Narishige SN-2N Stereotactic Instrument

Overview

The Narishige SN-2N Stereotactic Instrument is a precision-engineered mechanical platform designed for in vivo neuroscientific experimentation in small animal models. It operates on the foundational principle of stereotactic coordinate geometry—translating anatomical landmarks into reproducible three-dimensional Cartesian coordinates relative to a defined bregma-lambda zero point. This enables accurate, repeatable placement of microelectrodes, injection cannulae, optical fibers, or ablation probes within targeted brain nuclei or cortical layers. The instrument’s low center of gravity, massive cast-metal base (~30 kg), and rigid square-section AP (anterior–posterior) frame rod (18.7 mm) collectively minimize mechanical drift and vibration-induced positional error during long-duration electrophysiological recordings or chronic infusion protocols. Its design adheres to internationally recognized stereotactic conventions used in rodent neuroanatomy atlases (e.g., Paxinos & Watson), ensuring compatibility with standard surgical workflows and digital atlas registration systems.

Key Features

• Three-point independent head fixation system mounted on a U-shaped frame, enabling precise zeroing of the skull’s midline reference plane (bregma–lambda line) without torque-induced deformation.
• Micrometer-adjusted X-, Y-, and Z-axis translation stages with engraved scale markings and vernier readouts; typical resolution ≤10 µm per full turn, supporting sub-millimeter targeting accuracy required for hippocampal CA1, substantia nigra pars compacta, or ventral tegmental area interventions.
• Modular adapter interface: interchangeable clamping fixtures allow secure immobilization of mice, rats, hamsters, and ferrets via species-specific ear bars and incisor plates—each maintaining consistent interaural and bregma–lambda alignment across subjects.
• U-shaped frame assembly slides laterally along the base without tooling, facilitating rapid repositioning of the entire stereotactic apparatus relative to spinal or cranial surgical fields.
• Base plate features a standardized grid of M4 and M6 threaded holes (ISO metric thread specification), enabling direct attachment of vertebral clamps, spinal stabilizers, multi-electrode drives, or custom 3D-printed holders compliant with ISO 9001-certified lab hardware integration standards.
• Structural components fabricated from anodized aluminum alloys and medical-grade stainless steel (AISI 316L), with phenolic resin insulator blocks (large ×1, small ×1) providing electrical isolation for electrophysiology applications.

Sample Compatibility & Compliance

The SN-2N accommodates craniotomies and stereotactic procedures in rodents weighing 15–500 g. Its mechanical repeatability supports GLP-compliant longitudinal studies where inter-subject coordinate consistency is critical for histological verification and quantitative tract tracing. While the device itself does not carry CE or FDA clearance as an active medical device, its dimensional stability and traceable mechanical tolerances align with ISO/IEC 17025 requirements for laboratory equipment used in preclinical research governed by OECD Test Guidelines and NIH Office of Laboratory Animal Welfare (OLAW) protocols. All metallic surfaces meet ASTM F86-22 standards for surface passivation of implant-grade stainless steel.

Software & Data Management

As a purely mechanical stereotactic platform, the SN-2N requires no embedded firmware or proprietary software. However, it integrates seamlessly with third-party digital workflow tools: coordinate values from its micrometers can be manually entered into open-source platforms such as QuickNII, BrainStorm, or commercial packages including Neurolucida (MBF Bioscience) and Stereotaxic Atlas Tools (SAAT). When paired with motorized microdrives or electrophysiology rigs (e.g., Scientifica or PatchStar systems), its physical coordinate outputs serve as ground-truth validation inputs for closed-loop spatial calibration routines. Audit trails of manual adjustments are maintained via lab notebook entries or LIMS-integrated electronic records compliant with 21 CFR Part 11 when coupled with validated documentation practices.

Applications

• Acute and chronic extracellular single-unit recording in awake or anesthetized preparations.
• Stereotactic intracerebral drug microinjection (e.g., viral vectors, siRNA, pharmacological agents) with volumetric control down to 10 nL increments.
• Fiber photometry and optogenetic probe implantation with angular adjustment capability (±15° pitch/yaw) for non-vertical trajectories targeting deep midbrain structures.
• Lesion studies using electrolytic or radiofrequency electrodes under visual guidance via stereomicroscope mounting brackets.
• Spinal cord injury modeling requiring simultaneous cervical/thoracic vertebral stabilization and intraparenchymal injection.
• Validation of MRI-based stereotactic targeting pipelines through post-hoc histological reconstruction of electrode tracks.

FAQ

Is the SN-2N compatible with MRI-guided stereotaxy?
No—the SN-2N is a non-magnetic but non-MRI-compatible mechanical frame due to its ferromagnetic base mass and lack of RF-shielding certification. It is intended for use in conventional surgical suites only.
Can the AP rod be replaced with a custom-length version?
Yes—Narishige offers optional AP rods in 200 mm, 300 mm, and 400 mm lengths (part numbers SN-AP200, SN-AP300, SN-AP400), all maintaining the same 18.7 mm square cross-section and mounting interface.
What maintenance is required for long-term accuracy?
Annual recalibration of micrometer backlash using certified gauge blocks (ISO 3650) is recommended; lubrication of translation screws with silicone-free mineral oil every 6 months prevents particulate generation in sterile environments.
Does Narishige provide installation training or SOP templates?
Yes—authorized distributors offer on-site commissioning and GLP-aligned SOP development support, including risk assessments for ISO 13485-aligned quality management systems.