emotions in the brain
March 6, 2014

The Emotional Center Of Bat Brains Gives Insight Into Our Own Cognitive Processes

Brett Smith for redOrbit.com - Your Universe Online

A new study on the brains of mustached bats could provide a window into our own cognitive processes, according to a report published in the journal Frontiers in Physiology on Tuesday.

In the study, a pair of Georgetown University researchers found that a small region within the bats’ brains called the amygdala, a structure in the brains of all mammals, controls the production of emotionally-specific calls and sounds. The team said their find could lead to the discovery of a comparable center in human brains.

Study author Jagmeet S. Kanwal, an associate professor of neurology at Georgetown, said identifying and adjusting this structure in the brain may offer a way to deal with behavioral malfunctions in humans related to emotional reactions.

He added that manipulating the amygdala could make it possible to "give voice to the voiceless — allow those who are deeply withdrawn, perhaps even mute due to aberrant wiring in the amygdala, to speak."

Previous research has shown that the human amygdala, like the bat's amygdala, reacts to species-specific emotive noises, such as laughing and weeping. However, electrostimulation, like the type used in the study, is difficult to do in humans due to its invasive nature.

The study team said they observed "full blown emotive responses, including vocalizations" from a distinct point of electrostimulation within the amygdala. For example, stimulating one cluster of neurons made the bats produce angry sounds, while increasing their breathing and heart rates, Kanwal said. Stimulation at other points produced a wide range of emotional and physiological responses.

"Emotions are designed for survival," Kanwal noted. "The world humans and animals experience depends entirely on how sensory stimuli are perceived and processed through an emotional filter."

In a similar study reported on this week, an international team of researchers found a distinct gene pattern in the olfactory receptors of fruit-eating bats – potentially shedding some light on the mechanism behind our own sense of smell.

The researchers said they wanted to know if the development of other sensory systems, transformations in diet, or the random accumulation of transformations through time drove the progression of olfaction in mammals.

“Bats offer a prime opportunity to answer this question,” said Liliana Davalos, an evolutionary biologist at Stony Brook University in New York and co-author of the olfaction study. “They’ve evolved new sensory systems such as echolocation, and various bat species eat very different foods, including insects, nectar, fruit, frogs, lizards and even blood.”

After a genetic analysis of thousands of olfactory receptors from various bat species and analyzing an evolutionary tree including every one of the species, the scientists found distinctive patterns of olfactory receptors among bats that have fruit as a major part of their diet.

The researchers discovered that the genetic patterns for olfaction have arisen two times during bat evolution, once amongst New World leaf-nosed bats that mostly eat figs and another time amongst Old World fruit bats. These bats feed on a wide variety of fruits, including figs, guavas, bananas and mangoes. The study team also found that the olfactory receptors in these two different groups of bats are similar, yet distinction capabilities have arisen in different ways in New World and Old World bats.