thalamus

Examples of thalamus in the following topics:

• Thalamus

  • The thalamus is part of a nuclear complex of composed of four parts: the hypothalamus, epithalamus, the ventral thalamus, and the dorsal thalamus.
  • The thalamus is connected to the hippocampus via the mammillothalamic tract.
  • The thalamus has multiple functions, serving as a sort of switchboard of information.
  • The thalamus is believed to both process and relay sensory information.
  • Damage to the thalamus can lead to permanent coma.

• Visual Processing

  • One route takes the signals to the thalamus, which serves as the routing station for all incoming sensory impulses except smell.
  • In the thalamus, the magnocellular and parvocellular distinctions remain intact; there are different layers of the thalamus dedicated to each.
  • When visual signals leave the thalamus, they travel to the primary visual cortex at the rear of the brain.

• Functions of the Diencephalon

  • It is made up of four distinct components: the thalamus, the subthalamus, the hypothalamus, and the epithalamus.
  • The thalamus is a kind of switchboard of information, believed to act as a relay between a variety of subcortical areas and the cerebral cortex.
  • The thalamus also plays an important role in regulating states of sleep and wakefulness.
  • The thalamus plays a major role in regulating arousal, awareness level, and activity.
  • Damage to the thalamus can lead to permanent coma.

• Sensory Areas

  • The cerebral cortex is connected to various subcortical structures such as the thalamus and the basal ganglia.
  • Most sensory information is routed to the cerebral cortex via the thalamus.
  • Olfactory information, however, passes through the olfactory bulb to the olfactory cortex, bypassing the thalamus.
  • Parts of the cortex that receive sensory inputs from the thalamus are called primary sensory areas.
  • Olfaction is the only sensory system that is not routed through the thalamus.

• Somatic Sensory Pathways

  • The somatosensory pathway is composed of three neurons located in the dorsal root ganglion, the spinal cord, and the thalamus.
  • The axons of many of these neurons terminate in the thalamus, and others terminate in the reticular activating system or the cerebellum.
  • In the case of touch and certain types of pain, the third neuron has its cell body in the ventral posterior nucleus of the thalamus and ends in the postcentral gyrus of the parietal lobe.
  • Note that many ascending somatosensory pathways include synapses in either the thalamus or the reticular formation before they reach the cortex.
  • The thalamus is a midline symmetrical structure within the brain of vertebrates including humans; it is situated between the cerebral cortex and midbrain, and surrounds the third ventricle.

• Lower-Level Structures

  • The diencephalon is made up of four distinct components: the thalamus, the subthalamus, the hypothalamus, and the epithalamus.
  • The thalamus is part of the limbic system.
  • Lesions of, or stimulation to, the thalamus are associated with changes in emotional reactivity.
  • However, the importance of this structure on the regulation of emotional behavior is not due to the activity of the thalamus itself, but to the connections between the thalamus and other limbic-system structures.
  • The hypothalamus is a small part of the brain located just below the thalamus.

• Brain: Midbrain and Brain Stem

  • The thalamus (Greek for "inner chamber") acts as a gateway to and from the cortex.
  • The thalamus helps regulate consciousness, arousal, and sleep states.
  • Below the thalamus is the hypothalamus.
  • It plays a role in memory formation and includes parts of the thalamus and hypothalamus as well as the hippocampus.
  • It includes parts of the cerebral cortex located near the center of the brain, including the cingulate gyrus and the hippocampus as well as the thalamus, hypothalamus, and amygdala.

• The Limbic System

  • There are several important structures within the limbic system: the amygdala, hippocampus, thalamus, hypothalamus, basal ganglia, and cingulate gyrus.
  • Both the thalamus and hypothalamus are associated with changes in emotional reactivity.
  • The thalamus, which is a sensory "way-station" for the rest of the brain, is primarily important due to its connections with other limbic-system structures.
  • The hypothalamus is a small part of the brain located just below the thalamus on both sides of the third ventricle.

• Pons

  • The pons is a relay station between the forebrain and cerebellum that passes sensory information from the periphery to the thalamus.
  • The white matter of the pons includes tracts that conduct signals from the cerebrum down to the cerebellum and medulla, and tracts that carry the sensory signals up into the thalamus.

• Clusters of Neuronal Cell Bodies

  • For example, the reticular nucleus of the thalamus is a thin layer of inhibitory neurons that surround the thalamus.