Source+8

http://www.healing-arts.org/n-r-limbic.htm

Actually, we have three cerebral units in a single brain. The primitive one is responsible for self preservation. It is there that the mechanisms of aggression and repetitive behavior are developed

It is there that occur the instinctive reactions of the so-called reflex arcs and the commands which allow some involuntary actions and the control of certain visceral functions (cardiac, pulmonary, intestinal, etc), indispensable to the preservation of life

The development of the olfactory bulbs and their connections made possible an accurate analysis of olfactory stimuli and the improvement of answers oriented by odors, such as approach, attack, flight and mating The entirety of these structures, that, years later would receive the name of "limbic system", developed with the emergence of the inferior ( primitive) mammals.

The archipallium or primitive (reptilian) brain, comprising the structures of the brain stem - medulla, pons, cerebellum, mesencephalon, the oldest basal nuclei - the globus pallidus and the olfactory bulbs. It corresponds to the reptile brain, also called "R-complex", by the famous neuroscientist Paul MacLean.

The paleopallium or intermediate (old mammalian) brain, comprising the structures of the limbic system. It corresponds to the brain of the inferior mammals. The neopallium, also known as the superior or rational (new mammalian) brain, comprises almost the whole of the hemispheres (made up of a more recent type of cortex, called neocortex) and some subcortical neuronal groups. It corresponds to the brain of the superior mammals, thus including the primates and, consequently, the human species.

Humans display the largest web of connections between the prefrontal area and the traditional limbic structures

This area comprises the entire non-motor anterior region of the frontal lobe.

It does not belong to the traditional limbic circuit, but its intense bi-directional connections with thalamus, amygdala and other subcortical structures, account for the important role it plays in the genesis and, specially, in the expression of affective states When the pre-frontal cortex suffers a lesion, the subject looses his sense of social responsibility as well as the capacity for concentration and abstraction. In some cases, although consciousness and some cognitive functions, like speech, remain intact, the subject can no longer solve problems, even the most elementary ones.

When pre-frontal lobotomy was used for treatment of certain psychiatric disturbances, the patients entered into a stage of "affective buffer", no longer showing any sign of joy, sadness, hope or despair. In their words or attitudes, no traces of affection could be detected.