Biopsych

Question 1

The nervous system - the CNS

Answer 1

• Brain and spinal cord - controls behaviour and regulates physiological processes (breathing) - spinal cord made up of pairs of nerves which connect muscles to glands
• Receives information from sensory receptors in the sense organs via sensory neurons - sends messages to effector organs
• Cerebrum - Left and right hemispheres which control higher order thinking
• Cerebellum - Balance and coordination
• Diencephalon - Relays sensory information between brain regions and controls many autonomic functions of the PNS - made up of thalamus and hypothalamus
• Brain stem - Regulates autonomic functions such as breathing, heart rate

Lobes of the cerebrum;

• Frontal - Thought and speech production
• Occupital - Visual processing
• Prefrontal - Personality, reasoning, judgement, guilt
• Temporal - Auditory processes
• Hypothalamus - regulates body temperature and other homeostatic functions, links to the endocrine system via the pituitary gland
• Thalamus - relays impulses from sensory neurons

Question 2

The nervous system - the PNS

Answer 2

• Somatic Nervous System - made up of sensory neurons and motor neurons
• Autonomic Nervous System - controls involuntary bodily functions such as heartbeat and digestion
• Parasympathetic NS - rest and digest, decreases heart rate - Acetylcholine is the main neurotransmitter (reduces blood pressure)
• Sympathetic NS - fight or flight - noradrenaline main neurotransmitter

Question 3

Neurons and synaptic transmission - structure and functions of neurons

Answer 3

• Relay - connect sensory and motor neurons and are found in the CNS in brain and spinal cord - They are also known as inter-neurons.
• Sensory - carry nerve impulses from nerve impulses to receptors - located in sensory glands (eyes/ears) - convert info from receptors into neural impulses and when reach the brain transferred into sensations
• Motor - long axons which carry nerve impulses to muscles, triggering muscle contractions

Question 4

Neurons and synaptic transmission - synaptic transmission

Answer 4

• action potential reaches terminal at end of axon
• travels across the synapse
• at the end of axons are vesicles - contain chemical messengers
• action potential reaches vesicles causing them to release their contents through exocytosis
• released neurotransmitter travels across synaptic gap and binds to receptor cells
• receptor molecules either produce and excitorary or inhibitory neurotransmitter

Question 5

Endocrine system - glands and hormones

Answer 5

• Endocrine glands produce and secrete hormones into the bloodstream
• Hormones are - chemical messengers - Bind to specific receptor sites on the surface of target cells, stimulating a response in these cells
• Endocrine system is self regulated by a feedback system - known as negative feedback
• hypothalamus releases CRH - stimulates pituitary to release ACTH - stimulates adrenal gland to release cortisol

Question 6

Endocrine system - pituitary gland

Answer 6

• Controlled by hypothalamus - known as master gland
• Front pituitary releases ACTH as a response to STRESS and also produces reproductive hormones LH and FSH
• Back pituitary releases oxytocin

Question 7

Endocrine system - adrenal gland

Answer 7

• On top of kidneys
• Adrenal cortex produces cortisol, which regulates important cardiovascular and anti-inflammatory functions in the body
• The adrenal medulla releases adrenaline and noradrenaline which prepare the body for fight or flight response

Question 8

Fight or flight - AO1

Answer 8

• Amygdala - associates sensory signals with emotions relating to fight or flight (fear) - sends a distress signal to hypothalamus

Response to accute stressors;
- SNS triggered and sends signal through adrenal medulla and responds by releasing adrenaline - PNS then slows everything down

Response to chronic stressors;

• Hypothalamus activates an HPA axis
• H - hypothalamus - releases CRH
• P - pituitary - CRH causes release of ACTH
• A - adrenal - ACTH stimulates cortisol release

Feedback system;
- CRH and ACTH production are inhibited if cortisol levels are too high

