Definition of thalamus in US English:



  • Either of two masses of gray matter lying between the cerebral hemispheres on either side of the third ventricle, relaying sensory information and acting as a center for pain perception.

    • ‘The sleep cycle is controlled by a complex system of neurones (messenger cells) in the brain stem, thalamus, hypothalamus, and basal forebrain.’
    • ‘However, after controlling for this overall increase in metabolism in the methamphetamine abusers, the investigators showed that metabolism was significantly reduced in two brain regions - the thalamus and striatum.’
    • ‘By contrast, reduced activation in the mesencephalic brainstem and the thalamus was noted to be exclusively associated with mental relaxation.’
    • ‘Peripheral injury results in anatomic and physiologic changes within the dorsal horn, sensory thalamus and cerebral cortex.’
    • ‘They note that there is evidence to suggest that a circuit involving the thalamus and frontal lobes functions abnormally in autism.’


Late 17th century (denoting the part of the brain at which a nerve originates): via Latin from Greek thalamos.