Thalamus

related topics
{disease, patient, cell}
{specie, animal, plant}
{area, part, region}
{math, number, function}
{system, computer, user}

The thalamus (from Greek θάλαμος = room, chamber) is a midline paired symmetrical structure within the brains of vertebrates, including humans. It is situated between the cerebral cortex and midbrain, both in terms of location and neurological connections. Its function includes relaying sensation, spatial sense and motor signals to the cerebral cortex, along with the regulation of consciousness, sleep and alertness. The thalamus surrounds the third ventricle. It is the main product of the embryonic diencephalon.

Contents

Location and topography

The thalamus is the largest structure in the diencephalon, the part of the brain situated between the midbrain (mesencephalon) and forebrain (telencephalon). Anatomically, the thalamus is perched on top of the brainstem, near the center of the brain, in a position to send nerve fibers out to the cerebral cortex in all directions. The diencephalon includes also the dorsally located epithalamus (essentially the habenula and annexes) and the perithalamus (prethalamus formerly described as ventral thalamus) containing the zona incerta and the "reticulate nucleus" (not the reticular, term of confusion). Due to their different ontogenetic origins, the epithalamus and the perithalamus are formally distinguished from the thalamus proper.

In humans, the two halves of the thalamus are prominent bulb-shaped masses, about 5.7 cm in length, located obliquely (about 30°) and symmetrically on each side of the third ventricle.

Anatomy

The thalamus comprises a system of lamellae (made up of myelinated fibers) separating different thalamic subparts. Other areas are defined by distinct clusters of neurons, such as the periventricular gray, the intralaminar elements, the "nucleus limitans", and others.[1] These latter structures, different in structure from the major part of the thalamus, have been grouped together into the allothalamus as opposed to the isothalamus.[2] This distinction simplifies the global description of the thalamus.

Full article ▸

related documents
Agoraphobia
Thyroid cancer
Progesterone
Achondroplasia
Lafora disease
Myelin
Mastocytosis
Diuretic
Anatomical pathology
Gastrointestinal tract
Barbiturate
Spasticity
Cardiomyopathy
Vulvodynia
White blood cell
Breast reconstruction
Coxsackie A virus
MMR vaccine
Abetalipoproteinemia
General surgery
Vitiligo
Cerebral cortex
Exocrine gland
Essential tremor
Arthritis
Pelizaeus-Merzbacher disease
Cretinism
Myopia
Circulatory system
Obstetrics