Biopsych

• what does the nervous system do?

  concerned with:

  - receiving info. about the environment through sense organs

  - processing + co-ordinating info. from 1 part of the body to another - sending messages to various parts of the body for action
• what is the nervous system made up of?

  - central nervous system = brain + spinal cord

  - peripheral nervous system = autonomic nervous system (sympathetic + parasympathetic branches) + somatic nervous system

  
• what is the central nervous system - brain + spinal cord?

  - brain = centre of nervous system/ 80-100 billion cells all interconnection/ 2 interconnected hemispheres which communicate to rest of body via spinal cord

  - spinal cord = bodys way of communicating - if communication line goes down, the functioning of many other parts of body will be disrupted
• what is the peripheral nervous system?

  - system that comes off the spinal cord to rest of body

  - 2 major subdivisions - autonomic nervous system + somatic nervous system
• what is the autonomic nervous system?

  - automatic system responsible for all automatic actions -eg. heart rate, breathing + digestion (not consciously controlled)

  - 2 further subdivisions = sympathetic breach which excites body + gets it ready for action (eg. speeding up HR)/ parasympathetic branch which calms body down (eg. lowers HR)
• what is the somatic nervous system?

  - voluntary NS which receives sensory information (eyes, nose, touch) + then responding to it with consciously controlled motor actions (muscle movements)

  - intentioned behaviour
• what is the endocrine system?

  - a collection of glands which regulate hormone levels (eg. adrenaline, testosterone + oestrogen)

  - has implications on our thoughts, emotions + behaviours

  - one of bodys major info systems that instructs glands to release hormones directly into bloodstreams. Hormones carried towards target organs in body
• what are glands + hormones?

  - glands = organs in the body that regulate chemicals including hormones (eg. pituitary gland - brain/ thyroid - neck/ adrenal glands, ovaries + testes)

  - hormones = released by the glands + float around in the bloodstream, ( targeting other organs that react to them in various ways)

  
• what is the flight or fight response?

  - HYPOTHALAMUS = danger activation:

  - causes ACUTE RESPONSE (quick) = sympathetic branch of ANS = causes adrenal glands to release ADRENALINE (as hypothalamus is stimulated) = quickens our responses + helps us survive

  
  

  -OR causes CHRONIC RESPONSE (slow) = pituitary gland links to circulatory system = causes adrenal glands to release CORTISOL (stress hormone) = keeps body in state of alertness by constantly burning/ using energy = depletes immune system

  
• what are the types of neurones?

  - sensory neurone = carry messages from PNS to CNS

  - relay neurone = connect sensory neurones to motor or other relay neurones

  - motor neurone = connect CNS to effectors such as muscles and glands

  (parts of neurones = myelin sheath/ nodes of ranvier/ cell body/ axon/ dendrites/ terminal buttons

  
• describe neurones


  - cell body includes a nucleus containing genetic material

  - branch like structures called DENDRITES protrude from cell body - carry nerve impulse towards cell body

  - AXON carries impulses away from cell body down length of neurone

  - axon covered in fatty layer of MYELIN SHEATH that protects it + speeds up electrical transmission of impulse

  - lots of tiny gaps in myelin sheath called NODES OF RANVIER so electrical impulse is sped up by forcing it to 'jump' across gaps

  - TERMINAL BUTTONS at end of axon that communicate w/ the next neurone by firing neurotransmitters into the gap
• what is neural transmission?

  - neurons communicate w/ each other within groups (NEURAL NETWORKS)

  - each neurone separated by SYNAPSE (tiny gaps)

  - signals within neurons transmitted electrically

  - signals between neurons transmitted chemically across synapse

  - when electrical impulse reaches end of neurone (PRESYNAPTIC TERMINAL), triggers release of NEUROTRANSMITTER from sacs called SYNAPTIC VESICLES

  
• parts of neuron - neural transmission

  - axon

  - synaptic vesicle

  - presynaptic terminal

  - neurotransmitter

  - synapse

  - postsynaptic terminal

  
• what is excitation?


  - neurotransmitter has an EXCITATORY effect on neighbouring neuron

  - eg. adrenaline causes excitation in post-synaptic neurone by INCREASING ITS POSITIVE CHARGE + making it MORE LIKELY TO FIRE (eg. dopamine + adrenaline +ve charge so 'excite' NS)
• what is inhibition?


  - neurotransmitter has an INHIBITORY effect on neighbouring neuron

  - eg. serotonin causes inhibition in post-synaptic neuron, resulting in neuron becoming MORE NEGATIVELY CHARGED + so LESS LIKELY TO FIRE (eg. serotonin + GABA -ve charge so calm down NS)
• what is summation?


