Paper 2 - Biopsyc Flashcards
What does the CNS comprise of?
- the brain and the spinal cord SPINE: Relays info between brain and body, co-ordinates both voluntary and involuntary actions BRAIN: Cerebrum: comprises of 4 lobes Cerebellum: balance, posture, co-ord Brain stem: autonomic reg Diencephalon: thalamus, hypothalamus
What does the CNS do?
Controls behaviour and regulates physiological processes - will receive info from receptors and send impulses through the body
What does the PNS consist of?
Nerves outside of the CNS to relay impulses
Somatic pathway: 12 pairs of cranial nails and 31 pairs of spinal nerves. Relays sensory and motor to and from CNS. Voluntary and reflex
Autonomic pathway: serves as a relay between the brain/spine with the rest of the body - involuntary — splits into sympathetic: flight/fight, increases blood pressure, prep for rapid action
parasympathetic: rest/digest and relax after emergencies
Describe a neurone
Consists of a cell body, nucleus with axon and dendron (or small= dendrites) with myelin sheath
Extra info: sensory - sensory to impulse. relay - communicates between sensory and motor
motor - muscle/ contraction
What is synaptic transmission?
- Action potential travels down nerve to stimulate vesicles in the pre-synaptic knob
- Vesicles containing the neurotransmitter will move towards the membrane and excrete neurotransmitter out of the synapse (due to Ca+)
- Neurotransmitter diffuses across the gap
- It is reabsorbed - longer in the synapse, longer effect
What is the difference between excitatory and inhibitory neurotransmitters and which will be expressed?
Excitatory - fire up (adrenaline)
Inhibitory - calming (serotonin)
the summation of the two; whichever appears greater will be expressed
What does the endocrine system comprise of?
Glands and hormones: hypothalamus/ pituitary gland would be signalled to release hormones to respond to stimuli and target cells to induce physiological reactions; although dysfunction may cause Cushings syndrome/depression
- Pituitary gland regulates basic functions of the body; anterior (ACTH for stress responses and sex hormones like FSH) and posterior (oxytocin contracts uterus and important for bonding between child and mother)
- Regulated by negative feedback - keeps stable by stopping hormone levels from rising to high
- Adrenal gland; cortex - hormones necessary for life, cortisol responses to stress, for immune system and blood pressure. Aldosterone for maintaining blood pressure
- Adrenal gland; medulla - adrenaline and noradrenaline for flight/fight
- ovaries and testes
Outline the fight/flight response (PNS)
- responding to immediate stressors
- detected by amygdala which signals the hypothalamus
- activates the sympathomedullary pathway
- signal send to the adrenal medulla to release adrenaline/noradrenaline
- increases blood pressure, heart rate, digestion will stop (then switches to parasympathetic when stressor passes)
Outline the chronic stress response (HPA axis)
- when exposed to a stressor for a long period of time, it is detected by the hypothalamus to simulate the pituitary gland to produce ACTH
- ACTH stimulates adrenal cortex to release corticosteroids (cortisol) to provide energy to cope
What is localisation of brain function? What was the assumption of brain function prior to this discovery?
discovering that different areas of the brain are specifically responsible different functions
Before: holistic view of the brain but the case of Phineas Gage and psychologists like Wernicke and Broca are responsible for the change
Describe the division of the brain
- divided into two symmetrical halves (hemispheres) which are subdivided into 4 lobes - general rule: actions on the left side of the body are controlled by the right side of the brain
What are the different areas and functions of the brain? (Mums Find Sending People Videos Online Bring Wins)
Motor area (Frontal) = responsible for voluntary movements by sending signals to muscles Somatosensory area (Parietal) = receives incoming sensory info (pressure, pain temp) - more sensitive - more of the somatosensory devoted to it Visual area (Occipital) = receives and processes visual info (different types processed in different areas) Broca's area = left frontal, speech production (discovered through post-mortems) - any damage leads to aphasia (slow, lacking fluency) Wernicke's area = left temporal, language comprehension (meaningless chatter) - aphasia; nonsense words
Give strengths of research into localisation of brain function (but evaluate each strength)
- brain scanning evidence: supports neurological functions are localised - Petersen used brain scans to demonstrate how Wernicke’s area is active during listening but Broca’s active in reading. Shows diff tasks activate diff areas (also evident in Tulving’s research; episodic and semantic reside in different areas of prefrontal cortex) - objective research with mundane realism
Case : Phineas Gage: metal pole exploded through left cheek and damaged frontal lobe. Various changes in personality: aggressive, sexual - damage in specific area altered specific functions
HOWEVER… you cannot use idiographic approaches and apply them nomothetically
Neurosurgical evidence
Freeman ; surgically removing parts of the brain (lobotomy) can control different aspects (removing parts of the frontal lobe to treat aggression).
