Biopsych

Question 1

The PNS is subdivided into 2 more systems.
What are these 2 systems?

Answer 1

The PNS is further subdivided into the autonomic nervous system (which controls involuntary, vital functions of the body, such as maintaining heart rates and breathing rates) and the somatic nervous system (which receives information from sensory receptors belonging to each of the 5 senses, and results in effectors being stimulated by the CNS, via motor neurones).

Question 2

*The autonomic nervous system is also subdivided into 2 further systems
What are these systems

Answer 2

The autonomic nervous system is also subdivided into the sympathetic and parasympathetic branches. These branches work as part of an antagonistic pair during the ‘rest and digest’ response, and are crucial in producing the physiological arousal needed to maintain the fight or flight response.

Question 3

Name some of the effects of the parasympathetic system.

Answer 3

Decreases heart rate
Decreases breathing rate
Increases digestion
Causes vasodilation
Causes pupil constriction
Release of acetylcholine

Question 4

Name some of the effects of the sympathetic system.

Answer 4

Increases heart rates
Increases breathing rate
Causes vasoconstriction
Causes pupil dilation
Slows down processes like digestion
Reduces salivation
Increases oxygen and glucose supply to the brain and working muscles

Question 5

What is commonly known as the ‘master gland’ because it controls the release of hormones from all other glands in the body?

Answer 5

The pituitary gland

Question 6

Describe the fight or flight response

Answer 6

1.The body senses and becomes aware of a stressor in the environment
2.Through sensory receptors and sensory neurones in the PNS, this information is sent to the hypothalamus in the brain which coordinates a response and triggers
increased levels of activity in the sympathetic branch of the ANS.
3.Adrenaline is released from the adrenal medulla in the adrenal glands, and is transported to target effectors, via the blood and through the action of the endocrine system
4. This results in the rectum contracting, saliva production being inhibited and a greater breathing rate
5. Once the stressor is no longer a threat, as part of an antagonistic pairing, the hypothalamus triggers less activity in the sympathetic branch and more activity in the parasympathetic branch of the ANS

Question 7

Describe the somatic nervous system

Answer 7

Controls skeletal muscles for movement
Voluntary system (under conscious control)

Question 8

Describe the autonomic nervous system

Answer 8

Controls internal organs or glands
Involuntary system

Question 9

What structures make up the reflex arc?

Answer 9

Relay neurone, sensory neurone, motor neurone

Question 10

What does the localisation theory suggest?

Answer 10

• Localisation theory suggests that certain areas of the brain are responsible for certain processes,
  behaviours and activities.

Question 11

Describe the motor area

Answer 11

The motor area = Separated from the auditory area by the central suclus and found in the frontal lobe, this area is involved in regulating and coordinating movements. Lesions or damage in the motor area result in an inability to control voluntary fine motor movements.

Question 12

Describe the auditory area

Answer 12

• The auditory area = An area of the temporal lobe, located on the superior temporal gyrus, which is responsible for processing auditory information and speech. Lesions or damage in the auditory area causes hearing loss, whereas damage to specific parts of the auditory area (Wernicke’s area) results in Wernicke’s aphasia

Question 13

Describe the visual area

Answer 13

The visual area = An area in the occipital lobe which is responsible for processing visual information

Question 14

Describe the somatosensory area

Answer 14

The somatosensory area = An area of the parietal lobe which processes information associated with the senses e.g. touch, heat, pressure etc. “These regions receive neuronal input from specific nuclei of the thalamus that correspond with the handling of sensation along the lines of touch, pain, temperature and limb position”. Lesions in this area result in a loss of ability to denote sensitivity to particular bodily areas.

Question 15

Describe the Broca’s area

Answer 15

Broca’s Area = Responsible for speech production and located in the frontal lobe, usually in the left hemisphere. Lesions or damage results in Broca’s aphasia, characterised by difficulty forming complete sentences and understanding sentences, as well as failing to understand the order of words in a sentence and who they are directed towards i.e. I, you, we, him, me etc.

