Visual response properties in the dorsal lateral geniculate nucleus of mice lacking the β2 subunit of the nicotinic acetylcholine receptor

Abstract

We present a quantitative description of single-cell visual response properties in the dorsal lateral geniculate nucleus (dLGN) of anesthetized adult mice lacking the β2 subunit of the nicotinic acetylcholine receptor (β2-/-) and compare these response properties with data from wild-type animals. Some response features, including all spatial receptive field characteristics and bursting behavior, are entirely normal in β2-/- dLGN cells. In other respects, the responses of β2-/- dLGN cells are quantitatively abnormal: the mutation is associated with higher spontaneous and visually evoked firing rates, faster visual response latencies, a preference for higher temporal frequencies, and a trend toward greater contrast sensitivity. The normal response properties in the β2-/- dLGN show that none of the many effects of the mutation, including disrupted geniculate functional organization and abnormal cholinergic transmission, have any effect on spatial response characteristics and bursting behavior in dLGN neurons. The abnormal response characteristics in the β2-/-dLGN are most interesting in that they are no worse than normal; any visual processing deficits found in studies of the β2-/- visual cortex must therefore arise solely from abnormalities in cortical processing.