In OCD, Dougherty used 44 patients who had had a cingulotomy and successful results; suggests mental disorders are localised (33% success , 14% partial)
HOWEVER… very brutal
What are weaknesses into research in localisation of brain function?
- evidence involved in neuroplasticity:
suggests that when the brain is damaged, the rest of the brain attempts to compromise to that which is lost e.g. in stroke victims - this wouldn’t be possible if all areas of the brain are limited to one specific function
What is brain plasticity?
Refers to the brains ability to change and adapt based on experience (e.g. infants begins with a rapid growth of synaptic connections but slowly delete and strengthen those which are most frequently used - pruning - still forms beyond the critical period)
Outline Maguire’s research into neuroplasticity?
- investigated London’s cab drivers who would have extensive experience into spatial navigation (they also had to participate in ‘The Knowledge’ - memorising maps etc)
- compared them to a specifically matched control group
- found an increase in the vol of grey matter in the posterior hippocampus of the cab drivers (memory, spatial)
- correlation found between vol of grey matter and the time spent as a cab driver (growing with experience)
- SUPPORT - research by Mechelli found larger parietal cortex in bilinguals compared with monolinguals
What is functional recovery?
When the brain transfers functions from the damaged areas of the brain to non-damaged areas - begins spontaneous and then slows down (and may require rehabilitation)
How does functional recovery occur?
- rewiring and reorganisation by forming new synaptic connections and activating secondary neural pathways
- axonal sprouting (growth of nerve endings)
- reformation of blood vessels
- recruitment of homologous areas (equivalents)
Doidge
What are strengths of research into plasticity/ functional recovery?
- support from animal studies: Wiesel et al sewed a kitten’s eye shut and analysed for cortical responses. Found that the optical cortex associated with the shut-eye was not idle as it processed info from the other eye
HOWEVER… animals are different , we are potentially more complex - positive app: research contributes to the understanding of neurorehabilitation; forms of physical therapy can be used to improve functional - electrical stimulation can counter deficits in motor/cog functions to fix itself
Weaknesses of research into brain plasticity?
Negative plasticity - Medina :
- a brains ability to repair itself can be maladaptive: 60-80% of amputees have phantom limb syndrome and experience unpleasant sensation whey lost a limb- due to cortical reorganisation in somatosensory cortex
- this research doesn’t dispute plasticity as it is still an effect of it
Individual differences : Schneider; those with higher levels of education had greater disability free recovery
What is hemispheric lateralisation?
Suggests that the two halves of the brain are functionally different & certain behaviours/mental processes are mainly controlled by one half
LEFT: speech productions, analytics, language, knowledge
RIGHT: creative, emotional, visual motor
They communicate through the corpus callosum
What was Sperry’s method?
Aimed to see the extent to which different hemispheres are specialised
Used split-brain patients (undergone surgery which removed their corpus callosum to stop seizures) - this means they had lack of communication between the sides
Carried out several tasks
Explain Sperry’s findings
Describe what you see: picture in the RVF and they could describe it (left hemisphere processed it)
Shown in LVF, could not process/describe (lack of language)
Tactile task: object placed in right hand and they were able to describe and identify against alternatives (left hemisphere). When placed in left hand, couldn’t describe, but could feel and identify against alternatives
Drawing and matching faces: LVF (right hemisphere), consistently draw (still true even for right handed ppts) - visual motor in right. RVF - left hemisphere - never clear drawings but attempts made
What are strengths of research into hemispheric lateralisation?
- Lab experiments: controlled, standardised procedures which can be repeated. Controlled extraneous variable and only flashed images for 1/10th of a second to stop eyes communicating.
Control groups
HOWEVER… lacks mundane realism - Gazzinga and Sperry : Demonstrating a plethora of research which shows the right hemisphere is the synthesiser whereas the left hemisphere is analyser
- Theoretical basis: allowed theorists like Pucetti to suggest that the two hemispheres are functionally different and we have duality and two minds in everyday situation, using split brain patients just emphasises the duality rather than creating. Stimulates need for further research
What is a weakness of split brain research?