Question 9

F or F - AO3

Answer 9

• Tend and befriend response - researcher suggests for females the f or f response is diff - involves protecting themselves and their offspring through nurturing behaviours and forming alliances with other women - fleeing would be putting their offspring at danger
• Genetic diffs between men and women - research has shown men to have the SRY gene which promotes aggression and the f or f response - primes males to respond to stress this way because of the release of hormones like adrenaline - women don’t have it and instead oestrogen and oxytocin which may prevent the response
• Freeze response instead of f or f - Gray argues first response to stress is not to f or f but we typically have the freeze response - where you are hyper vigilant and allows you to focus attention and look for info to make best decision in that circumstance

Question 10

Localisation of function - AO1

Answer 10

• Motor cortex - responsible for generation of involuntary motor movements - located in frontal lobe
• Somatosensory cortex - detects sensory events arising from different regions of the body - in parietal lobe
• Visual centres - primary visual centre in visual cortex but visual processing starts in retina - nerve impulses transmitted to brain through optic nerve
• Auditory centres - concerned with hearing - lies within temporal lobes on each hemisphere - begins in cochlea and waves are converted into nerve impulses that travel auditory nerve to the auditory cortex - in brain stem basic decoding takes place
• Broca’s area - studied patient ‘Tan’ - could only express one syllable - could understand but not produce language - damaged left hemisphere - left hemisphere believed to be critical for language production
• Wernicke’s area - discovered producing language was in the posterior left temporal lobe - could speak but not understand language

Question 11

Localisation of function - AO3

Answer 11

• Support for language centres from aphasia studies - aphasia is where you an inability to produce or understand language - expressive aphasia (Broca) is inability to produce language - receptive aphasia (Wernicke) is inability to understand language - important as it shows the importance of the two language centres
• However - language production may not be in Broca’s area alone - researcher re-examined preserved brains of Broca’s patients and MRI scanned them for the extent of any lesions - found other areas could have also contributed to the patients reduced speech abilities - suggests that language and cognition are far more complicated than once thought and involve networks of brain regions rather than being localised to specific areas
• Individual diffs - patterns of activation in brain during language tasks vary for each person - researcher found a large variability in individual patterns of activation across different individuals - other studies have shown that there are significant gender differences in the size of the brain areas associated with languages - suggests that localisation of brain function isn’t able to be restricted to just one part of the brain

Question 12

Lateralisation and split brain research - HEMISPHERIC LATERALISATION - AO1

Answer 12

• Each hemisphere has functional specialisations - left = language and speech + right = visual motor tasks
• Two hemispheres are connected by bundles of nerve fibres such as the corpus callosum
• To treat severe epilepsy, surgeons would sometimes cut the bundle of nerve fibres that formed the corpus callosum - patients were researched to explore the different abilities of the two hemispheres

Question 13

Lateralisation and split brain research - SPLIT BRAIN RESEARCH - AO1

Answer 13

• Key study - Gazzaniga - studied split brain patients - presented information to one hemipshere at a time in order to study hemispheric lateralisation - if a picture is shown to the left visual field and right , the patient would say that they saw the picture on the right

Question 14

Lateralisation and split brain research - AO3

Answer 14

• Split brain research limitation - rare number of patients have had the procedure done - studies are presented with as few as three participants or just the one single participant - conclusions drawn from ppts who either have a confounding physical that made the split-brain procedure necessary, or have had a less complete sectioning of the two hemispheres than was originally believed
• Language may not be restricted to left hemisphere - researcher found a small but significant relationship between handedness and immune disorder - therefore neurosurgeons find out which hemisphere is dominant and contains language centres in an individual patient before carrying out treatments like ECT in order to minimise cognitive side effects - means we should not generalise or make assumptions about the lateralisation of language centres in individuals
• Split brain patients may develop abilities - example, a patient known as JW developed the capacity to speak about information presented to either hemisphere - damage to the left hemipshere was found to be far more detrimental to language function than to the right - means that some of the early studies from split-brain research have been dis-confirmed by recent studies

Question 15

Plasticity and functional recovery - AO1

Answer 15

Plasticity;

• Brain continues to create new and stronger connections
• Brain then able to adapt to a constantly changing environment - example - playing video games results in an increase in gray matter in vairous brain areas including the cortex, hippocampus and cerebrum
• A gradual decline in cognitive function with age, but even 60 year olds still can be taught a new skill
• Researcher found experienced meditators produced more permenant change

Recovery after trauma;

• When brain cells are damaged other parts sometimes take over their functions
• Happens where dormant synapses can be ineffective because the rate of neural input to them is far too low to be activated
• Stem cells implanted into the brain may help to treat brain damage through - replacing dead/dying cells, forming neural networks etc.