Question 16

Describe the Wernicke’s area

Answer 16

Wernicke’s Area = Responsible for speech comprehension and located in the temporal lobe (the left temporal lobe for most people). Lesions or damage (e.g. through stroke and trauma) results in Wernicke’s aphasia, which is characterised by the use of nonsensical words (called syllogisms), no awareness of using incorrect words, but no issues with pronounciation and intonation.

Question 17

What is the left hemisphere of the brain associated with?

Answer 17

Overall, the left hemisphere of the brain is associated with language production and comprehension. Therefore, language is an example of a cognitive ability which is both localised and lateralised (to the left hemisphere).

Question 18

What is Plasticity?

Answer 18

• Plasticity = Refers to the brain’s ability to physically and functionally adapt and change in response trauma, new experiences and learning. Neuroplasticity was demonstrated by Maguire et al (2006). The idea of plasticity opposes the previous theory that there is a ‘critical window’ for synaptic and neuronal connection formation, which occurred during the first 3 years of life, after which no new neuronal connections would be formed (Gopnik et al).

Question 19

How do we control the strength and number of neuronal connections in our brains?

Answer 19

We control the strength and number of neuronal connections in our brains through the process of synaptic pruning i.e. 4“the process by which extra neurons and synaptic connections are eliminated in order to increase the efficiency of neuronal transmissions”.

Question 20

Describe Maguire et al’s study

Answer 20

After studying the brains of London taxi drivers, Maguire et al. found a larger grey matter volume in the mid-posterior hippocampi ( and a lower volume in the anterior hippocampi) of their brains, alongside a positive correlation between an increasing grey matter volume and the longer the individuals had been taxi drivers. The researchers concluded that “a complex spatial representation, which facilitates expert navigation and is associated with greater posterior hippocampal gray matter volume, might come at a cost to new spatial memories and gray matter volume in the anterior hippocampus”. This may be because the hippocampus is associated with spatial awareness; an ability which taxi drivers must have when they complete The Knowledge test.

Question 21

Give two strengths for the localisation theory

Answer 21

+ Supporting evidence for localisation of brain function = Tulving et al demonstrated, using PET scans, that semantic memories were recalled from the left prefrontal cortex, whilst episodic memories were recalled from the right prefrontal cortex. This shows that different areas of the brain are responsible for different functions, as predicted by localisation theory. This idea was further supported by Petersen et al , who found that Wernicke’s area activation is required for listening tasks, whereas Broca’s area is required for reading tasks. This confirms the idea that Wernicke’s area is involved in speech comprehension, whilst Broca’s area is responsible for speech production.
+ Supporting Case Studies = Phineas Gage was injured by a blasting rod which intersected the left side of his face, tearing through his prefrontal cortex. The damage involved both left and right prefrontal cortices in a pattern that, as confirmed by Gage’s modern counterparts, causes a defect in rational decision making and the processing of emotion”. Such case studies, particularly those showing marked differences after trauma, demonstrate the idea that some areas of the brain are responsible for specific functions. However, with the use of case studies, the subjectivity of the conclusions drawn and the unusual sample, alongside a lack of control over confounding and extraneous variables, must also be considered.

Question 22

Give a weakness of the localisation theory

Answer 22

— Contradictory Theory = The opposite to localisation theory would be a holistic view of brain function, suggesting that each function requires several brain areas to be activated and that these functions are not restricted to these areas. For example, after removing 20-50% of the cortices belonging to rats, found that no specific brain area or lesion was associated with learning how to traverse through a maze. This suggests that intelligence, or even learning, is too complex and advanced a cognitive ability to be restricted to certain areas of the brain. Therefore, this suggests that localisation theory may provide a better explanation for ‘simple’, rather than complex, brain functions. (Lashley’s research)

Question 23

Define plasticity

Answer 23

Plasticity = Refers to the brain’s ability to physically and functionally adapt and change in response trauma, new experiences and learning. Neuroplasticity was demonstrated by Maguire et al (2006).

