Local GABA concentration is related to network-level resting functional connectivity.

Area of Science:

• Neuroscience
• Neuroimaging
• Neurochemistry

Background:

• Resting-state networks (RSNs) show functionally interconnected brain regions but their neurochemical underpinnings remain unclear.
• Understanding the neurochemical basis of RSNs is crucial for deciphering brain function and dysfunction.

Purpose of the Study:

• To investigate the neurochemical basis of functional connectivity within the resting motor network.
• To explore the relationship between GABA levels in the primary motor cortex (M1) and motor network connectivity.

Main Methods:

• Combined magnetic resonance spectroscopy (MRS) and resting-state functional magnetic resonance imaging (fMRI).
• Measured GABA levels in M1 and assessed functional connectivity of the motor network.
• Utilized anodal transcranial direct current stimulation (tDCS) to modulate GABA levels and network connectivity.

Main Results:

• Demonstrated an inverse relationship between M1 GABA levels and resting motor network connectivity.
• Confirmed this relationship was neurochemically and anatomically specific.
• Showed that tDCS, which reduces M1 GABA, increased resting motor network connectivity.

Conclusions:

• M1 inhibition, reflected by GABA levels, is a key determinant of functional connectivity within the resting motor network.
• Findings align with existing evidence suggesting a role for inhibition in network-level brain function.
• This study provides novel insights into the neurochemical regulation of RSNs.