Professor Sunil Gandhi, USA : "Rewiring the circuits of high acuity spatial vision"

Speaker:

Professor Sunil Gandhi

Department of Neurobiology and Behaviour, School of Biological Sciences, University of California, Irvine, USA

Title: "Rewiring the circuits of high acuity spatial vision"

Abstract:

In the visual circuits of the cerebral cortex, the maturation of a small population of inhibitory neurons has been linked to both the opening and closing of a critical period for binocular vision. We have discovered that the transplantation of embryonic inhibitory neurons into adult mouse visual cortex creates a new critical period for binocular vision. Functional imaging of transplanted interneurons reveals that these cells wire into the host visual system following an intrinsically determined developmental program. The transplanted inhibitory neurons reactivate juvenile cortical plasticity when the donor animal’s critical period would have occurred. We find in both neurophysiological and behavioral experiments that transplantation completely reverses visual acuity deficits in mice deprived of normal vision during development. We hypothesize that transplanted cells reactivate critical period plasticity by contributing a short-lived disinhibitory microcircuit to the host visual cortex. I will discuss evidence that inhibitory circuits respond rapidly to visual deprivation and that the disinhibition depends critically on Neuregulin-1/ErbB4 signaling, a key pathway implicated in schizophrenia. I will conclude my talk by presenting some new insights we have gained into the organization of binocularity and high spatial acuity in the mouse visual pathway that challenges our basic assumptions. Our transplantation experiments open up a new avenue for understanding the mechanisms of juvenile brain plasticity. Furthermore, our approach to reactivating juvenile plasticity in the adult cortex may lead to novel therapeutics for brain injury, neurodegeneration and neurodevelopmental disorders such as schizophrenia.