Two Types of Neurones Sensitive to Motion in the Optic Lobe of the Fly

Efficient representation as a design principle for neural coding and computation

“…The sensory-motor system responsible for this task, loosely referred to as the optomotor control loop, has been the subject of intense investigation in the fly, both in behavioral [5] and in electrophysiological studies. In particular, Bishop and Keehn [6] described wide field motion sensitive cells in the fly's lobula plate, and some neurons of this class have been directly implicated in optomotor control [7]. The fly's motion sensitive vi-sual neurons thus are critical for behavior, and one can record the action potentials or spikes generated by individual motion sensitive cells (e.g., the cell H1, a lobula plate neuron selective for horizontal inward motion) using an extracellular tungsten microelectrode, and standard electrophysiological methods [8]; unlike most such recordings, in the fly one can record stably and continuously for days.…”

“…For the simple case where we change the dynamic range of velocity signals, the input/output relation rescales so that the signal is encoded in relative units; the magnitude of the rescaling factor maximizes information transfer [16]. 6. In order to adjust the input/output relation reliably, the system has to collect enough samples to be sure that the input distribution has changed.…”

“…If we sit at t = 0, then X past ≡ x(t < 0) and X future ≡ x(t > 0). In the exponential of Eq (6), mixing between X past and X future is confined to a term which can be written as…”

Directionally Selective Motion Detection by Insect Neurons

“…Moreover, the response amplitude is not even unambiguously related to the speed or to the contrast frequency (product of angular velocity and spatial frequency) of the grating. These apparent "flaws" in a motion detector based on correlation (Hassenstein and Reichardt 1956) raise the question as to whether insects need these motion sensors for measuring speed or simply for indicating that motion has occurred in a given direction and within a given speed range (Buchner 1984): this information might be sufficient for some kinds of locomotor control such as corrective steering (Hassenstein and Reichardt 1956;Collett and King 1975). 3 The Directionally Selective HI-Neuron of the Fly as a Model Interneuron Ever since directionally selective (DS) motion-sensitive neurons were discovered in the arthropod visual system (Waterman et al 1964;Horridge et al 1965;Collett and Blest 1966;Bishop and Keehn 1966), electrophysiological recordings have been adding considerably to our knowledge of motion vision. Within the last 20 years, directionally selective cells have been found to exist in the optic lobes of many insects (see Table 3 in the comprehensive review by Wehner 1981).…”

Panoramic Motion Perception Inspired Fly Visual Brain Joint Neural Network on Omnidirectional Collision Detection

“…Fly's Visual Neuron. Since two neurophysiologists, Bishop and Keehn [13], discovered motion detection neurons in the fy visual system, electro-and neurophysiologists [14][15][16][17][18] have comprehensively probed into the relation between visual neurons and acquired multiple directional detection neurons capable of detecting the direction of visual movement. Particularly, two specifc neurons of T4 and T5 have been verifed to be able to detect the excitatory or inhibitory activities of direction-selective neurons in the four cardinal directions [5].…”