Interoception: Monkeys can sense their own heartbeat just like us

By Christa Lest.

The rhesus macaques seem to be as sensitive to their own heartbeats as human babies are.

The findings could lead to a better understanding of certain neurological and mental conditions in humans.

One of the components of interoception is the ability to detect the internal state of the body.

It has been suggested that individual variations in our sensitivity to internal signals and how they are interpreted in the brain may be related to our emotions and certain mental and neurological conditions.

There are certain structures in the brain and nervous system of Rhesus macaques that suggest they are capable of interoception, but this hasn't been tested before.

She and her team came up with a way to test the hypothesis after hearing about the study.

They monitored the heartbeat of four captive-born adult rhesus macaques while they watched videos that showed a blob-like image bouncing with a rhythm that was either slower, faster or the same as each monkey's own heartbeat. Each monkey had to complete 100 trials in exchange for sips of fruit juice.

Read more: Your heartbeat may help you sync up with other people to cooperate

The monkeys looked at the images for a longer time when the blob's beat was out of sync. When the beat was faster than the monkeys' heartbeat, they watched for more than twice as many bounces, and about one-and-a-half times as many.

She says that like humans, there were individual differences.

According to research, people's responses to interoceptive signals may have a role in mental health conditions such as anxiety, depression and panic disorder. It is possible that these responses have a role in the development of the condition. rhesus macaques might be useful models for further research into these conditions or forms of development.

Joey Charbonneau is a member of the team at the University of California, Davis.

The journal is called PNAS and is published on 10.1073/pnas.2119868119.