Differential spatial memory impairment after right temporal lobectomy demonstrated using temporal titration

Abstract

In this study a temporal titration method to explore the extent to which spatial memory is differentially impaired following right temporal lobectomy was employed. The spatial and non-spatial memory of 19 left and 19 right temporal lobectomy (TL) patients was compared with that of 16 normal controls. The subjects studied an array of 16 toy objects and were subsequently tested for object recall, object recognition and memory for the location of the objects. By systematically varying the retention intervals for each group, it was possible to match all three groups on object recall at sub-ceiling levels. When memory for the position of the objects was assessed at equivalent delays, the right TL group revealed disrupted spatial memory, compared with both left TL and control groups (P < 0.05). MRI was used to quantify the extent of temporal lobe resection in the two groups and a significant correlation between hippocampal removal and both recall of spatial location and object name recall in the right TL group only was shown. These data support the notion of a selective (but not exclusive) spatial memory impairment associated with right temporal lobe damage that is related to the integrity of the hippocampal functioning.

Spatial memory deficits in patients after unilateral selective amygdalohippocampectomy

“…More studies have examined spatial memory for a combination of positional information and object identities. For example, various authors have investigated the relocation of toy objects on a table top in patients with hippocampal lesions, commonly demonstrating a righthippocampal involvement (Nunn et al, 1999;Smith & Milner, 1989). In general, the current findings corroborate and extend previous results with similar paradigms.…”

Spatial Navigation Impairment in Healthy Aging and Alzheimer’s Disease

“…This interpretation is in agreement with reports showing less efficient encoding in elderly adults (Grady et al, 1995;Stebbins et al, 2002), was however not confirmed in a control study on a different group of subjects (Park et al, 1990). Interestingly, object location memory was shown to be dependent on the MTL region (Nunn et al, 1999;Pillon et al, 1999;Stepankova et al, 2004) or more specifically on the parahippocampal gyrus (Maguire et al, 1998b;Owen et al, 1996). Thus another interpretation of this age dependent object location memory deficit may attribute it to the decline in MTL activity.…”

Sexual orientation related differences in spatial memory

“…Object location memory on this task has been shown to be sensitive to hippocampal lesions (Nunn et al, 1999;Smith & Milner, 1981, 1989 hence the female advantage on this measure suggest sex-related differences in allocentric spatial memory dependent on hippocampal function. Supporting this possibility, sex differences in the size of the hippocampus have been previously reported; females possessing larger hippocampal volumes than males (Filipek et al, 1994;Giedd et al, 1997).…”

“…To our knowledge this is the first study to examine sexual orientation related effects in object location memory. Moreover, the Smith and Milner task has been shown to be sensitive to temporal lobe lesions and performance is dependant on the extent of hippocampal resection (Nunn et al, 1999;Smith & Milner, 1981, 1989. Hence, this is the first study to investigate sexual orientation related differences in cognitive functions dependent on the hippocampal regions.…”

“…Spatial memory involves the ability to encode, store, and retrieve information regarding route navigation and object locations (Kessels et al, 2001). A large body of evidence from animal studies, and lesion and neuroimaging studies in humans confirms a major role for the hippocampal formation in spatial memory functioning (e.g., Abrahams et al, 1997Abrahams et al, , 1999Gron et al, 2000;Johnsrude et al, 1999;Nunn et al, 1999;Save et al, 1998). Additionally, the right hippocampus appears to be critical in processing of positional and relational information regarding the locations of objects in the form of an allocentric cognitive map (a frame of reference formed on the basis of information about the environment that is independent of the observer; Kessels et al, 2001;O'Keefe & Nadel, 1978).…”