Firing Variability Is Higher than Deduced from the Empirical Coefficient of Variation

Ditlevsen, Susanne; Lánský, Petr

doi:10.1162/neco_a_00157

Cited by 19 publications

(18 citation statements)

References 45 publications

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“…The dependence of the Fano factor on the counting interval is also lost, meaning that unit activity is highly variable even at short time scales. This may be indicative of a simpler temporal structure of V1 activity under deeper anesthesia as well as of the gradual shift to lower frequencies with increasing inhibition, which may be general property of anesthesia (Erchova et al 2002).…”

Section: Discussionmentioning

confidence: 96%

“…Although various quantities, such as the coefficient of variation (Ditlevsen and Lansky 2011;Nawrot et al 2008), are used to characterize the variability of neural responses across trials, we applied the commonly used Fano factor, F(T), to assess the variability in spike trains (Churchland et al 2010). F(T) is the ratio of the variance to the mean of spike counts, n, calculated by binning the recorded spike trains into time intervals of length T, F(T) ϭ n 2 /ϽnϾ.…”

Section: Methodsmentioning

confidence: 99%

See 1 more Smart Citation

Suppression of cortical neural variability is stimulus- and state-dependent

White

Abbott

Fiser

2012

Journal of Neurophysiology

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Internally generated, spontaneous activity is ubiquitous in the cortex, yet it does not appear to have a significant negative impact on sensory processing. Various studies have found that stimulus onset reduces the variability of cortical responses, but the characteristics of this suppression remained unexplored. By recording multiunit activity from awake and anesthetized rats, we investigated whether and how this noise suppression depends on properties of the stimulus and on the state of the cortex. In agreement with theoretical predictions, we found that the degree of noise suppression in awake rats has a nonmonotonic dependence on the temporal frequency of a flickering visual stimulus with an optimal frequency for noise suppression ~2 Hz. This effect cannot be explained by features of the power spectrum of the spontaneous neural activity. The nonmonotonic frequency dependence of the suppression of variability gradually disappears under increasing levels of anesthesia and shifts to a monotonic pattern of increasing suppression with decreasing frequency. Signal-to-noise ratios show a similar, although inverted, dependence on cortical state and frequency. These results suggest the existence of an active noise suppression mechanism in the awake cortical system that is tuned to support signal propagation and coding.

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Section: Discussionmentioning

confidence: 96%

Section: Methodsmentioning

confidence: 99%

Suppression of cortical neural variability is stimulus- and state-dependent

White

Abbott

Fiser

2012

Journal of Neurophysiology

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“…This bin range was delimited by the shortest and the longest ISI of all the recordings. Because the widely used parameter, the coefficient of variation, was reported as an underestimate of firing variability in some cases (Ditlevsen & Lansky, ), we calculated the Shannon‐entropy of ISI distribution as well (Huang et al . ).…”

Section: Methodsmentioning

confidence: 99%

Divergent in vivo activity of non‐serotonergic and serotonergic VGluT3–neurones in the median raphe region

Domonkos

Ledri

Laszlovszky

et al. 2016

The Journal of Physiology

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Key points The median raphe is a key subcortical modulatory centre involved in several brain functions, such as regulation of the sleep–wake cycle, emotions and memory storage.A large proportion of median raphe neurones are glutamatergic and implement a radically different mode of communication compared to serotonergic cells, although their in vivo activity is unknown.We provide the first description of the in vivo, brain state‐dependent firing properties of median raphe glutamatergic neurones identified by immunopositivity for the vesicular glutamate transporter type 3 (VGluT3) and serotonin (5‐HT). Glutamatergic populations (VGluT3+/5‐HT– and VGluT3+/5‐HT+) were compared with the purely serotonergic (VGluT3–/5‐HT+ and VGluT3–/5‐HT–) neurones.VGluT3+/5‐HT+ neurones fired similar to VGluT3–/5‐HT+ cells, whereas they significantly diverged from the VGluT3+/5‐HT– population. Activity of the latter subgroup resembled the spiking of VGluT3–/5‐HT– cells, except for their diverging response to sensory stimulation.The VGluT3+ population of the median raphe may broadcast rapidly varying signals on top of a state‐dependent, tonic modulation. AbstractSubcortical modulation is crucial for information processing in the cerebral cortex. Besides the canonical neuromodulators, glutamate has recently been identified as a key cotransmitter of numerous monoaminergic projections. In the median raphe, a pure glutamatergic neurone population projecting to limbic areas was also discovered with a possibly novel, yet undetermined function. In the present study, we report the first functional description of the vesicular glutamate transporter type 3 (VGluT3)‐expressing median raphe neurones. Because there is no appropriate genetic marker for the separation of serotonergic (5‐HT+) and non‐serotonergic (5‐HT–) VGluT3+ neurones, we utilized immunohistochemistry after recording and juxtacellular labelling in anaesthetized rats. VGluT3+/5‐HT– neurones fired faster, more variably and were permanently activated during sensory stimulation, as opposed to the transient response of the slow firing VGluT3–/5‐HT+ subgroup. VGluT3+/5‐HT– cells were also more active during hippocampal theta. In addition, the VGluT3–/5‐HT– population, comprising putative GABAergic cells, resembled the firing of VGluT3+/5‐HT– neurones but without any significant reaction to the sensory stimulus. Interestingly, the VGluT3+/5‐HT+ group, spiking slower than the VGluT3+/5‐HT– population, exhibited a mixed response (i.e. the initial transient activation was followed by a sustained elevation of firing). Phase coupling to hippocampal and prefrontal slow oscillations was found in VGluT3+/5‐HT– neurones, also differentiating them from the VGluT3+/5‐HT+ subpopulation. Taken together, glutamatergic neurones in the median raphe may implement multiple, highly divergent forms of modulation in parallel: a slow, tonic mode interrupted by sensory‐evoked rapid transients, as well as a fast one capable of conveying complex patterns influenced by sensory inputs.

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“…The c v is most often estimated by the ratio of sample standard deviation to sample mean, however, the estimate may be considerably biased, [14].…”

Section: Methods Of Non-parametric Estimationmentioning

confidence: 99%

Nonparametric Estimation of Information-Based Measures of Statistical Dispersion

Kostal

Pokora

2012

Entropy

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Abstract:We address the problem of non-parametric estimation of the recently proposed measures of statistical dispersion of positive continuous random variables. The measures are based on the concepts of differential entropy and Fisher information and describe the "spread" or "variability" of the random variable from a different point of view than the ubiquitously used concept of standard deviation. The maximum penalized likelihood estimation of the probability density function proposed by Good and Gaskins is applied and a complete methodology of how to estimate the dispersion measures with a single algorithm is presented. We illustrate the approach on three standard statistical models describing neuronal activity.

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Firing Variability Is Higher than Deduced from the Empirical Coefficient of Variation

Cited by 19 publications

References 45 publications

Suppression of cortical neural variability is stimulus- and state-dependent

Suppression of cortical neural variability is stimulus- and state-dependent

Divergent in vivo activity of non‐serotonergic and serotonergic VGluT3–neurones in the median raphe region

Nonparametric Estimation of Information-Based Measures of Statistical Dispersion

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