In Depth: Sagittal Brain
A split-section of the brain along the longitudinal fissure, which divides the right and left hemispheres (halves) of the cerebrum, allows for an examination of the interior of the cerebrum. It also provides for a look at the part of the region called the diencephalon, which includes the thalamus and hypothalamus.
The same region also holds the spinal cord and the fourth ventricle, which helps with the production of cerebrospinal fluid.
Underneath the gray matter of the cerebral cortex is a layer of what is called white matter. White matter is insulated nerve fiber the brain needs to transmit information between different parts of a hemisphere or between the two hemispheres. The corpus callosum, visible in the center, allows the two hemispheres of the brain to communicate.
The diencephalon is in the cerebrum and above the brain stem.
Inside the diencephalon, the thalamus is the brain’s routing station for most sensory information coming from the nervous system. Once information arrives, it is sent to the appropriate part of the cerebral cortex for interpretation.
The hypothalamus is a region concerned with the regulation of basic body functions. It controls sleep, hunger, thirst, body temperature, and blood pressure.
All of this helps the body maintain what is called homeostasis, or equilibrium among its systems.
Around the diencephalon are areas of gray matter, uninsulated nerve fibers, that make up the limbic system.
The limbic system helps with information processing and retrieval. Because of white matter connections that travel between the limbic system and the cerebral cortex, a person can draw associations between sensory information, such as a smell, and a memory.
The limbic system is also responsible for human sex drive, along with emotions such as happiness, sorrow, anger, fear, and affection.
The limbic system consists of these regions: the amygdala, the fornix, the hippocampus, the mammillary body, and the stria terminalis.
As with much of the rest of the brain, each part takes on pieces of the system’s overall function. For instance, the stria terminalis is involved with sexual behavior, and the hippocampus handles storage and access to memory.