Often dismissed as an irrational or exaggerated feeling of anxiety, paranoia extends beyond the otherwise highly rational ability to maintain our wits in a chaotic environment.
The ability to adapt quickly can keep us alive when circumstances change. But at the extreme, there are delusional beliefs in the bad intentions of others Can be socially isolateddepriving people of the ability to maintain healthy relationships and keep jobs.
To understand why some brains metaphorically jump into the shadows more than others, a team of researchers led by Yale University psychiatrists Praveen Suthaharan and Samar Thompson analyzed the results of a simple test on a group of male rhesus macaques and human volunteers.
It is called probabilistic reflexive learning.Burl) task, the test was about choosing a symbol for a chance at a reward – food for the monkeys, points for the humans.
Different symbols gave varying chances of success, so, when choosing between three on the screen, the person was given a chance to see which symbol was most likely to receive a reward.
Just when participants thought they had it all figured out after half the number of trials, the results of the experiment reversed, with the more fortunate symbol paying out rewards less frequently, and the less fortunate symbol now being the optimal choice.
“So participants have to figure out what the best target is, and when there is a perceptible change in the environment, the participant then has to find a new best target.” He says Yale psychologist Steve Chang.
Six of the 20 macaques underwent a neurological procedure in separate studies that affected none of them Dorsal thalamic nuclei – an area believed to play a role in planning, abstract thinking, and organization – or An area in their prefrontal cortex Participation in decision making.
The human volunteers, on the other hand, were asked to complete a Thinking Scale questionnaire to assess their level of paranoia, and a second survey to identify signs of any depression.
By analyzing the behaviors of monkeys and humans before and after a switch and comparing the results with those from surveys, the team was able to judge which impaired brain regions might be affecting the monkey’s ability to calmly navigate a volatile gaming environment. .
“Not only did we use data in which monkeys and humans performed the same task, but we also applied the same computational analysis to both sets of data.” He says Yale psychiatrist Philip Corlett.
The data indicated that both the dorsal mesolimbic thalamus (MDmc) within the dorsal thalamic nucleus and sites in the orbitofrontal cortex (known as Walker’s areas 11, 13, and 14) all influenced the monkey’s behaviors after the test switch, in subtly different ways.
Among those with impaired Walker regions, the sudden loss of reward had little effect on their decisions to switch. The monkeys continued to click on what they thought was the “winning” ticket with reckless abandon.
Those who were corrupted in MDmc showed exactly the opposite behavior, switching back and forth even after discovering the new “high chance” symbol that was paying out the rewards, as if they suspected that the system had been rigged against them personally.
This was similar to behavior observed in humans whose survey responses indicated higher levels of paranoia.
While delusions and paranoid acts are undoubtedly complex behaviors that involve diverse thinking and different areas of the brain, tracing the line between a particular region and volatile decision-making can inform future studies that may lead to new treatments or help us better understand how Some actions. Increased risk of psychosis.
“Maybe we can use it in the future to find new ways to reduce paranoia in humans.” He says Chang.
This research was published in Cell reports.
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