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Probing real sensory worlds of receivers with unsupervised clustering.

Pfeiffer M, Hartbauer M, Lang AB, Maass W, Römer H - PLoS ONE (2012)

Bottom Line: Our results show that the reliability of burst coding in the time domain is so high that identical stimuli lead to extremely similar spike pattern responses, even for different preparations on different dates, and even if one of the preparations is recorded outdoors and the other one in the sound proof lab.Our study shows that burst coding can provide a reliable mechanism for acoustic insects to classify and discriminate signals under very noisy real-world conditions.This gives new insights into the neural mechanisms potentially used by bushcrickets to discriminate conspecific songs from sounds of predators in similar carrier frequency bands.

View Article: PubMed Central - PubMed

Affiliation: Institute for Theoretical Computer Science, TU Graz, Graz, Austria. pfeiffer@ini.phys.ethz.ch

ABSTRACT
The task of an organism to extract information about the external environment from sensory signals is based entirely on the analysis of ongoing afferent spike activity provided by the sense organs. We investigate the processing of auditory stimuli by an acoustic interneuron of insects. In contrast to most previous work we do this by using stimuli and neurophysiological recordings directly in the nocturnal tropical rainforest, where the insect communicates. Different from typical recordings in sound proof laboratories, strong environmental noise from multiple sound sources interferes with the perception of acoustic signals in these realistic scenarios. We apply a recently developed unsupervised machine learning algorithm based on probabilistic inference to find frequently occurring firing patterns in the response of the acoustic interneuron. We can thus ask how much information the central nervous system of the receiver can extract from bursts without ever being told which type and which variants of bursts are characteristic for particular stimuli. Our results show that the reliability of burst coding in the time domain is so high that identical stimuli lead to extremely similar spike pattern responses, even for different preparations on different dates, and even if one of the preparations is recorded outdoors and the other one in the sound proof lab. Simultaneous recordings in two preparations exposed to the same acoustic environment reveal that characteristics of burst patterns are largely preserved among individuals of the same species. Our study shows that burst coding can provide a reliable mechanism for acoustic insects to classify and discriminate signals under very noisy real-world conditions. This gives new insights into the neural mechanisms potentially used by bushcrickets to discriminate conspecific songs from sounds of predators in similar carrier frequency bands.

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Bursts in response to three artificial stimuli.Recordings are from three different insect preparations (marked by different colors), and bursts are displayed aligned to the stimulus onset. Only classes 1,2, and 4, were played at those recording dates. One can see a clear similarity of the responses, but also different latencies and variabilities of firing.
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pone-0037354-g005: Bursts in response to three artificial stimuli.Recordings are from three different insect preparations (marked by different colors), and bursts are displayed aligned to the stimulus onset. Only classes 1,2, and 4, were played at those recording dates. One can see a clear similarity of the responses, but also different latencies and variabilities of firing.

Mentions: The structure of bursts in response to the artificial stimulus classes from Figure 1B becomes visible if one aligns the bursts to the onset of the stimulus. For a single preparation, Figure 4 shows the bursts that follow these stimuli as spike train plots and PSTHs, respectively. Considering that the environmental noise before and during the presentation of the stimulus is very strong and inhomogeneous, the responses of the omega neuron to the same stimulus are remarkably similar. The same holds for responses of different preparations from different sessions to identical stimuli, which is illustrated in Figure 5. In those recording sessions from November 2003, only stimuli from class 1,2, and 4 were presented. Also here one can observe that the stimulus aligned firing patterns are qualitatively very similar, with slight variations in the latency of the bursts, or the variability of firing.


Probing real sensory worlds of receivers with unsupervised clustering.

Pfeiffer M, Hartbauer M, Lang AB, Maass W, Römer H - PLoS ONE (2012)

Bursts in response to three artificial stimuli.Recordings are from three different insect preparations (marked by different colors), and bursts are displayed aligned to the stimulus onset. Only classes 1,2, and 4, were played at those recording dates. One can see a clear similarity of the responses, but also different latencies and variabilities of firing.
© Copyright Policy
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC3368931&req=5

pone-0037354-g005: Bursts in response to three artificial stimuli.Recordings are from three different insect preparations (marked by different colors), and bursts are displayed aligned to the stimulus onset. Only classes 1,2, and 4, were played at those recording dates. One can see a clear similarity of the responses, but also different latencies and variabilities of firing.
Mentions: The structure of bursts in response to the artificial stimulus classes from Figure 1B becomes visible if one aligns the bursts to the onset of the stimulus. For a single preparation, Figure 4 shows the bursts that follow these stimuli as spike train plots and PSTHs, respectively. Considering that the environmental noise before and during the presentation of the stimulus is very strong and inhomogeneous, the responses of the omega neuron to the same stimulus are remarkably similar. The same holds for responses of different preparations from different sessions to identical stimuli, which is illustrated in Figure 5. In those recording sessions from November 2003, only stimuli from class 1,2, and 4 were presented. Also here one can observe that the stimulus aligned firing patterns are qualitatively very similar, with slight variations in the latency of the bursts, or the variability of firing.

Bottom Line: Our results show that the reliability of burst coding in the time domain is so high that identical stimuli lead to extremely similar spike pattern responses, even for different preparations on different dates, and even if one of the preparations is recorded outdoors and the other one in the sound proof lab.Our study shows that burst coding can provide a reliable mechanism for acoustic insects to classify and discriminate signals under very noisy real-world conditions.This gives new insights into the neural mechanisms potentially used by bushcrickets to discriminate conspecific songs from sounds of predators in similar carrier frequency bands.

View Article: PubMed Central - PubMed

Affiliation: Institute for Theoretical Computer Science, TU Graz, Graz, Austria. pfeiffer@ini.phys.ethz.ch

ABSTRACT
The task of an organism to extract information about the external environment from sensory signals is based entirely on the analysis of ongoing afferent spike activity provided by the sense organs. We investigate the processing of auditory stimuli by an acoustic interneuron of insects. In contrast to most previous work we do this by using stimuli and neurophysiological recordings directly in the nocturnal tropical rainforest, where the insect communicates. Different from typical recordings in sound proof laboratories, strong environmental noise from multiple sound sources interferes with the perception of acoustic signals in these realistic scenarios. We apply a recently developed unsupervised machine learning algorithm based on probabilistic inference to find frequently occurring firing patterns in the response of the acoustic interneuron. We can thus ask how much information the central nervous system of the receiver can extract from bursts without ever being told which type and which variants of bursts are characteristic for particular stimuli. Our results show that the reliability of burst coding in the time domain is so high that identical stimuli lead to extremely similar spike pattern responses, even for different preparations on different dates, and even if one of the preparations is recorded outdoors and the other one in the sound proof lab. Simultaneous recordings in two preparations exposed to the same acoustic environment reveal that characteristics of burst patterns are largely preserved among individuals of the same species. Our study shows that burst coding can provide a reliable mechanism for acoustic insects to classify and discriminate signals under very noisy real-world conditions. This gives new insights into the neural mechanisms potentially used by bushcrickets to discriminate conspecific songs from sounds of predators in similar carrier frequency bands.

Show MeSH