A Group of Cells in the Brain's Temporal Pole Specializes in Recognizing Familiar Faces

Article: Scientists discover a new class of neurons for remembering faces
Source: Rockefeller University, via ScienceDaily  and NEI
Published: July 1, 2021
Article: Cell Group, Not a Single Neuron, Responsible for Familiar Face Recognition
Source: Genetic Engineering & Biotechnology News
Published: July 6, 2021

An area in the brain’s temporal pole (highlighted)
specializes in recognizing familiar faces

The fabled "grandmother neuron," a neuron that in itself encodes the recognition of an individual person—such as one's grandmother or a celebrity—is a theoretical concept at the culmination of visual processing from the retina to the brain, including input from memory and emotions. While such a singular neuron remains hypothetical, researchers have discovered a group of "hybrid" neurons in the brain’s temporal pole (TP) region that represents the connection between the sensory and memory domains. These neurons behave like sensory cells in the sense that they have reliable and fast responses to visual stimuli, while at the same time responding only to stimuli that the brain has seen previously, much like memory cells. Earlier research by the investigators localized a small region in the anterior temporal cortex of the brain as involved in facial recognition. In the new experiments, they explored this region with fMRI in two Rhesus macaques as the monkeys watched familiar and unfamiliar faces. The researchers found that the neurons in the TP region were fast, immediately discriminating between familiar faces seen in-person and unfamiliar faces seen virtually. Furthermore, these neurons were highly selective, responding threefold more strongly to the familiar faces than to the unfamiliar faces. Interestingly, because the unfamiliar faces were presented virtually compared to the familiar faces having been seen in-person, the researchers hypothesized about the brain's preference for in-person recognition. The first author of the study comments, “Given the tendency nowadays to go virtual, it is important to note that faces that we have seen on a screen may not evoke the same neuronal activity as faces that we meet in-person.” While this population or "collective" of neurons is more accurately described as a "grandmother face area" of the brain rather than the still elusive face-specific grandmother neuron, their discovery is a step forward in investigating how brain cells encode facial recognition. The findings could also one day inform clinical strategies to help people suffering from prosopagnosia or face blindness.

My rating of this study: ⭐⭐⭐

Landi SM, Viswanathan P, Serene S, et al. "A fast link between face perception and memory in the temporal pole." Science.  373(6554):581-585. 30 July 2021. https://doi.org/10.1126/science.abi6671