Biopsychology Flashcards
(105 cards)
1
Q
Nervous system’s two main functions:
A
-To collect, process and respond to information in the environment.
-To co-ordinate the working of different organs and cells in the body.
2
Q
Two sub-systems of the nervous system:
A
Central nervous system
Peripheral nervous system
3
Q
Central nervous system, the brain:
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The centre of all conscious awareness. Cerebral cortex distinguishes our higher mental functions from those of animals.
4
Q
Central nervous system, the spinal cord:
A
An extension of the brain. Responsible for reflex actions.
5
Q
Peripheral system is sub-divided into:
A
Autonomic nervous system- governs vital functions of the body.
Somatic nervous system- Controls muscle movement and receives information from sensory receptors.
6
Q
Gland:
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An organ in the body that synthesises substances such as hormones.
7
Q
Endocrine system:
A
One of the body’s major information systems that instructs glands to release hormones directly into the bloodstream. These hormones are carried towards target organs in the body.
8
Q
Hormones:
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Chemical substances that circulate the bloodstream and only affects target organs. They are produced in large quantities but disappear quickpy.
9
Q
Localisation of function:
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The theory that different areas of the brain are responsible for different behaviours, processes or activities.
10
Q
Motor area:
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A region of the frontal lobe involved in regulating movement.
11
Q
Somatosensory area:
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An area of the parietal lobe that processes sensory information such as touch.
12
Q
Visual area:
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A part of the occipital lobe that receives and processes visual information.
13
Q
Auditory area:
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Located in the temporal lobe and concerned with the analysis of speech-based information.
14
Q
Broca’s area:
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An area of the frontal lobe of the brain in the left hemisphere (in most people) responsible for speech production.
15
Q
Wernicke’s area:
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An area of the temporal lobe (encircling the auditory cortex) in the left hemisphere (in most people) responsible for language comprehension.
16
Q
Lateralisation:
A
The brain is divided into two symmetrical halves called left and right hemispheres, some of our physical and psychological functions are controlled or dominated by a particular hemisphere.
17
Q
The four lobes:
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The frontal lobe, the parietal lobe, the occipital lobe and the temporal lobes.
18
Q
The frontal lobe:
A
At the back is the motor area which controls voluntary movement in the opposite side of the body. Damage can result in loss of control over fine movements.
19
Q
Parietal lobe:
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At the front is the somatosensory area which is separated from the motor area by a ‘valley’ called the central sulcus. The somatosensory area is where sensory information from the skin is represented.
20
Q
Occipital lobe:
A
At the back of the brain is the visual area. Each eye sends information from the right visual field to the left visual cortex and vice-versa. Damage to the left hemisphere can produce blindness in the right visual field of both eyes.
21
Q
Temporal lobes:
A
Houses the auditory area, which analyses speech-based information, damage may cause hearing loss.
22
Q
Lateralisation
Evaluation- Brain scan evidence of localisation.
A
Peterson et al (1988) used brain scans to demonstrate how Wernicke’s area was active during a listening task and Broca’s area was active during a reading task, suggesting these areas have different functions.
Tulving et al (1994) showed that semantic and episodic memories reside in different parts of the prefrontal cortex.
23
Q
Lateralisation
Evaluation- Neurosurgical evidence.
A
The practice of surgically removing/destroying areas of the brain to control aspects of behaviour developed in 1950s. Walter Freeman developed the lobotomy which severed connections in the frontal lobe attempting to control aggressive behaviour.
Neurosurgery is still used today in some extreme cases of OCD and depression.
24
Q
Lateralisation
Dougherty et al (2002)
A
Reported on 44 OCD patients who had undergone cingulotomy- a neurosurgical procedure that involves lesioning of the cingulate gyrus. At post-surgical follow up after 32 weeks a third had met the criteria for successful response to the surgery and 14% for partial response. The success of procedures like this strongly indicates that symptoms and behaviours associated with serious mental disorders are localised.
25
Case of Phineas Gage.
Working on a railroad in 1848, 25 yr old Phineas gage was going to blast a section of rock with explosives to create a new rail line. Gage dropped his tamping iron on the rick cause the explosive to ignite. The explosion hurled a meter length rod through his left cheek, passing his left eye and exiting his skull taking a portion of his brain with it- most of his left frontal lobe.
