Transcranial magnetic stimulation (TMS) inhibits cortical dendrites

Area of Science:

• Neuroscience
• Cellular Biology
• Neurophysiology

Background:

• Transcranial magnetic stimulation (TMS) is a key non-invasive brain treatment.
• The precise cellular and subcellular effects of TMS remain largely unknown.
• Understanding TMS's impact on neuronal dendrites is crucial for its clinical application.

Purpose of the Study:

• To investigate the effect of single-pulse TMS on dendritic activity.
• To examine TMS's impact at the subcellular level in pyramidal neurons.
• To elucidate the mechanisms underlying TMS-induced changes in dendritic activity.

Main Methods:

• Utilized optical fiber imaging to monitor dendritic activity.
• Focused on layer 5 pyramidal neurons in the somatosensory cortex.
• Applied single-pulse transcranial magnetic stimulation.

Main Results:

• TMS induced GABAB-mediated inhibition of sensory-evoked dendritic Ca(2+) activity.
• Observed direct activation of cortical fibers by TMS.
• Identified activation of dendrite-targeting inhibitory neurons.

Conclusions:

• TMS directly activates cortical fibers, leading to inhibitory neuron activation.
• This inhibitory process suppresses dendritic Ca(2+) activity.
• TMS exhibits specificity at the dendritic level, offering potential for non-invasive investigation.