Grids from bands, or bands from grids? An examination of the effects of single unit contamination on grid cell firing fields

Navratilova, Zaneta; Godfrey, Keith B.; McNaughton, Bruce L.

doi:10.1152/jn.00699.2015

Cited by 24 publications

(22 citation statements)

References 33 publications

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“…S3H). We could rule out the possibility that spatial periodicity was a result of spike-sorting artifact (33,34) by including only single units, which produced nonoverlapping waveform clusters with an average Mahalanobis intercluster distance of >20 (mean Mahal_d = 230; SI Appendix, Figs. S2 and S10-S28).…”

Section: Resultsmentioning

confidence: 99%

Context-dependent spatially periodic activity in the human entorhinal cortex

Nádasdy

Nguyen

Török

et al. 2017

Proc. Natl. Acad. Sci. U.S.A.

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The spatially periodic activity of grid cells in the entorhinal cortex (EC) of the rodent, primate, and human provides a coordinate system that, together with the hippocampus, informs an individual of its location relative to the environment and encodes the memory of that location. Among the most defining features of grid-cell activity are the 60°rotational symmetry of grids and preservation of grid scale across environments. Grid cells, however, do display a limited degree of adaptation to environments. It remains unclear if this level of environment invariance generalizes to human grid-cell analogs, where the relative contribution of visual input to the multimodal sensory input of the EC is significantly larger than in rodents. Patients diagnosed with nontractable epilepsy who were implanted with entorhinal cortical electrodes performing virtual navigation tasks to memorized locations enabled us to investigate associations between grid-like patterns and environment. Here, we report that the activity of human entorhinal cortical neurons exhibits adaptive scaling in grid period, grid orientation, and rotational symmetry in close association with changes in environment size, shape, and visual cues, suggesting scale invariance of the frequency, rather than the wavelength, of spatially periodic activity. Our results demonstrate that neurons in the human EC represent space with an enhanced flexibility relative to neurons in rodents because they are endowed with adaptive scalability and context dependency.grid cell | spatial memory | entorhinal cortex | single unit | human

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Section: Resultsmentioning

confidence: 99%

Context-dependent spatially periodic activity in the human entorhinal cortex

Nádasdy

Nguyen

Török

et al. 2017

Proc. Natl. Acad. Sci. U.S.A.

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“…However, their activity is likely informed by two other cell types found in the mEC; speed cells, which encode the movement velocity of the animal (Kropff et al, 2015), and a recent report of 'band cells' (Krupic et al, 2012 but see;Navratilova et al, 2016 andKrupic et al, 2015) which fire in discrete bands of activity and may aid in the formation of the hexagonal grids of grid cells.…”

Section: Grid Cellsmentioning

confidence: 99%

The representation of space in the brain

Grieves

Jeffery

2017

Behavioural Processes

205

124

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Animals can navigate vast distances and often display behaviours or activities that indicate a detailed, internal spatial representation of their surrounding environment or a 'cognitive map'. Over a century of behavioural research on spatial navigation in humans and animals has greatly increased our understanding of how this highly complex feat is achieved. In turn this has inspired half a century of electrophysiological spatial navigation and memory research which has further advanced our understanding of the brain. In particular, three functional cell types have been suggested to underlie cognitive mapping processes; place cells, head direction cells and grid cells. However, there are numerous other spatially modulated neurons in the brain. For a more complete understanding of the electrophysiological systems and behavioural processes underlying spatial navigation we must also examine these lesser understood neurons. In this review we will briefly summarise the literature surrounding place cells, head direction cells, grid cells and the evidence that these cells collectively form the neural basis of a cognitive map. We will then review literature covering many other spatially modulated neurons in the brain that perhaps further augment this cognitive map.

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“…Alternatively, computational models have proposed that directional information is received from stripe cells [5,21]. However, the proportion of stripe cells is low [22] and their existence is controversial because they could be obtained from the incomplete separation of the spike patterns of two grid cells [23]. …”

Section: Head-direction Signals Are Not Sufficient As Ongoing Inputs mentioning

confidence: 99%

Theta sequences of grid cell populations can provide a movement-direction signal

Zutshi

Leutgeb

2017

Current Opinion in Behavioral Sciences

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It has been proposed that path integration in mammals is performed by the convergence of internally generated speed and directional inputs onto grid cells. Although this hypothesis has been supported by the discovery that head direction, speed, and grid cells are intermixed within entorhinal cortex and by the recent finding that head-direction inputs are necessary for grid firing, many details on how grid cells are generated have remained elusive. For example, analysis of recording data suggests that substituting head direction for movement direction accrues errors that preclude the formation of grid patterns. To address this discrepancy, we propose that the organization of grid networks makes it plausible that movement-direction signals are an output from grid cells and that temporally precise grid cell sequences provide a robust directional signal to other spatial and directional cell types.

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Grids from bands, or bands from grids? An examination of the effects of single unit contamination on grid cell firing fields

Cited by 24 publications

References 33 publications

Context-dependent spatially periodic activity in the human entorhinal cortex

Context-dependent spatially periodic activity in the human entorhinal cortex

The representation of space in the brain

Theta sequences of grid cell populations can provide a movement-direction signal

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