The thalamus

Connections & Subdivisions of the thalamus Connections of the thalamus 1) Every thalamic nucleus (Except for reticular nucl...

Connections & Subdivisions of the thalamus



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	Mammillo – thalamic tract Hypothalamus Cingulate gyrus	Emotional tone Mechanism of recent memory
Medial part	Dorso – medial	Prefrontal cortex Hypothalamus	Integration of somatic, visceral & olfactory information and relate those information to one’s emotional feelings & subjective states
Lateral part	Dorsal tier
	Lateral dorsal Lateral posterior Pulvinar	Cerebra cortex	Unknown
	Ventral tier
	1.Ventralanterior	RF Substantia nigra Corpus striatum Premotor cortex	Influence the activities of the motor cortex
	2.Ventral lateral	Cerebellum Red nuclei RF Substantia nigra Corpus striatum Premotor cortex
	3. VP Medial	Trigeminal lemnisci Gustatory fibers Efferent – 1stry somatic sensory cortex (3, 2 & 1)	Relays common sensations to consciousness
	4. VP Lateral	Medial & spinal lemnisci Efferent – 1stry somatic sensory cortex (3, 2 & 1)
Other nuclei	1. Intra laminar	RF Spino – thalamic tract Trigemino – thalamic tract	Influence the level of alertness & consciousness
	2.Midline	RF	Unknown
	3. Reticular
	4. Medial geniculate body	Inferior colliculus Lateral lemnisci from both ears (Predominantly from the contra lateral ear) Efferent – Auditory radiation to superior temporal gyrus	Hearing
	5.Lateral geniculate body	Optic tract Efferent – Optic radiation to visual cortex of the occipital lobe	Visual information from the opposite visual field