Preserved capacity for scene construction and shifts in perspective after hippocampal lesions

Abstract

The hippocampus has long been recognized as important for the formation of long-term memory. Recent work has suggested that the hippocampus might also be important for certain kinds of spatial operations, as in constructing scenes, shifting perspective, or perceiving the geometry of scenes and their boundaries. We explored this proposal using a task similar to one used previously that related hippocampal activity to scenes and their boundaries. In our study, participants viewed scenes from above that displayed walls and towers. After viewing each scene, participants saw a scene from ground level and judged whether it was the same as or different from the scene just presented. The number of towers and walls in each scene was manipulated so that it was possible to assess how the structure of the scene affected performance. Patients with hippocampal lesions performed similarly to controls in all task conditions and had no special difficulty as a function of the layout of a scene and its boundaries. In contrast, a patient with large medial temporal lobe (MTL) lesions was impaired. Taken together, our findings suggest that the hippocampus is not needed for scene construction, shifts in perspective, or perceiving the geometry of scenes. The impairment associated with large MTL lesions may result from damage in or near parahippocampal cortex.

Spared Perception of the Structure of Scenes after Hippocampal Damage

“…Thus, in these studies, lesions limited to the hippocampus did not affect the ability to judge the structural coherence of objects, objects embedded in scenes, or scenes themselves. This conclusion is in accord with our earlier findings that the hippocampus is also not needed for a variety of other spatial tasks, so long as the tasks do not depend on long-term memory (Rungratsameetaweemana & Squire, 2018;Urgolites et al, 2016Urgolites et al, , 2017Kim et al, 2011Kim et al, , 2015Kim, Borst, et al, 2013;Kim, Sapiurka, et al, 2013;Shrager et al, 2008).…”

“…In these circumstances, patients with hippocampal lesions might have been disadvantaged due to their memory impairment. In our own studies of spatial tasks, where we attempted to minimize the contribution of long-term memory (by limiting the number of stimuli or by using trial-unique stimuli), hippocampal patients performed as well as controls (path integration, Kim, Sapiurka, Clark, & Squire, 2013;Shrager, Kirwan, & Squire, 2008; visual discrimination of scenes, Kim et al, 2011;spatial imagery, Kim, Borst, et al, 2013; scene construction, Kim, Dede, Hopkins, & Squire, 2015; map reading and navigation, Urgolites, Kim, Hopkins, & Squire, 2016; topographical memory with shifts of viewpoint, Urgolites, Hopkins, & Squire, 2017; scene construction with shifts of viewpoint, Rungratsameetaweemana & Squire, 2018). For a report of impaired performance in a task using trial-unique stimuli, see Lee et al (2005).…”

Map Learning in Aging Individuals: The Role of Cognitive Functioning and Visuospatial Factors

“…Underlying neuronal mechanisms may elucidate this difference. Indeed, partially distinct neuronal pathways encode categorical (relying more on the left hemisphere) and distance (relying more on the right hemisphere) spatial relations [42], as corroborated using brain imaging studies and studies of clinical populations [43][44][45][46]. Pathways could be susceptible to increasing age in different ways [47].…”

Improving Hippocampal Memory Through the Experience of a Rich Minecraft Environment

“…We should note, however, that while not explicitly spatial, the active process of building inherently becomes more spatial as building progresses. As the hippocampus plays a role in spatial mental imagery, including the ability to perceive objects or scenes from different perspectives (Hassabis et al, 2007; Bird et al, 2010; Summerfield et al, 2010) which may depend on the complexity of the scene or objects (Kim et al, 2013; Rungratsameetaweemana and Squire, 2018; Urgolites et al, 2018), the building condition should not be considered purely “non-spatial.” But, it has many rich non-spatial components and the scale of spatial involvement is certainly different than open-world exploration, giving us a different means within the same gaming environment of assessing whether enrichment, broadly defined, might have an impact on memory.…”