Question 24

How do we control the strength and number of neuronal connections in our brains?

Answer 24

We control the strength and number of neuronal connections in our brains through the process of synaptic pruning i.e. “the process by which extra neurons and synaptic connections are eliminated in order to increase the efficiency of neuronal transmissions”

Question 25

Summarise the Maguire et al study.

Answer 25

After studying the brains of London taxi drivers, Maguire et al. found a larger grey matter volume in the mid-posterior hippocampi ( and a lower volume in the anterior hippocampi) of their brains, alongside a positive correlation between an increasing grey matter volume and the longer the individuals had been taxi drivers. The researchers concluded that 5“a complex spatial representation, which facilitates expert navigation and is associated with greater posterior hippocampal gray matter volume, might come at a cost to new spatial memories and gray matter volume in the anterior hippocampus”. This may be because the hippocampus is associated with spatial awareness; an ability which taxi drivers must have when they complete The Knowledge test.

Question 26

What is functional recovery?

Answer 26

Functional recovery is the ability of the brain to transfer the functions of areas damaged through trauma, to other healthy parts of the brain, thus allowing for normal functioning to carry on.

Question 27

How is functional recovery carried out?

Answer 27

This is enabled through the law of equipotentiality (where secondary neural circuits surrounding the damaged area become activated), axonal sprouting (formation of new synapses and strengthening of axonal connections between damaged and healthy areas), reformation of blood vessels (as part of the haemodynamic response, where activated areas experience a higher blood deoxygenation level) and recruiting homologous areas on the opposite side of the brain. Showing that function is not always lateralised to specific hemispheres

Question 28

Give an example of functional recovery.

Answer 28

An example of functional recovery would be the case of Jodi Miller, whose entire right hemisphere was removed in an attempt to control her epileptic seizures. However, through the mechanisms of neuroplasticity, she was still able to control the right side of her body through the use of cerebral spinal fluid. This demonstrates positive plasticity, because the neuroplasticity results in desirable or positive consequences.

Question 29

Give two strengths of the Plasticity and Functional Recovery of the Brain

Answer 29

+ Evidence supporting the positive and negative effects of neuroplasticity = Much research has been carried out into the phenomenon of plasticity. Positive plasticity has been demonstrated by the case study of Jodi Miller, who has shown the power of recruiting homologous areas on the opposite side of the brain, axonal sprouting and the reformation of blood vessels. Therefore, there is evidence supporting not only the existence of, but also the uses of plasticity. + Neuroplasticity occurs in animals too = Hubel and Weisel (1970) sutured the right eye of kittens, who are blind from birth, for a period of 6 months, opening the eyes and several points and monitoring brain activity in the visual cortex. The researchers found that, although the right eye was closed, there was still activity in the left visual cortex, corresponding to the development of occular dominance columns. This was demonstrated by how “during the period of high susceptibility in the 7 fourth and fifth weeks eye closure for as little as 3-4 days leads to a sharp decline in the number of cells that can be driven from both eyes”. This therefore supports the idea that areas of the brain receiving no input can take over the function of highly stimulated areas, despite originally having different functions.

Question 30

Give a weakness of the Plasticity and Functional Recovery of the Brain

Answer 30

— There are limits to spontaneous and functional recovery = Although after trauma the brain activates secondary neural circuits which contribute towards reinstating normal function (law of equipotentiality), the brain can only ‘repair’ itself up to a specific point, after which motor therapy or electrical stimulation is needed to increase recovery rates. For example, Lieperta et al (1998) found that after constraint-induced movement therapy, the motor performance of stroke patients improved significantly. Therefore, this suggests that functional recovery cannot be relied upon to reinstate normal function.

Question 31

What is Hemispheric lateralisation?