Gage survived but his personality changed from calm and reserved to quick-tempered and rude.
26
Lateralisation
Evaluation-Karl Lashley (1950)
This work suggests that higher cognitive functions, such as the processes involved in learning, are not localised but distributed in a holistic way. Lashley removed areas of the cortex (10-50%) in rats that were learning a maze. No area was proven to be more important than any other in terms of their ability to learn the maze. This suggests that learning is too complex to be localised.
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Lateralisation
Evaluation- Plasticity
The notion of cortical remapping (plasticity). When the brain has become damaged and a particular function has been compromised or lost, the rest of the brain is able to reorganise itself in an attempt to recover the lost function.
Lashley described this as the 'law of equipotentiality' whereby surviving brain circuits 'chip in' so the same neurological action can be achieved.
This does not happen EVERY time.
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3 types of neurons:
Motor, relay and sensory
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Axon:
Carries impulses away from the cell body down the length of the neuron. Covered in a fatty layer (myelin sheath) that protects the axon and speeds up electrical transmission of the impulse.
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Cell body:
includes a nucleus, which contains the genetic material of the cell. Dendrites protrude from the cell body, these carry nerve impulses from neighbouring neurons towards the cell body.
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Electrical transmission:
A neuron in a resting state inside of the cell is negatively charged compared to the outside. When a neuron is activated by a stimulus, the inside of the cell becomes positively charged for a split second causing an action potential to occur.
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Synaptic transmission-
The process by which neighbouring neurons communicate with each other by sending chemical messages across the gap that separates them.
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Neurotransmitter-
Brain chemicals released from synaptic vesicles that relay signals across the synapse from one neuron to another. Neurotransmitters can be broadly divided into those that perform an excitatory function and those that perform an inhibitory function.
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Excitation-
When a neurotransmitter, such as adrenaline, increases the positive charge of the postsynaptic neuron. This increases the likelihood that the neuron will fire and pass on the electrical impulse.
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Inhibtion-
When a neurotransmitter, such as serotonin, makes the charge of the postsynaptic neuron more negative. This decreases the likelihood that the neuron will fire and pass on the electrical pass.
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Chemical transmission- synapses.
Neurons communicate with each other in groups known as neural networks. The synapse, space between neurons, includes the presynaptic terminal and postsynaptic receptor site. Signals within neurons are transmitted electrically, but between neurons they are transmitted chemically by synaptic transmission.
Electrical impulse reaches the end of the neuron (presynaptic terminal) it triggers the release if neurotransmitter from the synaptic vesicles.
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Neurotransmitter- sending signals.
Once it crosses the gap it is taken up by the postsynaptic receptor sites, here the chemical message is converted back into an electrical impulse, the process of transmission begins in this other neuron.
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Summation-
Whether a postsynaptic neuron does fire is decided by the process of summation. The excitatory and inhibitory influences are summed: if the net effect on the postsynaptic neuron is inhibitory then the post synaptic neuron is less likely to fire; if the net is excitatory then it is more likely to fire- and momentarily the inside of the postsynaptic neuron becomes positively charged.
Therefore action potential of the postsynaptic neuron is only triggered if the sum of the excitatory and inhibitory signals at any one time reaches the threshold.
39
Localisation vs holistic theory.
Holistic- Broca, Wernicke all support the holistic theory that all parts of the brain were involved in the processing of thought and action.
Localisation is the idea that different parts of the brain perform different tasks and are involved in different areas of the body.
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Plasticity:
This describes the brain's tendency to change and adapt as a result of experience and new learning.
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Functional recovery:
A form of plasticity. Following damage through trauma, the brain's ability to redistribute or transfer functions usually performed by a damaged area to other, undamaged area.
42
Brain plasticity through childhood.
During infancy, the brain experiences a rapid growth in the number of synaptic connections it has, peaking at approximately 15,000 at age 2-3 years. This is twice as many than there are in adult brains.
Originally though changes were restricted to only the developing childhood brain, and that the adult brain would remain fixed in function and structure. Recent research suggests that at any time neural connections can change and form as a result of learning and experience.
