Technical NoteFrameless stereotaxy in the nonhuman primate
Introduction
Magnetic resonance imaging (MRI) has greatly improved our ability to view the brain and its component structures in a noninvasive manner (for review, see Brownell et al., 1982, Haacke et al., 1999, Moonen et al., 1990, Westbrook and Kaut, 1998). Although MRI scans are routinely performed on nonhuman primates, using these scans to perform precise experimentation is limited due to the lack of real time feedback to the researcher about anatomical structures encountered during an invasive procedure in the laboratory or surgical suite. With the enormous cost in time and money in acquiring and training monkeys, and the need to reduce all unnecessary risks to animals, measures should be taken to ensure that the techniques used in monkey research are performed as accurately as possible.
Traditionally, a stereotaxic frame has been used to reach desired anatomical targets in the monkey brain, based on existing generalized stereotaxic atlases (Paxinos et al., 2000, Snider and Lee, 1961, Szabo and Cowan, 1984) or MRI images using a coordinate system for three axes (x, y, z) (Alvarez-Royo et al., 1991, Maciunas and Galloway, 1989, Rebert et al., 1991, Sapolsky et al., 1990). Making use of frame-based stereotaxic coordinates to localize brain structures with MRI originated in surgery for humans (Lunsford et al., 1986, Peters et al., 1986), its main advantage being accuracy when image distortion is eliminated (Dormont et al., 1994). Although a benefit to the frame-based method is that it provides structural support for tools that are needed for the different surgical procedures, the frame also limits access to large parts of the brain. Another significant limitation of a frame-based stereotaxic system in both human (Olivier and Bertrand, 1983, Popovic and Kelly, 1993, Ross et al., 1996, St-Jean et al., 1998) and monkey (Alvarez-Royo et al., 1991, Maciunas and Galloway, 1989, Saunders et al., 1990) is that the subject must be scanned with the actual frame in place. In the case of nonhuman primates, especially larger animals, this can be cumbersome as the animal must be placed in an unnatural position in the scanner and within the frame to obtain usable images. Although several researchers have used glass-filled copper sulfate beads embedded under the scalp to calculate stereotaxic coordinates without using a frame during MRI scanning, a standard stereotaxic frame is still necessary for all subsequent surgical procedures (Rebert et al., 1991, Sapolsky et al., 1990). It is also necessary with a frame-based technique to determine target approach and record coordinates for each target at a presurgical planning stage. Once this has been done, it cannot be changed without recalculating target approach. In contrast, with the frameless stereotaxic system presented here, the animal is simply scanned with several relocatable reference points (fiducials) in the standard supine position. When the fiducials are chronically implanted, they can be used to coregister the animal's head in reference to a 3D position sensor, allowing the researcher to proceed with any procedure or manipulation at a later date following the MRI scan. An advantage of the frameless stereotaxic system is that the registered coordinates and images are stored on file and only a few minutes are needed to calibrate the animal to its own previously acquired MRI scan. It is then possible to localize the target region and determine target approach just before surgery. The frameless technique is flexible enough that if necessary, the target approach can easily be changed to accommodate a different entry point during the surgical procedure. The frameless technique also allows the head of the animal to be positioned in virtually any position while still allowing access to the desired target area.
This report presents a novel approach using a frameless stereotaxic system to enable the precise localization of a target area in the monkey brain and to guide accurately a cannula to inject an anatomical tracer to the desired location. The accuracy of this technique was supported with histological evidence, and the overall system error was investigated by measuring target registration error with a custom-made MR imaging phantom.
Section snippets
Subject
The subject was an adult male rhesus monkey (Macaca mulatta) weighing approximately 9.7 kg. Further studies in three cynomolgus monkeys (Macaca fascicularis, two male, one female) weighing approximately 4.6–7.6 kg confirmed our present results with retrograde injections directed to different architectonic areas of the frontal cortex (areas 8B, 9, 44, and 45). The protocols used were approved by the Montreal Neurological Institute Animal Ethics Committee and conformed to the Canadian Council of
Anatomical results
Two series of brain sections were mounted on microscope slides. The first series was examined by epifluorescence microscopy for the presence of fluorescing cells and the second was stained with cresyl violet (a Nissl stain) to determine the location of the injection site and labeled cells in terms of the cortical architecture. The injections of DY were placed in the intended architectonic area 45 in ventrolateral prefrontal cortex (Fig. 4).