  - excitatory and inhibitory influences are summed

  - if NET EFFECT is INHIBITORY then the postsynaptic neurone is LESS LIKELY TO FIRE

  - if NET EFFECT is EXCITATORY then postsynaptic neurone is MORE LIKELY TO FIRE (inside of neurone becomes momentarily positive)
• what is localisation of function?

  theory that different areas of the brain are responsible for different behaviours, processes or activities

  (before was thought all parts of brain involved in processing thought + action)
• what are the regions/lobes of the brain and what are they responsible for?

  - frontal lobe (decision making)

  - parietal lobe (integrates senses + perception)

  - occipital lobe (visual processing + mapping)

  - temporal lobe (auditory info)

  (- cerebellum (balance + movement))

  (- brain stem)

  
• what are further areas of the brain?

  - Brocas area (frontal lobe - left side)

  - motor cortex (between frontal + parietal)

  - somatosensory cortex (between frontal + parietal)

  - auditory cortex (temporal)

  - Wernicke's area (temporal)

  - visual cortex (occipital)

  
• what is the function of the motor area of the brain?


  a region of the frontal lobe involved in regulating movement

  
• what is the function of the somatosensory area of the brain?

  an area of the parietal lobe that processes sensory information such as touch

  
• what is the function of the visual area of the brain?

  a part of the occipital lobe that recieves + processes visual info

  
• what is the function of the auditory area of the brain?

  located in the temporal lobe + concerned w/ analysis of speech-based info

  
• what areas of the brain are associated with language?

  - BROCA'S AREA = frontal lobe, left hemisphere, responsible for SPEECH PRODUCTION

  - WERNICKE'S AREA = temporal lobe, left hemisphere, responsible for LANGUAGE COMPREHENSION

  
• what does damage to Broca's area cause?

  - BROCA'S APHASIA

  - characterised by: speech that's slow, laborious + lacking in fluency

  (- can still understand meaning of words)

  
• what does damage to Wernicke's area cause?


  - WERNICKE'S APHASIA

  - characterised by: producing nonsense words (neologisms)

  (- do not understand meaning of words)

  
• what are the strengths/ supporting evidence of the localisation to function theory?

  - EVIDENCE FROM NEUROIMAGINING = TULVING et al LTM study - found semantic + episodic memories in diff. parts of pre-frontal cortex (suggests S + E LTM localised to PFC - s = left PFC/ e = right PFC)

  - NEUROSURGICAL EVIDENCE = DOUGHERTY et al - 44 OCD patients who had CINGULOTOMY (leisioning of cingulate gyrus), 32wks after surgey = 1/3 had succefull response to surgery + 14% had partially succesfull respinse (suggests OCD symptoms localised to cingulate gyrus - as improved by surgery)

  - CASE STUDIES = PHINEASE GAGE (rod through frontal lobe) - personality change (inc. aggression), but fine w/ everything else (eg. talking, memory, etc) - suggests localisation of personality to 1 area + other areas being fine so in other area)/ (CLIVE WEARING + KF - eg. from memory topic)
• what are the weaknesses of the localisation to function theory?

  - LASHLEY'S RATS = removed areas (10-50%) of cortex in rats learning a maze, no area proven more important in ability to learn maze (learning require every part of cortex) = suggests higher cog. funtions (eg. learning) not localised, but distributed hollistically as too complex + require whole brain involvement

  - ISSUE OF PLASTICITY = when brain damaged + particular function compromised/lost, brain can reorginise itself to recover lost function (law of equipotentiality) (eg. stroke patients recovering lost abilities) = contradicts localisation theory, as compensation of diff. parts suggests same funtion can occur in diff. parts of brain (more hollistic)

  - ISSUE OF FREE WILL = scans of psychopath criminals, have low levels of activity in orbital cortex (central), which regulates emotions, morality, aggression. study of ppl w/ antisocial personality disorder had average 18% reduction in vol. of middle frontal gyrus = localisation theory suggests don't have free will to change behaviour (issues of punishment + blame) as other areas of brain can't compensate for lower activity
• what is the law of equipotentiality (plasciticty of brain)?


  - surviving brain circuits 'chip in' so the same neurological action can be acheived

  ('chip in' to help w/ damaged part of brain)
• what is brain plasticity?

  - brain's tendency to change + adapt (functionally + physically) as result of new experience + learning

  - more plastic in infancy - brain experiences rapid growth of synaptic neurones (approx. 15,000 at 2/3yrs) (2x as many connections as adult brain)

  - synaptic pruning
• what is synaptic pruning?

