The neural brain network necessary for normal face recognition has been not fully understood yet until now.
Suppression of the brain area responsible for object recognition by that for face recognition is necessary for “normal face” recognition, a research group led by Prof. Ryusuke Kakigi and Prof. Norihiro Sadato of the National Institute for Physiological Sciences (NIPS), National Institutes of Natural Sciences (NINS) has found.
Using data from functional magnetic resonance imaging (fMRI), the researchers mathematically simulated networks between the brain areas and showed not only brain areas that execute face recognition, but also brain areas that had been considered non-essential to face recognition are important for “normal face” recognition.
The Thatcher Illusion
The research group focused on the phenomenon of how it becomes difficult to recognize a face that is presented upside-down, such as the so-called “Thatcher illusion”.
The group investigated the neural network in the brain during face recognition by using fMRI. They found that when faces were shown upright, the brain area responsible for object recognition was suppressed by the area responsible for face recognition.
On the other hand, when faces were inverted, the object recognition area was not suppressed by the face recognition area and the brain is in a state of “being clearly not sure if it is a face or an object”. In addition, mathematical simulation revealed that neural networks between the multiple areas in the brain are necessary for “normal face” recognition.
Said Prof. Ryusuke Kakigi:
“In this research, we have found that not only brain areas that execute face recognition but also brain areas that had been considered non-essential to face recognition are important for “normal face” recognition. It could be that disorders of face recognition such as developmental prosopagnosia may be attributable to the brain networks”.
Daisuke Matsuyoshi, Tomoyo Morita, Takanori Kochiyama, Hiroki C. Tanabe, Norihiro Sadato, and Ryusuke Kakigi Dissociable Cortical Pathways for Qualitative and Quantitative Mechanisms in the Face Inversion Effect The Journal of Neuroscience, 11 March 2015, 35(10): 4268-4279; doi: 10.1523/JNEUROSCI.3960-14.2015