neuro

• Wernicke area


  • Region of the brain that contains motor neurons involved in the comprehension of speech. The Wernicke area is located in the posterior third of the upper temporal convolution of the left hemisphere of the brain. Involved in the understanding of spoken and written language. (temporal lobe)
• Hypothalamus


  • Controls autonomic nervous system (e.g., blood pressure, rate and force of heartbeat, digestive tract motility, pupil size), Physical responses to emotions (limbic system), Perception of pleasure, fear, and rage, and in biological rhythms and drives, Regulates body temperature – sweating/shivering, Regulates hunger and satiety in response to nutrient blood levels or hormones, Regulates water balance and thirst, Regulates sleep-wake cycles( Suprachiasmatic nucleus (biological clock)), Controls endocrine system( Controls secretions of anterior pituitary gland, Produces posterior pituitary hormones)
• Critical Periods

  Time when experience and neural activity that reflects that experience have maximal effect on the acquisition or skilled execution of a particular behavior
• Basic Properties of Critical Periods

  • Time during which a given behavior requires specific environmental influences in order to develop normally
  • Once a critical period ends, the core features of a behavior are largely unaffected by subsequent experience
  • If not exposed to appropriate stimuli during the critical period it is difficult or impossible to remedy
• In most mammals, including humans, critical periods rely particularly on changes in organization and function of circuits in the cerebral cortex
• Gray matter grows throughout the cortex during early life; declines in adolescence
• Undamaged brain regions become reorganized to support functions that were disrupted due to the injury
• Regrowth of axons: peripheral ganglia or peripherally projecting axons

  1. Requires reactivation of the developmental processes for axon growth and guidance and initial synapse formation

  2. Seen primarily when sensory or motor nerves are damaged in the periphery; nerve cell bodies are intact

  3. Peripheral nerve regeneration is the most easily accomplished type of repair in the nervous system and the most clinically successful
• Generation of New Neurons (replace those that have been lost)

  1. Adult neuronal genesis occurs rarely

  2. Retention of a population of neural stem cells able to give rise to all cell types in the brain region that has been damaged

  3. Neural stem cells must be present in a "niche" that provides the appropriate environment for genesis and differentiation of new neurons and glia

  4. Regenerating tissue must retain the capacity to recapitulate migration, outgrowth of processes, and synapse formation to form local and distant functional networks
• Schwann cells

  • Glial cells that myelinate peripheral axons
• Macrophages

  • Immune cells that clear the degenerating remains of of severed axons
• Three ways damage occurs in the CNS

  • External physical trauma
  • Hypoxia – lack of oxygen often created by lack of blood flow (ischemia) due to stroke
  • Neurodegenerative diseases
• • Prosencephalon further divides to:
  • Telencephalon – cerebral cortex, hippocampus and basal ganglia
  • Diencephalon – thalamus and hypothalamus; optic cups – retina
• Mesencephalon – superior and inferior colliculi and midbrain tegmentum (ventral portion, substantia nigra)
• Rhombencephalon:

  • Metencephalon – cerebellum and pons
  • Myelencephalon - medulla
• Exercise


  Increases cell proliferation
• Anti-depressants


  Increase cell proliferation
• Stress


  Decreases cell proliferation in the DG
• Drugs of abuse, including opiates

  Decrease cell proliferation in the DG
• Prelimbic Cortex (PrL)


  Suppression or initiation of actions to avoid aversive events
• Dentate Gyrus (MoDG)


  Learning and memory, new neurons are produced here
• Substantia Nigra (SNR)


  Critical for dopamine production, involved in movement, dopamine neurons are lost in this area in Parkinson's disease
• periaqueductal gray (PAG)


  Involved in pain supression and perception
• Dorsal Raphe Nucleus(DR)


  Source region of serotonin
• Basolateral amygdaloid nucleus (BLA)


  Emotional regulation; fear
• Ventral Tegmental Area (VTA)


  Regulates reward system; mesolimbic and mesocortical pathways
• Nucleus Accumbens (AcbC)


  Part of reward system in addiction; interface between motivation and action