Locomotion modulates specific functional cell types in the mouse visual thalamus

Abstract

The visual system is composed of diverse cell types that encode distinct aspects of the visual scene and may form separate processing channels. Here we present further evidence for that hypothesis whereby functional cell groups in the dorsal lateral geniculate nucleus (dLGN) are differentially modulated during behavior. Using simultaneous multi-electrode recordings in dLGN and primary visual cortex (V1) of behaving mice, we characterized the impact of locomotor activity on response amplitude, variability, correlation and spatiotemporal tuning. Locomotion strongly impacts the amplitudes of dLGN and V1 responses but the effects on variability and correlations are relatively minor. With regards to tunings, locomotion enhances dLGN responses to high temporal frequencies, preferentially affecting ON transient cells and neurons with nonlinear responses to high spatial frequencies. Channel specific modulations may serve to highlight particular visual inputs during active behaviors.

Distinct Mechanisms for Visual and Motor-Related Astrocyte Responses in Mouse Visual Cortex

“…Visual responses in astrocytes were strong during locomotion, but almost absent during periods of stillness. Previous studies in head-fixed mice have demonstrated a clear link between locomotion and elevated arousal [15, 19, 20]. Accordingly, astrocyte responses were not only gated by locomotion but response amplitudes were also correlated with changes in pupil size [14, 16, 17].…”

Corticothalamic feedback sculpts visual spatial integration in mouse thalamus

“…We then functionally mapped the spatial profile of CT feedback effects by photostimulating the local population of transduced L6CT pyramidal cells during the presentation of full-screen drifting gratings ( Figure 1i ). To avoid potentially confounding, state-dependent response-modulations 41, 42 , we only considered trials in which the animal was quiescent (speed ≤ 0.25 cm/s for ≥ 80% of the trial) for the computation of direction-tuning curves and thus for the evaluation of CT feedback effects. From these curves ( Figure 1i , top), we determined, for each neuron, the relative CT feedback modulation strength as the ratio of responses under L6CT photostimulation to those seen under control conditions (fold change).…”

Reward Association Enhances Stimulus-Specific Representations in Primary Visual Cortex

“…As a growing number of studies demonstrate altered levels of neuronal activity according to behavioral-state-dependent changes, in subcortical regions, such as the superior colliculus [43], thalamus [24,44,45], and cerebellum [46][47][48], as well as contextual and experience-dependent changes in higher cortical areas with reciprocally connections to V1 [49], such as the retrosplenial cortex [50][51][52][53][54], the anterior cingulate cortex [35,55], parietal cortex [56], and visual association cortex [41,57,58], it seems likely that these experience-dependent changes in V1 involve modulation of activity in circuits at multiple processing levels. Additionally, neuromodulatory inputs likely play an important role in behavioral-state-dependent plasticity, as cholinergic and noradrenergic influence have already been shown to modulate cortical plasticity, attention, and learning [59,60] in V1, as well as responses to locomotion and behavioral-state changes [22,25,61,62].…”