Neuroanatomy Quiz

Genetics

• Mutation-selection balance: 2-3 new deleterious coding mutations per person, 500-2000 old slightly deleterious coding mutations per person
• Epigenetics: Environment can change structure and function of genes and whether they are expressed or not
• Challenges in finding genes:
  • Heterogeneity (different genes may be important in different families, gene pools)
  • Many genes involved, each with small effect
  • Some genes may depend on environmental stressors to be expressed
  • Unaffected relatives may have some degree of genotypic risk
• Take home points on GENETICS:
  • Mental disorders are moderately to highly heritable
  • Mode of transmission is complex, involving many genes of small effect
  • Genes confer not mental disorders directly, but rather disturbances in brain structure and function that make one susceptible to their symptoms
  • Multidimensional, comprehensive approach puts us in the best position to understand the causes of psychopathology and alleviate and prevent psychopathology

Neuroanatomy

• Genotype vs phenotype:
  • Genotype: genetic information (alleles in specific locations)
  • Phenotype: resulting traits that can be observed
  • Genotype codes for phenotype
• Endophenotype: an intermediate phenotype, something that can be observed and measured that falls between the gene and disorder
• Central Nervous System (CNS):
  • Command and control center that governs perception, thoughts, feelings, memories, decisions, and behavior
  • Consists of brain and spinal cord
• Peripheral Nervous System (PNS):
  • Relays sensory information about the world to the CNS
  • Carries commands from the CNS to muscles and organs
  • Consists of cranial nerves, spinal nerves, and autonomic nervous system

Brain Structure and Function

• Brain vasculature:
  • Like all body organs, the brain has a blood supply
  • Stroke: brain damage caused by a restriction of blood to the brain by a burst or weak blood vessel or by a blockage
• Blood-Brain Barrier (BBB):
  • Restrictive barrier between the CNS and circulatory system
  • Prevents many molecules from entering the brain through the bloodstream
• Meninges:
  • Meningitis: inflammation of the meninges, usually caused by bacterial or viral infection
• Cerebrospinal fluid (CSF):
  • Circulates very slowly through the brain's ventricular system (fluid-filled spaces around and within the brain)
  • Produced by tissue within the ventricles and subarachnoid space (about 500ml/day)

Brain Regions

• Brainstem:
  • All connections to the rest of the body pass through
  • Key role in regulation of cardiac, respiratory, and skeletal muscle tone and very basic functions like breathing and sleeping
• Cerebellum:
  • Helps generate smooth, coordinated movement
  • Integrates visual, motor, vestibular (balance), and somatosensory info
• Midbrain:
  • Dopamine system is involved in addiction, schizophrenia, and Parkinson’s disease
• Hypothalamus:
  • Controls a number of different drives, including sleep, hunger, thirst, sex, sleep/wake cycle
  • Controls hormone release by pituitary
• Thalamus:
  • "Gateway to the cortex", all information passes through the thalamus
• Limbic System:
  • Hippocampus (seahorse)
  • Amygdala (almond)
  • Cingulate cortex
  • Anterior thalamus
  • Mammillary bodies
  • Function: memory and emotions, important in psychopathology
• Hippocampus:
  • Memory
  • Spatial memory and navigation
  • Vulnerable – hypoxia and stress
• Amygdala:
  • Emotion – fear ; emotional memory
• Basal Ganglia:
  • Caudate nucleus and putamen
  • Important for action selection and motor control
  • Highly dopaminergic, related to schizophrenia, substance abuse