Response plasticity in primary visual cortex and its role in vision and visuomotor behavior: Bottom-up and top-down influences

Neurons in the primary visual cortex (V1) have been traditionally considered to respond exclusively and steadily to the physical properties of visual stimuli presented within their receptive fields. Indeed, since V1 neurons are mainly involved in processing elementary features of visual stimuli such as orientation or direction of motion, they were long believed to possess stable or unchanging properties. However, another view has emerged in the past 15 years. According to this view, V1 responses are strongly influenced by the history of visual stimulation. Such response changes can be driven by properties of previously viewed visual stimuli (bottom up changes), or by aspects of internal state, including an internal representation of previous stimuli (top-down changes). In effect, the temporal content of visual stimulation results in short term experience-dependent plasticity in local as well as distributed cortical circuits, and these changes are manifest as changes in neuronal responses, visual perception and visuomotor behavior. In this review, we describe our recent findings demonstrating rapid plasticity of responses in V1 neurons resulting from time-dependent bottom-up and top-down influences.