Publicação
A study on the impact of transcranial magnetic stimulation over hMT+ on neural visual adaptation
| Resumo: | This study explores the mechanisms underlying visual perception by means of a bistable stimulus (plaids) and the use of transcranial magnetic stimulation (TMS) over the human middle temporal visual area (hMT+), to further investigate the TMS-adaptation paradigm. While unchanging, the bistable moving stimulus can be perceived in two different ways: leading to either a coherent or an incoherent percept. After seeing a percept for some time, adaptation occurs at the neuronal level, through mechanisms yet to uncover. With a custom plaid stimulus that allows manipulation of the percept observed, we are able to induce neuronal adaptation and observe its impact on subsequent percepts, reported by participants.TMS is believed to induce state-dependent effects. Therefore, it might interact differently with the adapted neuronal networks. By using TMS after psychophysical adaptation we seek to understand if it can cancel adaptation effects.We gathered and analysed data, in the form of subject reports of the ongoing percept during plaid visualization, from 15 participants. Additionally, after the adaptation phase of the stimulus, a single-pulse TMS over the left hMT+ or a placebo (sham) pulse over the right hemisphere was delivered. Statistical analysis was done to compare the impact of TMS versus Sham stimulation and of adaptation, on perception. Eye tracking was used for quality control.Results demonstrate that adaptation significantly changes the probability of the subsequent interpretation of the stimulus, with a tendency of coherent perception after incoherent adaptation and vice versa. However, TMS did not show significative effects in the reversal of imposed adaptation, perceptual switching or durations, suggesting responsible neuronal assemblies are out of reach of the hypothesized state dependent effects. |
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| Autores principais: | Neto, João Pedro Costa |
| Assunto: | TMS hMT+ neuronal adaptation visual cortex bistable plaid EMT hMT+ adaptação neuronal estímulos ambíguos cortéx visual |
| Ano: | 2025 |
| País: | Portugal |
| Tipo de documento: | dissertação de mestrado |
| Tipo de acesso: | acesso aberto |
| Instituição associada: | Universidade de Coimbra |
| Idioma: | inglês |
| Origem: | Estudo Geral - Universidade de Coimbra |
| Resumo: | This study explores the mechanisms underlying visual perception by means of a bistable stimulus (plaids) and the use of transcranial magnetic stimulation (TMS) over the human middle temporal visual area (hMT+), to further investigate the TMS-adaptation paradigm. While unchanging, the bistable moving stimulus can be perceived in two different ways: leading to either a coherent or an incoherent percept. After seeing a percept for some time, adaptation occurs at the neuronal level, through mechanisms yet to uncover. With a custom plaid stimulus that allows manipulation of the percept observed, we are able to induce neuronal adaptation and observe its impact on subsequent percepts, reported by participants.TMS is believed to induce state-dependent effects. Therefore, it might interact differently with the adapted neuronal networks. By using TMS after psychophysical adaptation we seek to understand if it can cancel adaptation effects.We gathered and analysed data, in the form of subject reports of the ongoing percept during plaid visualization, from 15 participants. Additionally, after the adaptation phase of the stimulus, a single-pulse TMS over the left hMT+ or a placebo (sham) pulse over the right hemisphere was delivered. Statistical analysis was done to compare the impact of TMS versus Sham stimulation and of adaptation, on perception. Eye tracking was used for quality control.Results demonstrate that adaptation significantly changes the probability of the subsequent interpretation of the stimulus, with a tendency of coherent perception after incoherent adaptation and vice versa. However, TMS did not show significative effects in the reversal of imposed adaptation, perceptual switching or durations, suggesting responsible neuronal assemblies are out of reach of the hypothesized state dependent effects. |
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