What are grid-like responses doing in the orbitofrontal cortex?

Abstract

In 2005, the Moser group identified a new type of cell in the entorhinal cortex (ERC): the grid cell (Hafting, Nature, 436, 2005, pp. 801-806). A landmark series of studies from these investigators showed that grid cells support spatial navigation by encoding position, direction as well as distance information, and they subsequently found grid cells in pre-and para-subiculum areas adjacent to the ERC (Boccara, Nature Neuroscience, 13, 2010, pp. 987-994). Fast forward to 2010, when some clever investigators developed fMRI analysis methods to document grid-like responses in the human ERC (Doeller, Nature, 463, 2010, pp. 657-661). What was not at all expected was the co-identification of grid-like fMRI responses outside of the ERC, in particular, the orbitofrontal cortex (OFC) and the ventromedial prefrontal cortex (vmPFC). Here we provide a compact overview of the burgeoning literature on grid cells in both rodent and human species, while considering the intriguing question: what are grid-like responses doing in the OFC and vmPFC?

Spatial Representations in Rat Orbitofrontal Cortex

“…BOLD does not appear to suffer from this bias (Logothetis and Wandell, 2004). As a result, one interpretation of the low number of grid cells in our dataset is that the gridness reported in BOLD response reflects the influence of input from hippocampal areas, functioning to help support and properly organize or coordinate the map in OFC with that in other areas (Raithel and Gottfried, 2021). Another possibility is that the foraging task used in the present work was not sufficiently challenging to require or evoke gridlike representations in OFC In hippocampus, for instance, there is evidence that behavioral demands alter spatial representations, with place cells showing increased temporal reliability on tasks that require solving more challenging navigation problems (Olypher et al, 2002;Jackson and Redish, 2007;Fenton et al, 2010;Wikenheiser and Redish, 2011).…”

Five discoveries of Volodymyr Betz. Part one. Betz and the islands of entorhinal cortex

“…Chen, S.Q. Chen & Ding, 2020;Meier, Q. Wang, Ji Ganachaud & Burkhalter, 2021;Huang, Rolls, Hsu, Feng & Lin, 2021;Raithel & Gottfried, 2021;Syversen et al, 2021) and cover distal cortex areas, e.g., primary somatosensory cortex (С. and area prostriata (Hu et al, 2020).…”

Are Grid-Like Representations a Component of All Perception and Cognition?

“…Therefore, it is not impossible that the somatosensory cortex will respond in grid-like patterns when different parts of the objects are touched, so that all combined neural responses form a coherent allocentric representation of the object. Extending the original idea of cognitive map for spatial landscape (Tolman, 1948 ), the non-spatial information can be organized among visual, olfactory, social and imaging concepts (Bellmund et al, 2018b ; Herweg and Kahana, 2018 ; Raithel and Gottfried, 2021 ).…”

“…Conceptually, higher-order cortices can use the location-based framework to represent and organize knowledge and social hierarchy (Park et al, 2021 ). Similar to hippocampal sparse encoding of spatial memories, sparse representations of higher-order cortical population activity may encode abstract behavioral concepts or support flexible cognition and behavior (Constantinescu et al, 2016 ; Bellmund et al, 2018b ; Raithel and Gottfried, 2021 ). However, it is also worth pointing out that the fMRI-BOLD signal does not directly measure the neuronal activity, and therefore it cannot be interpreted in the same way as the electrophysiological signal (i.e., spiking activity).…”