43
Eleanor Maguire et al (2000)
Studied the brains of London taxi drivers and found significantly more volume of grey matter in the posterior hippocampus than in a matched control group. This part of the brain is associated with the development of spatial and navigational skills. For training London drivers must take a complex test called 'The knowledge' which asses their recall of streets and routes.
44
Draganski et al (2006)
Imaged the brains of medical students three months before and after their exams. Learning-induced changes were seen to occur in the posterior hippocampus and the parietal cortex.
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Mechelli et al (2004)
Found a larger parietal cortex in the brains of people who were bilingual compared matched monolingual controls.
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How fast/slow is functional recovery?
It can occur quickly after trauma (spontaneous recovery) and then slow down after several weeks/months.
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How does the brain recover?
(Doidge 2007)
It is able to rewire and reorganise itself by forming new synaptic connections close to the area of damage. Secondary neural pathways that would not typically be used to carry out certain functions are activated to enable functioning to continue as before.
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Structural changes in the brain during recovery:
-Axonal sprouting: The growth of new nerve endings which connect with other undamaged nerve cells to form new neuronal pathways.
-Reformation of blood cells.
-Recruitment of homologous (similar) areas: on the opposite side of the brain to perform specific tasks. An example would be if Broca's area was damaged on the left, the right sided equivalent would carry out its functions.
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Evaluation of Plasticity: Practical application.
Contributed to the field of neurorehabilitation. Following illness or injury to the brain, spontaneous recovery slows down after a few weeks so physical therapy may be needed to maintain improvements. This shows that although the brain can fix itself to a point this process requires further intervention to be completely successful.
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Evaluation of Plasticity: Negative Plasticity
The brain rewiring itself can have maladaptive behavioural consequences. Prolonged drug use, as been shown to result in poorer cognitive functioning as well as increased risk of dementia later in life (Medina et al 2007). 60-80% of amputees develop phantom limb syndrome which are thought to be due to cortical reorganisation on the somatosensory cortex (Ramachandran and Hirstein 1998).
51
Evaluation of Plasticity: Age and Plasticity
Ladina Bezzola et al (2012)
Functional plasticity reduces with age. The brain is better at reorganisation in childhood as it is constantly learning.
Ladina demonstrated how 40 hours of golf training produced changes in the neural representation of movement in p/pants aged 40-60. Using fMRI, researchers observed reduced motor cortex activity in the novice golfers compared to a control group, suggesting more efficient neural representations after training.
52
Evaluation of Plasticity: Animal studies
David Hubel and Torsten Wiesel (1963) sewed one eye of a kitten shut and analysing the brain's cortical responses. The area of the visual cortex associated with the shut eye was not idle but continued to process info from the open eye.
53
Evaluation of Plasticity: Cognitive reserve
Educational attainment may effect how the brain functionally adapts after injury.
Eric Schneider et al (2014) found that more time brain injury patients had spent in education (indication of their cognitive reserve) the greater the chances of a disability free recovery (DFR). 2-5 of patients who achieved DFR had 16+ years in education compared to 10% who had under 12 years.
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Plasticity Case Study- Gabby Giffords.
Former US democratic politician who survived a shot in the head from point blank range. Doctors placed Giffords into a waking coma. Within months she made staggering progress, with the aid of physical rehabilitation, Giffords was able to walk (supervised) with complete control of her left arm and leg. Her progress would place her in the top 5% of people recovering from serious brain injury- the brain healing itself.
55
Hemispheric Lateralisation-
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, as in the example of language.
56
Split- brain studies- Sperry, 1968
Unique group of individuals all of whom had undergone the same surgical procedure in which the connections of the two hemispheres were cut down the middle to separate the hemispheres and control frequent and severe epileptic seizures. The main communication line between the two hemispheres was removed.
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Split- brain studies- Sperry, 1968
Procedure.
An image of word could be projected to a patient's right visual field and the same/different could be projected to the left visual field. In the 'normal' brain, the corpus callosum would share the info between the hemispheres giving a complete visual picture. Presenting an image to one hemisphere meant the info could not be conveyed from that hemisphere to the other.
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Split- brain studies- Sperry, 1968
Findings- Describing what you see.
