Major Divisions of the Brain

Annotations:

• -Largest division -Complex functions (purposeful behaviour, language, perception) -Produces and inhibits emotions

1. Cerebral Cortex (Cortical)

   Annotations:

   • -Convolutions to +surface area -Longitudinal fissure: separates hemispheres -Corpus callosum: connects hemispheres -Central fissure (horizontal) and Lateral fissure: separate 4 lobes -Gyri: small ridges/protrusions
   1. Frontal Lobe

      Annotations:

      • -Executive planning -Complex cognition -Motor control -Emotion inhibition
      1. Precentral Gyrus (motor strip)

         Annotations:

         • -Controls motor movements, speech sounds, etc.
      2. Prefrontal Cortical Regions

         Annotations:

         • -Complex cognition (planning, evaluating, assessing behav. of others, inhibition of inappropriate behav.) -"Ego" and "Superego" -Damaged by continuous drinking (Korsokoff's syndrome - no inhibition)
   2. Occipital Lobe

      Annotations:

      • -Vision
      1. Visual Cortex

         Annotations:

         • -Divided by calcerine sulcus -Very back of brain -Processes visual info
   3. Parietal Lobe

      Annotations:

      • -Proprioceptive functions (info about position of body relative to environment)
      1. Post-Central Gyrus

         Annotations:

         • -Analysing sensations from body
   4. Temporal Lobe

      Annotations:

      • -Emotions (fear and aggression) -Epilepsy
      1. Superior Temporal Gyrus

         Annotations:

         • -Hearing/auditory perception -Language comprehension
         1. Inferior Temporal Gyrus

            Annotations:

            • -Complex visual patterns
         2. Medial Temporal Gyrus

            Annotations:

            • -Encoding certain memories
2. Limbic System (Subcortical)

   Annotations:

   • -Motivated behaviours (4 F's)
   1. Amygdala

      Annotations:

      • -Anterior temporal lobe -Produces emotions (fear & aggression) -Conditioned fear learning & fear expression (damage = inability to express/detect normal fear)
      1. Lateral Nuclei
      2. Basal Nuclei
      3. Central Nuclei
   2. Hippocampus

      Annotations:

      • -Medial temporal lobe -Transfers short-term memories to declarative & explicit long-term memories (ex/ patient HM not forming new explicit memories after hippocampus removal) -Korsakoff's Syndrome: drinking damages hippocampus and leads to memory problems -Contextual fear learning -Spatial cue memory
   3. Fornix
   4. Cingulate Cortex
   5. Septum

      Annotations:

      • -Midline nucleus near cingulate cortex -Fibres connect it to amygdala, hippocampus, & hypothalamus -Aggression, rage, anxiety, stress, Alzheimer's
   6. Mammillary Bodies
3. Basal Ganglia (Subcortical)

   Annotations:

   • -Modulates motor output -Fine motor control -Planned & purposeful movements -Cognitive functions (Projects to cortical areas)
   1. Amygdala

      Annotations:

      • -Works with nucleus accumbens to produce motivational behav.
   2. Striatum

      Annotations:

      • -Caudate + putamen (they appear striped) -Linked to substantia niagra (SN) in a dopamine pathway (deterioration leads to Parkinson's)
      1. Putamen

         Annotations:

         • -Centre of caudate (connected by fibre bridges)
      2. Caudate

         Annotations:

         • -C-shaped -includes the putamen
      3. Nucleuss Accumbens

         Annotations:

         • -Rewarding behaviours (drugs, food, etc) -Receives dopamine input from VTA and amygdala
         1. Shell
         2. Core
   3. Globus Pallidus

      Annotations:

      • -Medial to putamen -Pale & circular -Linked to SN in dopamine pathway

1. Midbrain
2. Tectum

   Annotations:

   • -The "roof"
   1. Inferior Colliculi

      Annotations:

      • -Receives & processes auditory info
   2. Superior Colliculi

      Annotations:

      • -Processes visual info
3. Tegmentum

   Annotations:

   • -Ventral to tectum
   1. Periaquiductal Gray (PAG)

      Annotations:

      • -Opioid receptors mediate pain -Where morphine binds to; mediates bain via descending pathways -Emotionality & fear expression (circa-strike attacks & aggression, fear-induced defensive freezing)
   2. Substantial Niagra (SN)

      Annotations:

      • -Important in sensorimotor system -Loss of dopamine-producing neurons leads to Parkinson's
      1. Nigro-Striatal Dopamine Pathway
   3. Ventral Tegmental Area (VTA)

      Annotations:

      • -Projects to cortical & limbic regions -Connects with accumbens to produce rewarding effects & addictive behaviours
      1. Mesocortico-limbic Dopamine Pathway

         Annotations:

         • -Stress & conditioned stress behavioural responses -Stressor = +dopamine to mPFC = disrupts cognition & planning -Overactive DA pathways may be linked to schizophrenia/paranoid behaviours
   4. Reticular Formation (anterior aspects)
   5. Red Nucleus

      Annotations:

      • -Connects to cerebellum -Descending projections to brain stem & spinal cord -Posture, balance, coordinated movements

Annotations:

• -Most posterior division

1. Fibre Tracts

   Annotations:

   • -Carry signals btn rest of brain & body
2. Reticular Formation

   Annotations:

   • -Comprised of 100 sub-nuclei in core of brainstem -Sleep & attention -Movement -Muscle tone -Reflexes (heartbeat, breathing, etc)

1. Thalamus

   Annotations:

   • -Relays sensory info to cortex, limbic system, & basal ganglia (lik a switchboard)
   1. Lateral Geniculate Nucleus (LGN)

      Annotations:

      • -Relays visual info
   2. Medial Geniculate Nucleus (MGN)

      Annotations:

      • -Relays auditory info
   3. Ventral Posterior Nucleus (VPN)

      Annotations:

      • -Relays somatosensory info (touch, pressure, pain, temp)
   4. Posterior Intralaminar Nucleus (PIN) and Central Nucleus (CNT)

      Annotations:

      • -Relay nociceptive (pain) info to amygdala & parietal cortex
2. Hypothalamus

   Annotations:

   • -Regulates motivated behaviours (ex/ brain-stimulation-reward in rats) -Hormone release via pituitary and adrenal glands

1. Brainstem
2. Ascending/Descending Fibre Tracts
3. Pons

   Annotations:

   • -Regulates acoustic startle response to loud noises -Heart activity during fear/arousal
4. Cerebellum

   Annotations:

   • -Balance & coordination (sensorimotor functions)