Multiple Single-Unit Long-Term Tracking on Organotypic Hippocampal Slices Using High-Density Microelectrode Arrays

Area of Science:

• Neuroscience
• Electrophysiology
• Cell Biology

Background:

• Organotypic brain slice cultures are valuable models for studying neuronal function.
• Previous methods lacked the resolution or duration to track individual neuron activity within network dynamics over extended periods.

Purpose of the Study:

• To develop and validate a novel system for long-term, high-resolution electrophysiological recording from organotypic brain slices.
• To investigate the electrical activity patterns of single neurons and neuronal networks in organotypic hippocampal slice cultures over several weeks.

Main Methods:

• Development of a system for cultivating organotypic brain slices on high-density microelectrode arrays (HD-MEAs).
• Implementation of an unsupervised iterative spike-sorting algorithm (PCA and k-means clustering) for single-unit activity assignment.
• Tracking of single-unit 'footprints' (spike-triggered average extracellular waveforms) over extended recording durations.

Main Results:

• The system successfully enabled continuous, high-spatial-resolution recording of individual neuron and network activity.
• Daily recordings over several weeks allowed for the first time the study of electrical activity patterns of single neurons and their corresponding network.
• A novel spike-sorting algorithm and waveform tracking method were developed and validated.

Conclusions:

• The developed system provides an unprecedented capability for chronic in vitro studies of neuronal function.
• This technology facilitates the investigation of long-term effects of pharmacological or genetic manipulations on individual neurons and neural networks.
• It opens new avenues for understanding neuronal plasticity and network dynamics in health and disease.