Describing what you see- a picture shown to the right visual field (VF) the patient could describe it, if it was shown to the left VF the patient typically reported there was nothing there. The patients inability to describe objects in the left VF was due to lack of language centres in the right VF. Messages are relayed in language centres
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Split- brain studies- Sperry, 1968
Findings- Recognition by touch.
Patients could select a matching object from a grab-bag of objects using their left hand to match the one shown to their left VF. The objects were behind a screen so not to be seen. The left hand was able to grab an object most closely associated with to the object in their left VF. They could not verbal identify what they had seen but could understand what the object was.
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Split-brain studies- Sperry, 1968
Findings- Composite words.
If two words were presented simultaneously, one on either side of the visual field (key on left, ring on right) they could select a key with their left hand and say the word ring.
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Split-brain studies- Sperry, 1968
Findings- Matching faces.
Right hemisphere is dominant in matching faces. When asked to match a face from a series of other faces, the picture processed by the right hemisphere was consistently selected and the pic shown to the left hemisphere was ignored. When a picture of two different halves of a face was shown, one to each hemisphere, the left hemisphere dominated in verbal description yet the right was better at matching faces.
62
Split-brain studies.
Evaluation- Demonstrated lateralised brain functions.
Sperry's work into split-brain has produced an impressive and sizeable body of research findings- main conclusion being the left hemisphere is better for verbal and analytic tasks whilst the right is for spatial tasks and music.
Key contribution to our understanding of brain processes.
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Split-brain studies.
Evaluation- Strengths of methodology.
Experiments made use of highly specialised and standardised procedures. By giving the patients one piece of information at a time he developed a useful, well-controlled procedure.
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Split-brain studies.
Evaluation- Theoretical basis.
Prompted a theoretical and philosophical debate of communication between the two hemispheres in daily functioning and the nature of consciousness. Pucetti (1977) suggested the 2 hemispheres are so functionally different that they represent duality in the brain.
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Split-brain studies.
Evaluation- Generalisation.
All p/pants had epilepsy and the control group was made up of 11 p/pants who had no history with epilepsy which may have been inappropriate.
66
Functional magnetic resonance imagining (fMRI)
A method used to measure brain activity by detecting changes in blood oxygen and flow that occur. More active brain areas use more oxygen. fMRI uses 3-D images showing which parts of the brain are involved in a particular mental process- important for localisation of function.
67
Electroencephalogram (EEG)
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 patterns that are generated from the action of millions of neurons, providing an overall account of brain activity. EEG is often used as a diagnostic tool as unusual arrhythmic patterns may mean epilepsy, tumours or sleep disorders.
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Event-related potentials (ERPs)
Method that isolates neural responses to specific sensory, cognitive and motor events. Using a statistical averaging technique, all extraneous brain activity from the EEG recording is filtered out leaving only those responses that relate to the performance of a specific task. What remains are event-related potentials: types of brainwave that are triggered by particular events.
69
Post-mortem examinations
Technique that analyses a person's brain following their death. Individuals whose brains are subject to post-mortem likely had a rare disorder and experienced unusual deficits in mental processes during their life. Areas of damage in the brain are examined as a mean of establishing the likely cause of the affliction the person suffered.
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fMRI- Strengths
It does not rely on the use of radiation like other scanning methods such as PET. If administered correctly it is virtually risk-free, non-invasive and straight-forward to use. It produces images that have high spatial resolution, detail by millimetre, and providing a clear picture of how brain activity is localised.
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fMRI- Weaknesses
fMRI is expensive compared to other neuroimaging techniques and can only capture a clear image if the person is completely still. Poor temporal resolution because there is around a 4 second time lag behind the image on screen and the firing of neuronal activity. fMRI can only measure blood flow in the brain, not specific activity of individual neurons.
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Electroencephalogram- Strengths
Proved invaluable in the diagnosis of conditions such as epilepsy as the random bursts of brain activity can be detected on screen. Contributed much to our understanding of the stages involved in sleep. High temporal resolution- a single millisecond.
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Electroencephalogram- Weaknesses
Main drawback is the generalised nature of the information received. It is not useful for pinpointing the exact source of neural activity, and it doesn't allow researchers to distinguish between activities originating in different but adjacent locations.
