Implications of Functionally Different Synaptic Inputs for Neuronal Gain and Computational Properties of Fly Visual Interneurons

• Published in: Journal of neurophysiology Vol. 96; no. 4; pp. 1838 - 1847
• Main Authors: Grewe, Jan, Matos, Nelia, Egelhaaf, Martin, Warzecha, Anne-Kathrin
• Format: Journal Article
• Language: English
• Published: United States Am Phys Soc 01.10.2006
• Subjects: Animals; Behavior, Animal - physiology; Diptera - physiology; Electrophysiology; Female; Ganglia, Invertebrate - physiology; Interneurons - physiology; Movement - physiology; Neurons, Afferent - physiology; Synapses - physiology; Visual Perception - physiology
• ISSN: 0022-3077; 1522-1598
• DOI: 10.1152/jn.00170.2006

1 Lehrstuhl für Neurobiologie, Universität Bielefeld, Bielefeld; and 2 Psychologisches Institut II, Westfälische Wilhelms-Universität Münster, Münster, Germany Submitted 16 February 2006; accepted in final form 16 June 2006 Neurons embedded in networks are thought to receive synaptic inputs that do not drive them on their own, but modulate the responsiveness to driving input. Although studies on brain slices have led to detailed knowledge of how nondriving input affects dendritic integration, its origin and functional implications remain unclear. We tackle this issue using an ensemble of fly wide-field visual interneurons. These neurons offer the opportunity not only to combine in vivo recording techniques and natural sensory stimulation but also to interpret electrophysiological results in a behavioral context. By targeted manipulation of the animal's visual input we find a pronounced modulating impact of nondriving input, whereas functionally important cellular properties like direction tuning and the coding of pattern velocity are left almost unaffected. We propose that the integration of functionally different synaptic inputs is a mechanism that immanently equalizes the ensemble's sensitivity irrespective of the specific stimulus conditions. Address for reprint requests and other correspondence: J. Grewe, Lehrstuhl für Neurobiologie, Universität Bielefeld, Postfach 10 01 31, 33501 Bielefeld, Germany (E-mail: jan.grewe{at}uni-bielefeld.de )