therefore could be argued to LACK VALIDITY