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Event-related potentials- Strengths
Limitations of EEG are addressed through ERPs. These are much more specific to the measurement of neural processes than could ever be achieved using raw EEG data. Excellent temporal resolution that has led to the widespread use in measurement in cognitive functions and deficits. Researchers have identified many types of ERP and described the precise roles of these in cognitive functioning.
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Post-mortems- Strengths
Vital in providing a foundation for early understanding of key processes in the brain. Improve medical knowledge and help generate hypotheses for further study.
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Event-related potentials- Weaknesses
Lack of standardisation in ERP methodology between different research studies which makes it difficult to confirm findings. To establish pure data, background noise and extraneous material must be removed which isn;t always easy.
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Post-mortems- Weakness
Causation is an issue within these investigations. Observed damage to the brain may not be linked to the deficits under review but to some other unrelated trauma. Ethical issues of consent from the patient prior to death. Informed consent- HM lost his ability to form memories and was not able to provide consent but that didn't stop them!
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Biological rhythms:
Governed by two things: body's internal biological clocks (endogenous pacemakers) and external changes in the environment (exogenous zeitgebers). Include: ultradian rhythms, infradian rhythms and circannual rhythms.
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Ultradian rhythms:
Occur many times during the day, subject to a 24-hour cycle.
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Infradian rhythms:
Take longer than a day to complete.
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Circannual rhythms:
Takes multiple months/years.
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Sleep/wake cycle:
Feeling drowsy at night time and alert during the day shows the effect of daylight (exogenous zeitgeber) on our sleep/wake cycle.
83
Siffre's cave study.
He spent several extended periods underground to study the effects on his own biological rhythms. Deprived of exposure to natural light and sound but with access to food/drink he re-surfaced mid-September 1962 after 2 months in a cave. His 'free-running' biological rhythm settled down to one that was just over 24 hours (approx 25 hours) though he continued to sleep and wake up on a regular cycle.
84
Aschoff and Wever (1976)
Convinced a group of p/pants to spend 4 weeks in a WW2 bunker deprived of natural light. All but one p/pant (whose sleep wake cycle became 29 hours) displayed a circadian rhythm of 24/25 hours.
85
Folkard et al (1985)
Studied a group of 12 people who agreed to live in a dark cave for 3 weeks, sleeping when a clock said 11.45pm and waking when it said 7.45am. Researchers gradually sped up the clock so an apparent 24 hour day was actually only 22. Only one of the p/pants could comfortably adjust. Free-running circadian rhythm can not be easily over ridden.
86
Circadian rhythms- Evaluation.
-Practical application to shift work.
Night workers engaged in shift work experience a period of reduced concentration around 6am meaning mistakes are more likely (Boivin et al 1996). Research suggests a relationship between shift work and poor health: Knutsson 2003, shift workers are 3X more likely to develop heart disease.
Economic implications.
87
Circadian rhythms- Evaluation.
-Practical application to drug treatments.
Circadian rhythms co-ordinate lots of the body's basic processes, heart rate, digestion, hormone levels. This has an effect on pharmacokinetics, that is the action of drugs on the body and how well they are absorbed/distributed. Research shows there are peak times during the day or the night when drugs are most effective.
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Circadian rhythms- Evaluation.
-Use of case studies and small samples.
Studies tend to involve small groups of p/pants or studies of individuals. May not be representative of the wider population and this limits generalisation.
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The menstrual cycle:
This is an infradian rhythm as it is governed by monthly changes in hormone levels which regulate ovulation.
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Menstrual cycle as an infradian rhythm- Research Study
Kathleen Stern and Martha McClintock (1998)
It is an endogenous system that can be affected by exogenous factors.Stern and McClintock involved 29 women with history of irregular periods. Samples of pheromones were gathered from 9 p/pants at different stages of their menstrual cycles (MC). The pads (with pheromones on from armpits) were treated with alcohol and frozen, to be rubbed on the upper lip of other p/pants. Pads from the start of the MC were applied to all 20 women and on the 2nd day they were given a pad from day 2 of the cycle and so on. 68% of women experienced changes to their cycle which brought them closer to their 'odour donor.'
