Imaging fast electrical activity in the brain with electrical impedance tomography

Area of Science:

• Neuroscience
• Biomedical Engineering
• Medical Imaging

Background:

• Imaging neuronal depolarization is crucial for understanding brain function.
• Current techniques lack the spatiotemporal resolution for whole-brain neural activity imaging.
• Electrical impedance tomography (EIT) is an emerging non-invasive imaging modality.

Purpose of the Study:

• To investigate the feasibility of using EIT for imaging neural activity.
• To assess the spatiotemporal resolution and imaging volume of EIT in the brain.
• To explore EIT's potential for mapping whole-brain functional connectivity.

Main Methods:

• Utilized EIT with epicortical arrays (30 electrodes) on rat somatosensory cortex.
• Recorded impedance changes during evoked potentials with 2ms resolution and <200μm spatial resolution.
• Validated EIT images against local field potential recordings and current source-sink density analysis.

Main Results:

• Successfully imaged neural activity in a 7x5x2mm volume of the rat somatosensory cortex.
• Achieved high spatiotemporal resolution (2ms, <200μm), surpassing existing methods.
• Demonstrated reduced invasiveness compared to other neural imaging techniques.

Conclusions:

• EIT is a viable technique for high-resolution, real-time imaging of neural activity.
• The method offers significant advantages in resolution, imaging volume, and invasiveness.
• EIT holds promise for whole-brain functional connectivity mapping, including subcortical structures.