Functional and morphological analysis of visual feature-detecting neurons in Chasmagnathus.

MEDAN, VIOLETA; OLIVA, DAMIÁN; TOMSIC, DANIEL

Oxford

Conferencia; Gordon Research Conferences on Neuroethology: Behavior, evolution and neurobiology; 2005

Gordon Research Conferences

Long term visual memory generated in Chasmagnathus crab as a result of repetitive stimulation with a danger stimulus is driven, at least in part, by changes occurring on neurons located in a profound retinotopic neuropile: the lobula. Electrophysiological studies done on the intact animal shown that these elements, known as Movement Detector Neurons (MDN), comprise a system of matching filters composed by at least two types of neurons with distinct physiological responses. One group of neurons has a circumscripted visual field and in many cases a preference for a certain direction of movement. The other group has elements with wide or total visual fields and lack of directional preference. Besides, previous anatomical studies revealed that MDN correspond to one of at least two distinguishable morphological classes: monostratified neurons (M-MDN) and bistratified neurons (B-MDN). Correspondence between M-MDN and B-MDN with the several types of MDN physiologically characterized has not been established yet. In this work we combined functional characterization with intracellular dyeing of MDN to begin to elucidate the matching between physiology and morphology in MDN. Results indicate that MDN with preference for a certain direction and restricted visual fields correspond to M-MDN while those of wide or complete visuald field are one of several different types of B-MDN.