| Reference code: | PT/FB/BL-2018-347.12 |
| Location: | BF-GMS
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Title:
| Impairments of visually-guided reach plans after transcranial magnetic stimulation over the human medial posterior parietal cortex
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| Publication year: | 2021
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URL:
| https://jov.arvojournals.org/article.aspx?articleid=2776919
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| Abstract/Results: | ABSTRACT:
The medial posterior parietal cortex (mPPC) is involved in the visual guidance of reaching. Although several studies investigated reaching performed towards different directions, only a few correlational studies investigated different depths. Here, we studied the causal role of mPPC (putatively, human area V6A - hV6A) in encoding depth and direction of reaching performed under visual guidance. Fifteen healthy humans performed a visually-guided reaching task which required different eye-hand configurations (foveal and peripheral reaching): Constant gaze configuration (central gaze fixation while reaching to one of 8 peripheral targets); Constant reach configuration (reaching to the central target while fixating one of 8 peripheral targets); Foveal reach configuration (coincident fixation and reaching targets). We applied single-pulse transcranial magnetic stimulation (TMS) over the left hV6A at 100 or 200 ms after reaction time onset, over area V1 to check for non-specific effect of TMS, and in a SHAM condition with the coil tilted 90° over the vertex. We found a site-specific and time-dependent effect: in particular, TMS delivered over hV6A 200ms after the Go signal affected the encoding of the depth of reaching by decreasing the accuracy (in depth) of movements towards targets located farther with respect to the gazed position, but only when they were far from the body (Constant gaze configuration: repeated-measure ANOVA, Stimulation Condition x Stimulation Time x Depth interaction, F(4,56) = 3.00; p = 0.03, partial ?2 = 0.17). Reach end-point precision was not affected by TMS over hV6A. The effectiveness of both retinotopic (farther with respect to the gaze) and spatial (far from the body) position is in agreement with the presence in the monkey V6A of neurons employing either retinotopic, spatial, or mixed reference frames during reach plan. This work provides the first causal evidence of the critical role of hV6A in planning visually-guided reaching movements in depth.
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| Accessibility: | Document does not exist in file
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Language:
| eng
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Author:
| Breveglieri, R.
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Secondary author(s):
| Bosco, A., Borgomaneri, S., Tessari, A., Galletti, C., Avenanti, A., Fattori, P.
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Document type:
| Abstract
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Number of reproductions:
| 1
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Reference:
| Breveglieri, R., Bosco, A., Borgomaneri, S., Tessari, A., Galletti, C., Avenanti, A., & Fattori, P. (2021). Impairments of visually-guided reach plans after transcranial magnetic stimulation over the human medial posterior parietal cortex. Journal of Vision, 21(9), 2042. https://doi.org/10.1167/jov.21.9.2042
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| Indexed document: | No
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| Keywords: | Reaching movements / Medial posterior parietal cortex
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