Answer 31

Hemispheric lateralisation = The idea that each hemisphere (half) of the brain is mainly responsible for certain behaviours, processes and activities. This is in contrast with the holistic theory of brain function, which suggests that function is distributed across the whole brain (i.e. is global).

Question 32

Summarise Sperry and Gazzanigas split brain research

Answer 32

• Each visual field has two sides - left and right. The right hemisphere controls the left side of the body, and vice versa. • Sperry and Gazzaniga (1968) conducted split-brain research on 11 epileptic patients. In order to control their seizures, these patients underwent surgical lesioning of the corpus callosum, which meant information processed by one hemisphere cannot be relayed to the other hemisphere. Therefore, it is possible to expose a single hemisphere to certain stimuli in split-brain patients, and thus infer the functions of each hemisphere. • The patients had one of their eyes covered. The stimuli was flashed onto a screen for one-tenth of a second. This prevented both visual fields of the eye being exposed to the information, so only one hemisphere would process it. Therefore, their research was conducted under strictly controlled conditions, through the use of a laboratory experiment

Question 33

Describe the procedure of sperry and gazanigas split brain research

Answer 33

1. Describing what you see = If the stimulus word was exposed to the right visual field, then it would be processed by the left hemisphere and the patient would say the word. This is because the left hemisphere contains the ‘language centres’ of the brain and so allows for speech. However, if the same stimulus word was exposed to the left visual field, then it would be processed by the right hemisphere and the patient would write the word using their left hand. This is because the right hemisphere contains the visuo-spatial centres of the brain, allowing for the physical act of writing. The patient would not be able to give a verbal description of the word, because the right hemisphere contains no language centres. 2. Matching words or faces = The right hemisphere appeared to dominate the ability to match a list of faces to a given stimulus. This is due to the right hemisphere containing the brain’s visuo-spatial centres, thus allowing for the visual identification and processing of the faces. 3. Recognizing objects placed into the hands = If an object was placed into the patient’s right hand, they would be unable to identify that it is there, because the information would be processed by the left hemisphere which only has language centres, and no visuo-spatial centres. Therefore, if an object was placed into the patient’s left hand, they would be able to identify the object and choose a similar one from a hidden bag, due to the action of the visuo-spatial centres.

Question 34

Give a weakness of split brain research (lack of control with sample selection)

Answer 34

Lack of control with the sample selection = The epileptic patients had been taking anti-epilepsy medications for extended and different periods of time, which may have affected their ability to recognise objects and match words, due to causing cerebral neuronal changes. Secondly, although all patients had undergone a commissurotomy, there may have been differences in the exact procedures e.g. differing extent of the lesioning of the corpus callosum. This would have affected the degree to which the two hemispheres could relay information between themselves. Therefore, these two confounding variables had not been controlled, meaning that the lateralised functions may be examples of unreliable causal conclusions.

Question 35

Give a strength of split brain research

Answer 35

+ Clearly demonstrated lateralisation of function = Split-brain research was pivotal in establishing the differences in functions between the two hemispheres, and so opposing the holistic theory of brain function. The left hemisphere was demonstrated as being dominant for language tasks, due to containing language centres, whereas the right hemisphere was demonstrated as being dominant for visuo-spatial tasks. Therefore, this suggests that the left hemisphere is the analyser, whereas the right hemisphere is the synthesiser, and so there are marked differences between the two.

Question 36

Give a weakness of split brain research (The differences in function may not be so clear-cut)

Answer 36

— The differences in function may not be so clear-cut = With evidence making the drastic distinctions that the left hemisphere is responsible for language (analyser) whilst the right is responsible for visual-spatial tasks (synthesiser), this has given the public the false impression that the two hemispheres are ‘opposite’ in function and that they can receive such labels. However, as suggested by Pucetti (1980), there have been cases of split-brain patients who are left-handed but produce and comprehend speech in the right hemisphere, which opposes the predictions made by lateralisation theory. Therefore, it is important not to jump to conclusions and to appreciate that, through recruitment of homologous areas on the opposite side of the brain, each hemisphere is not restricted to specific function

Question 37

How does the body react to stress?

