Brain and neuropsychology

• Subdivisions of the nervous system

  • CNS and PNS
  • PNS-ANS SNS
  • ANS-sympathetic and parasympathetic
  • CNS brain and spinal cord
• The nervous system


  • Collects and responds to information
  • Coordinates organs including the brain
• Central nervous system (CNS)

  • Right hemisphere controls left side of body and vice versa
  • Brain conscious awareness and decision making
  • Brain stem autonomic functions, some reflex responses and consciousness
• Peripheral nervous system (PNS)


  • Information from outside world to CNS
  • Information from CNS to muscles
• Autonomic nervous system (ANS)


  Automatic functions, eg breathing heart sale, stress response
• Somatic nervous system (SNS)


  • Voluntary movement of muscles and reflex responses
  • Sends messages to muscles and takes in information from sensory organs
• Homeostasis


  Maintaining a balanced internal state (e.g. temperature at 37°C) by monitoring activity of the body organs
• Autonomic nervous system


  • An automatic system
  • No conscious contral because functions are vital to life, eg. heartbeat
• Sympathetic nervous system


  Physiological arousal, triggered when stressed and leads to fight or flight response
• Parasympathetic nervous system

  • Opposite to sympathetic
  • Produces rest and digest response to return body to resting state
• The fight or flight response

  1. Brain detects threat

  2. Hypothalamus identifies a threat (stressor)

  3. Sympathetic division of the ANS triggered, fight or flight

  4. Release of adrenaline

  5. ANS changes from parasympathetic rest state to aroused sympathetic state
• Once the threat has passed


  Parasympathetic division of ANS takes over 'rest and digest'
• The James-Lange theory of emotion


  • Physiological arousal first
  • Hypothalamus arouses sympathetic division of ANS
  • Adrenaline released leading to physiological arousal (fight or flight)
  • Emotion afterwards
  • Brain interprets physiological activity
  • Causes emotion, eg love, fear
• An example


  • Meet bear in forest
  • Sympathetic arousal muscles tense, heart sate increases
  • Interpret as fear
  • No physical changesso emotion
  • Speaking in front of class, no increase in heart rate means you don't experience any sense of fear
• Types of neuron


  • Sensory: From PNS to CNS. Long dendrite, short aan
  • Relay Connect sensory to motor Short dendrite, short axon
  • Motor: From CNS to muscles/glands Short dendrite, long axon
• Structure of neurons


  • Cell body: Nucleus containing DNA
  • Axon: Carries signals, covered in myelin sheath which helps and protects
  • Myelin sheath: Fatty covering of axon with gaps (nodes of Ranvier), insulation and speeds signal
  • Terminal button: End of axon, part of synapse
• Electric transmission-how neurons fire

  • Resting state: negative charge
  • When firing, the charge inside the cell changes which creates an action potential
• Synapses and chemical transmission

  • The synapse: Where neurons communicate with each other: terminal button at presynaptic neuron + synaptic cleft + receptor sites on postsynaptic neuron
  • Release of neurotransmitters: Electrical signal causes vesicles (in presynaptic terminal button) to release neurotransmitter into synaptic cleft
  • Reuptake of neurotransmitter: Neurotransmitter in synaptic cleft attaches to postsynaptic receptor sites, chemical message turns into electrical impulse, remaining neurotransmitter reabsorbed
• Excitation and inhibition


  • Excitatory neurotransmitter increases postsynaptic neuron's charge, more likely to fire
  • Inhibitory neurotransmitter increases negative charge, less likely to fire
• Summation


  More excitatory than inhibitory signals means that neuron fires, creating an electrical impulse
• The brain is plastic Hebb’s theory


  • Synaptic connections become stronger the more they are used
  • Brain can change and develop
  • Brain changes in response to new experiences, at any age
  • Learning produces an engram: Learning leaves a trace called an engram, this can be permanent if we rehearse learning
• Cell assemblies and neuronal growth

  • Groups of neurons that fire together
  • Neuronal growth occurs as cell assemblies rewire
• Hebb's theory is scientific
• Hebb's theory has real-world application to education
• Hebb's theory is reductionist, reducing learning to the neuronal level and ignoring higher levels like Piaget's idea of accommodation
• Structure of the brain

  • Two hemispheres, four lobes
  • Top layer of brain is the cerebral cortex, divided into four lobes
  • Cerebellum
• Frontal lobe


  • At front of brain
  • Controls thinking, planning and motor area controls movement
• Parietal lobe


  • Behind frontal lobe
  • Somatosensory area is where sensations are processed
• Occipital lobe


  • At back of brain
  • Controls vision
• Temporal lobe


  • Behind frontal lobe and below parietal lobe
  • Auditory (sound) area, related to speech and learning
• Cerebellum


  • Receives information from spinal cord and the brain
  • Coordinates movement and balance; attention and language too
• Localisation of function in the brain

  • Specific brain areas do particular jobs
  • Motor area: Damage to the left hemisphere affects the right side of the body, and vice versa
  • Somatosensory area: Most sensitive body parts take up most 'space', damage means less ability to feel pain
  • Visual area: Damage to left hemisphere affects right visual field of each eye, and vice versa
  • Auditory area: Damage can lead to deafness
  • Language area: Usually in left hemisphere only, Broca's area: damage leads to difficulty remembering and forming words, Wernicke's area: damage leads to difficulty understanding and producing meaningful speech
• Later research on the interpretative cortex had mixed results, it may not always respond as Penfield had concluded
• Neuropsychology


  Scientific study of the influence of brain structures on mental processes
• Cognitive neuroscience


  • Aims to create a detailed map of localised functions in the brain
  • Structure and function of the brain relates to behaviour
  • Structure and function of the brain relates to cognition
• Cognitive neuroscience and mental illness

  Low serotonin affects thinking (e.g. suicidal thoughts) and behaviour (low mood, depression)
• CT scans


  • Large doughnut-shaped scanner that rotates
  • Takes lots of X-rays of brain which are combined to give a detailed picture
• PET scan


  • Patient injected with radioactive glucose
  • Brain activity shown on computer screen
• MRI Scan


  • Measures changes in blood oxygen levels
  • Displayed as 3-D computer image