TY - JOUR
T1 - Structural and functional correlates of unilateral mesial temporal lobe spatial memory impairment
AU - Glikmann-Johnston, Yifat
AU - Saling, Michael
AU - Chen, Jian
AU - Cooper, Kimberlea Ann
AU - Beare, Richard John
AU - Reutens, David Charles
PY - 2008
Y1 - 2008
N2 - The aim of this study was to explore the effects of preoperative and postoperative lateralized mesial temporal damage on three measures of spatial learning: navigation, object location and plan drawing, and to determine the relationship between volumetry of the hippocampus and memory performance. Fifteen patients with well-characterized unilateral hippocampal sclerosis, 15 patients who had undergone unilateral anterior temporal lobectomy (ATL), and a comparison group consisting of 15 patients with idiopathic generalized epilepsy and 25 neurologically healthy participants explored a novel virtual environment. Volumetric analyses of both hippocampi were conducted on unilateral hippocampal sclerosis and idiopathic generalized epilepsy patients T(1)-weighted magnetic resonance imaging scans. Performance of temporal lobe epilepsy (TLE) patients (either unilateral hippocampal sclerosis or anterior temporal lobectomy) on the different spatial memory variables, namely navigation, object location and plan drawing, was significantly worse relative to the comparison groups (either idiopathic generalized epilepsy or controls). Patients with right TLE did not differ from patients with left TLE on any of the spatial memory measures. An index of absolute hippocampal asymmetry did not correlate with any of the spatial memory measures. Together, our lesion and volumetry findings suggest that the domain of spatial memory is systematically related to the integrity of both right and left mesial temporal lobe, and is unlikely to be a strongly lateralized function. From the standpoint of cerebral organization (lateralization), the notion of material-specificity, which postulates that all components of verbal and spatial memory are lateralized in their entirety to the left and right hemispheres, respectively, requires modification. Instead it would appear that the notion of task-specificity is a more accurate description of patterns of lateralization of spatial memory.
AB - The aim of this study was to explore the effects of preoperative and postoperative lateralized mesial temporal damage on three measures of spatial learning: navigation, object location and plan drawing, and to determine the relationship between volumetry of the hippocampus and memory performance. Fifteen patients with well-characterized unilateral hippocampal sclerosis, 15 patients who had undergone unilateral anterior temporal lobectomy (ATL), and a comparison group consisting of 15 patients with idiopathic generalized epilepsy and 25 neurologically healthy participants explored a novel virtual environment. Volumetric analyses of both hippocampi were conducted on unilateral hippocampal sclerosis and idiopathic generalized epilepsy patients T(1)-weighted magnetic resonance imaging scans. Performance of temporal lobe epilepsy (TLE) patients (either unilateral hippocampal sclerosis or anterior temporal lobectomy) on the different spatial memory variables, namely navigation, object location and plan drawing, was significantly worse relative to the comparison groups (either idiopathic generalized epilepsy or controls). Patients with right TLE did not differ from patients with left TLE on any of the spatial memory measures. An index of absolute hippocampal asymmetry did not correlate with any of the spatial memory measures. Together, our lesion and volumetry findings suggest that the domain of spatial memory is systematically related to the integrity of both right and left mesial temporal lobe, and is unlikely to be a strongly lateralized function. From the standpoint of cerebral organization (lateralization), the notion of material-specificity, which postulates that all components of verbal and spatial memory are lateralized in their entirety to the left and right hemispheres, respectively, requires modification. Instead it would appear that the notion of task-specificity is a more accurate description of patterns of lateralization of spatial memory.
UR - http://brain.oxfordjournals.org/cgi/reprint/131/11/3006
M3 - Article
SN - 0006-8950
VL - 131
SP - 3006
EP - 3018
JO - Brain
JF - Brain
IS - 11
ER -