A cortical representation of the local visual environment

Abstract

Medial temporal brain regions such as the hippocampal formation and parahippocampal cortex have been generally implicated in navigation and visual memory. However, the specific function of each of these regions is not yet clear. Here we present evidence that a particular area within human parahippocampal cortex is involved in a critical component of navigation: perceiving the local visual environment. This region, which we name the 'parahippocampal place area' (PPA), responds selectively and automatically in functional magnetic resonance imaging (fMRI) to passively viewed scenes, but only weakly to single objects and not at all to faces. The critical factor for this activation appears to be the presence in the stimulus of information about the layout of local space. The response in the PPA to scenes with spatial layout but no discrete objects (empty rooms) is as strong as the response to complex meaningful scenes containing multiple objects (the same rooms furnished) and over twice as strong as the response to arrays of multiple objects without three-dimensional spatial context (the furniture from these rooms on a blank background). This response is reduced if the surfaces in the scene are rearranged so that they no longer define a coherent space. We propose that the PPA represents places by encoding the geometry of the local environment.

Evidencing a place for the hippocampus within the core scene processing network

“…Overall, the results of our group‐level analyses were consistent with previous studies that observed strong scene‐sensitivity in these regions during standard localiser tasks [Bettencourt and Xu, 2013; Epstein, 2008; Epstein and Kanwisher, 1998; Lee et al, 2008; Spiridon et al, 2006]. Our main scene‐selective contrast revealed significant bilateral activity in each tested ROI at the whole brain level, including HC and TOS.…”

“…In line with its well established role in scene perception and working memory more broadly [Epstein and Kanwisher, 1998; Ranganath et al, 2004], the greatest degree of inter‐subject overlap (across all ROIs and thresholds) was found in posterior PHG (59%). Further, the region of maximum overlap in the PHG was close to the group‐level peak voxel in the same hemisphere.…”

“…As such, it is unsurprising that functional neuroimaging techniques have revealed a putative “core” scene processing network in the human brain that responds strongly when viewing navigationally relevant stimuli (e.g., scenes) versus other visual categories. This core network is thought to include posterior parahippocampal gyrus [PHG; Aguirre et al, 1998a; Epstein et al, 2003; Epstein and Kanwisher, 1998], retrosplenial cortex [RSC; Auger et al, 2012; Epstein et al, 2007; Vann et al, 2009] and the transverse occipital sulcus [TOS; Dilks et al, 2013; Ganaden et al, 2013; He et al, 2013; Mullin and Steeves, 2011; Nasr et al, 2011]. As seen in the neural processing of other visual categories [Taylor and Downing, 2011], these regions appear to support distinct but complementary aspects of scene processing, and are differentially modulated by changes in viewpoint [Epstein et al, 2003, 2007; Park and Chun, 2009], spatial layout [Harel et al, 2013; Park et al, 2015], and lower‐level spatial features [Kravitz et al, 2011a; Nasr et al, 2014].…”

The Neural-Cognitive Basis of the Jamesian Stream of Thought

“…per se, but on underlying cortices in the parahippocampal region (Murray & Mishkin, 1998;Suzuki et al, 1993), with the perirhinal cortex specialized for encoding object representations (Buckley & Gaffan, 1998), the parahippocampal cortex specialized for spatial representations (Epstein & Kanwisher, 1998;Suzuki & Amaral, 1994), and the entorhinal cortex acting to combine input from these two regions to form representations of objects within locations (Suzuki, Miller, & Desimone, 1997).…”

Transient topographical disorientation due to right‐sided hippocampal hemorrhage

“…was indicated by a nearly complete loss of his internal cognitive map for space during the acute stage of symptoms (Hartley et al., 2003; Howard et al., 2014). An increase in search saccades together with a pronounced deficit in the recognition and incorporation of landmarks were associated with parahippocampal dysfunction (Aguirre et al., 1996; Epstein & Kanwisher, 1998). The pathological changes in gaze behavior and spatial navigation abilities in our patient resembled the pattern of other hippocampal navigation disorders such as MCI‐patients (unpublished data).…”