Gain control in the sensorimotor system

Azim, Eiman; Seki, Kazuhiko

doi:10.1016/j.cophys.2019.03.005

Cited by 57 publications

(51 citation statements)

References 68 publications

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“…It might be possible that backward signals did not modulate the strength of suppression because afferent information associated with generating and maintaining adequate grasping forces was relevant for controlling the task 30 , 31 . In this case, the need to process sensory feedback signals from the grasping digits might compromise any suppression of afferent information from these digits.…”

Section: Discussionmentioning

confidence: 99%

The influence of afferent input on somatosensory suppression during grasping

Broda

Fiehler

Voudouris

2020

Sci Rep

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The processing of somatosensory information is hampered on a moving limb. This suppression has been widely attributed to sensorimotor predictions that suppress the associated feedback, though postdictive mechanisms are also involved. Here, we investigated the extent to which suppression on a limb is influenced by backward somatosensory signals, such as afferents associated with forces that this limb applies. Participants grasped and lifted objects of symmetric and asymmetric mass distributions using a precision grip. We probed somatosensory processing at the moment of the grasp by presenting a vibrotactile stimulus either on the thumb or index finger and asked participants to report if they felt this stimulus. Participants applied greater forces with the thumb and index finger for objects loaded to the thumb’s or index finger’s endpoint, respectively. However, suppression was not influenced by the different applied forces. Suppression on the digits remained constant both when grasping heavier objects, and thus applying even greater forces, and when probing suppression on the skin over the muscle that controlled force application. These results support the idea that somatosensory suppression is predictive in nature while backward masking may only play a minor role in somatosensory processing on the moving hand, at least in this context.

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Section: Discussionmentioning

confidence: 99%

The influence of afferent input on somatosensory suppression during grasping

Broda

Fiehler

Voudouris

2020

Sci Rep

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“…Sparsification of cortical activity also occurs contemporaneously with the sudden emergence of local inhibition in cortex (Ben-Ari et al, 2007;Dooley and Blumberg, 2018;Colonnese, 2014). Given that inhibitory neurons modulate cortical sensory processing in adults (Wood et al, 2017;Azim and Seki, 2019), the emergence of inhibition in M1 may explain the developmental reduction in redundant tuning properties we observed here at P12.…”

Section: Population Activity In Developing M1mentioning

confidence: 57%

A developmental transition in the sensory coding of limb kinematics in primary motor cortex

Glanz

Dooley

Sokoloff

et al. 2020

Preprint

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Primary motor cortex (M1) undergoes protracted development in rodents, functioning initially as a sensory structure. As we reported previously in neonatal rats (Dooley and Blumberg, 2018), self-generated forelimb movements—especially the twitch movements that occur during active sleep—trigger sensory feedback (reafference) that strongly activates M1. Here, we expand our investigation by using a video-based approach to quantify the kinematic features of forelimb movements with sufficient precision to reveal receptive-field properties of individual M1 units. At postnatal day (P) 8, nearly all M1 units were strongly modulated by movement amplitude, but only during active sleep. By P12, the majority of M1 units no longer exhibited amplitude-dependence, regardless of sleepwake state. At both ages, movement direction produced changes in M1 activity, but to a much lesser extent than did movement amplitude. Finally, we observed that population spiking activity in M1 becomes more continuous and decorrelated between P8 and P12. Altogether, these findings reveal that M1 undergoes a sudden transition in its receptive field properties and population-level activity during the second postnatal week. This transition marks the onset of the next stage in M1 development before the emergence of its later-emerging capacity to influence motor outflow.

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“…They receive both descending cortical and proprioceptive afferent input and form monosynaptic contacts onto premotor neurons and motor neurons [ 44 ]. The diversity of convergent excitatory drive onto these integrative populations highlights the need for inhibitory gating mechanisms to select context-relevant stimuli in order to elicit the appropriate behavioral response [ 13 , 59 , 64 ].…”

Section: Excitatory Input To Sensorimotor Pathwaysmentioning

confidence: 99%

Spinal Inhibitory Interneurons: Gatekeepers of Sensorimotor Pathways

Stachowski

Dougherty

2021

IJMS

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The ability to sense and move within an environment are complex functions necessary for the survival of nearly all species. The spinal cord is both the initial entry site for peripheral information and the final output site for motor response, placing spinal circuits as paramount in mediating sensory responses and coordinating movement. This is partly accomplished through the activation of complex spinal microcircuits that gate afferent signals to filter extraneous stimuli from various sensory modalities and determine which signals are transmitted to higher order structures in the CNS and to spinal motor pathways. A mechanistic understanding of how inhibitory interneurons are organized and employed within the spinal cord will provide potential access points for therapeutics targeting inhibitory deficits underlying various pathologies including sensory and movement disorders. Recent studies using transgenic manipulations, neurochemical profiling, and single-cell transcriptomics have identified distinct populations of inhibitory interneurons which express an array of genetic and/or neurochemical markers that constitute functional microcircuits. In this review, we provide an overview of identified neural components that make up inhibitory microcircuits within the dorsal and ventral spinal cord and highlight the importance of inhibitory control of sensorimotor pathways at the spinal level.

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Gain control in the sensorimotor system

Cited by 57 publications

References 68 publications

The influence of afferent input on somatosensory suppression during grasping

The influence of afferent input on somatosensory suppression during grasping

A developmental transition in the sensory coding of limb kinematics in primary motor cortex

Spinal Inhibitory Interneurons: Gatekeepers of Sensorimotor Pathways

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