Visuospatial asymmetries and interocular transfer in the split-brain rat.

Abstract

Interocular transfer (IOT), hemispheric superiority, and cerebral dominance were examined in split-brain female albino rats. Callosum-sectioned and intact animals were monocularly trained in the Morris water maze and tested in IOT and reversal phases. In the IOT phase, split-brain rats entered more nontarget quadrants and headed less accurately toward the platform than did controls. For both split-brain animals and controls, right-eye training resulted in shorter latencies and fewer nontarget entries than did left-eye training. Analyses of cerebral dominance showed shorter latencies and smaller heading errors over all 3 phases in rats that were trained with the nondominant eye. Right-eye dominant controls were less affected by platform reversal. Split-brain rats were inferior to controls in latency to find the platform and in target quadrant entries. This finding establishes a spatial cognitive deficit from callosum section.

A precision surgical approach for complete or partial callosotomy in the mouse

“…Examination of all mounted sections from the brains of surgical subjects indicated that the extent of callosal transsection was approximately 89% to 100%. This lies well within the range considered to constitute a total transsection in the literature on rats (1,5).…”

A lateralized avian hippocampus: preferential role of the left hippocampal formation in homing pigeon sun compass‐based spatial learning

“…(Lateralization has been demonstrated for other regions of the rat brain involved in solving spatial tasks, e.g. Adelstein & Crowne, 1991; King & Corwin, 1992) By contrast, hippocampal lateralization in humans is well known (Smith & Milner, 1989), but it is not necessarily different aspects of spatial cognition that lateralize. In humans, the right hippocampus has been reported to be more heavily recruited in tasks of navigation, the left more heavily recruited in the encoding of episodic memories (Burgess et al ., 2002).…”

Design of a noninvasive face mask for ocular occlusion in rats and assessment in a visual discrimination paradigm

“…Alternatively, it could be that the "untrained" eye does not have access to the representation of the visual information that was clearly acquired and stored during training. Given these findings, it appears that additional, invasive surgeries to further disconnect the cerebral hemispheres (e.g., cutting the optic chiasm or corpus callosum; e.g., Adelstein & Crowne, 1991;Chang & Greenough, 1982;Crowne et al, 1994;Shinohara et al, 2012) are not required to achieve a highly lateralized training effect, at least for the behavioral paradigm used in the present investigation.…”

“…An advantage of the mask designed here is the ease of switching the eye patch between the two eyes, thus allowing for an uncomplicated study of interocular transfer of visual information. The noninvasive and relatively stress-free nature of the eye patch devised here clearly offers advantages over alternative methods of restricting visual input, such as adhesive eye patches (Adelstein & Crowne, 1991;Crowne et al, 1994), lid suturing (Chang & Greenough, 1982;Fig. 2 Monocular visual discrimination performance.…”

“…In previous work on rodents, techniques to restrict visual input to one eye have involved adhesive eye patches (Adelstein & Crowne, 1991;Crowne, Forsyth, & Fitzgerald, 1994), lid suturing (Chang & Greenough, 1982;Prusky et al, 2006) or enucleation (Prusky et al, 2006;Shinohara et al, 2012). Problems with adhesive patches remaining in place have been reported (Adelstein & Crowne, 1991). Lid suturing and enucleation both necessitate surgical procedures under general anesthesia and are either nonreversible, or require a further surgical procedure to open the sutured eye.…”