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Vibrotactile discrimination in the rat whisker system is based on neuronal coding of instantaneous kinematic cues.

Waiblinger C, Brugger D, Schwarz C - Cereb. Cortex (2013)

Bottom Line: We find that discrimination performance based on instantaneous kinematic cues far exceeds the ones provided by frequency and intensity.The present study is the first to show that perceptual read-out is superior in situations allowing the subject to base perception on detailed trajectory cues, that is, instantaneous kinematic variables.A possible impact of this finding on tactile systems of other species is suggested by evidence for instantaneous coding also in primates.

View Article: PubMed Central - PubMed

Affiliation: Werner Reichardt Center for Integrative Neuroscience, Systems Neuroscience, Hertie Institute for Clinical Brain Research, Department of Cognitive Neurology, Eberhard Karls University, Tübingen, Germany.

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Population analyses of responses to DOC stimuli. (A) Distributions of evoked activity across time (bin width 1 ms) for the whole population of units (multiunits, n = 30; single units, n = 24) recorded in Experiment 1b. (Note that the ordinate scales responses as “changes of firing rate” because the sustained firing rate to the S− background stimulus has been subtracted). Each subplot shows the unitary responses to a different S+ stimulus or catch trial (schematized on top). The curves indicate the median (black) and the 75th (top) and 25th (bottom) percentile (gray). Note that the firing rate distributions labeled “+24 Hz” were the ones obtained with the extra stimuli of Experiment 1b, in which frequency was manipulated and waveform kept constant (cf. Fig. 2D). These responses, although obtained in Experiment 1b, in fact belong to the same category of stimuli as the ones used in Experiment 2a. (B) Distributions of neuronal activity evoked by the strongest amplitude change (7.2°, black bars) and catch trials (gray bars) as observed in Experiments 1a and b. The abscissa scales response as spike counts in 3 different intervals. Left: immediately after stimulus onset (0–50 ms peristimulus time). Center: before the stimulus offset (950–1000 ms peristimulus time). Right: the whole stimulus period (0–1000 ms peristimulus time). Multi- (MU, n = 91, top) and single-unit data (SU, n = 74, bottom) are shown.
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BHT305F5: Population analyses of responses to DOC stimuli. (A) Distributions of evoked activity across time (bin width 1 ms) for the whole population of units (multiunits, n = 30; single units, n = 24) recorded in Experiment 1b. (Note that the ordinate scales responses as “changes of firing rate” because the sustained firing rate to the S− background stimulus has been subtracted). Each subplot shows the unitary responses to a different S+ stimulus or catch trial (schematized on top). The curves indicate the median (black) and the 75th (top) and 25th (bottom) percentile (gray). Note that the firing rate distributions labeled “+24 Hz” were the ones obtained with the extra stimuli of Experiment 1b, in which frequency was manipulated and waveform kept constant (cf. Fig. 2D). These responses, although obtained in Experiment 1b, in fact belong to the same category of stimuli as the ones used in Experiment 2a. (B) Distributions of neuronal activity evoked by the strongest amplitude change (7.2°, black bars) and catch trials (gray bars) as observed in Experiments 1a and b. The abscissa scales response as spike counts in 3 different intervals. Left: immediately after stimulus onset (0–50 ms peristimulus time). Center: before the stimulus offset (950–1000 ms peristimulus time). Right: the whole stimulus period (0–1000 ms peristimulus time). Multi- (MU, n = 91, top) and single-unit data (SU, n = 74, bottom) are shown.

Mentions: In Figure 5A the distribution of PSTHs obtained from the whole sample are shown for 4 different stimuli and catch trial used in Experiment 1b. Median firing rate changes (black) and 25% and 75% percentile levels (gray) are depicted for the 30 multiunits (top) and 24 single units (bottom) recorded in this experiment. The sustained firing rate to S− was subtracted, so that positive/negative firing rates would indicate a higher/lower sustained response to S+ as compared with S−. The median firing rate of multiunits was clearly modulated by the first pulses with amplitude changes down to +2.2°. Inspection of different percentile levels reveals that more than 75% of the multiunits showed an excitatory response to amplitude changes of 7.2° and 3.9°. Owing to very low firing rates, single-unit population activity appeared noisier but generally matched the observation from multiunits. Interestingly, in experiments which kept the pulse kinematics constant but varied the frequency (labeled “+24 Hz”), all recorded neurons showed flat PSTHs varying around zero change in firing rate. This result reveals the near complete absence of neuronal responses to an isolated switch in stimulus frequency.Figure 5.


Vibrotactile discrimination in the rat whisker system is based on neuronal coding of instantaneous kinematic cues.

