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Afferent and Efferent Projections of the Thalamus

Afferent and Efferent Projections of the Thalamus

In a previous article, we covered the basic terminology and nuclei of the thalamus. Today, we are going to look at the projections that synapse onto the thalamus and those that depart from the thalamus!

The Anterior Nucleus

The anterior nucleus receives afferent projections from the hypothalmus. More specifically from the mammillary bodies of the hypothalamus (through the mammillothalamic tract). It seems to be involved in the processing of memories.

The anterior nucleus then sends projections out to the cingulate gyrus.

The Dorsomedial Nucleus

The dorsomedial nucleus also receives afferent projections from the hypothalmus and as well as from the prefrontal cortex.

It’s efferents are then sent back to the prefrontal cortex.

It appears that the dorsomedial nucleus is heavily involved in the processing of “personality” characteristics, and more specifically to “personal care.”

Thalamus

Thalamus. Image Credit: Madhero88

The Lateral Dorsal Nucleus

It receives projections from the cingulate gyrus and from the parietal cortex, and sends efferent projections back to the cingulate gyrus and to the parietal lobe.

The Lateral Posterior Nucleus

It receives afferents from the occipital cortex (involved in vision processing).
It then sends projections to the parietal cortex.

The Pulvinar

The pulvinar receives afferents from the occipital cortex and from the parietal and temporal lobes.
The pulvinar sends most of its efferent projections to the occipital cortex, and some to the temporal and parietal cortex.

The Ventral Anterior Nucleus

The ventral anterior nucleus receives afferents from the basal ganglia, and sends axons to the frontal cortex.

The Ventral Lateral Nucleus

It receives afferent projections from the cerebellar nuclei, then sends projections to the motor area of the frontal cortex.

The Ventral Posterior Medial Nucleus

The VPM receives input from the face and olfactory information, and sends information to the part of the parietal cortex associated with the face.

The Ventral Posterior Lateral Nucleus

The VPL receives information from the trunk, and sends its efferents to the part of the parietal cortex associated with the trunk.

The Medial Geniculate Body

The medial geniculate body receives afferents from the ear (auditory information) and sends efferents to the primary auditory area of the temporal lobe.

The Lateral Geniculate Body

The lateral geniculate body receives its afferent from the retina (visual informations) and sends efferents to the primary visual area.

The Internal Medullary Lamina

The internal medullary lamina contains a group of nuclei known as the intralaminar nuclei. They receive afferents from a bunch of places (basal ganglia, prefrontal cortex, midbrain, frontal lobe) and seem to be involved in controlling our levels of consciousness.

The intralaminar nuclei, in turn, send efferent projections to the basal ganglia and to the frontal cortex.

If you take a close look at the afferent and efferent projections to the different nuclei of the thalamus, you will realize that for many of them, the nuclei send at least some efferents back to the place from which they received the information originally. If not, they send the information to cortical areas involved in the processing of the information from the area they just received the information.

 

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  • I hope this helps you have a clearer map of the different “highways” that go in and out of the thalamus!

 

If you want more articles and videos about the Nervous System, you can find them here. More resources are available to help make Biology fun. I invite you to absorb all the content you can find here at Interactive-Biology.com.


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