Gamma rhythms and visual information in mouse V1 specifically modulated by somatostatin+ neurons in reticular thalamus

Abstract

Visual perception in natural environments depends on the ability to focus on salient stimuli while ignoring distractions. This kind of selective visual attention is associated with gamma activity in the visual cortex. While the nucleus reticularis thalami (nRT) has been implicated in selective attention, its role in modulating gamma activity in the visual cortex remains unknown. Here we show that somatostatin- (SST) but not parvalbumin-expressing (PV) neurons in the visual sector of the nRT preferentially project to the dorsal lateral geniculate nucleus (dLGN), and modulate visual information transmission and gamma activity in primary visual cortex (V1). These findings pinpoint the SST neurons in nRT as powerful modulators of the visual information encoding accuracy in V1, and represent a novel circuit through which the nRT can influence representation of visual information.

The synaptic inputs and thalamic projections of two classes of layer 6 corticothalamic neurons in primary somatosensory cortex of the mouse

“…Finally, the retina was washed six times (10 min each) in PBS and mounted in Vectashield between a microscope slide and a precision (Crabtree, 2018;Pinault, 2004), distinguishing them from L5 CThNs in primary sensory cortices which do not target TRN (Deschênes et al, 1994;Guillery, 1995;Veinante et al, 2000). Not only is the TRN topographically organized, but anatomical, molecular and functional studies indicate that the somatosensory TRN (ssTRN) is further divided into sublaminae, each targeted by distinct sets of TC axons (Clemente-Perez et al, 2017;Hoseini et al, 2021;Lam & Sherman, 2007;Lee et al, 2014;Martinez-Garcia et al, 2020;Pinault et al, 1995). Axon collaterals from POm TC neurons target the outer edges of the TRN, the shell, which includes somatostatin-expressing (SOM) TRN neurons (Clemente-Perez et al, 2017;Martinez-Garcia et al, 2020).…”

Secondary thalamic neuroinflammation after focal cortical stroke and traumatic injury mirrors corticothalamic functional connectivity

“…To determine more precisely how this key structure affects the site of thalamic inflammation secondary to cortical injury, we examined the effects of stroke and TBI on the location of neuroinflammation in various sectors of the nRT. The nRT can be roughly subdivided into three components with distinct functional specializations: the head, which connects to the visual thalamocortical nuclei (Campbell et al., 2020; Hoseini et al., 2021), the body, which connects to the somatosensory thalamocortical nuclei (Clemente‐Perez et al., 2017; Lam & Sherman, 2011), and the tail, which connects to the limbic thalamocortical nuclei and to a lesser extent the motor thalamus (Crabtree, 2018; Lozsadi, 1994; Zikopoulos & Barbas, 2006; Cornwall et al., 1990; Lee et al., 2019; Zikopoulos & Barbas, 2012). The nRT also receives cortical projections that are topographically segregated according to the function of their cortical origin (Crabtree, 1992; Lam & Sherman, 2011).…”

“…The nRT sends GABAergic inputs to the thalamocortical nuclei in a manner that mirrors the topographical organization of thalamocortical circuits. For example, the head of the nRT is thought to modulate visual information because it projects to the dLGN (Campbell et al., 2020; Hoseini et al., 2021). Similarly, the body of the nRT is primarily devoted to somatosensory processing and projects to first and higher order somatosensory thalamic nuclei, while the tail is considered a prefrontal or limbic center and contains neurons that project to higher order limbic thalamic nuclei, with some role in motor processing (Crabtree, 2018; Zikopoulos & Barbas, 2006; Collins et al., 2018).…”

Rodents’ visual gamma as a biomarker of pathological neural conditions

“…A large body of research in awake animals has focused on the effects that behavioural and internal state signals exert on V1 activity. Gamma V1 peak and power are increased by locomotion (Hoseini et al., 2021; Hoy & Niell, 2015), speed of motion (Niell & Stryker, 2010; Saleem et al., 2017) and arousal or attention (Vinck et al., 2015). Additionally, other sensory modalities, especially auditory, exert a strong influence on visual cortical activity (Deneux et al., 2019; Garner & Keller, 2022; Ibrahim et al., 2016; McClure & Polack, 2019; Meijer et al., 2017; but see also Bimbard et al., 2023 for differing perspectives) and specifically on visual gamma oscillations (Iurilli et al., 2012; Lemercier et al., 2023; Yuval‐Greenberg & Deouell, 2007).…”