Answer 37

The amygdala sends a signal to the hypothalamus, this is communicated with the rest of the body via the sympathetic nerve It is involves acute stressor or long term stressors

Question 38

How does the body react to acute stressors?

Answer 38

Amygdala signals the hypothalamus Hypothalamus sends stress signal to the SNS SNS sends signal to the adrenal medulla Adrenal medulla releases adrenaline into the blood system Adrenaline causes a number of body changes associated with the fight or flight response When the threat has passed the parasympathetic system brings the body back to normal again

Question 39

What is the endocrine system?

Answer 39

A collection of glands that produces hormones

Question 40

Where is the pituitary gland located?

Answer 40

In the hypothalamus

Question 41

Describe the pituitary gland

Answer 41

Master gland Decides when other glands release their hormones Found in the hypothalamus Split into the anterior and posterior

Question 42

Describe the anterior pituitary gland

Answer 42

Releases reproductive functioning hormones: LH FSH

Question 43

Describe the adrenal gland

Answer 43

Sits on top of the kidneys Split into the adrenal cortex and adrenal medulla

Question 44

Describe the posterior pituitary gland

Answer 44

Releases Oxytocin - stimulates the contraction of the uterus; is important for mother-infant bonding

Question 45

Describe the adrenal cortex

Answer 45

Produces hormones essential for life: Cortisol - (stress hormone), maintains CV health, anti-inflammatory, promotes a good metabolism

Question 46

Describe the adrenal medulla

Answer 46

Produces hormones not essential for life: adrenaline noradrenaline

Question 47

What is EEG?

Answer 47

Electroencephalogram . An imaging technique to record electrical activity in the brain. Through the use of electrodes attached to the scalp, EEG scans measures and amplifies the electric activity across the whole brain i.e. action potentials being transmitted across the axons of neurons

Question 48

ERP

Answer 48

Event-related potential - an imaging technique similar to an EEG, except baseline activity is filtered, so electrical activity in response to a stimulus can be recorded Brain’s Electrophysiological responses to specific events (sensory, motor or cognitive event) are isolated by doing a statistical analysis of EEG data. The statistical averaging technique removes all extraneous brain activity from the original EEG recording by filtering it out leaving only those responses that relate to the presentation of a specific stimulus or performance of a specific task. What is left is event-related potentials – brainwaves that are triggered by particular events.

Question 49

fMRI

Answer 49

Functional magnetic resonance imaging - an imaging technique that monitors blood flow in the brain. It allows insight into which areas of the brain are used for particular activities. Areas of the brain with high levels of activity have a larger requirement for oxygenated blood, leading to a higher rate of blood deoxygenation. As measured through the bold response, the deoxyhaemoglobin in the blood in these highly active areas absorbs the signal produced by the scan, so such areas appear brightly coloured on the scan

Question 50

Inhibition (Biopsych)

Answer 50

A signal sent to the next nerve making it less likely to fire

Question 51

Plasticity

Answer 51

The ability of the brain to adapt to situations, and change its structure - even to potentially regain previously lost function

Question 52

Suprachiasmatic nucleus

Answer 52

Two small, paired nuclei in the brain that are responsible for controlling many circadian rhythms in the human body. For example, they regulates the sleep-wake cycle

Question 53

Evaluate EEG

Answer 53

+ Particularly useful in investigating the characteristics of the different stages of sleep, as demonstrated by Dement and Kleitman. + Much higher temporal resolution than fMRI scans, and so more appropriate for the monitoring of ongoing cerebral states and activity. — Lower spatial resolution compared to fMRI scans, with particular difficulty in differentiating activity between adjacent areas. + Useful in the diagnosis of epilepsy, which is characterised by random bursts of activity.

