Chronic Microdrive Package

Hardware

Adjustable microdrive assembly enabling precise post-implantation depth control of chronically implanted silicon probes.

Overview

The Chronic Microdrive Package (pkg_cmm) is a precision mechanical assembly that allows researchers to advance or retract a silicon probe after the craniotomy has been closed and the animal has recovered from surgery. A precision-threaded drive screw translates rotation into vertical displacement at sub-50µm resolution.

Design

Drive Mechanism: Threaded screw drive, ~50µm per full turn
Travel Range: 3–8mm (model dependent)
Drive Direction: Vertical (can be angled with custom holders)
Probe Interface: Accepts standard Omnetics-connected probes
Fixation: Anchors to skull screws using dental acrylic
Weight: 0.8–2.0g depending on configuration

Use Cases

Microdrives are used when the target recording site cannot be precisely identified before surgery, or when recording quality needs to be optimized post-implantation. Common applications include:

Hippocampal CA1: Tuning depth to place the site layer in stratum pyramidale
Cortical Layer Targeting: Advancing through cortical layers to identify optimal recording depth
Deep Brain Structures: Reaching targets such as thalamus, VTA, or basal ganglia with post-surgery fine adjustment

Available Configurations

Chronic microdrive packages are available for 16-channel and 32-channel probes. Custom configurations for higher channel counts are available on request.

Species Compatibility

Designed primarily for rats. Mouse-compatible lightweight versions are available but add significant mass relative to mouse body weight and should be used with care.