Issues with generalisation: only 11 people who had undergone a rare procedure - cannot be applied nomothetically
Pop-psychological literature:
- overemphasises and oversimplifies the functional distinction
- modern neuroscientists show the distinction is less clean cut
What is a circadian rhythm ?
A biological rhythm that exerts influence on body systems; e.g. sleep wake cycle, core body temp (all circadian as they last 24 hours)
What are endogenous pacemakers and exogenous zeitgebers?
ENDOGENOUS PACEMAKERS: regulates internal biological rhythms (suprachiasmatic nucleus; detects light when eyes are closed)
EXOGENOUS ZEITGEBERS: external factors in the environment which reset biological clocks (light/ social cues)
Describe Siffre’s research into the sleep/wake cycle
In 1962, Siffre spent extended periods in a cave to asses his biological rhythms without the influence of sunlight/clocks.
Found his biological rhythms to be free running and was around 25 hours.
He did a follow up in a Texan cave; he was only meant to stay for 6 months but settled into a 25-30 hour day so ended up staying 7
Research supports the endogenous influences
Outline further research into the sleep/wake cycle
- Aschoff and Wever et al asked groups of ppts to stay in a WW2 bunker for four weeks (without natural light) and found that the sleep/wake cycle assumed 25 hours (and in some cases 29) but could’ve been trained by exogenous zeitgebers
- Folkard isolated 12 ppts from natural light for 3 weeks but set a clock for them to get 25 hours but they gradually reduced the cycle to 22 hours but none of the ppts could adjust comfortably - suggesting that there are strong free running circadian rhythms which override exogenous zeitgebers
What are strengths into sleep/wake cycle research?
Economic implication (Boivin):
- managing productivity
- there are adverse consequences of disrupting the cycle - desynchronisation; night shift workers tend to experience periods of reduced concentration from around 6am (leading to mistakes) - CIRCADIAN TROUGH
- correlation between shift work and poor health (heart disease)
- We can therefore se interventions to prevent this so positive applications
Practical implications for drug treatments (Baraldo):
- circadian rhythms co-ordinate the body’s basic processes - this effects pharmacokinetics. Research suggests certain peaks in the cycle where drugs would be most effective and therefore led to the development of guidelines (drug dosing in cancer etc has proved to be effective)
Explain one weakness into research into the sleep/wake cycle
Poor control in studies: although deprived of natural light, they had access to artificial light (lamps) that may have acted as exogenous zeitgebers (confounding variable)
Use of case studies; cannot be generalised ; variation between 13-65 hours
Individual differences; Duffy showed natural preference for sleeping and rising earl (larks) and the opposite (owls)
Indivi
What is an infradian rhythm?
biological rhythm lasting longer than 24 hours (weekly, monthly)
Describe one example of an infradian rhythm in women
The menstrual cycle - 28 days
- monthly and regulated by hormones
- ovulation at 14 days (when oestrogen is at his highest)
- After ovulation, progesterone levels increase (readying for possible embryo)
- if pregnancy doesn’t occur, lining shed
How can the menstrual cycle be effected by exogenous zeitgebers?
Impact of light:
Reinberg spent 3 months in a cave and found that the cycle shortened to 25.7 days
Impact of pheromones:
Stern & McClintock - used 29 female ppts with irregular periods.
Gathered pheromones from the armpits of 9 women with regular periods.
Rubbed the sweat (after being sterilised) on ppts upper lip
Found that 68% of the women experienced synchronisation with their odour donor
What are weaknesses in research into infradian rhythms?