Question 54

Evaluate ERP

Answer 54

+ Excellent Temporal Resolution-Neural processes are measured more specifically than in an EEG. +Widely used in the measurement of cognitive deficits and functions. -Lack of standardisation in ERP methodology in different research studies. -Background noise and extraneous material can be an obstacle.

Question 55

Evaluate fMRI

Answer 55

+ High spatial resolution as up to 4 images can be produced per second. + Can be used whilst a patient is carrying out a task, and so data from fMRI scans can help us to make inferences about brain function and localisation. + Does not use ionising radiation, unlike PET scans, and so is safer. — Poor temporal resolution because there is approximately a 5 second difference between neuronal activity and the produced image

Question 56

Post-mortem examinations

Answer 56

These involve a comparison of the patient’s brain with that of a healthy, neurotypical brain. Any differences (e.g. lesions, damage, abnormally large or small areas) are assumed to have caused the neurological problem the patient faced in their lifetime.

Question 57

Evaluate Post-mortem examinations

Answer 57

— Incorrectly makes the assumption that differences compared with the neurotypical brain must be the explanation for neurological or cognitive deficits. Prolonged drug use, stress and genetic factors may be other plausible explanations. — Ethical issues arise because informed consent cannot always be obtained before the patient dies or from the family. The patient may be unable to give informed consent e.g. HM suffered from deficits in his short-term memory, and so would not remember having signed the document. + Particularly useful for advancing medical knowledge, and being the basis of further research into certain areas of the brain e.g. Broca used a post-mortem examination on his patient Tan, which led to the identification of Broca’s area and was the foundation of further research into the theory of the localisation of brain function

Question 58

What are biological rhythms?

Answer 58

“Periodic biological fluctuations in an organism that corresponds to, and is in response to, periodic environmental change”. These include changes in core bodily temperature, attention (such as a circadian trough at 6 AM) and the sleep-wake cycle. Biological rhythms can be endogenous (controlled by internal clocks e.g. the suprachiasmatic gyrus) or exogenous (controlled by external, environmental factors e.g. exposure to sunlight). The three types of biological rhythms are circadian, infradian and ultradian

Question 59

What are exogenous zeitgebers?

Answer 59

External changes in the environment which affect or ‘entrain’ our biological rhythms. The main example of an exogenous zeitgeber would be light. Changes in light exposure can trigger desynchronisation of a ‘pre-set’ sleep-wake cycle.

Question 60

Circadian Rhythms

Answer 60

A type of biological rhythm which completes one full cycle every 24 hours e.g. the sleep-wake cycle. Like other biological rhythms, it is affected by both endogenous pacemakers and exogenous zeitgebers.

Question 61

Who studied the effect of light as an exogenous zeitgeber on the sleep-wake cycle?

Answer 61

Siffre

Question 62

How did Siffre study the effect of light as an exogenous zeitgeber on the sleep-wake cycle?

Answer 62

This was extensively studied by Siffre (1962), who descended into a cave on July 16th 1962, completely devoid of natural light. He finished his experiment on September 14th, believing it to be August 20th! This demonstrates that prolonged exposure to a strong exogenous zeitgeber such as light, the sleep-wake cycle becomes disrupted and there is a disconnection between psychological time and the clock. His sleep-wake cycle did not conform to a cyclical 24 hour-period, but was around 24 hours and 30 minutes, with Siffre himself determining when to sleep and when to eat. Therefore, this demonstrates that “there was an internal clock independent of the natural terrestrial day/night cycle”. This describes a ‘free-running’ circadian rhythm i.e. one which is not affected by exogenous zeitgebers.

Question 63

Who (other than Siffre) studied free-running circadian rhythms.

