Researchers from The Rockefeller University have got success in discovering two areas in the monkey brains that are involved in face recognition. According to researchers, these two previously unknown areas of the brain are capable of integrating Visual Perception with different types of memory.

The mystery of face recognition

How human brain recognizes familiar faces has always been a mystery for scientists. In 1960s, the US neuroscientist, Jerry Lettvin, came up with his notion of “grandmother cells” suggesting that human brains have hyper-specific neurons that respond to some specific objects.

In other words, a specific neuron in a human brain would fire on seeing a specific person, such as, his/her father, grandfather, etc. Then, some recent studies proposed the idea of “face patches” or neuron clusters that respond almost exclusively to different faces.

In June this year, researchers from the California Institute of Technology announced that they have used brain waves to create nearly perfect replicas of human faces that were shown to monkeys.

Face-processing system in rhesus macaque monkeys

The latest study was carried out by Winrich Freiwald, head of the Laboratory of Neural Systems at Rockefeller University, and Sofia Landi, a graduate student in the lab with rhesus macaque monkeys—the animals whose face-processing systems and capabilities are thought to be quite similar to those of humans.

Researchers selected a group of macaque monkeys for the experiment and showed them the images of faces of some other monkeys. The faces shown fell into three categories: (1) personally familiar faces belonging to those monkeys that the experimental group had lived with for years; (2) visually familiar faces whose pictures were shown to macaque monkeys several times in the past; (3) and completely unfamiliar faces.

While showing the pictures, researchers measured the brain activity of macaque monkeys using functional magnetic resonance imaging. The researchers were surprised to observe that there was more activity in macaque brains after they were shown the faces of long-time acquaintances. Such faces were found to prompt activation of two previously unknown areas in monkeys’ brains.

According to researchers, one of these areas is embedded in brain’s region associated with declarative memory, while the other area lies in a region linked with social knowledge. Researchers also noticed a reduction in activity in some brain areas in experimental monkey group when faces of only visually familiar monkeys were shown to them.

Researchers believe these new results will help them in further investigating the neural mechanisms associated with face recognition.

The detailed findings of the study have been published in Science Magazine.
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