The Identification of Peaks in Physiological Signals

Todd, Bryan S.; Andrews, D. C.

doi:10.1006/cbmr.1999.1518

Cited by 50 publications

(32 citation statements)

References 27 publications

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“…Spikes were detected online by RELACS, using the peakdetection algorithm proposed by Todd and Andrews (76). Raw data as well as spike times were stored for subsequent offline analysis.…”

Section: Methodsmentioning

confidence: 99%

Synchronous spikes are necessary but not sufficient for a synchrony code in populations of spiking neurons

Grewe

Kruscha

Lindner

et al. 2017

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

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Synchronous activity in populations of neurons potentially encodes special stimulus features. Selective readout of either synchronous or asynchronous activity allows formation of two streams of information processing. Theoretical work predicts that such a synchrony code is a fundamental feature of populations of spiking neurons if they operate in specific noise and stimulus regimes. Here we experimentally test the theoretical predictions by quantifying and comparing neuronal response properties in tuberous and ampullary electroreceptor afferents of the weakly electric fish Apteronotus leptorhynchus. These related systems show similar levels of synchronous activity, but only in the more irregularly firing tuberous afferents a synchrony code is established, whereas in the more regularly firing ampullary afferents it is not. The mere existence of synchronous activity is thus not sufficient for a synchrony code. Single-cell features such as the irregularity of spiking and the frequency dependence of the neuron's transfer function determine whether synchronous spikes possess a distinct meaning for the encoding of time-dependent signals. Because of the strong nonlinearity of the spiking threshold, neural noise can be beneficial by improving the representation of stimuli in populations of spiking neurons (3-7). Noise reduces the precision with which spikes lock to the stimulus (1). In populations of neurons that share a common input, for example by having overlapping receptive fields, noise as well as population heterogeneity has the advantage to decorrelate the responses (8, 9). That is, only those stimulus features that drive the population strongest could synchronize the response across neurons and thereby signal the presence of a particularly important stimulus.The role of synchronous activity in the cortex is widely discussed (6, 10-12), e.g., as a possible solution for the binding problem (for review see, e.g., refs. 13 and 14), as a separate information channel to relay visual information from thalamus to visual cortex (15), as a mechanism for gain control in visual cortex (16), or as a code for odor categories in zebrafish olfactory bulb (17).A synchrony code requires that asynchronously firing populations are synchronized or, vice versa, synchronization is escaped under certain conditions or by specific stimuli. In weakly electric fish, changes in the level of synchronization are considered an important cue for the detection of communication signals on the level of the receptor afferents (18-21) and subsequent processing in hind-and midbrain neurons (22,23). Middleton et al. (24) demonstrated that reading out population activity of electrosensory neurons with either integrators or coincidence detectors results in two distinct representations of sensory stimuli. Integrators encode low stimulus frequencies, approximately matching frequencies characteristic of prey detection and navigation. Coincidence detectors discard low-frequency information and encode predominantly higher frequencies matching the ones of c...

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“…Spikes were detected online by RELACS, using the peakdetection algorithm proposed by Todd and Andrews (76). Raw data as well as spike times were stored for subsequent offline analysis.…”

Section: Methodsmentioning

confidence: 99%

Synchronous spikes are necessary but not sufficient for a synchrony code in populations of spiking neurons

Grewe

Kruscha

Lindner

et al. 2017

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

View full text Add to dashboard Cite

show abstract

“…Spikes were detected online as peaks that exceeded a dynamically adjusted threshold value above the previous detected trough (Todd and Andrews 1999). To track changes in amplitude of the recorded spikes, the threshold was set to 50% of the amplitude of a detected spike but not below a minimum threshold that was set above the noise in the recording based on a histogram of all peak amplitudes.…”

Section: Methodsmentioning

confidence: 99%

Static frequency tuning accounts for changes in neural synchrony evoked by transient communication signals

Walz

Grewe

Benda

2014

Journal of Neurophysiology

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“…Intracellular recordings presented here were obtained from 10 different animals. From the digitized recordings, the spike times were extracted by a peak detection algorithm (Todd and Andrews, 1999).…”

Section: Electrophysiologymentioning

confidence: 99%

Multiple Arithmetic Operations in a Single Neuron: The Recruitment of Adaptation Processes in the Cricket Auditory Pathway Depends on Sensory Context

Hildebrandt

Benda²,

Hennig³

2011

J. Neurosci.

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Sensory pathways process behaviorally relevant signals in various contexts and therefore have to adapt to differing background conditions. Depending on changes in signal statistics, this adjustment might be a combination of two fundamental computational operations: subtractive adaptation shifting a neuron's threshold and divisive gain control scaling its sensitivity. The cricket auditory system has to deal with highly stereotyped conspecific songs at low carrier frequencies, and likely much more variable predator signals at high frequencies. We proposed that due to the differences between the two signal classes, the operation that is implemented by adaptation depends on the carrier frequency. We aimed to identify the biophysical basis underlying the basic computational operations of subtraction and division.We performed in vivo intracellular and extracellular recordings in a first-order auditory interneuron (AN2) that is active in both mate recognition and predator avoidance. We demonstrated subtractive shifts at the carrier frequency of conspecific songs and division at the predator-like carrier frequency. Combined application of current injection and acoustic stimuli for each cell allowed us to demonstrate the subtractive effect of cell-intrinsic adaptation currents. Pharmacological manipulation enabled us to demonstrate that presynaptic inhibition is most likely the source of divisive gain control.We showed that adjustment to the sensory context can depend on the class of signals that are relevant to the animal. We further revealed that presynaptic inhibition is a simple mechanism for divisive operations. Unlike other proposed mechanisms, it is widely available in the sensory periphery of both vertebrates and invertebrates.

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The Identification of Peaks in Physiological Signals

Cited by 50 publications

References 27 publications

Synchronous spikes are necessary but not sufficient for a synchrony code in populations of spiking neurons

Synchronous spikes are necessary but not sufficient for a synchrony code in populations of spiking neurons

Static frequency tuning accounts for changes in neural synchrony evoked by transient communication signals

Multiple Arithmetic Operations in a Single Neuron: The Recruitment of Adaptation Processes in the Cricket Auditory Pathway Depends on Sensory Context

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