Thalamus

Figure 12.

In a later chapter, we will talk more about melatonin and the circadian rhythm. The reasons why the pineal gland is located in the brain are not clear.

THALAMUS

The thalamus is very important to brain physiology. There are different nuclei within that structure—each of which acts like a relay structure that collects and relays both motor and sensory signals. They are also somewhat responsible for your being alert or even conscious at any point in time.

The thalamus is a gray matter structure located in the central portion of the brain just above the midbrain. This central location allows for a great many of possible connections within and from outside the brain. Figure 13 shows the location of the thalamus:

Figure 13.

There are several nuclei within this modestly large structure. There are nerve cells within these nuclei that take on excitatory information and those that take on inhibitory information. There are neurons called thalamocortical neurons that receive either sensory or motor information from the periphery of the body, sending just some of this information to the cortex. The connections to the thalamus are broader than that, however, and include those to the mammillary bodies, hippocampus, and fornix. Because the thalamus connects with the emotional or limbic parts of the brain, it is also important in episodic memory and learning processes. Again, sleep and wakefulness are part of the thalamus’s function as well.