Answer 63

Aschoff and Wever

Question 64

How did Aschoff and Wever study free-running circadian rhythms

Answer 64

A second example of a free-running circadian rhythm was demonstrated by Aschoff and Wever (1967). 55 participants were deprived of natural light whilst spending 4 weeks in an underground bunker. The researchers found that “all subjects showed free-running circadian rhythms, with the 12 average periods of wakefulness and sleep ranging from 23.9 to 50.0 hours. 36 subjects remained internally synchronized during the whole experiment”. Therefore, these findings demonstrate that although the free-running circadian rhythm is more than 24 hours long, as a society we have specific exogenous zeitgebers which entrain the rhythm to conform to a 24 hour cycle.

Question 65

Give a weakness of Siffre's research

Answer 65

— The confounding effect of artificial light = As demonstrated by Czeisler et al (1999), artificial lighting can create shifts in circadian rhythms by up to 6 hours. Siffre’s research was conducted at a time where researchers believed that artificial lighting had no effect on biological rhythms. The use of artificial light meant that over 2 months, Siffre could have entrained his own circadian rhythm through signaling sleeping and waking times by using the light, meaning that the conclusions made about his ‘free-running’ circadian rhythm may not be entirely accurate.

Question 66

Give a weakness of research into exogenous zeitgeber on circadian rhythms

Answer 66

— Use of case studies and small samples in isolation investigations = Although Siffre conducted multiple isolation studies, his results may not be able to be generalised to the wider population, especially as individual differences in the duration and stages of circadian rhythms has been shown (i.e. Monkseaton High School), hence his results may lack ecological validity. For example, even Siffre himself noted that as he grew older, his endogenous pacemaker ticked at a slower rate, which may have acted as an uncontrolled confounding variable in his investigations. The same can be said for other isolation studies, such as Aschoff and Wever, where large numbers of participants are unlikely to want to participate. This again limits the extent to which the findings represent the experiences of the general population.

Question 67

Infradian Rhythm

Answer 67

One of 3 types of biological rhythms, with a frequency of one complete cycle occurring less than once every 24 hours. Such rhythms are entrained by endogenous pacemakers and exogenous zeitgebers. Notable examples of infradian rhythms include the menstrual cycle and SAD (seasonal affective disorder)

Question 68

Who demonstrated menstrual cycle synchronisation?

Answer 68

McClintock et al

Question 69

What did McClintock et al investigate?

Answer 69

McClintock et al (1998) demonstrated menstrual cycle synchronisation amongst 29 women who all had irregular periods. The pheromones from 9 of the women were collected through the use of a pad under the armpit, and then rubbed onto the upper lip of the remaining 20 women, corresponding to the specific days of their cycle. The researchers found that “recipients had shorter cycles when receiving axillary compounds producing by donors in the follicular phase of the menstrual cycle (+ 1.7 +/- 0.9 days) and longer cycles when receiving ovulatory compounds (+ 1.4 +/— 0.5 days

Question 70

What is SAD?

Answer 70

Seasonal affective disorder is an example of the influence of endogenous pacemakers on the circadian sleep-wake cycle. SAD is an infradian disorder caused by disruption to the sleep-wake cycle, and commonly occurs in the winter. Longer nights means that more melatonin is secreted from the pituitary gland, via the endocrine system, which changes the production of melatonin, leading to feelings of loneliness and depression.

Question 71

Ultradian Rhythm

Answer 71

One of 3 types of biological rhythms, with a frequency of one complete cycle occurring more than once every 24 hours. A notable example are the stages of sleep, where a full sleep cycle takes 90 minutes to complete.

Question 72

Describe the stages of sleep

Answer 72

Stages 1 and 2 represent the ‘sleep escalator’ where the participant can easily be awoken, stages 3 and 4 coincide with deeper and slower delta waves (compared to theta waves during the sleep escalator), whilst stage 5 represents REM sleep. REM sleep is closely associated with dreaming and characterised by movement inhibition and a sensory blockade. The stages of sleep have been demonstrated by Dement and Kleitman.

Question 73

What are the first 2 stages of the sleep cycle?

