Temporal Patterns Related to the Texture Discrimination Coding in the Rat Vibrissal System

ALBARRACÍN AL; FARFÁN FD; FELICE CJ

Howars Hughes Medical Institute - Janelia Farm Research Campus, Washington USA

Conferencia; Conferences on The Neural Basis of Vibrissa-Based Tactile Sensation; 2010

Howars Hughes Medical Institute

Studies in tactile discrimination agree that rats are able to learn a rough-smooth discrimination task by actively touching (whisking) objects with their vibrissae. This behavior induces specific patterns of temporal encoding at different levels of the whisker pathway. In the present work we analyzed the multifiber afferent discharge of one vibrissal nerve during active whisking. Vibrissa movements were induced by electrical stimulation of motor branches of the facial nerve. We used sandpapers of different grain size as roughness discrimination surfaces and we also consider the change pressure as a way to improve the tactile information acquisition. We propose here two methods to analyze the multifiber activity: the RMS values and the Interevent time (IET) analysis. The last allows us extracting temporal patterns or ´events´ related to texture discrimination coding. We also obtained three parameters (Ra, Rz and DBLP- Distance Between Local Peaks) that characterized the roughness surfaces. The results showed that as roughness increased, theRMS values also increased in almost all cases, thus suggesting a direct relation. In addition, we observed a better discrimination performance in the retraction phase. Finally, we related the IET obtained with the physical characteristic of the surfaces. We concluded that temporal patterns found in the multifiber activity of a single vibrissa innervation would be related with the texture coding and that the DBLP would be the better parameter described by these patterns.