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The preference of cells in mouse primary visual cortex are thought to be randomly distributed in a salt-and-pepper map, in contrast to the smooth cortical maps observed in higher mammals. Here the authors show that excitatory cells in mouse primary visual cortex are spatially clustered, resembling a degraded version of the organization seen in higher mammals.

How cortical populations adapt to the statistics of sensory input is not fully understood. Here the authors show that a power law captures how the magnitude of population responses change across different sensory environments.

A study now reveals that ON and OFF thalamic inputs to visual cortex are partially segregated in space and predict the preferred orientation of neurons of the target cortical column. This finding brings us a step closer to a full understanding of the origin of simple cells and orientation maps in primary visual cortex.

Cortical responses are highly heterogeneous, making it difficult to describe how they behave as a population. Here, the author overcomes this problem by introducing a geometric approach to study the representation of orientation and its transformation under the presence of a mask.

Neurons in the early visual system respond preferentially to the onset or offset of light. Here the authors show that ON/OFF responses cluster in the mouse primary visual cortex, shaping the receptive fields of cortical cells.

Using large-network calcium imaging in alert mouse frontal cortex, the authors identify a significant covariance of responses of VIP interneurons and pyramidal cells. Optogenetic interrogation of this brain region revealed a pull–push inhibitory circuit driven by neuromodulation of VIP interneurons that contrasts with canonical feedforward push–pull excitation.

This paper demonstrates that orientation maps, as found in the cortex of higher mammals, are likely to arise from the spatial layout of retinal ganglion cell receptive fields in the retina. The predictions of this model are borne out in four different species.

Psychophysics suggests that binocular information at multiple spatial scales is used in depth perception. A new study provides physiological evidence for this idea in primary visual cortex.

In the brains of anaesthetized animals, neurons create spontaneous patterns of activity that resemble representations of visual stimuli. This finding may change our notions about visual perception.

By simultaneously recording spikes and local field potentials (LFPs) in cat and monkey visual cortex, the authors demonstrate that the magnitude and spread of LFP waves from the originating spike are reduced with increasing stimulus contrast. This suggests that visual cortex functional connectivity is not fixed, but is instead modulated by stimulus contrast.

The authors use voltage-sensitive dye imaging and multielectrode recordings to show that the average population response to rapid sequences of orientations can largely be predicted by summation of the responses to each of the individual elements in the sequence. However, they find that following stimulus removal the population response is more persistent than expected.

A transient circuit that links cholinergic neuromodulation and inhibition is responsible for the dendritic compartmentalization of evoked responses in the mouse visual cortex during the critical period of robust plasticity.

Theories of consciousness have a long and controversial history. One well-known proposal — integrated information theory — has recently been labeled as ‘pseudoscience’, which has caused a heated open debate. Here we discuss the case and argue that the theory is indeed unscientific because its core claims are untestable even in principle.