The brain is a complex organ that acts as the control center of the body. The main divisions of the brain include the forebrain, midbrain, and hindbrain. The forebrain is further divided into 2 subdivisions: telencephalon and diencephalon. The diencephalon includes the thalamus, hypothalamus, and pineal gland. Thalamus is a paired structure located in the forebrain which performs several functions. Thalamus function is to act as a relay centre in between the subcortical areas and the cerebral cortex.
What is Thalamus?
The thalamus may be a small structure within the brain located just above the brainstem between the cerebral mantle and therefore the midbrain has extensive nerve connections to both. The main and primary function of the thalamus is to relay motor and sensory signals to the cerebral mantle. It also aids in the regulation of sleep, alertness, and wakefulness.
The brain consists of the ventricles or fluid-filled spaces. The thalamus surrounds the third ventricle. It is a subdivision of a part of the brain called the diencephalon and is one of the most important structures derived from the diencephalon during embryonic development.
The thalamus lies at the highest of the brain stem near the middle of the brain, from where the nerve fibers project out towards the cerebral mantle. The thalamus is split into two prominent bulb-shaped masses of around 5.7 cm long and positioned symmetrically on all sides of the ventricle.
The thalamus is a paired structure of gray matter that is located in the forebrain and is superior to the midbrain. It is also near the center of the brain, where the nerve fibers project out to the cerebral cortex in all directions. The medial surface of the thalamus constitutes the upper part of the lateral wall of the third ventricle and is connected to the surface that is corresponding to the opposite thalamus by a flattened gray band, the interthalamic adhesion.
The lateral part of the thalamus consists of the pulvinar, the lateral nuclei, and the medial and lateral geniculate nuclei. These are the newest part of the thalamus phylogenetically. There are areas of substantia alba within the thalamus including the stratum zonale that covers the dorsal surface, and therefore the external and internal medullary lamina. The external lamina covers the lateral surface and the internal lamina helps to divide the nuclei into anterior, medial, and lateral groups.
The thalamus is furnished with blood by four branches of the posterior arteria cerebri, namely the polar artery, paramedian thalamic-subthalamic arteries, thalamogeniculate arteries, and therefore the posterior choroidal arteries.
What is the Function of the Thalamus?
The thalamus performs multiple functions, generally, they are believed to act as a relay station, or hub, and act as relaying information between different subcortical areas and the cerebral cortex. Every sensory system particularly includes a thalamic nucleus that receives sensory signals and sends them to the associated primary cortical area.
For example, in the sensory system, the inputs are from the retina that is sent to the lateral geniculate nucleus of the thalamus, which successively projects to the visual area within the lobe. The thalamus is believed to process both the sensory information as well as a relay of each of the primary sensory relay areas that receive strong feedback connections from the cerebral cortex. Similarly, the medial geniculate nucleus acts as a key auditory relay between the center of the midbrain and therefore the primary auditory area. The ventral posterior nucleus may be a key somatosensory relay, which sends touch and proprioceptive information to the first somatosensory cortex.
The function of thalamus in the human brain is it plays a crucial role in regulating states of sleep and wakefulness. Thalamic nuclei have strong reciprocal connections with the cerebral mantle that helps in the formation of thalamo-cortico thalamic circuits that are believed to be involved in consciousness. The thalamus plays a serious role in regulating arousal, the extent of awareness, and activity. Damage to the thalamus in humans can lead to a permanent coma.