Investigating occipito-temporal contributions to reading with TMS

Area of Science:

• Neuroscience
• Cognitive Science
• Psycholinguistics

Background:

• The precise role of the ventral occipito-temporal cortex (vOTC) in visual word recognition remains debated.
• Delineating vOTC's function is challenging due to its integration within the broader reading network.
• Previous research faced difficulties in isolating vOTC's specific contributions.

Purpose of the Study:

• To investigate the feasibility of using transcranial magnetic stimulation (TMS) to probe vOTC's role in visual word recognition.
• To determine if TMS can specifically interfere with vOTC processing.
• To explore the temporal dynamics of vOTC involvement in reading.

Main Methods:

• Three visual lexical decision experiments utilizing neuronavigated TMS.
• Repetitive TMS applied to vOTC to assess disruption effects on word and nonword processing.
• Paired-pulse TMS employed to investigate the time course of vOTC activation.

Main Results:

• Repetitive TMS over vOTC significantly slowed word recognition, but not nonword recognition.
• The observed effect was specific to vOTC, with no significant impact on the adjacent lateral occipital complex.
• Paired-pulse TMS indicated vOTC activation as early as 80-120 ms post-stimulus onset.
• Lexical status and word frequency were found to significantly influence vOTC processing.

Conclusions:

• TMS is a viable tool for stimulating and investigating previously inaccessible parts of the vOTC.
• The findings provide strong evidence for vOTC's critical and early involvement in visual word recognition.
• Results challenge prelexical accounts of vOTC function, supporting its role in higher-level lexical processing.