Neurons Responsible For Remembering Faces Have Been Identified In The Brain
Scientists have searched for brain cells that could explain the flash of recognition we all feel when we see a familiar face. The neuron was dubbed the "grandmother neuron" because the flash of recognition happens with very familiar faces like our grandmothers. The cell is described as at the crossroads of sensory perception and memory and can prioritize an important face over others.
While scientists have searched for the cell, it has proven difficult to find. However, researchers have now revealed a class of neurons in the temporal pole region of the brain that links face perception to long-term memory. It's not quite the grandmother neurons scientists were searching for since it's not a single cell. However, it is a population of cells that collectively remembers faces.
The study is the first to explain how the brain remembers the faces of loved ones. Researcher Winrich Freiwald, head of the Rockefeller laboratory of neural systems, says that in an obscure and understudied corner of the brain, scientists have found the closest thing to a grandmother neuron in the form of cells linking face perception to memory. Researchers note that the idea for the grandmother neuron first surfaced in the 1960s as a theoretical brain cell that would code for specific, complex concepts all alone.
The thought was there was one neuron for the memory of a person's grandmother, one for the mother, and so on. Scientists have discovered numerous sensory neurons specializing in processing facial information over the years and many memory cells dedicated to storing data from personal encounters. However, a grandmother neuron or even a hybrid cell able to link vision to memory was never discovered.
The team has discovered that neurons in the TP region are highly selective, responding to faces that the subject has seen before more strongly than unfamiliar faces. The neurons were also very fast able to discriminate between known and unknown faces immediately on processing the image. Researchers found the cells responded with three times the strength to familiar faces compared to unfamiliar faces even though the subjects had seen the unfamiliar faces many times virtually on screens.
The team believes this could pinpoint the importance of knowing someone in person. Cells in the TP region behave like sensory cells with reliable and fast responses to visual stimuli and act as memory cells. Researchers say the ability of the cells to respond to stimuli the brain has seen before reflects a change in the brain as a result of past encounters.