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Abstract

Stripe rearing, the restriction of visual experience to contours of
only one orientation, leads to an overrepresentation of the experienced
orientation among neurons in the visual cortex. It is unclear, however,
how these changes are brought about. Are they caused by silencing of
neurons tuned to non-experienced orientations, or do some neurons
change their preferred orientation? To address this question, we
stripe-reared juvenile mice using cylinder lens goggles. Following
stripe rearing, the orientation preference of cortical neurons was
determined with two-photon calcium imaging. This allowed us to sample
all neurons in a given field of view, including the non-responsive
ones, thus overcoming a fundamental limitation of extracellular
electrophysiological recordings. Stripe rearing for 3 weeks resulted in
a clear overrepresentation of the experienced orientation in cortical
layer 2/3. Closer inspection revealed that the stripe rearing effect
changed with depth in cortex: The fraction of responsive neurons
decreased in upper layer 2/3, but changed very little deeper in this
layer. At the same time, the overrepresentation of the experienced
orientation was strongest in lower layer 2/3. Thus, diverse mechanisms
contribute to the overall stripe rearing effect, but for neurons in
lower layer 2/3 the effect is mediated by an instructive mechanism,
which alters the orientation tuning of individual neurons.