(HealthDay News) – Electrical stimulation of two closely-spaced areas in the fusiform gyrus region of the brain (mid and posterior fusiform [mFus and pFus]) causes a profound change in perception that is specific for the face, implicating these areas in facial recognition.

Building on previous results showing that the fusiform gyrus in the brain is involved in face recognition, Josef Parvizi, MD, PhD, from Stanford University in California, and colleagues used electrocorticography, high-resolution functional magnetic resonance imaging (fMRI), and electrical brain stimulation on a patient who was undergoing monitoring to identify the focus of his epileptic seizures.

The researchers identified two distinct fusiform gyrus face-selective regions from fMRI: pFus-faces and mFus-faces. Electrical stimulation of a pair of electrodes overlapping pFus-faces and mFus-faces caused a profound face-specific perceptual distortion, where the patient reported that faces appeared to metamorphose. This change was specific to faces in the room and had no significant effect on recognition of famous faces on the computer or the appearance of non-face objects.

“Overall, our findings reveal a striking convergence of fMRI, electrocorticography, and electrical brain stimulation, which together offer a rare causal link between functional subsets of the human fusiform gyrus network and face perception,” Parvizi and colleagues conclude.

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