Mental space travel: Damage to posterior parietal cortex prevents egocentric navigation and reexperiencing of remote spatial memories.

Abstract

The ability to navigate in a familiar environment depends on both an intact mental representation of allocentric spatial information and the integrity of systems supporting complementary egocentric representations. Although the hippocampus has been implicated in learning new allocentric spatial information, converging evidence suggests that the posterior parietal cortex (PPC) might support egocentric representations. To date, however, few studies have examined long-standing egocentric representations of environments learned long ago. Here we tested 7 patients with focal lesions in PPC and 12 normal controls in remote spatial memory tasks, including 2 tasks reportedly reliant on allocentric representations (distance and proximity judgments) and 2 tasks reportedly reliant on egocentric representations (landmark sequencing and route navigation; see Rosenbaum, Ziegler, Winocur, Grady, & Moscovitch, 2004). Patients were unimpaired in distance and proximity judgments. In contrast, they all failed in route navigation, and left-lesioned patients also showed marginally impaired performance in landmark sequencing. Patients' subjective experience associated with navigation was impoverished and disembodied compared with that of the controls. These results suggest that PPC is crucial for accessing remote spatial memories within an egocentric reference frame that enables both navigation and reexperiencing. Additionally, PPC was found to be necessary to implement specific aspects of allocentric navigation with high demands on spontaneous retrieval.

The occipital place area represents first-person perspective motion information through scenes

“…This activation is consistent with a number of studies showing parietal activation during navigation tasks (Burgess, 2008; Kravitz et al, 2011; Marchette et al, 2014; Persichetti & Dilks, 2016; Spiers & Maguire, 2007; van Assche et al, 2016). Interestingly, this activation is also consistent with neuropsychological data from patients with damage to posterior parietal cortex who show a profound inability to localize objects with respect to the self (a condition known as egocentric disorientation) (Aguirre & D’Esposito, 1999; Ciaramelli, Rosenbaum, Solcz, Levine, & Moscovitch, 2010; Stark, Coslett, & Saffran, 1996; Wilson et al, 2005). …”

Understanding age-related reductions in visual working memory capacity: Examining the stages of change detection

“…The possible absence of recollection in older adults, as suggested by the lack of LPC-like activity, is also consistent with our earlier supposition that older adults may maintain the same quantity of information in VWM but suffer from a lower quality of information than is present in younger adults. Recent research has also suggested that recollection entails—primarily due to the role of parietal areas—a subjective “reexperiencing” of the memory encoding (Ally, Simons, McKeever, Peers, & Budson, 2008; Ciaramelli, Rosenbaum, Solcz, Levine, & Moscovich, 2010; Simons, Peers, Mazuz, Berryhill, & Olson, 2010). This subjective reexperience might be crucial for the change detection task, because the retrieved contents of VWM must be explicitly compared to the probe, and lack of this reexperience in older adults would lower their ability to make the comparison.…”

Multimodal Feature Integration in the Angular Gyrus during Episodic and Semantic Retrieval

“…Exploratory analysis using Horner et al 's (2015) hippocampal peak coordinate (30, Ϫ31, Ϫ5) revealed marginally significantly higher hippocampal activation for multimodal compared with unimodal episodic memories in the present data (33, Ϫ33, Ϫ9; t (15) ϭ 2.59, p ϭ 0.059). It has been suggested previously that, compared with hippocampus, AnG may be more involved in the processing of egocentric compared with allocentric information (Zaehle et al, 2007;Ciaramelli et al, 2010;cf. Yazar et al, 2014).…”