Relationship between Growth of Brain and Skull of <i>Macaca mulatta,</i>and its Importance for the Stereotaxic Technique

Abstract

An analysis of the brain weight of 196 rhesus monkeys and lateral X-rays of 91 more was made to determine and correct the effect of growth and development on stereotaxic variability. A comparison of body weight to brain weight shows that the brain grows rapidly initially in a linear relationship with body weight and can increase in weight even into adulthood, with a significant amount of variability found throughout its development. The examination of the cranial base and stereotaxic reference points indicates that the brain rotates during growth in a forward and downward direction in relation to the stereotaxic planes. The distance between the anterior clinoid process and AP-0 shows an increase of little variability from linearity during growth. This distance can be used to correct for the anterior-posterior plane found in standard stereotaxic atlases. The flattening out of the cranial base results in a horizontal plane readjustment during growth. A horizontal correction can be made by measuring the distance between the base of the pituitary fossa and H-10 plane.

Method for making selective lesions of the hippocampus in macaque monkeys using NMDA and a longitudinal surgical approach

“…In macaques, extensive interanimal variability in distance of target structures from the auditory meatus (Wagman et al, 1975), from which stereotaxic coordinates are typically derived, severely limits the value of stereotaxic atlases of the brain for guiding surgery. One approach to making selective lesions of limbic structures involves x-ray localization of bony landmarks, which, when used together with the position of the auditory meatus, provide improved reliability in predicting the locations of forebrain structures (Aggleton and Passingham, 1981;Aggleton, 1985).…”

A method for localizing microelectrode trajectories in the macaque brain using MRI

“…For all three brain regions, the majority of sites were defined in a congruent fashion using anatomical and physiological criteria (82.8% of MT sites, 57.5% of LIP sites and 76.9% of FEF sites were defined as hits or misses based on both physiological and anatomical criteria). Most of the incongruently defined sites were physiological hits but anatomical misses (15.5% of MT sites, 41.3% of LIP sites and 23.1% of FEF sites), possibly reflecting individual variability in the exact location of these cortical areas (Lewis and Van Essen, 2000; Wagman et al, 1975). …”

“…Stereotaxic procedures define the location of any position in the brain relative to a known coordinate system (Horsely V, 1908). Although stereotaxic procedures yield consistent results in smaller animals, neuroanatomical structures in larger mammals, such as macaques, are just roughly aligned with cranial landmarks (Glimcher et al, 2001; Percheron and Lacourly, 1973) and are subject to substantial inter-animal variability (Wagman et al, 1975). Thus, this method is especially imprecise for monkey neurophysiology (Aggleton and Passingham, 1981; Olzewski, 1952; Percheron, 1975; Percheron and Lacourly, 1973; Saunders et al, 1990; Subramanian, 2001; Subramanian et al, 2005) and requires verification and possible adjustment.…”

MRI-guided dissection of the nonhuman primate brain: A case study

“…Stereotaxic procedures are typically performed using atlas-based coordinates which can often be limited in accuracy due to inconsistencies in stereotaxic precision between researchers. This is especially true in relation to the auditory meatus from which stereotaxic coordinates typically derive [14]. Currently available atlases of the macaque brain [15, 16] are generally based on a single animal and therefore cannot take into account intersubject or interspecies variability.…”