Transcranial magnetic stimulation in study of the visual pathway

Area of Science:

• Neuroscience
• Cognitive Science
• Neuroimaging

Background:

• Transcranial magnetic stimulation (TMS) offers a non-invasive method to investigate brain function.
• The higher visual pathway is crucial for complex visual processing.
• Understanding neural mechanisms in visual perception requires precise stimulation techniques.

Purpose of the Study:

• To critically review experimental findings using TMS and repetitive TMS (rTMS) on the higher visual pathway.
• To elucidate the basic mechanisms of neural excitation and inhibition by TMS in visual processing.
• To explore the application of TMS in studying various aspects of visual perception and related cognitive functions.

Main Methods:

• Systematic literature review of experiments employing TMS and rTMS targeting the human visual pathway.
• Analysis of studies investigating neural excitation and inhibition, suppression, unmasking, and phosphene generation.
• Examination of TMS effects on specific visual areas like the calcarine cortex and V5, as well as higher-level temporoparietooccipital regions.

Main Results:

• TMS and rTMS can induce both excitatory and inhibitory effects within the visual pathway.
• Stimulation of the calcarine cortex and V5 leads to observable effects like suppression and phosphenes.
• TMS application to higher visual areas reveals impacts on perceptual errors, unmasking phenomena, and attentional processes.

Conclusions:

• TMS and rTMS are valuable tools for dissecting the functional roles of the higher visual pathway.
• The review highlights TMS's utility in understanding visual perception, including its relationship with frontal lobe activity and consciousness.
• Further research using TMS can advance our comprehension of neural underpinnings of vision and cognition.