The brain consists of the hindbrain, the midbrain, the forebrain, and the cerebral cortex with the following regions and functions:

  • Hindbrain
    • Medulla: involuntary functions (breathing, heart rate, blood pressure), sensitive to damage (damage can lead to death)
    • Cerebellum: motor functions, balance, damage causes ataxia
  • Midbrain
    • Ascending Reticular Activation System: active during sleep, filters sounds (unfamiliar sounds = waking up)
    • Hypothalamus: hunger, thirst, sex, sleep, emotions, homeostasis, emotions converted into physiological responses
      • Superchiasmatic nucleus: circadian and seasonal cycles
      • Mammillary bodies: memory
    • Thalamus: relay station for all senses except smell, damage causes Korsakoff Syndrome (long-term alcohol use, symptoms: anterograde amnesia, retrograde amnesia, and confabulation)
    • Basal Ganglia: coordination, damage related to Huntington’s, Parkinson’s, Tourette’s, OCD, Schizophrenia, and ADHD
      • Caudate Nucleus
      • Putamen
      • Globus Pallius
  • Forebrain
    • The Limbic System
      • Amygdala: attach emotion to memory, emotional reactivity, problems lead to Kluver-Bucy Syndrome (reduced emotional responses), damage can lead to problems in emotional responses (esp fear)
      • Hippocampus: consolidation of short-term memory to long-term, sexual dimorphism, PTSD and Depression
  • Cerebral Cortex
    • Frontal Lobe: primary motor cortex, prefrontal cortex, damage leads to loss of reflex, executive functioning, cognitive functioning, personality and emotional changes (Phineas Gage)
      • Broca’s area: expressive language
    • Parietal Lobe: somatosensory cortex, pressure, temperature. Damage can cause: contralateral neglect, apraxia, tactile agnosia, asomatognosia, anosognosia, Gerstmann’s Syndrome (left parietal damage, acalculia, agraphia, finger agnosia, inability to distinguish from left to right)
    • Temporal Lobe: auditory cortex, sensation, perception. Damage can lead to auditory agnosia and hallucinations, impaired declarative memory
      • Wernicke’s area: understanding and comprehension of speech
    • Occipital Lobe: primary visual cortex, sensation, perception related to vision. Damage can lead to prosopagnosia, visual agnosia, color agnosia, cortical blindness.

Brain has two hemispheres: left and right. Left is primary for language, logic, memory, and positive emotions. Right is primary for visual-spatial, creativity, and negative emotions. Except for smell, every sense goes in the opposite side (e.g. left eye to right hemisphere). Split-brain patients have their Corpus Callosum severed (it connects the two hemispheres), so two sides are functioning independently.