Answer 73

Stages 1 and 2 represent the ‘sleep escalator’ where the participant can easily be awoken. Coincide with theta waves

Question 74

What are the 3rd and 4th stages of the sleep cycle?

Answer 74

Stages 3 and 4 coincide with deeper and slower delta waves (compared to theta waves during the sleep escalator)

Question 75

What is t e5th stage of sleep?

Answer 75

Stage 5 represents REM sleep. REM sleep is closely associated with dreaming and characterised by movement inhibition and a sensory blockade.

Question 76

How did Dement and Kleitman demonstrate the stages of sleep? (AO3)

Answer 76

The stages of sleep have clearly been demonstrated = Dement and Kleitman (1957) studied 33 adults, where their caffeine and alcohol intake had been controlled, in order to remove the effect of these extraneous variables and increase the reliability of the findings. Using EEG scans, the researchers found that “discrete periods of rapid eye movement potentials were recorded without 15 exception during each of 126 nights of undisturbed sleep”. Since participants were able to accurately recall their dreams when awoken during REM sleep, the assumption was made that dreaming is associated with REM sleep. Therefore, there is clear evidence supporting the idea of a distinct set of sleep stages.

Question 77

Give a weakness of McClintock et al's study

Answer 77

— Menstrual synchronisation is not always present in all-female samples = For example, Trevathan et al (1993) noted that he had found no evidence of menstrual synchronisation in the all-female participants used, which suggests that there are external (extraneous) variables which may affect the timing and duration of their menstrual cycles. McClintock et al. did not control for such extraneous factors e.g. smoking, physical activity and alcohol consumption. Therefore, this raises doubts about the strength of the influence of pheromones, as an exogenous zeitgeber which can entrain infradian rhythms.

Question 78

Endogenous Pacemakers

Answer 78

Internal bodily regulators of biological rhythms, affecting or ‘entraining’ such biological rhythms to conform to certain cyclical periods e.g. one cycle every 24 hours for circadian rhythms.

Question 79

When the eye is exposed to little light light, what biological processes occur?

Answer 79

Less light - eye - processed by visual area in occipital lobe - information relayed to SCN by optic chiasm - SCN processes information - triggers increase in melatonin from pineal gland - triggers a decrease in serotonin - causing feelings of sleepiness

Question 80

How were the effects of the SCN investigated?

Answer 80

The effect of the SCN was demonstrated by researchers, who surgically lesioned the SCNs of 30 chipmunks, and compared their circadian rhythms in their natural habitat with 17 controls. The researchers found that the vast majority of the experimental group had been killed within the first 80 days after being returned to their habitat and “episodes of nocturnal movement were detected within the permanent dens by radio telemetric data logging, especially in suprachiasmatic nucleus-lesioned animals”. * Researchers extracted SCN cells from hamsters which showed abnormal sleep-wake cycles, and inserted these cells into healthy hamster foetuses. The researchers found that “the restored rhythms always exhibited the period of the donor genotype, regardless of the direction of the transplant or genotype of the host. The basic period of the overt circadian rhythm therefore is determined by cells of the suprachiasmatic region”.

Question 81

What are the ethical issues with the

Answer 81

— There are considerable ethical issues with the use of animals in such research, particularly if they are deliberately put in harms way as was the case with Decoursey et al, thus breaching the BPS ethical guideline of protection from psychological and physical harm. Although this does not impact upon the utility or validity of the findings, a cost-benefit analyses would have to be conducted to assess whether such ethical costs outweigh the benefits of an improved understanding of exogenous zeitgebers and endogenous pacemakers. A second problem occurs with the limitations of generalising findings from animal studies to humans, particularly due to differences in physiology and the number/types of circadian rhythms, thus limiting the ecological validity of such findings

Question 82

What side of the brain contains the visuospatial centrea?

Answer 82

right hemisphere contains the visuo-spatial centres Left hemispher contains the speech centres