Do gamma oscillations play a role in cerebral cortex?

Ray, Supratim; Maunsell, John H. R.

doi:10.1016/j.tics.2014.12.002

Cited by 226 publications

(168 citation statements)

References 106 publications

(121 reference statements)

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“…Much attention has been focused on gamma LFP activity in cortical areas and their possible function, for example in coordinating activation between distant cortical areas (72)(73)(74). At the same time, it has been noted that gamma oscillations in sensory cortices tend to be poorly coupled to aspects of visual stimuli or decision-related task variables, calling into question whether they are sufficiently reliable indicators of cortical processing (75). The gamma oscillations we demonstrate in the BF certainly do not lack robustness, and their activity levels, particularly during hitherto largely unstudied neutral behavioral states, may be some of strongest gamma observable anywhere in the central nervous system.…”

Section: Discussionmentioning

confidence: 99%

Basal forebrain contributes to default mode network regulation

Nair

Klaassen

Arató³

et al. 2018

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

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The default mode network (DMN) is a collection of cortical brain regions that is active during states of rest or quiet wakefulness in humans and other mammalian species. A pertinent characteristic of the DMN is a suppression of local field potential gamma activity during cognitive task performance as well as during engagement with external sensory stimuli. Conversely, gamma activity is elevated in the DMN during rest. Here, we document that the rat basal forebrain (BF) exhibits the same pattern of responses, namely pronounced gamma oscillations during quiet wakefulness in the home cage and suppression of this activity during active exploration of an unfamiliar environment. We show that gamma oscillations are localized to the BF and that gamma-band activity in the BF has a directional influence on a hub of the rat DMN, the anterior cingulate cortex, during DMNdominated brain states. The BF is well known as an ascending, activating, neuromodulatory system involved in wake-sleep regulation, memory formation, and regulation of sensory information processing. Our findings suggest a hitherto undocumented role of the BF as a subcortical node of the DMN, which we speculate may be important for switching between internally and externally directed brain states. We discuss potential BF projection circuits that could underlie its role in DMN regulation and highlight that certain BF nuclei may provide potential target regions for up-or down-regulation of DMN activity that might prove useful for treatment of DMN dysfunction in conditions such as epilepsy or major depressive disorder.gamma suppression | anterior cingulate cortex | granger causality A highly consistent finding across a wide range of functional imaging studies in humans is that a network of brain regions, referred to as the "default mode network" (DMN), increases its activity during passive mental states compared with the performance of cognitive tasks. This was initially shown in a metaanalysis of several PET studies (1), in which a distribution of brain regions broadly including the medial prefrontal, retrosplenial, and anterior cingulate cortex (ACC), as well as lateral parietal and temporal cortices, was shown to be activated when subjects were in a state of quiet restfulness. The DMN areas are thought to form a cohesive set of intrinsically coupled brain regions, such that fMRI activations in its component regions exhibit similar time courses, allowing them to be identified reliably using seed-region analysis (2-4). Activity in the DMN exhibits anticorrelation with a complementary, largely nonoverlapping, set of fronto-parietal brain areas known as the "dorsal attention network" (DAN) (5). It should be noted, however, that particular brain structures may harbor functionally heterogeneous elements and thus may contribute to multiple functions, as was shown for the ACC (6). During wakefulness, the human brain thus alternates between DAN-and DMN-dominated activation states, corresponding to effortful cognitive task performance on the one hand and quiet restful...

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Section: Discussionmentioning

confidence: 99%

Basal forebrain contributes to default mode network regulation

Nair

Klaassen

Arató³

et al. 2018

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

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“…Although many studies have provided evidence for 19,20 and suggested that 26,27 broadband activity correlates strongly with the underlying firing rate, this point remains controversial. Specifically, Ekstrom and colleagues 28 found that spike rate in the hippocampus was not directly related to any frequency activity in the local field potential.…”

Section: Discussionmentioning

confidence: 99%

Mild Traumatic Brain Injury Decreases Broadband Power in Area CA1

Paternò

Metheny

Xiong

et al. 2016

Journal of Neurotrauma

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Cognitive impairment caused by traumatic brain injury (TBI) can lead to devastating consequences for both patients and their families. The underlying neurological basis for TBI-induced cognitive dysfunction remains unknown. However, many lines of research have implicated the hippocampus in the pathophysiology of TBI. In particular, past research has found that theta oscillations, long thought to be the electrophysiological basis of learning and memory, are decreased in the hippocampus post-TBI. Here, we recorded in vivo electrophysiological activity in the hippocampi of 16 mice, 8 of which had previously undergone a TBI. Consistent with previous data, we found that theta power in the hippocampus was decreased in TBI animals compared to sham controls; however, this effect was driven by changes in broadband power and not theta oscillations. This result suggests that broadband fluctuations in the hippocampal local field potential can be used as an electrophysiological surrogate of abnormal neurological activity post-TBI.

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“…Ultimately though, it is the number, not the timing, of action potentials generated by motoneurons that determines a movement, so efforts toward understanding how a temporal code is converted to a rate code will be required to understand the operation of these circuits fully. Also, whether these oscillations are a mechanism of attention requires experimental investigation (Ray & Maunsell 2015). …”

Section: Microcircuits Of the Superior Colliculusmentioning

confidence: 99%

Circuits for Action and Cognition: A View from the Superior Colliculus

Basso¹,

May

2017

Annu. Rev. Vis. Sci.

305

245

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The superior colliculus is one of the most well-studied structures in the brain, and with each new report, its proposed role in behavior seems to increase in complexity. Forty years of evidence show that the colliculus is critical for reorienting an organism toward objects of interest. In monkeys, this involves saccadic eye movements. Recent work in the monkey colliculus and in the homologous optic tectum of the bird extends our understanding of the role of the colliculus in higher mental functions, such as attention and decision making. In this review, we highlight some of these recent results, as well as those capitalizing on circuit-based methodologies using transgenic mice models, to understand the contribution of the colliculus to attention and decision making. The wealth of information we have about the colliculus, together with new tools, provides a unique opportunity to obtain a detailed accounting of the neurons, circuits, and computations that underlie complex behavior.

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Do gamma oscillations play a role in cerebral cortex?

Cited by 226 publications

References 106 publications

Basal forebrain contributes to default mode network regulation

Basal forebrain contributes to default mode network regulation

Mild Traumatic Brain Injury Decreases Broadband Power in Area CA1

Circuits for Action and Cognition: A View from the Superior Colliculus

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