Biology subjects

Kosugi, A.

Publications and source records attributed to Kosugi, A..

3 recordsLinked to original sources

bioRxiv2025

Protocol for intra-nerve AAV injection and dorsal root potential recording for optogenetic modulation of the peripheral sensory nerve activity

Optogenetic modulation of peripheral sensory nerve activity holds great potential for the treatment of sensory disorders. Here, we present a protocol for applying optogenetic techniques to peripheral sensory nerves using an adeno-associated virus (AAV) vector. We describe the procedure for gene transduction into dorsal root ganglion neurons via retrograde transport following intra-nerve AAV injection. We then outline a terminal, acute electrophysiological experiment to evaluate optogenetic effects at the level of the dorsal root. For complete details on the use and execution of this protocol, please refer to Kosugi et al1. Graphical abstract O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=195 SRC="FIGDIR/small/693516v1_ufig1.gif" ALT="Figure 1"> View larger version (33K): org.highwire.dtl.DTLVardef@5a2de4org.highwire.dtl.DTLVardef@7ad4f0org.highwire.dtl.DTLVardef@32113aorg.highwire.dtl.DTLVardef@10918c9_HPS_FORMAT_FIGEXP M_FIG C_FIG

neuroscience↗

bioRxiv2024

Bidirectional Optogenetic Modulations of Peripheral Sensory Nerve Activity: Induction vs. Suppression through Channelrhodopsin and Halorhodopsin

In this study, we investigated the potential of optogenetics for modulating activity of peripheral sensory nerves, particularly tactile and proprioceptive afferents, which are vital for movement control. Using adeno-associated virus serotype 9 vector, we selectively transduced channelrhodopsin (ChR2) and halorhodopsin (eNpHR3.0) into large-diameter sciatic nerve afferents of rats. Diverging from conventional dorsal root ganglion (DRG) approaches, we applied optical stimulation at the distal portion of the afferent nerve. The intensity of optical stimulation varied to modulate the extent of induction and suppression of afferent activity. Then, the effect of optical stimulation was determined by the activity recorded in the dorsal root of the same afferents. Our findings show successful induction and suppression of activity in large-diameter afferents via optical stimulation. By increasing the intensity of blue (for ChR2) and yellow (for eNpHR3.0) light stimulation, the activity of fast-conducting afferent fibers was preferentially evoked or inhibited in an intensity-dependent manner. These data indicate that the activity of large-diameter afferents can systematically be regulated by optogenetics. The present innovative methodology for manipulating specific sensory modalities at the nerve level offers a targeted and accessible alternative to DRG stimulation, expanding the therapeutic scope of optogenetics for treating sensory disorders.

neuroscience↗

bioRxiv2024

Posture-dependent modulation of marmoset cortical motor maps detected via rapid multichannel epidural stimulation

In this study, rapid topographical changes were detected in the forelimb motor maps in the primary motor cortex (M1) of awake marmoset monkeys using our previously developed accurate short-time stimulation mapping procedure (Takemi et al. 2017; Kosugi et al. 2018). The results revealed that although the hotspot (the location in M1 that elicited a forelimb muscle twitch with the lowest stimulus intensity) remained constant across postures, the stimulus intensity required to elicit the forelimb muscle twitch in the perihotspot region and the size of motor representations were posture-dependent. Hindlimb posture was particularly effective in inducing these modulations. The angle of the body axis relative to the gravitational vertical line did not alter the motor maps. These results provide a proof of concept that a rapid stimulation mapping system with chronically implanted cortical electrodes can capture the dynamic regulation of forelimb motor maps in natural conditions. The flexible nature of the motor maps necessitates the reconsideration of the results of motor control and neuroplasticity studies. Neural mechanisms regulating forelimb muscle representations in M1 by the hindlimb sensorimotor state warrant further exploration.

neuroscience↗