Septum Verum (true septum) is a region in the lower medial part of the

telencephalon The cerebrum (: cerebra), telencephalon or endbrain is the largest part of the brain, containing the cerebral cortex (of the two cerebral hemispheres) as well as several subcortical structures, including the hippocampus, basal ganglia, and olf ...

that separates the two

cerebral hemisphere The vertebrate cerebrum (brain) is formed by two cerebral hemispheres that are separated by a groove, the longitudinal fissure. The brain can thus be described as being divided into left and right cerebral hemispheres. Each of these hemispheres ...

s. The human septum consists of two parts: the

septum pellucidum The septum pellucidum (Latin for "translucent wall") is a thin, triangular, vertical double membrane separating the anterior horns of the left and right lateral ventricles of the brain. It runs as a sheet from the corpus callosum down to the f ...

(translucent septum), a thin membrane consisting of

white matter White matter refers to areas of the central nervous system that are mainly made up of myelinated axons, also called Nerve tract, tracts. Long thought to be passive tissue, white matter affects learning and brain functions, modulating the distr ...

and

glial cell Glia, also called glial cells (gliocytes) or neuroglia, are non-neuronal cells in the central nervous system (the brain and the spinal cord) and in the peripheral nervous system that do not produce electrical impulses. The neuroglia make up ...

s that separate the

lateral ventricle The lateral ventricles are the two largest ventricular system, ventricles of the brain and contain cerebrospinal fluid. Each cerebral hemisphere contains a lateral ventricle, known as the left or right lateral ventricle, respectively. Each later ...

s, and the lower, precommisural septum verum, which consists of nuclei and

grey matter Grey matter, or gray matter in American English, is a major component of the central nervous system, consisting of neuronal cell bodies, neuropil ( dendrites and unmyelinated axons), glial cells ( astrocytes and oligodendrocytes), synapses, ...

. The term is sometimes used synonymously with Area Septalis, to refer to the precommisural part of the lower base of the

. The Septum verum contains the

septal nuclei The septal area (medial olfactory area), consisting of the lateral septum and medial septum, is an area in the lower, posterior part of the medial surface of the frontal lobe, and refers to the nearby septum pellucidum. The septal nuclei are loca ...

, which are usually considered part of the

limbic system The limbic system, also known as the paleomammalian cortex, is a set of brain structures located on both sides of the thalamus, immediately beneath the medial temporal lobe of the cerebrum primarily in the forebrain.Schacter, Daniel L. 2012. ''P ...

Syntopy In biology, two closely related species or populations are considered sympatric when they exist in the same geographic area and thus frequently encounter each other. An initially interbreeding population that splits into two or more distinct spe ...

Laterally, the septum verum reaches the lower part of the lateral ventricles, with the septal nuclei forming a bulge into the medial side of the ventricles. Dorsally can be found the

, a thin membrane of glial cells and fibres that separate the ventricles, and anteriorly is the

lamina terminalis The lamina terminalis is a thin layer that forms the median portion of the wall of the forebrain. It stretches from the interventricular foramen (foramen of Monro) to the recess at the base of the optic stalk (optic nerve) and contains the vas ...

. It continues caudally as the pre-optic area and hypothalamus. The

subfornical organ The subfornical organ (SFO) is one of the circumventricular organs of the brain. Its name comes from its location on the ventral surface of the fornix near the interventricular foramina (foramina of Monro), which interconnect the lateral ventric ...

(SFO) can also be found in this area, between the ventral side of the fornix and the interventricular foramina.

Function

The septum is considered a part of the limbic system, mediating the connection between the cortex and subcortical limbic nuclei. The septum projects fibres to the hypothalamus, hippocampus, amygdala, reticular formation and olfactory cortical areas, suggesting a role in limbic regulation. While the exact function remains controversial, the septum is considered a pleasure zone in animals, studies have shown that stimulation of the septal area can bring feelings of satisfaction to euphoria and damage can cause hyperactivity and fury.

Evolutionary Significance

With the exception of the nucleus septalis triangularis, all septal nuclei appear to have progressed in size during the evolution of higher primates.

References

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External links

NEUROANATOMY I. - Structures of the central nervous system

Brain Info University of Washington
Brain Neuroanatomy

Syntopy In biology, two closely related species or populations are considered sympatric when they exist in the same geographic area and thus frequently encounter each other. An initially interbreeding population that splits into two or more distinct spe ...

Function

Evolutionary Significance

See also

References

External links