Neural origins of 'awareness of ignorance' Frontopolar cortex plays key role in judging confidence of nonexperience

September 5, 2018

Illustration of monkey's brain mechanisms
Brain mechanisms for 'self-awareness of one's own ignorance'
The frontopolar cortex, the most novel cortical area evolutionarily, interacts with the neural network of memory and generates "self-awareness of one's own ignorance."
© 2018 Kentaro Miyamoto.

A group of University of Tokyo researchers and their collaborators discovered that a particular region in the front end of the brain contributes to macaque monkeys' ability to judge their level of confidence toward events they have not experienced. This finding suggests that the frontopolar cortex, the region at the anterior end of the prefrontal cortex, the part of the brain said to be involved in executive functions such as planning and judgment, gives rise to self-awareness of one’s own ignorance.

As in the words of the Greek philosopher Socrates, "I know that I know nothing," our mind's function for evaluating nonexperienced events and facts is essential for abstract and conceptual reasoning. However, the brain's mechanisms for generating our self-awareness of our own ignorance remained a complete mystery.

The research group led by Japan Society for the Promotion of Science postdoctoral fellow Kentaro Miyamoto and Visiting Professor Yasushi Miyashita (concurrently project professor at Juntendo University Graduate School of Medicine) at the University of Tokyo Graduate School of Medicine had already established an objective and behavioral method for measuring to what extent the macaque monkeys, a species closely related to humans, are confident about their own memory ("Macaque brains judge confidence of own memory," Research News 03/16/2017).

In the present study, the group used functional magnetic resonance imaging (fMRI) to record the whole-brain activity of monkeys while they engaged in judging their confidence of nonexperienced events. The researchers found that activation in the bilateral frontopolar cortex (designated on the brain map as area 10 of the prefrontal cortex) correlated to the animals' performance of their confidence judgment of nonexperienced events. Moreover, when the scientists injected a chemical (GABA-A receptor agonist muscimol) to temporally suppress neuronal activities in this region, they found that while the monkeys preserved their ability to carry out their confidence judgment of experienced events and their memory retained its capability to distinguish nonexperienced events from experienced events, their capacity to optimally perform confidence judgment on nonexperienced events was impaired.

The current outcome holds promise of contributing to the development of effective education methods based scientifically on brain functions, and the establishment of rehabilitation procedures for higher cognitive dysfunction.

"It was surprising to find the neuronal substrate for the awareness of ignorance at the frontopolar cortex, evolutionarily the most novel cortical area," Miyamoto says. He continues, "Further investigation of the function of this area will reveal our thought's highly intellectual operating process when we search for new information or try to generate new ideas on the grounds of self-awareness of ignorance."


Kentaro Miyamoto, Rieko Setsuie, Takahiro Osada, Yasushi Miyashita, "Reversible silencing of the frontopolar cortex selectively impairs metacognitive judgment on non-experience in primates," Neuron: January 26, 2018, doi:10.1016/j.neuron.2017.12.040.
Link (PublicationOpen a new window)

Related links

Access Map
Kashiwa Campus
Hongo Campus
Komaba Campus