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. 2023 Aug 7:17:1221777.
doi: 10.3389/fnins.2023.1221777. eCollection 2023.

Plasticity of face-hand sensorimotor circuits after a traumatic brachial plexus injury

Fernanda de Figueiredo Torres  1   2 , Bia Lima Ramalho  1   2   3 , Marcelle Ribeiro Rodrigues  1   2 , Ana Carolina Schmaedeke  1   2 , Victor Hugo Moraes  1   2 , Karen T Reilly  4   5 , Raquel de Paula Carvalho  2   3   6 , Claudia D Vargas  1   2   3
Affiliations

Plasticity of face-hand sensorimotor circuits after a traumatic brachial plexus injury

Fernanda de Figueiredo Torres et al. Front Neurosci. .

Abstract

Background: Interactions between the somatosensory and motor cortices are of fundamental importance for motor control. Although physically distant, face and hand representations are side by side in the sensorimotor cortex and interact functionally. Traumatic brachial plexus injury (TBPI) interferes with upper limb sensorimotor function, causes bilateral cortical reorganization, and is associated with chronic pain. Thus, TBPI may affect sensorimotor interactions between face and hand representations.

Objective: The aim of this study was to investigate changes in hand-hand and face-hand sensorimotor integration in TBPI patients using an afferent inhibition (AI) paradigm.

Method: The experimental design consisted of electrical stimulation (ES) applied to the hand or face followed by transcranial magnetic stimulation (TMS) to the primary motor cortex to activate a hand muscle representation. In the AI paradigm, the motor evoked potential (MEP) in a target muscle is significantly reduced when preceded by an ES at short-latency (SAI) or long-latency (LAI) interstimulus intervals. We tested 18 healthy adults (control group, CG), evaluated on the dominant upper limb, and nine TBPI patients, evaluated on the injured or the uninjured limb. A detailed clinical evaluation complemented the physiological investigation.

Results: Although hand-hand SAI was present in both the CG and the TBPI groups, hand-hand LAI was present in the CG only. Moreover, less AI was observed in TBPI patients than the CG both for face-hand SAI and LAI.

Conclusion: Our results indicate that sensorimotor integration involving both hand and face sensorimotor representations is affected by TBPI.

Keywords: afferent inhibition; brachial plexus lesion; corticospinal excitability; deafferentation; pain; transcranial magnetic stimulation.

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Conflict of interest statement

The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest.

