Experimental evidence for sparse firing in the neocortex

Barth, Alison L.; Poulet, James F.A.

doi:10.1016/j.tins.2012.03.008

Cited by 348 publications

(346 citation statements)

References 109 publications

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“…4F). Because of the very sparse firing in upper cortical layers (Barth and Poulet 2012;Chauvette et al 2010), we did not observe a significant reduction of firing in the transition to silent states in superficial channels.…”

Section: Resultsmentioning

confidence: 63%

“…GABAergic baskets cells target essentially the soma of neocortical pyramidal neurons (Tamás et al 1997), where GABAergic synapses dominate (Freund et al 1983;Gu et al 1993). Because deep layer neurons fire more than those of superficial layers (Barth and Poulet 2012;Chauvette et al 2010;Sakata and Harris 2009;Sanchez-Vives and McCormick 2000), layers V and VI are more likely to maintain the recurrent activity generating the active state. In other words, silencing these neurons directly at the soma would be the most efficient way to trigger a disfacilitation and silent state.…”

Section: Discussionmentioning

confidence: 99%

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Neocortical inhibitory activities and long-range afferents contribute to the synchronous onset of silent states of the neocortical slow oscillation

Lemieux

Chauvette

Timofeev

2015

Journal of Neurophysiology

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Lemieux M, Chauvette S, Timofeev I. Neocortical inhibitory activities and long-range afferents contribute to the synchronous onset of silent states of the neocortical slow oscillation. J Neurophysiol 113: 768-779, 2015. First published November 12, 2014 doi:10.1152/jn.00858.2013.-During slowwave sleep, neurons of the thalamocortical network are engaged in a slow oscillation (Ͻ1 Hz), which consists of an alternation between the active and the silent states. Several studies have provided insights on the transition from the silent, which are essentially periods of disfacilitation, to the active states. However, the conditions leading to the synchronous onset of the silent state remain elusive. We hypothesized that a synchronous input to local inhibitory neurons could contribute to the transition to the silent state in the cat suprasylvian gyrus during natural sleep and under ketamine-xylazine anesthesia. After partial and complete deafferentation of the cortex, we found that the silent state onset was more variable among remote sites. We found that the transition to the silent state was preceded by a reduction in excitatory postsynaptic potentials and firing probability in cortical neurons. We tested the impact of chloride-mediated inhibition in the silent-state onset. We uncovered a long-duration (100 -300 ms) inhibitory barrage occurring about 250 ms before the silent state onset in 3-6% of neurons during anesthesia and in 12-15% of cases during natural sleep. These inhibitory activities caused a decrease in cortical firing that reduced the excitatory drive in the neocortical network. That chain reaction of disfacilitation ends up on the silent state. Electrical stimuli could trigger a network silent state with a maximal efficacy in deep cortical layers. We conclude that long-range afferents to the neocortex and chloride-mediated inhibition play a role in the initiation of the silent state. slow oscillation; long-range afferents; chloride-mediated inhibition; intracellular recordings SLOW OSCILLATION IS THE HALLMARK of the slow-wave sleep but also of several anesthetics, including ketamine-xylazine (Contreras and Steriade 1995; Steriade et al.

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Section: Resultsmentioning

confidence: 63%

Section: Discussionmentioning

confidence: 99%

Neocortical inhibitory activities and long-range afferents contribute to the synchronous onset of silent states of the neocortical slow oscillation

Lemieux

Chauvette

Timofeev

2015

Journal of Neurophysiology

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“…Overall, the data are biased towards the infragranular layers, as the total number of neurons in each layer in all experiments together is as follows: L2/3: 28; L4: 54; L5A: 170; L5B/6: 111. The limited sample from L2/3 can be attributed either to a technical difficulty of sampling supragranular layers with the silicon probes (Reyes-Puerta et al 2014) or to the sparse firing of neurons in this layer (Barth and Poulet 2012). In five of the seven analyzed experiments, spontaneous activity was recorded for periods between 8.3 and 33.3 Fig.…”

Section: Resultsmentioning

confidence: 99%

Long-range intralaminar noise correlations in the barrel cortex

Reyes‐Puerta

Amitai

Sun

et al. 2015

Journal of Neurophysiology

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Reyes-Puerta V, Amitai Y, Sun JJ, Shani I, Luhmann HJ, Shamir M. Long-range intralaminar noise correlations in the barrel cortex. J Neurophysiol 113: 3410 -3420, 2015. First published March 18, 2015 doi:10.1152/jn.00981.2014.-Identifying the properties of correlations in the firing of neocortical neurons is central to our understanding of cortical information processing. It has been generally assumed, by virtue of the columnar organization of the neocortex, that the firing of neurons residing in a certain vertical domain is highly correlated. On the other hand, firing correlations between neurons steeply decline with horizontal distance. Technical difficulties in sampling neurons with sufficient spatial information have precluded the critical evaluation of these notions. We used 128-channel "silicon probes" to examine the spike-count noise correlations during spontaneous activity between multiple neurons with identified laminar position and over large horizontal distances in the anesthetized rat barrel cortex. Eigen decomposition of correlation coefficient matrices revealed that the laminar position of a neuron is a significant determinant of these correlations, such that the fluctuations of layer 5B/6 neurons are in opposite direction to those of layers 5A and 4. Moreover, we found that within each experiment, the distribution of horizontal, intralaminar spike-count correlation coefficients, up to a distance of ϳ1.5 mm, is practically identical to the distribution of vertical correlations. Taken together, these data reveal that the neuron's laminar position crucially affects its role in cortical processing. Moreover, our analyses reveal that this laminar effect extends over several functional columns. We propose that within the cortex the influence of the horizontal elements exists in a dynamic balance with the influence of the vertical domain and this balance is modulated with brain states to shape the network's behavior. single unit recordings; 128-channel silicon probes; cortical layers; eigen decomposition; principal component analysis

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“…This can be related to the characteristic sparse activity in cortical circuits (Molotchnikoff and Rouat, 2011;Jayakumar et al, 2012;Barth and Poulet, 2012). Even though no increase of firing rate was noticed in the 50 ms bin, yet cross-correlating their neural spike trains yielded a significant cross-correlogram between neurons.…”

Section: Functional Consequencesmentioning

confidence: 93%