Nonlinear, binocular interactions underlying flow field selectivity of a motion-sensitive neuron.
Neurons in many species have large receptive fields that are selective for specific optic flow fields. Here, we studied the neural mechanisms underlying flow field selectivity in lobula plate tangential cells (LPTCs) of the blowfly. Among these cells, the H2 cell responds preferentially to visual stimuli approximating rotational optic flow. Through double recordings from H2 and many other LPTCs, we characterized a bidirectional commissural pathway that allows visual information to be shared between the hemispheres. This pathway is mediated by axo-axonal electrical coupling of H2 and the horizontal system equatorial (HSE) cell located in the opposite hemisphere. Using single-cell ablations, we found that this pathway is sufficient to allow H2 to amplify and attenuate dendritic input during binocular visual stimuli. This is accomplished through a modulation of H2's membrane potential by input from the contralateral HSE cell, which scales the firing rate of H2 during visual stimulation but is not sufficient to induce action potentials.
Farrow
Karl
K
Max-Planck-Institute of Neurobiology, Department of Systems and Computational Neurobiology, Am Klopferspitz 18, 82152 Martinsried, Germany. kfarrow@partners.org
Haag
Juergen
J
Borst
Alexander
A
D000200:Action Potentials / Q000502:physiology; D000818:Animals; D001522:Behavior, Animal; D004175:Diptera; D019706:Excitatory Postsynaptic Potentials / Q000502:physiology; D005260:Female; D007313:Insecta; D008564:Membrane Potentials / Q000502:physiology; D009039:Motion Perception / Q000502:physiology*; D009415:Nerve Net; D009474:Neurons / Q000502:physiology*; D017711:Nonlinear Dynamics; D010775:Photic Stimulation / Q000379:methods; D011930:Reaction Time / Q000502:physiology; D015348:Vision, Binocular / Q000502:physiology*; D014794:Visual Fields / Q000502:physiology*; D014795:Visual Pathways / Q000502:physiology*