II. Definitions

  1. Thalamus
    1. Functions as a central hub for incoming sensory signals relayed to the cerebral cortex
    2. Motor interconnections between the Cerebellum, cerebral cortex and target peripheral Neurons
    3. Thalamus functionality is divided among its 9 thalamic nucleii

III. Anatomy

  1. General
    1. Paired sensory relays
    2. Located in the posterior Diencephalon of the brain
    3. Thalamus located on each side of Third Ventricle
  2. Nucleii
    1. Ventral Posterolateral Nucleus (VPL)
      1. Spinal sensory Neurons from the periphery Synapse
    2. Ventral Posteromedial Nucleus (VPM)
      1. Trigeminal LemniscusSynapse
    3. Anterior Thalamic Nucleus
      1. Portion of the Papez Circuit
    4. Ventral Lateral Nucleus (VL)
      1. Cerebellum input
  3. Images
    1. neuroThalamus.png
    2. neuroBrainXsGrayBB717.gifLewis (1918) Gray's Anatomy 20th ed (in public domain at Yahoo or BartleBy)
    3. neuroBrainXsGrayBB716.gifLewis (1918) Gray's Anatomy 20th ed (in public domain at Yahoo or BartleBy)

IV. Physiology

  1. Thalamus acts as a relay and integrative center for sensory input
  2. Receives peripheral sensory signals through the Brainstem
  3. Communicates with the Cerebellum, Basal Ganglia and Hypothalamus
  4. Transmits sensory signals to the cerebral cortex
    1. Motor signsal from the cerebral cortex bypass the Thalamus via the Internal Capsule

V. Signs: Brain Lesion

  1. Contralateral sensory loss
  2. Behavioral changes
  3. Language disorder

VI. References

  1. Netter (1997) Atlas Human Anatomy, ICON Learning, p. 105
  2. Newton (1994) Am Fam Physician 49(4): 787-97 [PubMed]

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