Nat Rev Neurosci. 2008 Aug;9(8):601-12.

'Where' and 'What' in the whisker sensorimotor system


Diamond ME, von Heimendahl M, Knutsen PM, Kleinfeld D, Ahissar E.

Cognitive Neuroscience Sector, International School for Advanced Studies (SISSA),
34014 Trieste, Italy. diamond@sissa.it

In the visual system of primates, different neuronal pathways are specialized for
processing information about the spatial coordinates of objects and their identity - that
is, 'where' and 'what'. By contrast, rats and other nocturnal animals build up a neuronal
representation of 'where' and 'what' by seeking out and palpating objects with their
whiskers. We present recent evidence about how the brain constructs a representation of the
surrounding world through whisker-mediated sense of touch. While considerable knowledge
exists about the representation of the physical properties of stimuli - like texture, shape
and position - we know little about how the brain represents their meaning.
Future research may elucidate this and show how the transformation of one representation to
another is achieved.