Figures

Figure 1
Figure 1
Experimental groups. Control group (in blue, on the left) was assessed on the dominant upper limb. The TBPI group was composed of TBPI-I and TBPI-UI subgroups. The TBPI-I subgroup (in green, center) was formed by participants with at least partial sensorimotor function in the hand of the injured side, allowing it to be evaluated using the afferent inhibition protocol. The TBPI-UI subgroup (in red, on the right) was formed by participants with a total absence of sensorimotor function in the affected hand. Thus, they were assessed on the uninjured side. Peripheral electrical stimulation (indicated by a ray symbol) was applied either on the tip of the ipsilateral index finger or above the upper lip, depending on the experimental condition. Transcranial magnetic stimulation was applied over the scalp contralateral to the assessed limb.
Figure 2
Figure 2
Short afferent inhibition (SAI) and long afferent inhibition (LAI) results. (A, C) Hand–hand interaction: peripheral electrical stimulation applied on the tip of the index finger followed by contralateral transcranial magnetic stimulation over the first dorsal interosseous hot spot. (B, D) Face–hand interaction: peripheral electrical stimulation applied on the face, above the upper lip, followed by contralateral transcranial magnetic stimulation over the first dorsal interosseous hot spot. Different interstimulus intervals were applied (15–65 ms for SAI and 100–400 ms for LAI). Group mean motor evoked potential amplitudes for each interstimulus interval were normalized to the TMS-only mean MEP amplitude (transcranial magnetic stimulation without previous peripheral electrical stimulation) in that experimental condition. Control group (blue); TBPI group, all TBPI participants (gray). Bars represent the standard error of the mean. Values below the dotted line at 100% indicate an inhibition effect, and values above the dotted line indicate a disinhibition effect. Repeated-measures one-way ANOVA and Dunnett's post-test were performed for within-group analysis. Two-way ANOVAs and Šidák's post-test were used for between-group comparisons. *p < 0.05; *above bar indicates significant results at within-group analysis; and *above brackets indicate significant results in between-group analysis. Repeated-measures one-way ANOVA and Dunnett's post-test results. (A) CG: F3.231, 35.54 = 5.824, p = 0.002; 25 ms: p = 0.036, 95% C.I. = [0.014; 0.432], 35 ms: p = 0.012, 95% C.I. = [0.067; 0.539], 45 ms: p = 0.005, 95% C.I. = [0.108; 0.577], and 55 ms: p = 0.009, 95% C.I. = [0.086; 0.597]. TBPI: F2.615, 18.30 = 5.753, p = 0.008; 45 ms: p = 0.028, 95% C.I. = [0.050; 0.773]. (B) CG: F2.735, 27.35 = 1.511, p = 0.236. TBPI: F2.112, 12.67 = 1.094, p = 0.368. (C) CG: F2.015, 20.15 = 3.772, p = 0.040; 100 ms: p = 0.008, 95% C.I. = [0.088; 0.540]. TBPI: F2.492, 14.95 = 2.780, p = 0.085. (D) CG: F2.139, 21.39 = 0.6515, p = 0.541. TBPI: F1.855, 11.13 = 2.159, p = 0.163. Two-way ANOVAs results can be found in the text.
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References

    1. Alle H., Heidegger T., Kriváneková L., Ziemann U. (2009). Interactions between short-interval intracortical inhibition and short-latency afferent inhibition in human motor cortex. J. Physiol. 587, 5163–5176. 10.1113/jphysiol.2009.179820 - DOI - PMC - PubMed
    1. Asmussen M. J., Jacobs M. F., Lee K. G. H., Zapallow C. M., Nelson A. J. (2013). Short-latency afferent inhibition modulation during finger movement. PLoS ONE 8, e60496. 10.1371/journal.pone.0060496 - DOI - PMC - PubMed
    1. Asmussen M. J., Zapallow C. M., Jacobs M. F., Lee K. G., Tsang P., Nelson A. J. (2014). Modulation of short-latency afferent inhibition depends on digit and task-relevance. PLoS ONE. 9, e104807. 10.1371/journal.pone.0104807 - DOI - PMC - PubMed
    1. Batista e Sá V. W., Gomes M. K., Rangel M. L. S., Sanchez T. A., Moreira F. A., Hoefle S., et al. . (2015). Primary motor cortex representation of handgrip muscles in patients with leprosy. PLoS Negl. Trop. Dis. 9, e0003944. 10.1371/journal.pntd.0003944 - DOI - PMC - PubMed
    1. Bhat D. I., Devi B. I., Bharti K., Panda R. (2017). Cortical plasticity after brachial plexus injury and repair: a resting-state functional MRI study. Neurosurg. Focus 42, E14. 10.3171/2016.12.FOCUS16430 - DOI - PubMed

Grants and funding

This study was part of the Research, Innovation, and Diffusion in Neuromathematics project (CEPID NeuroMat, FAPESP 2013/07699-0) and the Brain Plasticity after Brachial Plexus Injury projects (FAPERJ E-26/010.002474/2016, CNE 202.785/2018, and E-26/010.002418/2019). It received funding from FINEP (PROINFRA HOSPITALAR 18.569-8). This research was also supported by the Conselho Nacional de Desenvolvimento Científico e Tecnológico, CNPq (grant number 310397/2021). FT was supported by a doctoral grant (CAPES 88882.332096/2019-01) and a postdoctoral grant (FAPERJ E-26/200.214/2022). BR was supported by a FAPESP grant (#2022/00582-9).

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