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 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.”
The Lateral Dorsal Nucleus
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 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 Lateral Nucleus
The Ventral Posterior Medial Nucleus
The Ventral Posterior Lateral Nucleus
The Medial Geniculate Body
The Lateral Geniculate Body
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.
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.
- I hope this helps you have a clearer map of the different “highways” that go in and out of the thalamus!
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