Biology subjects

Busse, L.

Publications and source records attributed to Busse, L..

3 recordsLinked to original sources

bioRxiv2018

Mouse dLGN receives input from a diverse population of retinal ganglion cells with limited convergence

In the mouse, the parallel output of more than 30 functional types of retinal ganglion cells (RGCs) serves as the basis for all further visual processing. Little is known about how the representation of visual information changes between the retina and the dorsolateral geniculate nucleus (dLGN) of the thalamus, the main relay station between the retina and cortex. Here, we functionally characterized responses of retrogradely labeled dLGN-projecting RGCs and dLGN neurons to the same set of visual stimuli. We found that many of the previously identified functional RGC types innervate the dLGN, which maintained a high degree of functional diversity. Using a linear model to assess functional connectivity between RGC types and dLGN neurons, we found that the responses of dLGN neurons could be predicted as a linear combination of inputs from on average five RGC types, but only two of those had the strongest functional impact. Thus, mouse dLGN receives input from a diverse population of RGCs with limited functional convergence.

neuroscience↗

bioRxiv2018

Layer 3 dynamically coordinates columnar activity during spatial integration in mouse V1

Spatial integration is a fundamental, context-dependent neural operation that involves extensive neural circuits across cortical layers of V1. To better understand how spatial integration is dynamically coordinated across layers we recorded single- and multi-unit activity and local field potentials across V1 layers of awake mice, and used dynamic Bayesian model comparisons to identify when laminar activity and inter-laminar functional interactions showed surround suppression, the hallmark of spatial integration. We found that surround suppression is strongest in layer 3 (L3) and L4 activity, showing rapidly sharpening receptive fields and increasing suppression strength. Importantly, we also found that specific directed functional connections were strongest for intermediate stimulus sizes and suppressed for larger ones, particularly for the L3->L5 and L3->L1 connections. Taken together, the results shed light on the different functional roles of cortical layers in spatial integration and show how L3 dynamically coordinates activity across a cortical column depending on spatial context.

neuroscience↗

bioRxiv2016

Learning enhances sensory processing in mouse V1 before improving behavior

A fundamental property of visual cortex is to enhance the representation of those stimuli that are relevant for behavior, but it remains poorly understood how such enhanced representations arise during learning. Using classical conditioning in mice, we show that orientation discrimination is learned in a sequence of distinct behavioral stages, in which animals first rely on stimulus appearance before exploiting its orientation to guide behavior. After confirming that orientation discrimination under classical conditioning requires primary visual cortex (V1), we measured, during learning, response properties of V1 neurons. Learning improved neural discriminability, sharpened orientation tuning and led to higher contrast sensitivity. Remarkably, these learning-related improvements in the V1 representation were fully expressed before successful orientation discrimination was evident in the animals behavior. We propose that V1 plays a key role early in discrimination learning to enhance behaviorally relevant sensory information.

neuroscience↗