Waiblinger C, Brugger D, Schwarz C - Cereb. Cortex (2013)

Population analyses of responses to DOC stimuli. (A) Distributions of evoked activity across time (bin width 1 ms) for the whole population of units (multiunits, n = 30; single units, n = 24) recorded in Experiment 1b. (Note that the ordinate scales responses as “changes of firing rate” because the sustained firing rate to the S− background stimulus has been subtracted). Each subplot shows the unitary responses to a different S+ stimulus or catch trial (schematized on top). The curves indicate the median (black) and the 75th (top) and 25th (bottom) percentile (gray). Note that the firing rate distributions labeled “+24 Hz” were the ones obtained with the extra stimuli of Experiment 1b, in which frequency was manipulated and waveform kept constant (cf. Fig. 2D). These responses, although obtained in Experiment 1b, in fact belong to the same category of stimuli as the ones used in Experiment 2a. (B) Distributions of neuronal activity evoked by the strongest amplitude change (7.2°, black bars) and catch trials (gray bars) as observed in Experiments 1a and b. The abscissa scales response as spike counts in 3 different intervals. Left: immediately after stimulus onset (0–50 ms peristimulus time). Center: before the stimulus offset (950–1000 ms peristimulus time). Right: the whole stimulus period (0–1000 ms peristimulus time). Multi- (MU, n = 91, top) and single-unit data (SU, n = 74, bottom) are shown.
© Copyright Policy - creative-commons
Related In: Results  -  Collection

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Show All Figures
getmorefigures.php?uid=PMC4380004&req=5

BHT305F5: Population analyses of responses to DOC stimuli. (A) Distributions of evoked activity across time (bin width 1 ms) for the whole population of units (multiunits, n = 30; single units, n = 24) recorded in Experiment 1b. (Note that the ordinate scales responses as “changes of firing rate” because the sustained firing rate to the S− background stimulus has been subtracted). Each subplot shows the unitary responses to a different S+ stimulus or catch trial (schematized on top). The curves indicate the median (black) and the 75th (top) and 25th (bottom) percentile (gray). Note that the firing rate distributions labeled “+24 Hz” were the ones obtained with the extra stimuli of Experiment 1b, in which frequency was manipulated and waveform kept constant (cf. Fig. 2D). These responses, although obtained in Experiment 1b, in fact belong to the same category of stimuli as the ones used in Experiment 2a. (B) Distributions of neuronal activity evoked by the strongest amplitude change (7.2°, black bars) and catch trials (gray bars) as observed in Experiments 1a and b. The abscissa scales response as spike counts in 3 different intervals. Left: immediately after stimulus onset (0–50 ms peristimulus time). Center: before the stimulus offset (950–1000 ms peristimulus time). Right: the whole stimulus period (0–1000 ms peristimulus time). Multi- (MU, n = 91, top) and single-unit data (SU, n = 74, bottom) are shown.
Mentions: In Figure 5A the distribution of PSTHs obtained from the whole sample are shown for 4 different stimuli and catch trial used in Experiment 1b. Median firing rate changes (black) and 25% and 75% percentile levels (gray) are depicted for the 30 multiunits (top) and 24 single units (bottom) recorded in this experiment. The sustained firing rate to S− was subtracted, so that positive/negative firing rates would indicate a higher/lower sustained response to S+ as compared with S−. The median firing rate of multiunits was clearly modulated by the first pulses with amplitude changes down to +2.2°. Inspection of different percentile levels reveals that more than 75% of the multiunits showed an excitatory response to amplitude changes of 7.2° and 3.9°. Owing to very low firing rates, single-unit population activity appeared noisier but generally matched the observation from multiunits. Interestingly, in experiments which kept the pulse kinematics constant but varied the frequency (labeled “+24 Hz”), all recorded neurons showed flat PSTHs varying around zero change in firing rate. This result reveals the near complete absence of neuronal responses to an isolated switch in stimulus frequency.Figure 5.

Bottom Line: We find that discrimination performance based on instantaneous kinematic cues far exceeds the ones provided by frequency and intensity.The present study is the first to show that perceptual read-out is superior in situations allowing the subject to base perception on detailed trajectory cues, that is, instantaneous kinematic variables.A possible impact of this finding on tactile systems of other species is suggested by evidence for instantaneous coding also in primates.

View Article: PubMed Central - PubMed

Affiliation: Werner Reichardt Center for Integrative Neuroscience, Systems Neuroscience, Hertie Institute for Clinical Brain Research, Department of Cognitive Neurology, Eberhard Karls University, Tübingen, Germany.

Show MeSH
Related in: MedlinePlus