Properties of the extra-positional signal in hippocampal place cell discharge derived from the overdispersion in location-specific firing

Olypher, Andrey V.; Lánský, Petr; Fenton, André A.

doi:10.1016/s0306-4522(01)00586-3

Cited by 86 publications

(99 citation statements)

References 82 publications

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“…Both studies argue that place cell variability reflects changes in active cell assemblies, whether these changes are attributable to attentional reference-frame shift (Olypher et al, 2002;Fenton et al, 2010;Kelemen and Fenton, 2010) or to a more general internal mapswitching process (Jackson and Redish, 2007). We, however, found a positive correlation between place cell firing variability and the cognitive load of the behavioral task, as assessed by the behavioral performance toward long delays in the DNMTP task.…”

Section: Overdispersion Degree Predicts Individual Cognitive Performancecontrasting

confidence: 52%

“…These perforated synapses are thought to play an important role in synaptic plasticity thanks to their multiple partitioned transmission zones (Geinisman, 1993;Nicholson and Geinisman, 2009). In an early attempt to model the mechanisms underlying CA1 output overdispersion, Olypher et al (2002) suggested that this variability could be ascribed to random inhibition affecting a subset of synaptic inputs. In this context, the synaptic loss of efficacy attributable to the decrease of the PSD in CA1 might lead to the reduction of time variability in the inputs, resulting in a reduction of the overdispersion.…”

Section: Overdispersion and Synaptic Plasticitymentioning

confidence: 99%

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Hippocampal Dynamics Predict Interindividual Cognitive Differences in Rats

Hok¹,

Chah²,

Reilly³

et al. 2012

J. Neurosci.

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There are important and sustained interindividual differences in cognition during aging. Here, we investigated hippocampal spatial representations in a rat model of cognitive aging characterized by individual differences in a mnemonic task. Individual cognitive capabilities in old rats were assessed in a delayed non-matching-to-position task. We recorded hippocampal CA1 place cells as the rats explored a familiar environment. Unlike the usual place cells commonly described in the literature, we found that a significant fraction of pyramidal neurons recorded in our study showed a substantial delayed onset of their place field activity. We established that this firing onset delay naturally occurs under basal conditions in old rats and is positively correlated with the remapping status of the animals. The lack of firing during the first few hundred seconds after the animals were introduced into a familiar environment was also associated with an increased locomotion in the remapping rats. This delayed activity is central to understanding the individual basis of age-related cognitive impairment and to resolving numerous discrepancies in the literature on the place cell contribution to the etiology of agedrelated decline. Finally, we also found a positive correlation between the degree of firing variability of place cells ("overdispersion") and performance during the long delays in the delayed non-matching-to-position task. Place cell overdispersion might provide the functional basis for interindividual differences in behavior and cognition.

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Section: Overdispersion Degree Predicts Individual Cognitive Performancecontrasting

confidence: 52%

Section: Overdispersion and Synaptic Plasticitymentioning

confidence: 99%

Hippocampal Dynamics Predict Interindividual Cognitive Differences in Rats

Hok¹,

Chah²,

Reilly³

et al. 2012

J. Neurosci.

View full text Add to dashboard Cite

show abstract

“…However, in combination with the remapping studies, these observations suggest that hippocampal cells respond conjunctively to spatial and nonspatial variables, with the latter represented as changes in the rate distribution. Experience-related changes in rate distribution can also account for moment-to-moment variability of firing rates within place fields (overdispersion) 119 . The conjunctive nature of spatial and eventrelated firing is demonstrated elegantly in a more recent study of hippocampal activity after systematic variation of location, food cups (objects), and color or pattern of the recording box (context) 120 .…”

Section: Co M M E N Ta Rymentioning

confidence: 99%

Spatial representation in the hippocampal formation: a history

2017

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“…We avoided confounding the TTXinduced dynamic changes in discharge with those associated with the rat's motor (Ranck, 1973;O'Keefe and Recce, 1993;Harris et al, 2003), cognitive (Olypher et al, 2002;Ferbinteanu and Shapiro, 2003), or perceptual activity (Gothard et al, 1996a,b;Rotenberg and Muller, 1997) by studying the electrophysiological effects of the TTX injection in urethane-anesthetized rats.…”

Section: Introductionmentioning

confidence: 99%

Cognitive Disorganization in Hippocampus: A Physiological Model of the Disorganization in Psychosis

Olypher¹,

Klement²,

Fenton³

2006

J. Neurosci.

106

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Cognitive coordination refers to processes that organize the timing of activity among neurons without altering individual discharge properties. Coordinating processes allow neural networks to coactivate related representations and prevent the coactivation of unrelated representations. Impaired cognitive coordination, also called cognitive disorganization, is hypothesized to be the core deficit in the disorganized syndrome of schizophrenia (Phillips and Silverstein, 2003), a condition characterized by hallucinations, disorganization, and thought disorder. This disorganization hypothesis is based on the observation that schizophrenic subjects are impaired at segregating relevant and irrelevant stimuli and selectively using associations between relevant cues. We report that injecting the neural activity blocker tetrodotoxin (TTX) into one hippocampus persistently coactivated pyramidal cells in the uninjected hippocampus that initially discharged independently. In accord with the definition of cognitive disorganization, pyramidal cell firing rates only changed for 15 min and did not accompany the coactivation. The TTX-induced coactivity was maximal at gamma periods, consistent with altered gamma oscillations and disorganization in schizophrenia. A network model confirmed that increasing the coupling of weakly associated cells impairs the selective activation and inhibition of stored spatial representations. This TTX-induced cognitive disorganization correctly predicted that the same TTX injection selectively impaired the ability of rats to segregate relevant associations among distal spatial stimuli from irrelevant local stimuli (Wesierska et al., 2005). The TTX-induced coactivity of hippocampal pyramidal cell discharge has construct and predictive validity as a physiological model of psychosis-related disorganization.

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Properties of the extra-positional signal in hippocampal place cell discharge derived from the overdispersion in location-specific firing

Cited by 86 publications

References 82 publications

Hippocampal Dynamics Predict Interindividual Cognitive Differences in Rats

Hippocampal Dynamics Predict Interindividual Cognitive Differences in Rats

Spatial representation in the hippocampal formation: a history

Cognitive Disorganization in Hippocampus: A Physiological Model of the Disorganization in Psychosis

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