Substrate Thickness

Substrate thickness is the width of the silicon or wire shank that forms the probe body, typically measured in micrometers. This physical dimension affects both the mechanical properties of the probe and the amount of tissue damage during insertion.

Trade-offs:

• Thin substrates (15-50 µm): Minimal tissue damage, more flexible, may bend during insertion
• Medium substrates (50-100 µm): Balance between rigidity and damage, most common
• Thick substrates (100-200 µm): Maximum rigidity for deep insertions, more tissue disruption

Practical implications: Thinner probes cause less tissue damage and gliosis but may not reach deep structures without buckling. Thicker probes can penetrate deeper but disrupt more tissue and may cause more scarring.

Selection guidance: For cortical recordings, thinner is often better. For deep brain structures or chronic implants requiring stability, thicker substrates provide necessary mechanical strength.