The slow pathway in the electrosensory lobe of Gymnotus omarorum: Field potentials and unitary activity

Publication date: Available online 1 August 2014 Source:Journal of Physiology-Paris Author(s): Ana Carolina Pereira , Alejo Rodríguez-Cattáneo , Angel A. Caputi This is a first communication on the self-activation pattern of the electrosensory lobe in the pulse weakly electric fish Gymnotus omarorum. Field potentials in response to the fish’s own electric organ discharge (EOD) were recorded along vertical tracks (50μm step) and on a transversal lattice array across the electrosensory lobe (resolution 50μm×100μm). The unitary activity of 82 neurons was recorded in the same experiments. Field potential analysis indicates that the slow electrosensory path shows a characteristic post-EOD pattern of activity marked by three main events: (i) a small and early component at about 7ms, (ii) an intermediate peak about 13ms and (iii) a late broad component peaking after 20ms. Unit firing rate showed a wide range of latencies between 3 and 30ms and a variable number of spikes (median 0.28units/EOD). Conditional probability analysis showed monomodal and multimodal post-EOD histograms, with the peaks of unit activity histograms often matching the timing of the main components of the field potentials. Monomodal responses were sub-classified as phase locked monomodal (variance smaller than 1ms), early monomodal (intermediate variance, often firing in doublets, peaking range 10–17ms) and late monomodal (large variance, often firing two spikes separated about 10ms, peaking bey...
Source: Journal of Physiology Paris - Category: Physiology Source Type: research