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The thalamus


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Connections & Subdivisions of the thalamus

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Connections of the thalamus


1) Every thalamic nucleus (Except for reticular nucleus) sends axons to specific part of the cerebral cortex

2) Every part of the cerebral cortex sends reciprocal fibers back to the thalamic nuclei

3) Thalamus is an important station for 2 sensory – motor axonal loops involving cerebellum & basal nuclei (Important for voluntary movements)

1. Cerebellar – Rubro – Thalamic – Cortical – Ponto – Cerebellar loop
2. Cortico striatal – pallidal – thalamic – cortical loop



Thalamic nuclei, their connections & functions





Part of the thalamus
Nuclei
Connections
Functions
Anterior part Anterior thalamic nuclei
  1. Mammillo – thalamic tract
  2. Hypothalamus
  3. Cingulate gyrus   
Emotional tone
Mechanism of recent memory
Medial part Dorso – medial
  1. Prefrontal cortex
  2. Hypothalamus
Integration of somatic, visceral & olfactory information and relate those information to one’s emotional feelings & subjective states
Lateral part Dorsal tier
  1. Lateral dorsal
  2. Lateral posterior
  3. Pulvinar 
Cerebra cortex

Unknown
Ventral tier
1.Ventralanterior
  1. RF
  2. Substantia nigra
  3. Corpus striatum
  4. Premotor cortex 


Influence the activities of the motor cortex
2.Ventral lateral 
  1. Cerebellum
  2. Red nuclei
  3. RF
  4. Substantia nigra
  5. Corpus striatum
  6. Premotor cortex 
3. VP Medial
  1. Trigeminal lemnisci
  2. Gustatory fibers
  3. Efferent – 1stry somatic sensory cortex (3, 2 & 1)

Relays common sensations to consciousness
4. VP Lateral
  1. Medial & spinal lemnisci
  2. Efferent – 1stry somatic sensory cortex (3, 2 & 1)
Other nuclei 1. Intra laminar
  1. RF
  2. Spino – thalamic tract
  3. Trigemino – thalamic tract
Influence the level of alertness & consciousness
2.Midline
RF
Unknown
3. Reticular
4. Medial geniculate body
  1. Inferior colliculus
  2. Lateral lemnisci from both ears (Predominantly from the contra lateral ear)
  3. Efferent – Auditory radiation to superior temporal gyrus

Hearing
5.Lateral geniculate body
  1. Optic tract
  2. Efferent – Optic radiation to visual cortex of the occipital lobe
Visual information from the opposite visual field
The thalamus The thalamus Reviewed by Radiology Madeeasy on August 05, 2010 Rating: 5
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