[Is understanding the mechanism of perception possible?]

Perception is the understanding by the brain of the different sensory information. In humans, information is mostly visual and is conveyed to the occipital cortex. MRI techniques suggest that it is deciphered in different areas of the temporal cortex, depending upon the observed scene. The neural codes used by neurons of these areas will be discussed in two instances: Recognition of written words and of faces. In the first case, an hypothesis using basic properties of neurons and hierarchy of local combination detectors, accounts for the invariance of their visual form. That it is relevant is emphasized by its successful application to reading mechanism. In the second more recent instance, recognition of human faces by macaques is shown to reside in neuron patches in the inferior temporal cortex, forming a system identifying faces with view invariance. The code allowing facial identification using the electrical activity of 200 neurons was cracked.