  - as we age, RARELY used connections are DELETED/ FREQUENTLY used connections are STRENGTHENED
• what is the supporting research of brain plasticity?

  MAGUIRE ET AL:

  - studied brains of LONDON TAXI DRIVERS

  - found significantly more volume of GREY MATTER IN POSTERIOR HIPPOCAMPUS (than controls)

  - p.hippocampus = associated w/ development of SPATIAL + NAVIGATIONAL SKILLS

  - studying for test 'The Knowledge' alters taxi drivers brain structures

  - also pos. correlation - length of time in job + more pronounced structual diffs.
• how does the taxi driver study support the theory of plasticity? (maguire et al)

  - because their breains have changed (inc. grey matter in hippocampus) compared to controls, this is as a result of new experience
• what are the limitations of the taxi driver study? (maguire et al) (theory of plasticity)

  BIOLOGICALLY REDUCTIONIST

  - only examines a single biological factor (size of hippocampus) in relation to spatial memory

  - doesnt account for other cognitive bio. processes invloved in spatial memory
• what is functional recovery?

  - a form of plasticity

  - following DAMAGE through TRAUMA = brains ability to REDISTRIBUTE/ TRANSFER FUCNTIONS usually performed by damaged area(s) to other undamaged area(s)

  (trauma = eg. stroke/ physical trauma)

  - suggested this process can occur QUICKLY AFTER TRAUMA (spontaneous recovery), then slow down after several wks/months (+ then rehab required)
• what happens to the brain during recovery? (functional recovery)


  - SECONDARY NEURAL PATHWAYS not typically used to carry out certain functions r ACTIVATED/'UNMASKED' so functioning can continue (often same way as before)

  - process supported by 3 changed in brain:

  1. AXONAL SPROUTING = growth of new nerve endings, connect w/ other undamaged nerve cells, form neuronal pathways

  2. REFORMATION OF BLOOD VESSELS

  3. RECRUITMENT OF HOMOLOGOUS AREAS ON OPP. SIDE OF BRAIN (eg. if Broca's area damaged, right side would carry out its function)
• how does age affect plasticity/ functional recovery of brain? (evaluation)

  - possible functional recovery can deteriorate w/ age

  - ELBERT ET AL = capacity for neural reorganisation much greater in children than adults (neural regeneration less effective in older brains)

  - THEREFORE = must consider INDIVIDUAL DIFFERENCES when assessing LIKELIHOOD OF FUNCTIONAL RECOVERY in brain after trauma
• what is research against functional recovery/ plasticity deterorating w/ age?

  BEZZOLA ET AL:

  - showed that 40hrs of golf training produced changes in neural representation of movement in ps age 40-60

  - using fMRI - observed reduced motor cortex acitivty in novice golfers (compared to controls)

  - suggests there were more efficient neural representations after training showing neural plasticity does continue through lifespan/ adulthood
• what are the strengths of the plasticity of the brain?

  PRACTICAL APPLICATIONS

  - understanding process of plasticity has contributed to NEUROREHABILITATION

  - cause spontaneous recovery of brain after injury/illness slows down after some wks - physical therapy required to maintain improvements in functioning

  - TECHNIQUES FOR IMPROVEMENT = MOVEMENT THERAPY + ELECTRICAL STIMULATION OF BRAIN

  - these counter deficits in motor/cognitive functioning

  - shows that although brain has capacity to 'fix itself' to a point, it requires further intervention to be completely successfull

  - MEANS MORE BRAIN INJURY PATIENTS WILL RECOVER CAUSE THEY ARE GIVEN FURTHER INTERVENTION TO STIMULATE FUNCTIONAL RECOVERY

  (- evidence for plasticity - phantom limb + recovery of language (eg. after stroke) highlights that other areas of brain can accommodate for lost functions - so brain is plastic)
• what are the negatives/ negative effects of the plasticity of the brain?

  NEGATIVE PLASTICITY/ PHANTOM LIMB

  - instances of neg. plasticity where brain rewires itself leading to MALADAPTIVE BEHAVIOURAL CONSEQUENCES

  - 60-80% of AMPUTEES experience PHANTOM LIMB syndrome

  - thought to be due to CORTICAL REORGANISATION in SOMATOSENSORY CORTEX that occurs as result of limb loss

  
  

  (+ limits to plasticity = localisation of function is well researched - some degree of flexibility/plasticity possible, but not loads/ plasticity limited by age - less plastic when older)