Robust effects of corticothalamic feedback and behavioral state on movie responses in mouse dLGN

Abstract

Neurons in the dorsolateral geniculate nucleus (dLGN) of the thalamus receive a substantial proportion of modulatory inputs from corticothalamic (CT) feedback and brain stem nuclei. Hypothesizing that these modulatory influences might be differentially engaged depending on the visual stimulus and behavioral state, we performed in vivo extracellular recordings from mouse dLGN while optogenetically suppressing CT feedback and monitoring behavioral state by locomotion and pupil dilation. For naturalistic movie clips, we found CT feedback to consistently increase dLGN response gain and promote tonic firing. In contrast, for gratings, CT feedback effects on firing rates were mixed. For both stimulus types, the neural signatures of CT feedback closely resembled those of behavioral state, yet effects of behavioral state on responses to movies persisted even when CT feedback was suppressed. We conclude that CT feedback modulates visual information on its way to cortex in a stimulus-dependent manner, but largely independently of behavioral state.

Mega-scale movie-fields in the mouse visuo-hippocampal network

“…Among the visual areas, continuous movie tuning was greater in V1, more than the upstream LGN. This is surprising but can explain the recent findings that silencing V1 reduces movie tuning in the thalamus 61 . Similarly, the preference for the continuous movie over scrambled sequence was greater in LGN and AM-PM than V1, which does not follow the expected hierarchy of visual processing.…”

Sensory cortical ensembles exhibit differential coupling to ripples in distinct hippocampal subregions

“…The thalamus acts as a state-dependent gate for sensory inputs to the cortex (Aydın et al, 2018; Busse, 2018; Erisken et al, 2014; Liang et al, 2020; Molnár et al, 2021; Reinhold et al, 2023; Spacek et al, 2022; Williamson et al, 2015). Thalamic activity decreases around hippocampal ripples (Logothetis et al, 2012; Logothetis, 2015; Lara-Vásquez et al, 2016; Yang et al, 2019; Chambers et al, 2022), potentially preventing sensory stimuli from interfering with ripple-related neural processing.…”

Primary Somatosensory Cortex Bidirectionally Modulates Sensory Gain and Nociceptive Behavior in a Layer-Specific Manner

“…The robust aversive effects of L6-CT were unexpected, as existing research has primarily studied L6-CT in purely sensory contexts and left unresolved how L6-CT functions link to subjective sensory experiences and to the modulation of behavior. It is broadly established that L6-CT pathways endow sensory systems with 'beneficial' information processing functions, such as controlling sensory gain 7,8,11,54,60 , tuning selectivity, and mediating bursttonic transitions in the thalamus 10,12,61 . Such sensory functions for L6-CT neurons have not yet been revealed in the S1 hindlimb cortex.…”

“…Advances in recording technology and cell-type-specific interventions have allowed delineation of cell-type-specific contributions to gain control, particularly between specific cortical output pathways from pyramidal tract (PT) neurons in layer 5 (L5), which target diverse subcortical structures, and corticothalamic (CT) neurons in layer 6 (L6) 5,6 . The emerging consensus is that L6-CT neurons of primary sensory cortices control cortical gain by simultaneously recruiting cortical inhibitory neurons [7][8][9] and modulating multiple cellular and circuit mechanisms in the thalamus 1,[10][11][12][13][14] .…”