@article {540, title = {Sensory flow as a basis for a novel distance cue in freely behaving electric fish}, journal = {Journal of Neuroscience}, year = {2016}, month = {Nov-24-2016}, abstract = {

ABSTRACT

The sensory input that an animal receives is directly linked to its motor activity. Behavior thus enables animals to influence their sensory input, a concept referred to as active sensing. How such behavior can serve as a scaffold for generating sensory information is of general scientific interest. In this article, we investigate how behavior can shape sensory information by using some unique features of the sensorimotor system of the weakly electric fish.

Based on quantitative behavioral characterizations and computational reconstruction of sensory input, we show how electrosensory flow is actively created during highly patterned, spontaneous behavior in Gnathonemus petersii. The spatiotemporal structure of the sensory input provides information for the computation of a novel distance cue, which allows for a continuous estimation of distance. This has significant advantages over previously known non-dynamic distance estimators as determined from electric image blur.

Our investigation of the sensorimotor interactions in pulsatile electrolocation show, for the first time, that the electrosensory flow contains behaviorally relevant information only accessible through active behavior. As patterned sensory behaviors are a shared feature of (active) sensory systems, our results have general implications for the understanding of (active) sensing, with the proposed sensory flow based-measure being potentially pertinent to a broad range of sensory modalities.

SIGNIFICANCE STATEMENT

Acquisition of sensory information depends on motion, as either an animal or its sensors move. Behavior can thus actively influence the sensory flow, and in this way, behavior can be seen as a manifestation of the brain\&$\#$39;s integrative functions. The properties of the active pulsatile electrolocation system in Gnathonemus petersii allow for the sensory input to be computationally reconstructed, enabling us to link the informational content of spatiotemporal sensory dynamics to behavior. Our study reveals a novel sensory cue for estimating depth that is actively generated by the fishes\&$\#$39; behavior. The physical and behavioral similarities between electrolocation and other active sensory systems suggest that this may be a mechanism shared by (active) sensory systems.

}, issn = {0270-6474}, doi = {10.1523/JNEUROSCI.1361-16.2016}, url = {http://www.jneurosci.org/cgi/doi/10.1523/JNEUROSCI.1361-16.2016}, author = {Hofmann, V. and Sanguinetti-Scheck, J. I. and Gomez-Sena, L. and Engelmann, J.} } @article {537, title = {Behavioral and Single-Neuron Sensitivity to Millisecond Variations in Temporally Patterned Communication Signals}, journal = {Journal of Neuroscience}, volume = {36}, year = {2016}, month = {Feb-16-20162220}, pages = {8985 - 9000}, abstract = {

In many sensory pathways, central neurons serve as temporal filters for timing patterns in communication signals. However, how a population of neurons with diverse temporal filtering properties codes for natural variation in communication signals is unknown. Here we addressed this question in the weakly electric fish Brienomyrus brachyistius, which varies the time intervals between successive electric organ discharges to communicate. These fish produce an individually stereotyped signal called a scallop, which consists of a distinctive temporal pattern of \∼8\–12 electric pulses. We manipulated the temporal structure of natural scallops during behavioral playback and in vivo electrophysiology experiments to probe the temporal sensitivity of scallop encoding and recognition. We found that presenting time-reversed, randomized, or jittered scallops increased behavioral response thresholds, demonstrating that fish\&$\#$39;s electric signaling behavior was sensitive to the precise temporal structure of scallops. Next, using in vivo intracellular recordings and discriminant function analysis, we found that the responses of interval-selective midbrain neurons were also sensitive to the precise temporal structure of scallops. Subthreshold changes in membrane potential recorded from single neurons discriminated natural scallops from time-reversed, randomized, and jittered sequences. Pooling the responses of multiple neurons improved the discriminability of natural sequences from temporally manipulated sequences. Finally, we found that single-neuron responses were sensitive to interindividual variation in scallop sequences, raising the question of whether fish may analyze scallop structure to gain information about the sender. Collectively, these results demonstrate that a population of interval-selective neurons can encode behaviorally relevant temporal patterns with millisecond precision.

SIGNIFICANCE STATEMENT The timing patterns of action potentials, or spikes, play important roles in representing information in the nervous system. However, how these temporal patterns are recognized by downstream neurons is not well understood. Here we use the electrosensory system of mormyrid weakly electric fish to investigate how a population of neurons with diverse temporal filtering properties encodes behaviorally relevant input timing patterns, and how this relates to behavioral sensitivity. We show that fish are behaviorally sensitive to millisecond variations in natural, temporally patterned communication signals, and that the responses of individual midbrain neurons are also sensitive to variation in these patterns. In fact, the output of single neurons contains enough information to discriminate stereotyped communication signals produced by different individuals.

}, issn = {0270-6474}, doi = {10.1523/JNEUROSCI.0648-16.2016}, url = {http://www.jneurosci.org/cgi/doi/10.1523/JNEUROSCI.0648-16.2016}, author = {Baker, C. A. and Ma, L. and Casareale, C. R. and Bruce A. Carlson} }