A micromachined silicon multielectrode for multiunit recording

Area of Science:

• Neuroscience
• Bioengineering
• Materials Science

Background:

• Recording propagating action potentials from multiple neurons is crucial for understanding neural circuits.
• Existing extracellular electrode arrays face limitations in spike resolution and anatomical correlation.
• Microfabrication techniques offer potential for improved neural recording devices.

Purpose of the Study:

• To develop and evaluate a novel 16-channel multielectrode for recording from the cricket ventral nerve cord.
• To assess the fabrication process using deep reactive ion etching (DRIE) for creating rigid, high-density electrode structures.
• To analyze neural activity, including action potential conduction velocities, using the developed multielectrode.

Main Methods:

• Fabrication of a 16-channel multielectrode using photolithography and deep reactive ion etching (DRIE).
• Recording of propagating action potentials from the ventral nerve cord of Gryllus bimaculatus.
• Utilizing principle component analysis and clustering to generate spike templates for eight neurons.
• Analysis of stimulus-evoked activity and calculation of conduction velocities.

Main Results:

• Successfully recorded propagating action potentials from multiple units in the cricket ventral nerve cord.
• Generated clean spike templates for eight neurons from a 40-second recording.
• Determined neural conduction velocities ranging from 2.59+/-0.05 to 4.99+/-0.12 m/s.
• Demonstrated the capability of the microfabricated device for stable positioning and isolation of recording sites.

Conclusions:

• The novel microfabricated multielectrode, utilizing DRIE, enables high-density, precise neural recordings.
• This technology addresses limitations of current extracellular arrays, improving spike resolution and anatomical correlation.
• The rigid, stable electrode design is suitable for various nerve cord applications, including clamping and squeezing.