Local cortical networks consist of feedforward and feedback circuits, found within and across layers. Little is known, however, about their functional role in the processing of sensory inputs. Which kinds of transformations occur in each cortical layer? Do the local recurrent connections amplify distal inputs? What is the role of cortical inhibition in determining the shape of response to an input? How the cortical circuits are affected by adaptation? How inputs arriving from different parts of a receptive field are integrated? Unveiling the mechanisms that generate cortical activity is a crucial step towards understanding information processing in the cortex. To address these questions we study in-vivo the subthreshold and firing properties of neurons in the barrel cortex of the rat.