MRI phantom and calibration procedures
Target registration error can be defined as the
Discussion
This report describes the development of a novel technology, namely a frameless stereotaxic system that enables the investigator to reach accurately specific target areas in the nonhuman primate brain. This new system was used to visualize, on the monkey's own MRI image, a preselected morphological target site, the ventrolateral prefrontal cortex, where architectonic area 45 lies, and it was shown that an injecting cannula, containing an anatomical tracer, could be tracked to the intended
Acknowledgment
This work was supported by the Natural Sciences and Engineering Research Council of Canada.
References (36)
- et al.
Stereotaxic lesions of the hippocampus in monkeys: determination of surgical coordinates and analysis of lesions using magnetic resonance imaging
J. Neurosci. Methods
(1991) - et al.
Assessment of locus and extent of neurotoxic lesions in monkeys using neuroimaging techniques: a replication
J. Neurosci. Methods
(2002) - et al.
Stereotactic procedures for lesions of the pineal region
Mayo Clin. Proc.
(1993) - et al.
A procedure for using proton magnetic resonance imaging to determine stereotaxic coordinates of the monkey's brain
J. Neurosci. Methods
(1991) - et al.
An assessment of the reinforcing properties of foods after amygdaloid lesions in rhesus monkeys
J. Comp. Physiol. Psychol.
(1982) - et al.
Head registration techniques for image-guided surgery
Neurol. Res.
(1998) - et al.
Least-squares fitting of two 3-D point sets
IEEE Trans. Pattern Anal. Mach. Intell.
(1987) - et al.
Positron tomography and nuclear magnetic resonance imaging
Science
(1982) - et al.
Registration in neurosurgery and neuroradiotherapy applications
J. Image Guid. Surg.
(1995) - et al.
A technique of measuring the precision of an MR-guided stereotaxic installation using anatomic specimens
Am. J. Neuroradiol.
(1994)
Predicting error in rigid-body point-based registration
IEEE Trans. Med. Imag.
Magnetic Resonance Imaging. Physical Principles and Sequence Design
Stereotaxic surgery with a magnetic resonance- and computerized tomography-compatible system
J. Neurosurg.
Magnetic resonance and computed tomographic image-directed stereotaxy for animal research
Stereotact. Funct. Neurosurg.
MRI-based evaluation of locus and extent of neurotoxic lesions in monkeys
Hippocampus
Effects of aspiration versus neurotoxic lesions of the amygdala on emotional responses in monkeys
Eur. J. Neurosci.
Functional magnetic resonance imaging in medicine and physiology
Science
Object recognition and location memory in monkeys with excitotoxic lesions of the amygdala and hippocampus
J. Neurosci.
Cited by (45)
A method for chronic and semi-chronic microelectrode array implantation in deep brain structures using image guided neuronavigation
2023, Journal of Neuroscience MethodsCo-registration of Imaging Modalities (MRI, CT and PET) to Perform Frameless Stereotaxic Robotic Injections in the Common Marmoset
2022, NeuroscienceCitation Excerpt :Therefore, the success of procedures that depend upon accurate localisation of targets and replication in different animals may be compromised by the use of traditional stereotaxic atlases and requires a more reliable and robust approach to identify target structures. The paradigm shift from frame-based stereotaxic approaches to frameless stereotaxic neuronavigation in research and clinical settings (Moorthy et al., 2016) has improved upon limitations of traditional approaches such as difficulty to access large areas of the brain, particularly, subcortical targets, scanning with a frame in place, and the lack of flexibility to change target coordinates without modifying the target approach (Frey et al., 2004). Moreover, frameless stereotaxic neuronavigation, as seen in humans, has demonstrated equivalent accuracy to frame-based stereotaxy (Mascott, 2006) and allowed for real-time feedback during procedures (Gempt et al., 2012), which has resulted in improved safety and patient outcome by reducing surgical time (Dorward et al., 2002) and associated morbidity and mortality (Golfinos et al., 1995; Carvalho et al., 2009).
Open-source 3D printable frameless stereotaxic system for young and adult pigs
2021, Journal of Neuroscience Methods