Tms V5 Mt Modulates Thalamus Visual Speech

---
name: tms-v5-mt-modulates-thalamus-visual-speech
description: "TMS modulates thalamus during visual speech recognition."
metadata:
  arxiv_id: "2608.19034"
  published: "2026-08-19"
  authors: "Jeschke, Lisa; Mueller-Axt, Christa; Tabas, Alejandro; Diaz, Begona; von Kriegstein, Katharina"
  tags: [transcranial-magnetic-stimulation, visual-speech-recognition, corticothalamic-feedback, fMRI, lateral-geniculate-nucleus, V5-MT]
license: Complete terms in LICENSE.txt
---

# Transcranial Magnetic Stimulation of V5/MT Modulates Thalamus Responses

## Overview

This study investigates whether sensory thalamic response modulations during perceptual tasks rely on feedback from cerebral cortex in humans. Specifically, it examines the role of visual-motion area V5/MT in modulating lateral geniculate nucleus (LGN) responses during visual speech recognition.

## Key Findings

- **Corticothalamic feedback mechanism**: Visual association cortex (V5/MT) has a causal role in modulating LGN responses during speech recognition
- **TMS intervention**: Inhibitory TMS over bilateral V5/MT significantly reduced LGN signal modulation between visual speech and color tasks
- **Functional connectivity**: V5/MT stimulation reduced task-dependent functional connectivity between V5/MT and LGN
- **Experimental design**: 26 healthy adults performed visual speech and color recognition tasks on identical muted videos during fMRI

## Methodology

### Experimental Design
1. **Participants**: 26 healthy adults
2. **Stimulation**: Inhibitory TMS over bilateral V5/MT vs Vertex (active control)
3. **Tasks**: Visual speech recognition vs color recognition on identical muted speaking face videos
4. **Imaging**: fMRI during task performance
5. **Analysis**: BOLD response analysis in LGN, functional connectivity between V5/MT and LGN

### Key Measurements
- **LGN BOLD responses**: Differential responses to visual speech vs non-speech control tasks
- **Task-dependent modulation**: Signal change between visual speech and color tasks
- **Functional connectivity**: Task-dependent connectivity between V5/MT and LGN

## Implications

### Theoretical Implications
- **Corticothalamic feedback**: Provides causal evidence for top-down modulation of thalamic processing
- **Visual speech processing**: Demonstrates specific role of motion-sensitive areas in speech recognition
- **Sensory processing**: Shows that even basic sensory nuclei are influenced by higher-order cortical areas

### Clinical Applications
- **Speech disorders**: Potential therapeutic target for visual speech processing deficits
- **Thalamic dysfunction**: Understanding corticothalamic mechanisms in sensory processing disorders
- **Neuromodulation**: TMS protocols for modulating thalamocortical circuits

## Implementation Guidelines

### For Research Replication
1. **TMS targeting**: Use neuronavigation for precise V5/MT localization
2. **Stimulus design**: Create matched visual speech and control stimuli
3. **fMRI analysis**: Focus on LGN and V5/MT regions of interest
4. **Connectivity analysis**: Use psychophysiological interaction (PPI) or dynamic causal modeling (DCM)

### For Clinical Translation
1. **Patient selection**: Consider individuals with visual speech recognition deficits
2. **Protocol optimization**: Determine optimal TMS parameters for therapeutic effect
3. **Outcome measures**: Develop behavioral and neuroimaging biomarkers

## Activation Keywords

- transcranial magnetic stimulation
- visual speech recognition
- corticothalamic feedback
- lateral geniculate nucleus
- V5/MT area
- fMRI thalamus
- sensory thalamus modulation
- visual-motion cortex

## References

- Original paper: https://arxiv.org/abs/2608.19034
- Related work: tms-eeg-biomarkers, brain-network-controllability, functional-connectivity-graph-neural-networks