2022.10.07

Cerebrocortical activation following unilateral labyrinthectomy in mice characterized by whole-brain clearing: implications for sensory reweighting

Sci Rep. 2022 Sep 14;12(1):15424. doi: 10.1038/s41598-022-19678-4.

Kai R1,2, Takahashi K1, Tainaka K3, Iwakura Y2,4, Namba H2, Saito N5, Sasaoka T5, Yamaguchi S6, Nawa H2, Horii A1

1Department of Otolaryngology Head and Neck Surgery, Niigata University Graduate School of Medical and Dental Sciences.
2Department of Molecular Neurobiology, Brain Research Institute, Niigata University.
3Department of System Pathology for Neurological Disorders, Brain Research Institute, Niigata University.
4Department of Brain Tumor Biology, Brain Research Institute, Niigata University.
5Department of Comparative and Experimental Medicine, Brain Research Institute, Niigata University.
6Department of Morphological Neuroscience, Gifu University Graduate School of Medicine.

Abstract

Posture and gait are maintained by sensory inputs from the vestibular, visual, and somatosensory systems and motor outputs. Upon vestibular damage, the visual and/or somatosensory systems functionally substitute by cortical mechanisms called "sensory reweighting". We investigated the cerebrocortical mechanisms underlying sensory reweighting after unilateral labyrinthectomy (UL) in mice. Arc-dVenus transgenic mice, in which the gene encoding the fluorescent protein dVenus is transcribed under the control of the promoter of the immediate early gene Arc, were used in combination with whole-brain three-dimensional (3D) imaging. Performance on the rotarod was measured as a behavioral correlate of sensory reweighting. Following left UL, all mice showed the head roll-tilt until UL10, indicating the vestibular periphery damage. The rotarod performance worsened in the UL mice from UL1 to UL3, which rapidly recovered. Whole-brain 3D imaging revealed that the number of activated neurons in S1, but not in V1, in UL7 was higher than that in sham-treated mice. At UL7, medial prefrontal cortex (mPFC) and agranular insular cortex (AIC) activation was also observed. Therefore, sensory reweighting to the somatosensory system could compensate for vestibular dysfunction following UL; further, mPFC and AIC contribute to the integration of sensory and motor functions to restore balance.

*Reprinted under the terms of the Creative Commons Attribution License (CC BY).

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System Pathology for Neurological Disorders -Tainaka Lab
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