Surgical Guide -- Silicon probes, acute neural recording/stimulation

Technical Note

Document Title: Surgical Guide -- Silicon probes, acute neural recording/stimulation

Document Number: NN-TN-2025-001

Version: 1.0

Date: March 16, 2025

Author: NeuroNexus Technical Support Team

Revision History: N/A (Initial Release)

Status: Approved for Publication

Intended Audience: Researchers conducting acute neural recordings with NeuroNexus silicon probes

Application Area: Electrophysiology techniques, electrodes, micro-scale neural interfaces, brain-computer interfaces

Associated Resources:

• surgical guide as a pdf document
• NeuroNexus website

1. Introduction

This technical note provides an overview of general principles for using NeuroNexus silicon probes in acute experimental preparations. Acute experiments involve temporary probe implantation for data collection during a single session, after which the probe is removed.

It is important to note that detailed surgical procedures vary by lab based on experimental design, species, and institutional protocols. This document outlines a general, typical approach to illustrate proper probe handling and configuration details within the basic procedural framework. Researchers should adapt these recommendations to fit their specific methodologies while complying with all applicable ethical and regulatory guidelines.

For additional technical support, visit the NeuroNexus Resource Center.

2. Pre-Surgical Preparations

a. Subject Preparation

• Follow institutional guidelines for anesthesia, monitoring, and perioperative care.
• Ensure proper stabilization of the subject for surgical accuracy.
• Maintain thermal support throughout the procedure as required.

b. Surgical Instruments and Materials

• Essential Tools:
  • Fine forceps, scissors, hemostats, scalpels, needle holders
  • High-speed drill with appropriate burrs

  • Micropipette or blunt needle for saline application

    Sterilization Supplies:

  • 70% ethanol, iodine-based solutions (e.g., Betadine)

  • Autoclaved or disinfected instruments

    Grounding and Reference Materials:

  • Stainless steel or Ag/AgCl wires for ground/reference
  • Bone screws for anchoring wires if required

c. Equipment Setup

• Stereotaxic Frame: Ensure a stable setup with auxiliary ear bars and a micromanipulator for controlled probe insertion.
• Microscopy: A dissecting microscope with a cold light source enhances visibility.

3. Surgical Procedure (General Framework)

a. Preparing the Surgical Site

• Positioning: Secure the subject in the stereotaxic frame.
• Scalp Incision: Make an incision to expose the skull.
• Cleaning: Remove the periosteum with a cotton swab and rinse with saline.

b. Craniotomy and Electrode Placement

• Marking and Drilling:
  • Outline the craniotomy location and bone screw positions.

  • Carefully drill the craniotomy, ensuring it is appropriately sized for the probe.

    Screw Placement (if used):

  • Secure bone screws for ground/reference connections, avoiding dural penetration.

    Dura Removal (if required):

  • In some protocols, dura removal facilitates probe insertion.

  • This step may not be necessary for all subjects.

    Probe Insertion:

  • Attach the probe to the micromanipulator for linear insertion
  • Lower it slowly to minimize tissue dimpling and damage.

c. Wiring Configuration

• 16-Channel Probes:
  • If using a separate reference electrode, insert a reference wire into a saline-filled craniotomy (contralateral or ipsilateral).
  • If using no separate reference, connect the probe reference input to a bone screw near the site.
• 32-Channel Probes:
  • If using an internal reference, connect the designated reference wire to a bone screw.
  • If disabling the internal reference, modify the connector and follow external referencing steps.

4. Post-Surgical Considerations

a. Data Acquisition

• Impedance Check: Verify proper probe function before recording.
• Signal Quality: Connect the probe to the acquisition system and confirm expected activity.

b. Probe Removal and Cleaning

• Probe Withdrawal: Retract slowly to reduce tissue disruption.
• Cleaning: Immediately rinse the probe in distilled water and soak in an enzymatic solution if necessary.