Neurons with Stereotyped and Rapid Responses Provide a Reference Frame for Relative Temporal Coding in Primate Auditory Cortex

Brasselet, Romain; Panzeri, Stefano; Logothetis, Nikos K.; Kayser, Christoph

doi:10.1523/jneurosci.5435-11.2012

Cited by 45 publications

(52 citation statements)

References 58 publications

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“…Even though these MI values could be interpreted as rather low, similar MI values have been found in the auditory cortex (Brasselet et al 2012). The surrogate test was only passed in the engaged brain state, and these results suggest that the engaged state carries more information than the first one.…”

Section: Resultssupporting

confidence: 71%

Variability and information content in auditory cortex spike trains during an interval-discrimination task

Abolafia

Martínez-García

Deco

et al. 2013

Journal of Neurophysiology

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Abolafia JM, Martinez-Garcia M, Deco G, Sanchez-Vives MV. Variability and information content in auditory cortex spike trains during an interval-discrimination task. J Neurophysiol 110: 2163-2174, 2013. First published August 14, 2013 doi:10.1152/jn.00381.2013.-Processing of temporal information is key in auditory processing. In this study, we recorded single-unit activity from rat auditory cortex while they performed an interval-discrimination task. The animals had to decide whether two auditory stimuli were separated by either 150 or 300 ms and nose-poke to the left or to the right accordingly. The spike firing of single neurons in the auditory cortex was then compared in engaged vs. idle brain states. We found that spike firing variability measured with the Fano factor was markedly reduced, not only during stimulation, but also in between stimuli in engaged trials. We next explored if this decrease in variability was associated with an increased information encoding. Our information theory analysis revealed increased information content in auditory responses during engagement compared with idle states, in particular in the responses to task-relevant stimuli. Altogether, we demonstrate that task-engagement significantly modulates coding properties of auditory cortical neurons during an interval-discrimination task. auditory processing; firing modulation; auditory cortex A RELEVANT ASPECT OF AUDITORY perception is the analysis of temporal information. Different studies have shown how single units of auditory cortex discriminate relevant temporal information for behavior (Bao et al. 2004;Fritz et al. 2007;Lemus et al. 2009;Polley et al. 2006). Temporal processing in auditory cortex has been previously studied by means of a number of experimental manipulations. Some studies have focused on interval production tasks (Merchant et al. 2008), discrimination of stimuli repetition rate (Bao et al. 2004;Fritz et al. 2007;Lemus et al. 2009;Polley et al. 2006), or frequency categorization of tones (Ohl et al. 2001;Selezneva et al. 2006). However, the mechanisms of temporal discrimination at the level of the cortical single unit are not well known. This issue was explored in a recent study where monkeys had to compare two acoustic flutter stimuli (Lemus et al. 2009). In that study, an absence of modulation of neuronal firing related to working memory or to decision components of the task was found. We were interested to explore the task-modulation of neuronal discharges to identical stimulation patterns, in particular in a task where the interval between stimuli would be behaviorally relevant. For that purpose, we devised an interval-discrimination task where the same patterns of auditory stimulation were carried out during engaged (correct choices provided reward) and in idle states (performance not required), and studied spontaneous and evoked firing patterns of single auditory cortical neurons.Studies of neural mechanisms of auditory processing in auditory cortex have reported both an increased excitability and respons...

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Section: Resultssupporting

confidence: 71%

Variability and information content in auditory cortex spike trains during an interval-discrimination task

Abolafia

Martínez-García

Deco

et al. 2013

Journal of Neurophysiology

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“…Thus we speculate that FSUs may have a role in stimulus onset detection. Interestingly, in the auditory system, direct evidence for stimulus onset detectors has recently been reported (Brasselet et al 2012).…”

Section: Discussionmentioning

confidence: 99%

Comparison of latency and rate coding for the direction of whisker deflection in the subcortical somatosensory pathway

Storchi

Bale

Biella

et al. 2012

Journal of Neurophysiology

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The response of many neurons in the whisker somatosensory system depends on the direction in which a whisker is deflected. Although it is known that the spike count conveys information about this parameter, it is not known how important spike timing might be. The aim of this study was to compare neural codes based on spike count and first-spike latency, respectively. We extracellularly recorded single units from either the rat trigeminal ganglion (primary sensory afferents) or ventroposteromedial (VPM) thalamic nucleus in response to deflection in different directions and quantified alternative neural codes using mutual information. We found that neurons were diverse: some (58% in ganglion, 32% in VPM) conveyed information only by spike count; others conveyed additional information by latency. An issue with latency coding is that latency is measured with respect to the time of stimulus onset, a quantity known to the experimenter but not directly to the subject's brain. We found a potential solution using the integrated population activity as an internal timing signal: in this way, 91% of the first-spike latency information could be recovered. Finally, we asked how well direction could be decoded. For large populations, spike count and latency codes performed similarly; for small ones, decoding was more accurate using the latency code. Our findings indicate that whisker deflection direction is more efficiently encoded by spike timing than by spike count. Spike timing decreases the population size necessary for reliable information transmission and may thereby bring significant advantages in both wiring and metabolic efficiency.

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“…Information is encoded by the timing of spikes with respect to each other in interspike interval temporal code. Inter-spike interval temporal code can also carry more information than other codes [Brasselet et al 2012;Reich et al 2000]. Furthermore, only inter-spike interval temporal code can be directly applied to echo-state-network (ESN) a based reservoir computing.…”

Section: Rate Code and Temporal Code Implementationsmentioning

confidence: 99%

Spike-Time-Dependent Encoding for Neuromorphic Processors

Zhao

Wysocki

Liu

et al. 2015

J. Emerg. Technol. Comput. Syst.

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This article presents our research towards developing novel and fundamental methodologies for data representation using spike-timing-dependent encoding. Time encoding efficiently maps a signal's amplitude information into a spike time sequence that represents the input data and offers perfect recovery for band-limited stimuli. In this article, we pattern the neural activities across multiple timescales and encode the sensory information using time-dependent temporal scales. The spike encoding methodologies for autonomous classification of time-series signatures are explored using near-chaotic reservoir computing. The proposed spiking neuron is compact, low power, and robust. A hardware implementation of these results is expected to produce an agile hardware implementation of time encoding as a signal conditioner for dynamical neural processor designs.

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Neurons with Stereotyped and Rapid Responses Provide a Reference Frame for Relative Temporal Coding in Primate Auditory Cortex

Cited by 45 publications

References 58 publications

Variability and information content in auditory cortex spike trains during an interval-discrimination task

Variability and information content in auditory cortex spike trains during an interval-discrimination task

Comparison of latency and rate coding for the direction of whisker deflection in the subcortical somatosensory pathway

Spike-Time-Dependent Encoding for Neuromorphic Processors

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