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Seasonal affective disorder (SAD)
Seasonal pattern of onset. Main symptoms are persistent low moods alongside a general lack of activity/ interest in life. Triggered as daylight hours get shorter. Circannual rhythms as it is in a yearly cycle. Psychologists have theorised that the hormone melatonin is implicated in the cause of SAD. During the night, the pineal gland secretes melatonin until there is an increase of light.
92
Stages of the sleep cycle:
5 stages that altogether span approx 90 minutes and continues to cycle through the night.
Stages 1/2: Sleep escalator, light sleep where the person is easily woken. Brainwaves become slower and more rhythmic.
Stages 3/4: Delta waves which are slower still and have a greater amplitude that earlier wave patterns (deep sleep).
Stage 5, REM sleep: Body is paralysed yet brain activity speeds up significantly that resembles an awake brain.
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Circadian Rhythms- Evaluation.
-Evolutionary basis of menstrual cycle.
For ancestors it may have been advantageous for females to have synced periods and fall pregnant at the same time. The validity has been questioned. Jeffery Schank (2004) has argued that if too many females were synced up this would produce competition for the highest quality males.
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Circadian Rhythms- Evaluation.
-Methodological limitations in synchronisation studies.
There are many factors that effect change in a woman's menstrual cycle that might act as confounding variable. This means that any supposed pattern of synchronisation is no more than what would be expected by chance.
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Circadian Rhythms- Evaluation.
-Evidence supports the idea of distinct stages in sleep.
Dement and Kleitman (1957) monitored sleep patterns of 9 adult p/pants in a sleep lab. Brainwave activity was recorded on an EEG and the researchers controlled the effects of caffeine/ alchohol. REM sleep was highly correlated with dreaming. Replications of this investigation have noted similar findings.
Shows REM sleep is an important component of the ultradian sleep cycle.
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The suprachiasmatic nucleus (SCN)
A tiny bundle of nerve cells in the hypothalamus in each hemisphere of the brain. It is one of the primary endogenous pacemakers in mammals and is influential in maintaining circadian rhythms.
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Animals Studies- SCN
-Patricia DeCoursey
Patricia DeCoursey et al (2000) destroyed the SCN connections in the brains of 30 chipmunks who then returned to their natural habitat snd observed for 80 years. Their sleep/wake cycle disappeared and a significant proportion of them had been killed by predators.
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Animals Studies- SCN
-Martin Ralph
Martin Ralph et al (1990) bred 'mutant' hamsters with a 20-hour sleep/wake cycle. When SCN cells from the foetal tissue of mutant hamsters were transplanted into the brains of normal hamsters, the cycles of the 2nd group defaulted to 20 hours.
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The pineal and melatonin.
The SCN passes the information on day length and light that it receives to the pineal gland. During the night, the pineal gland increases production of melatonin.
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Exogenous Zeitgebers- Light
It can reset the body's main endogenous pacemaker, the SCN, 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.
101
Exogenous Zeitgebers- Campbell and 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. 15 p/pants 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 p/pants usual sleep/wake cycle of up to 3 hours.
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Exogenous Zeitgebers- Social cues
Human infants the initial sleep/wake cycle is pretty much random. At about 6 weeks of age, the circadian rhythms begin and by about 16 weeks most babies are entrained.
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The SCN- Evaluation.
-Beyond the master clock.
There are numerous circadian rhythms in many organs and cells of the body. These are called peripheral oscillators, and are found in the adrenal gland, oesophagus, lungs, liver, etc. These peripheral clocks are influenced by the SCN they can act independently. Damiola (2000) demonstrated how changing feeding patterns in mice could alter the circadian rhythms of cells in the liver by up to 12 hours, whilst leaving the rhythm of the SCN unaffected.
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The SCN- Evaluation.
-Ethics in animal studies.
Problems involved in generalising findings of the sleep/wake cycle from animal studies to human. DeCoursey et al's study has ethical issues as he animals were exposed to harm and rick when returned to their habitat.
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The SCN- Evaluation.
-Influence of exogenous zeitgebers may be overstated.
Laughton Miles et al (1977) recount the story of a young man who was blind from birth with a 24.9 hours circadian rhythm. Despite exposure to social cues his sleep/wake cycle could not be adjusted.