Question 16

Plasticity and functional recovery - AO3

Answer 16

• Support from animal studies - researcher investigated whether an enriched environment could alter the neurons in the brain - evidence of an increased number of new neurons in the brains of rats housed in more complex environments - supports the idea that the number of new neurons can change in adult animals in response to environmental stimulation
• Taxi drivers support idea of plasticity - researcher measured the grey matter in taxi drivers’ brains using MRI scanning, and found a positive correlation between the size of their posterior hippocampus and how long they had worked as a taxi driver - posterior hippocami of taxi drivers were significantly larger relative to those of control ppts
• Functional plasticity reduces with age - a commonly accepted view that functional plasticity reduces with age BUT - studies have suggested that even abilities commonly thought to be fixed in childhood can still be modified in adults with intense retraining

Question 17

Ways of studying the brain - AO1

Answer 17

Post mortem exams;

• If a researcher suspects that a patient’s behavioural changes were caused by brain damage, they may look for abnormalities after the person dies - example - Broca observed his patient Tan, who displayed speech problems when alive and was subsequently found to a lesion in Broca’s area
• HM’s brain has been extensively investigated post-mortem, confirming that his ability to store new memories was linked to lesions in the hippocampus

Brain scanning techniques;

• fMRI - measures changes in brain activity while a person performs a task
• measuring changes in blood flow in particular areas of the brain, which indicates increased neural activity in those areas
• EEG - measure changes in the electrical activity of the brain using electrodes attached to the scalp - diagnose brain disorders
• ERP - small voltage changes triggered by specific events or stimuli, such as cognitive processing of a specific stimulus

Question 18

Ways of studying the brain - AO3

Answer 18

• Strength of post mortem is - they allow for a more detailed examination of anatomical and neurochemical aspects of the brain - Changes in neurotransmitters can also be investigated as well as deeper structures - eg - abnormalities with schizophrenia - contributed to greater understanding of the brain
• Strength of fMRI - non-invasive and does not expose the brain to potentially harmful radiation - LIMITATION - not a direct measure of neural activity in particular brain areas
• Strength of EEG - records brain activity in real time -LIMITATION - only detect the activity in superficial regions of the brain
• Strength of ERP - provide a continuous measure of processing in response to a particular stimulus - makes it possible to determine how processing is affected by a specific experimental manipulation - LIMITATION - requires a large number of trials to gain meaningful data

Question 19

Circadian rythmns - AO1

Answer 19

• driven by our body clocks
• SCN is the master circadian pacemaker
• light provides the primary input to this system
• light-sensitive cells within the eye act as brightness detectors, sending messages about environmental light levels direct to the SCN
• sleep-wake cycle - dictates when we should be sleeping - two dips at 2-4 am and 1-3pm - internal circadian clock is free running - maintains cycle of about 24-25 hours
• body temperature is another circadian rythmn - body temperature is lowest first thing in morning and highest in the early evening

Question 20

Circadian rythmns - AO3

Answer 20

• Evidence of free running circadian rythmn - studies from cave explorer - underground for long periods of time to study his own rythmn - found that his body clock ticked more slowly sometimes stretching his circadian rhythms to 48 hours - shows that circadian rhythm is not fully dependent on light or social cues
• Individual differences - two important types of individual differences in circadian rhythms - cycle length and cycle onset - ‘morning people’ prefer to rise early and go to bed early, whereas ‘evening people tend to wake and go to bed early - individuals seem to have innate differences in their cycle length and onset
• Real world applications of circadian rythmns - to be most effective, the drugs need to be released into the body at the optimal time - specific time that patients take their medication is very important as it can have a significant impact on their treatment - prompted the development of novel drug delivery systems so that the drug is released into the bloodstream during the vulnerable period

