thalamus

American  

[thal-uh-muhs] / ˈθæl ə məs /

noun

plural

thalami

1. Anatomy. the middle part of the diencephalon through which sensory impulses pass to reach the cerebral cortex.

2. Botany. a receptacle or torus.

3. Also called thalamium.  an apartment for women in an ancient Greek house.

---

thalamus British  

/ ˈθæləməs, θəˈlæmɪk /

noun

1. either of the two contiguous egg-shaped masses of grey matter at the base of the brain

2. both of these masses considered as a functional unit

3. the receptacle or torus of a flower

---

thalamus Scientific  

/ thăl′ə-məs /

plural

thalami

1. The part of the vertebrate brain that lies at the rear of the forebrain. It relays sensory information to the cerebral cortex and regulates the perception of touch, pain, and temperature.

---

thalamus Cultural  

1. The part of the brain that coordinates nerve impulses relating to the senses of sight, hearing, touch, and taste.

---

Other Word Forms

• postthalamic adjective
• subthalamic adjective
• thalamic adjective
• thalamically adverb
• transthalamic adjective

Etymology

Origin of thalamus

1695–1705; < New Latin; Latin: bedroom < Greek thálamos

Compare meaning

How does thalamus compare to similar and commonly confused words? Explore the most common comparisons:

• hypothalamus vs. thalamus

Explanation

The thalamus is an egg-shaped mass of gray matter that's located in the middle of the brain. The thalamus is responsible for transmitting sensory signals between different parts of the brain. The thalamus plays a crucial role in regulating consciousness, sleep, and alertness by directing sensory information to different parts of the brain. It receives input from sensory organs such as the eyes, ears, and skin and then relays that information to other regions of the brain for further processing. This important structure, which is located near the center of the brain, gets its name from the Greek word thalamos, which means "inner chamber."

Example Sentences

Neurons in the mediodorsal thalamus appeared to track changes in the value of different choices.

From Science Daily • Apr. 3, 2026

However, how the thalamus and cortex interact during circuit formation in the human brain has remained largely unknown.

From Science Daily • Jan. 7, 2026

Professor Fumitaka Osakada, graduate student Masatoshi Nishimura, and their colleagues at the Graduate School of Pharmaceutical Sciences at Nagoya University developed assembloids that model interactions between the thalamus and the cortex.

From Science Daily • Jan. 7, 2026

Correlation alone could not answer the key questions, so co-lead Celine Chen created a CRISPR-based screening platform to alter gene activity in the thalamus and cortex.

From Science Daily • Nov. 30, 2025

The small italics throughout signify the following homologous parts: m, medulla; cb, cerebellum; op, optic lobes; cr, cerebrum and thalamus; ol, olfactory lobes.

From Darwin, and After Darwin (Vol. 1 and 3, of 3) An Exposition of the Darwinian Theory and a Discussion of Post-Darwinian Questions by Romanes, George John