Biopsychology

• CNS


  Central nervous system, consists of brain and spinal cord, control of behaviour and regulation of the body's physiological processes
• Brain


  • Receives info from sensory receptors e.g. eyes or skin
  • Sends info to muscles and glands via spinal cord - nerve cells
• PNS consists of


  • SNS - Somatic nervous system
  • ANS - Automatic nervous system
• SNS


  Relays sensory messages to CNS using sensory neurones, CNS to other parts of body - motor neurones, reflex actions - without CNS - quick reflex
• ANS


  Regulates involuntary bodily functions like heartbeat, digestion, and breathing, consists of two divisions: sympathetic and parasympathetic
• Sympathetic division


  Prepares the body for action
• Parasympathetic division


  Promotes relaxation and rest
• Fight or flight response

  1. Stressor activates hypothalamus

  2. Activates ANS

  3. Nerves from ANS to internal organs and glands

  4. ANS causes adrenal medulla to release adrenaline and noradrenaline into blood

  5. Hormones create changes in body preparing for fight or flight

  6. After threat disappears parasympathetic restores to calm state (rest and digest)
• Localisation of function in the brain

  • Specific areas of the brain associated with specific cognitive processes
  • Brain is divided in two hemispheres - right and left (responsible for different functions)
  • Lateralisation - dominance of one particular physical and psychological characteristic
• Language


  Left hemisphere - Broca's area converts thoughts to speech, Wernicke's area - understanding speech and producing coherent speech
• Parts of the brain

  • Central core - regulates primitive and involuntary behaviours
  • Limbic system - controls emotions
  • Cerebrum - regulates higher intellectual processes
• 4 lobes of the cerebrum

  • Parietal - location of sensory and motor neurones
  • Frontal - location for awareness of environment - consciousness
  • Occipital - location for vision
  • Temporal - auditory ability and memory acquisition
• Plasticity


  Brain's ability to change and adapt to experiences, how experience reorganizes neural pathways in the brain
• Supporting evidence for plasticity

  • Maguire taxi drivers 2000 - higher volume in right posterior hippocampus of taxi drivers
  • Blakemore's cats 1973 - kittens raised in dark room, horizontal or vertical lines
  • Boyke's jugglers 2008
  • Tajiiri's rats 2013 - stem cell transplant in brain after injury
• Hemispheric lateralisation and split brain research

  Certain mental processes and behaviours controlled or dominated in one hemisphere, commissurotomy - severing of corpus callosum - treats epilepsy
• Biological rhythms


  Circadian - 24hr, Ultradian - more every than 24hrs, Infradian - occur less that every 24 hr
• Endogenous pacemakers


  Internal body clocks that regulate biological rhythms
• Exogenous zeitgebers


  External cues that influence biological rhythms
• Circadian rhythms


  1. Circadian clock located in suprachiasmatic nucleus (SCN) in hypothalamus

  2. Sends signals to brain to regulate daily sleep wake cycle, body temp, hormones etc

  3. Melatonin produced in pineal gland causes drowsiness, cortisol in adrenal gland makes us feel more awake

  4. Sleep/wake cycle works in sync with body temp
• Supporting studies for circadian rhythms

  • Siffre - lived in cave for 2 months, body clock became 25 hrs
  • Aschoff and Wever 1976 - deprived of natural light for 4 weeks, all participants except 1 displayed circadian rhythm between 24-25hrs
• Infradian rhythms


  E.g. menstrual cycle - monthly changes in hormone levels
• Ultradian rhythms


  Stages of sleep cycle - five distinct lasting 90mins total
• EP and sleep wake cycle

  1. SCN in hypothalamus - master clock, synchronises and coordinates signals alongside peripheral clocks

  2. SCN info from optic nerve on light to synchronise internal clock according to outside world

  3. SCN sends signals to pineal gland to increase melatonin at night to induce sleep
• Supporting studies for EP and sleep wake cycle

  • Decoursey et al - destroyed SCN in chipmunks, sleep wake cycle disrupted
  • Campbell and Murphy - light receptors on skin at back of knees produced deviation of sleep wake cycle
• EZ and sleep wake cycle

  Environmental events resetting bio clock - light, social cues e.g. mealtimes and activities
• Ways of studying the brain

  • CAT
  • PET
  • MRI
  • fMRI
  • EEG
  • ERP
  • Post-mortem dissection
• EEG and ERP


  Record brain activity via electrodes
• Post-mortem dissection


  Compare brains of those with trauma or mental illness to neurotypical ones
• ERP


  Records brain response to repeated stimuli, contributing to understanding of cognitive processes
• Post-mortem dissection


  Has been key in identifying areas like Broca's for speech production
• Limitations of brain study methods

  High cost of fMRI, moderate accuracy of EEG and ERP, and inability of post-mortem dissection to measure live brain activity
• Synaptic transmission


  1. Electrical impulse arrives at the end of the axon on the presynaptic neurone

  2. Chemical messengers (neurotransmitters) are released from vesicles at the presynaptic membrane

  3. Neurotransmitters diffuse across the synaptic cleft

  4. Neurotransmitters temporarily bind with receptor molecules on the postsynaptic membrane

  5. Postsynaptic neurone generates an electrical impulse that travels down the axon

  6. Neurotransmitters are destroyed or recycled to prevent continued stimulation of the second neurone
• hemispheric laterilisation


  certain mental processes and bvrs controlled or dominated in one hemisphere
• Sperry Study method

  Used a tachistoscope to present images to either the right or left visual field
• Sperry Results

  • Images presented in one visual field were recognized in that field but not if shown in the other field
  • Patients could not name objects presented in the left visual field but could pick them up with their left hand
  • When two objects were shown, patients could draw the object in the right visual field but could only report the object in the right field
• split brain AO3

  • very small sample size and all corpus callosum severed not generalisbale and not generalisable to person with severed yet two eyes
  • highly specualised and standardised procedures increase reliability
  • h/ not controlled how sever epilepsy was and if taken drugs so do not know if effects findings
  • led to further research on laterilization - applicability
  • high int validity e/g control of image flasjing 0.1sec every time
  • low ext validity - artificial stimuli
• endocrine system

  • secretes hormons required to regulate bodily functions
  • chemical system of communication via bloodstream
  • works alongside NS
  • H/ can be slow compared to NS, chemical is in blood - may takes years to complete response e.g growth, development
• localisation AO3 - brain scan evidence

  • peterson 1988 - brain scans to demonstrate how Wernicke's area active during listening task and Brocas area active during reading task
  • tulving et al 1994 - study of ltm found semantic and episodic meomories reside in diff parts of prefontal cortex
• localisation AO3 - neurosurgical evidence

  • lobotomy - removal of brain tissue
  • leucotomy - cutting connections of particular part of brain
  • neurosurgery still used today to treat OCD and depression in extreme cases - this evidence siggests symptoms and bvr associates is localised
• Localisation A03 - case study

  • GAGE CASE STUDY
  • metal rod through head still conscious - left cheek to skull - prefontal cortex damaged
  • personality change after accident rude and boisterous
  • psychological process in brain
  • case study - not generalisable uncommon experience