Motivational and demotivational pathway in the brain; Research

MotivationScientists have found the cells that are possibly involved in motivation and the pathway through which motivation moves from one brain region to another.

This research has been published online in the November 18 issue of the journal Nature.

Scientists for a long time were not aware of the possible causes of “psychomotor retardation” i.e. slowing down of motivation in depressed patients. In this condition, patients failed or find it hard to work-out the positive results of the action or they may not be able to respond as for example due to physically heavy limbs.

“It’s challenging because we do not have a fundamental understanding of the circuitry that controls this sort of behavioral pattern selection. We don’t understand what the brain is doing wrong when these behaviors become dysfunctional, or even what the brain is supposed to be doing when things are working right,”  Karl Deisseroth, MD, PhD, a professor of bioengineering and of psychiatry and behavioral sciences at Stanford University, said in a statement. “This is the level of the mystery we face in this field.”

Scientists in this study worked on rat model utilizing the techniques single-unit electrophysiology and an optogenetic method called projection targeting in synchronization. Through these techniques, they were able to determine the neuronal pathway involved in motivation.

Scientists worked on the prefrontal cortex of the brain that is the foremost part of the brain and helps in the planning and coordinated action. They found that simple stimulation of the prefrontal cortex didn’t help in motivation of the rats. They also found that many of the neurons were not simply related to movement but their action in firing patterns may change from time to time.

Scientists found that the cells projecting from the medial prefrontal cortex “to the brainstem dorsal raphe nucleus (DRN), a serotonergic nucleus implicated in major depressive disorder, induced a profound, rapid and reversible effect on selection of the active behavioural state.”

On the other hand, scientists were also able to produce the opposite effect by stimulating the prefrontal neurons moving towards the lateral habenula that is a part atop the brain stem involved in depression. When this region got signals from the prefrontal cortex rats put less efforts to challenges.

Demotivation

After reading this study, we can guess that sooner the medicines will come to enhance motivation or the real world Procrastin-X (phenalazidine slackahide) that is a fictional drug to treat lack of motivation Piled Higher and Deeper – Life (or the lack thereof) in Academia (also known as PhD Comics) written and drawn by Jorge Cham.

Reference:

Melissa R. Warden, Aslihan Selimbeyoglu, Julie J. Mirzabekov, Maisie Lo, Kimberly R. Thompson, Sung-Yon Kim, Avishek Adhikari, Kay M. Tye, Loren M. Frank & Karl Deisseroth, (2012). A prefrontal cortex–brainstem neuronal projection that controls response to behavioural challenge. Nature, doi:10.1038/nature11617