- Evolutionary basis: It would have been advantageous for women to menstruate together as they would fall pregnant at the same time and care for new-borns collectively (which would increase survival chances)
HOWEVER… the validity is questioned by Schank et al as it is argued that if too many females cycled together, there would be competition for the highest quality males and therefore lowering gene pool - this would therefore suggest that avoiding synchrony would be most adaptive
Limitations of methods:
- confounding variables may have effected the menstrual cycle (e.g. stress or could have been due chance)
- the synchronisation is no more than what was expected by chance
- small samples using self reports
- unreproducible results; Trevathan could not replicate
Describe SAD and give one strength
SAD = seasonal affective disorder; depressive disorder diagnosed by DSM-5
- persistent low mood, lack of motivation as number of daylight hours decreases
- caused by circannual rhythms and disruption of the sleep/wake cycle due to daylight decrease
- in winter, melatonin would be released constantly from the pineal gland - this would stop serotonin therefore causing depression
- practical applications: Eastman - effective treatments administered through phototherapy; lightbox in morning and evening to reset melatonin to relieve symptoms (effective for up to 60% of sufferers)
HOWEVER…placebo effected 30%
What is an ultradian rhythm? Give one example (in detail)
Lasts fewer than 24 hours (occurs multiple times within)
Sleep cycle: distinct stages and can be monitored by using EEG (90 min cycles)
STAGE 1-2: light sleep, ‘sleep escalator’, slow and rhythmic brain waves: alpha and gradually becomes theta
STAGE 3-4: greater amplitude, deep sleep, delta waves
STAGE 5: REM sleep, body paralysed but brain activity speeds up (dreaming)
Give one strength into research into the sleep stages
Dement et al: monitored 9 sleep patterns using EEG’s and controlled caffeine and alcohol intake
- REM activity highly correlates with experience of dreaming - if they wake up then, they have more accurate recall
HOWEVER… unnatural
Describe endogenous pacemakers (suprachiasmatic nucleus)
SCN is a tiny bundle of nerves that are influential in maintaining the sleep/wake cycle: receives info from the eyes (special photoreceptors)
At night, pineal gland secretes melatonin but during the day, it is inhibited
Descoursey: destroyed the SCN connections in 30 chipmunks and found that when returned to their natural habitat, they were killed by predators (awake and vulnerable when they should’ve been asleep)
Describe exogenous zeitgebers (light, social cues)
zeitgeber = time giver
Light:
- can reset endogenous pacemakers
- influences the cycle and can control hormone secretions
- Campbell and Murphy: light can be detected by skin receptor cells (back of the knees) - can alter cycle by up to 3 hours (light does not need to enter through the eyes to influence)
Social cues:
- biological rhythms are entrained by social convention and influenced by social norms, sleeping, eating etc
Schedules of infants are imposed by parents
Evaluate research into endogenous pacemakers and exogenous zeitgebers
- Reductionist approach: assumes the SCN is purely responsible but research has revealed in numerous peripheral oscillators that act independently - Damiola et al: feeding patterns in mice could alter circadian rhythms of cells in the liver by 12 hours (with SCN unaffected)
- Methodological issues: the findings from Campbell and Murphy lacked control (limited light exposure to the eye, could have been a confounding variable) - isolating one zeitgeber does not give clearer insight into the rest
- Debates on ethics: generalised finding from chipmunks (different) - harming animals (but do are finding justify it?)
Alternative: interactionist approach: exogenous and endogenous are constantly separated. Isolation studies, like Siffre’s are rare and therefore could be lacking validity. Interaction in real life - sense to separate?
Miles : influence of exogenous zeitgebers is overstated - blind man (24.9) - tried to entrain using sedatives and stimulants but did not work. Has little bearing on our internal rhythms
What is fMRI?
- functional magnetic resonance: detects changes in blood oxygenation - more oxygen, more blood flow and therefore more active (as it is a haemodyamic response)
- produces 3D shapes and important in understanding brain localisation
PROS: doesn’t rely on radiation (safe), risk free, non-invasive, images of high spatial resolution and clear pictures
CONS: very expensive and perfect images only when person is still
Poor temporal resolution: time lad
Cannot measure individual neurone activity
What is EEG?
- electroencephalogram
- measures electrical activity via electrodes (from skull cap) and the scan records action potentials and nerve impulses
- often used to determine unusual patterns of activity (epilepsy)
PROS: important in diagnosis of brain conditions, contributes to understanding of sleep
Extremely high temporal resolutions
CONS: generalised info; not useful in pinpointing exact sources of neural activity (can’t distinguish between different activities)
What are ERP’s?
Brain responses to specific events; isolated through statistical analysis of data: types of brainwaves are triggered by different evens (filtering and refining)
PROS: addresses problems of EEG’s - brings specificity to measurement of neural activity as it identifies different types of ERP
CONS: lack of standardisation: difficult to confirm
Difficult to remove extraneous noise which is necessary in establishing ERP
What is a post-mortem?
Analysis of a person’s brain following their death (identifying cause of death, rare disorders etc)
- areas of the brain are examined and compared with normal brains
PROS: vital in understanding key processes: Broca and Wernicke used them to establish links in language before neuroimaging was a thing
CONS: observed damage may not link to deficits but link to unrelated trauma
Raises ethical issues; consent is usually not given before death
HM lost his memory, didn’t provide consent but post-mortem research still happened
