Imaging brain electric signals with genetically targeted voltage-sensitive fluorescent proteins

Area of Science:

• Neuroscience
• Molecular Biology
• Biophysics

Background:

• Cortical circuits involve complex synaptic interactions between diverse neuron types.
• Understanding neural circuit function necessitates monitoring electrical activity in specific neuronal populations.

Purpose of the Study:

• To demonstrate the utility of genetically encoded voltage-sensitive fluorescent proteins (VSFPs) for optical voltage reporting in targeted neurons.
• To validate VSFPs for analyzing cortical circuit activity in vivo.

Main Methods:

• Expression of VSFPs in genetically defined neuronal populations (pyramidal cells) in mouse somatosensory cortex.
• Optical recording of electrical activity from targeted neurons in culture, acute brain slices, and living mice.
• In vivo electrophysiological recordings correlated with VSFPs' optical signals.

Main Results:

• VSFPs successfully provided optical voltage reports from targeted neurons across different experimental preparations.
• In vivo expression of VSFPs in mouse cortical pyramidal cells allowed reporting of electrical responses to sensory stimuli.
• VSFPs demonstrated the ability to track neuronal electrical activity in genetically defined populations.

Conclusions:

• Genetically encoded VSFPs are effective tools for optical voltage monitoring in targeted neuronal populations.
• VSFPs facilitate the analysis of cortical circuit dynamics in vivo.
• These protein-based voltage probes represent a significant advancement for optogenetics and neuroscience research.