An overview of brain activity provides new insights into the relationship between the brain and behavior for individuals who together constitute a social entity
Living in a group has clear benefits. As a member of a community group, one can share resources with others, seek protection from predators, and search for forage in an efficient manner. In a research paper published in 2020 in Science advancesNeuroscientist Ji Hyun Choi and her student Jisoo Kim of the Institute of Brain Sciences at the Korea Institute of Science and Technology (KIST) argue that there are plenty of stories about the advantages of group life and social behaviors of the mammalian brain that have yet to be identified. Discover. Their research was conducted using CBRAIN (Collective Brain Research Assisted by Illuminating Neural Activity), a unique neurometry device with LED lights, enabling the real-time measurement and analysis of group brain activities.
While many experiments have been conducted to determine individual behaviors and situations under cost-benefit schemes, the question of how a group of animals shapes specific social behaviors is receiving increasing concerns from the neuroscience community. Understanding how individuals devise strategies to produce concrete group behavior is fundamental to understanding social groups and their behavioral patterns. For example, recent studies have found that the overall risk imposed to predators during successful predation attempts decreases when predation is coordinated as a group.
“In nature, animals are likely to face many threats during which acting as a group may not be beneficial to all members of the group,” explains lead author Ji Hyun Choi. Indeed, forming a tight mass may make some organs difficult to effectively avoid predators. We aim to find group brain activities that represent behavioral phenotypes that emerge from the group in a complex environment and make the association of brain behavior between group members. “
In collaboration with Sung Q Lee of ETRI in South Korea, the research team developed CBRAIN, a wireless recorder with an edge-lit LED that fits into a mouse’s head. This tiny device was implanted in the subcortical brain to collect voltage signals from a specific sub-region of the amygdala called the basal lateral amygdala (BLA), a brain region known to be highly sensitive to emotional stimuli such as stress and anxiety. When the rhythmic activity of the frequency occurs on the board while scanning in real time the nerve activities, the LED indicator lights up on the device. These rhythmic events, along with signals from a group of mice, are sent to a receiver. CBRAIN’s ability to generate a live report of group brain activities is amazing in contrast to other neural recording devices that analyze signals after all experiments are complete.
Choi and her team developed experimental protocols to confirm electrode coordinates and fast transient rhythms calibrated in BLA made up of the gamma frequency band, called gamma bursts, via mice. Researchers studied this explosion phenomenon during active and passive manifestations of fear when a large group of mice was attacked by a robot that looked like a spider. Using CBRAIN, they observed that the occurrence of gamma bursts during fear-driven behaviors was dependent on social situations. The mice showed fewer gamma bursts when they encountered the robot as a group, avoiding the mice and defending themselves against the robot in a group, just as they would in nature.
Subsequent analysis of the movement pathways computed by deep learning tools revealed that clustering shapes correlate with gamma activities. While the mice at the edge of the group showed higher gamma activity, those within the group showed a level of gamma activity similar to the level at which no robot was present. “Reducing gamma bursts in the amygdala may reflect the social buffering effect of being together,” said Jisoo Kim, first author of the paper. “However, activity testing in different environmental situations and different demographics is required to reach a final conclusion.”
Regarding the newly developed technology and the prospects for social and behavioral neuroscience, many neuroscientists are optimistic. Choi concludes: “We analyze the data obtained by CBRAIN in a manner similar to that of conventional neuronal recordings, but direct observation without the need to record and examine the data first gives us a greater degree of freedom in discovering functions of specific brain activities.” “I think this work serves as a pilot study that highlights the effectiveness of neural recordings for illuminating edges in real time for individuals in a group, and the immediate connectivity of the brain and behaviors will broaden our understanding of the underlying drivers of complex social behaviors.”