Learning objectives
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Thalamus
This is the largest mass of cell bodies within the nervous system. The thalamus may be affected by both haemorrhage and infarction involving the posterior cerebral artery and its branches. It is a large paired egg shaped structures sitting opposite each other across 3rd ventricle. Contains discrete collections of neuronal cell bodies called nuclei. Separated by a y shaped internal lamina. All but the reticular nucleus send fibres to the cortex. Receives all sensory stimuli (except olfactory) including from the cerebellum, spinal cord and cranial nerves. Bilateral thalamic strokes can cause amnesia as well as hypersomnolesence. Others cause hemisensory loss. Thalamic damage can also lead to so called thalamic pain syndromes where patients experience severe often sharp neuropathic pain in the corresponding contralateral side and it is notoriously hard to treat satisfactorily and causes much morbidity. It contains several discrete thalamic nuclei
- Medial dorsal thalamus
- Anterior thalamus
- Back of thalamus
- Lateral Geniculate body: Fibres from the optic tracts
- Medial Geniculate body: fibres from inferior colliculus
- lateral thalamus
- Dorsal nucleus
- Ventral nucleus