Question 21

Ultradian and infradian rythmns - AO1

Answer 21

Ultradian;
- Cycles that last less than 24 hours
- 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
- 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
- Stage 5 is REM sleep. Here is the body is paralysed and brain activity resembles that of an awake person
- BRAC cycle - physiological arousal mechanism in humans hypothesized to occur during both sleep and wakefulness - 90 minute ultradian rhythm continues throughout the day, even when we are awake
Infradian;
- rythmns that have a duration greater than 24 hours and it also includes the female menstrual cycle
- male testosterone levels are elevated at weekends and young couples report more sexual activities on the weekends than on weekdays the frequency of births during the weekends is lower than the weekdays
- monthly infradian rhythm is the female menstrual cycle

Question 22

Ultradian and infradian rythmns - AO3

Answer 22

• Menstrual cycle can also be governed by exogenous cues - study - childbearing age women together with cycles not in sync - one group had daily samples of sweat taken and rubbed onto upper lip of rest of women - their cycles became synced - shows cycles can be affected by pheromones of others
• Menstrual cycle affects mate choice - researcher showed women generally expressed a preference for ‘slightly feminised’ male faces when picking a partner for a long-term relationship. However, when in the ovulatory phase of their menstrual cycle women showed a preference for more masculine faces
• Research support for BRAC cycles - studied a group of elite violinits and found that, among this group, practice sessions were usually limited to a duration of no more than 90 minuites at a time, with practice systematically distributed during the day in these 90 minuite segments

Question 23

Endogenous pacemakers - AO1

Answer 23

• mechanisms within the body that govern the internal, biological body ryhthms
• SCN in hypothalamus sends signals throughout the body in response to dark and light
• receives information about light levels via the optic nerve
• Neurons in the SCN spontaneously synchroise with eachother, so that their target neurons in sites elsewhere across the body recieve correctly coordinated time signals
• neural pathway connecting the SCN and the pineal gland
• Melatonin from the pineal gland induces sleep by inhibiting brain mechanisms that promote wakefullness

Question 24

Exogenous zeitbegers - AO1

Answer 24

• environmental cues such as light, that helps to regulate the biological clock in an organism
• light resets the internal biological clock each day, keeping it on a 24-hour cycle
• influenced by social cues, such as mealtimes and social activities
• specialised light detecting cells in the rods and cones of the retina detect light to for visual images
• third type of light detecting cell in the retina that gages overall brightness to help reset the internal biological body clock

Question 25

Exogenous zeitbegers and Endogenous Pacemakers - AO3

Answer 25

• Animal studies support role of SCN as an endogenous pacemaker - bred a strain of hamsters so that they had abnormal circadian rhythms of 20 hours rather than 24 hours. SCN neurons from these abnormal hamsters were then transplanted into the brains of normal hamsters - found that these normal hamsters then displayed the same abnormal circadian rhythms of 20 hours - confirms the importance of the scn in setting circadian rhythms
• However, body rhythms can be adversely affected by exposure to artificial light at night - research has shown that teenagers spend increasing amount of time on electronic media at night - LED bulbs of these devices are enriched with a blue light component very active on the circadian clock, which leads to suppression of melatonin secretion and circadian disruption - also shows that the SCN ‘master clock’ does not have total control of other biological rhythms
• Using light exposure to avoid jet lag - application of research and exogenous zeitgebers comes from burgess who found that exposure to bright light prior to an east- west flight decreases the time needed to readjust to local time on arrival - Volunteers participated in one of 3 treatments each of which shifted their sleep- wake cycle back by 1 hour a day over 3 days - ppts who had been exposed to bright light felt sleepy 2 hours earlier in the evening and woke 2 hours earlier in the morning - uggests that light exposure prior to a flight would allow travellers to arrive with their circadian rhythms already partially re- entrained to local time