New research has found the neural projection responsible for preventing people from acting out their instincts and impulses, with possible impact on schizophrenia and mood disorders such as depression. Prior to this study, researchers were aware that the prefrontal cortex is a key region responsible for validating which instincts to turn into behaviors and which ones to control. However, the exact mechanism was unknown.
The brainstem, which is positioned above the spinal chord, is responsible for our instinctual impulses and behaviors, and the prefrontal cortex is the brain area which controls the manifestation of our impulses.
Prefrontal Cortex – Responsible For Dealing With Impulses
As part of the new research published on Jan. 9 in the journal Nature Neuroscience, scientists from the European Molecular Biology Laboratory (EMBL) analyzed the connections between neurons in mice, discovering that the prefrontal cortex is directly connected to the brainstem.
Further, the team wanted to confirm the hypothesis as to which instinctive behavior is inhibited by the region of the brain. They observed that, when it comes to mice that were tortured by a bully counterpart, the connection is weaker, and the mice show more signs of being scared. Following this discovery, the team concluded that it is possible to create through drugs the same reaction in mice that have never been aggressed by blocking the connection between the brainstem and the prefrontal cortex.
"Social defeat caused a weakening of functional connectivity between these two areas, and selective inhibition of these projections mimicked the behavioral effects of social defeat. These findings define a specific neural projection by which the prefrontal cortex can control and adapt social behavior," noted the research.
The research represents an anatomical explanation on how easy it is to control behavior compared with impulses. Should someone feel angry, that person is more likely not to act on that feeling of anger but less likely to stop the very impulse of the feeling. As it turns out, a specific region of the prefrontal cortex is in direct relation with the PAG area in the brainstem, which controls our behavioral responses to instincts.
Additionally, this connection is not shared with the hypothalamus, which is responsible for our affective stimuli and the responses to them. This observation provides a stable explanation as to why it is much easier to control our behavioral response to stimuli than to control our affective or emotional responses.
"One fascinating implication we're looking at now is that we know the pre-frontal cortex matures during adolescence. Kids are really bad at inhibiting their instincts; they don't have this control, so we're trying to figure out how this inhibition comes about, especially as many mental illnesses like mood disorders are typically adult-onset," noted Cornelius Gross, lead author from EMBL.
The Human Brain As A Scientific Cornucopia
Various studies have been conducted in an attempt to understand the specific mechanisms of brain activity in humans. Recent research showed that there is a connection between the way we breathe and our judgment of emotions, impacting the way we remember different events.
"One of the major findings in this study is that there is a dramatic difference in brain activity in the amygdala and hippocampus during inhalation compared with exhalation," noted the author of that research.
This proves that brain activity is governed by a very wide array of cognitive and neural mechanisms, many of which are yet to be defined.
