Thalamus and Hypothalamus

Thalamus and Hypothalamus

1. Parts of the Hypothalamus

   • Optic Chiasma
   • tuber cinereum
   • mamillary bodies

2. DIENCEPHALON

   • SUBTHALAMUS
     • BET. THALAMUS AND MIDBRAIN TEGMENTUM
   • Epithalamus
     • Pineal Gland
     • Habernacular Nuclei

3. THALAMUS

   • Connected by massa intermedia
     • Separation: Hypothalamic sulcus
       • superior surface covered: stratum zonale
         • External/Internal medullary lamina
   • Boundaries
     • Superior: tela choroidea
       • Inferior: hypothalamic sulcus
       • Anterior: Interventricular foramen
         • Posterior: Pulvinar
           • Laterial: Internal capsule
             • Medial : interthalamic adhesion
   • Anterior
     • limbic system, mammillothalamic nuclei, emotion, recent memory
       • mammillothalamic tract,cingulate gyrus
   • Medial
     • sensory information, abstract thinking, prefrontal cortex
       • hypothalamus, amygdala, dorsomedial nucleus
   • Lateral
     • interconnections: nuclei, parietal lobe, cingulate gyrus, occipital/temporal lobes
       • lateral dorsal, lateral posterior, pulvinar
         • lateral dorsal nucleus: extension of anterior nuclei, receives from mamillothalamic input
           • lateral posterior nucleus: areas 5 and 7, cxn with superior parietal cortex
             • Pulvinar: LARGEST, integration of input, association cortex connection with O,PAR,POST TEMP Lobes
       • Ventral Anterior, Ventral Lateral, Ventral Posterior
         • Ventral Anterior: cxn reticular information, substantia nigra, corpus striatum, motor cortex influence
           • Ventral Lateral: similar ^ , motor activity
             • Ventral Posterior:
               • VPM: gustatory pathway,
               • VPL: ascending, impt sensory tracts
   • Intralaminar Nuclei
     • influence of levels of concsciousness, alertness, pain perception
       • send efferent fibers/receive afferent
   • Midline Nuclei
     • receive from reticular formation, unknown fxn
   • Reticular Nucleus
     • converge pt of afferent fibers from cerebral cortex, output to other thalamic nuclei
   • Medial Geniculate Body
     • beneath pulvinar, receive auditory info,
       • Auditory Radiation: auditory cortex -> superior temporal gyrus
   • Lateral Geniculate Body
     • swelling under Pulvinar, receive visual info from opposite side, Visual Radiation: Visual cortex -> occipital lobe
   • FUNCTIONS
     • Receives all sensory info except olfactory from the body
       • Voluntary Motor Activity (Basal Ganglia)
         • Limbic System: mood, emotions, memory
   • Lesions
     • Thalamic Pain: loss sensation > burning
       • Thalamic syndrome: hemianesthesia (loss of feelings 1 side, loss of pain and temp perception on the other side), hemiparesis, spontaneous pain

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