scholarly journals Hypercomplex properties of Drosophila object detecting neurons

2016 ◽  
Author(s):  
Mehmet F. Keleş ◽  
Mark A. Frye
Keyword(s):  
Compound Eye ◽  
Optic Lobe ◽  
Visual Space ◽  
Ionic Currents ◽  
Object Motion ◽  
Small Object ◽  
Axon Terminals ◽  
Photon Excitation ◽  
High Acuity ◽  
Directional Motion

SUMMARYMany animals rely on vision to detect objects such as conspecifics, predators, and prey. Hypercomplex cells of the feline cortex and small target motion detectors of the dragonfly and hoverfly optic lobe demonstrate robust tuning for small objects with weak or no response to elongated edges or movement of the visual panorama [1–4]. However, the relationship between anatomical, molecular, and functional properties of object detection circuitry is not understood. Here, we characterize a previously identified lobula columnar neuron (LC11) in Drosophila [5]. By imaging calcium dynamics with two-photon excitation microscopy we show that LC11 responds to the non-directional motion of a small object darker than the background, with little or no responses to static flicker, elongated bars, or panoramic gratings. LC11 dendrites reside at the boundary between GABA-ergic and cholinergic layers of the lobula, each dendrite spans enough columns to sample 75-degrees of visual space, yet the functional receptive field is only 20-degrees wide, and shows robust responses to an object spanning less than one 5-degree facet of the compound eye. The dendrites of neighboring LC11s encode object motion retinotopically, but the axon terminals fuse into a glomerular structure in the central brain where retinotopy is lost. Blocking inhibitory ionic currents abolishes small object sensitivity and facilitates responses to elongated bars and gratings. Our results reveal high acuity small object motion detection in the Drosophila optic lobe.

Discrimination Between Movements of Eye and Object by Visual Interneurones of Crickets

1969 ◽  
Vol 50 (3) ◽  
pp. 723-732
Author(s):  
JOHN PALKA
Keyword(s):  
Eye Movement ◽  
Voluntary Movement ◽  
Compound Eye ◽  
Visual Fields ◽  
Object Motion ◽  
Visual Environment ◽  
Inhibitory Mechanism ◽  
Object Movement ◽  
Moving Stimulus ◽  
Homogeneous Environment

1. One large neurone on each side of the cervical and thoracic ventral nerve cord of crickets responds to object motion anywhere in the visual field of the ipsilateral compound eye, but not to the forced or voluntary movement of the eye itself. 2. This discrimination between self-movement and object-movement is accomplished by an inhibitory mechanism mediated by the same eye. 3. Inhibition must be present because a potent moving stimulus becomes ineffective if presented during a forced eye movement. 4. Its visual origin is demonstrated in two ways: (a) abolishing all known mechanosensory feedback does not disrupt the mechanism, but (b) alteration of visual conditions does so in a predictable way. Sweeping the eye past a complex visual environment suppresses the neurone's response to a concurrently or subsequently presented moving target, whereas the same movement past a simplified or homogeneous environment produces little or no inhibition. 5. Responses to eye movement itself are greatly enhanced in appropriately simplified visual fields, reinforcing the conclusion that the inhibition preventing response in complex fields is of visual origin. 6. Suggestive evidence for an additional inhibitory mechanism associated with voluntary movement is presented.

A looming-sensitive pathway responds to changes in the trajectory of object motion

2012 ◽  
Vol 108 (4) ◽  
pp. 1052-1068 ◽  
Author(s):  
Glyn A. McMillan ◽  
John R. Gray
Keyword(s):  
Visual Field ◽  
Firing Rate ◽  
Visual Motion ◽  
Compound Eye ◽  
Angular Acceleration ◽  
Leading Edge ◽  
Object Motion ◽  
Near Miss ◽  
Movement Detector ◽  
Contralateral Movement

Two identified locust neurons, the lobula giant movement detector (LGMD) and its postsynaptic partner, the descending contralateral movement detector (DCMD), constitute one motion-sensitive pathway in the visual system that responds preferentially to objects that approach on a direct collision course and are implicated in collision-avoidance behavior. Previously described responses to the approach of paired objects and approaches at different time intervals (Guest BB, Gray JR. J Neurophysiol 95: 1428–1441, 2006) suggest that this pathway may also be affected by more complicated movements in the locust's visual environment. To test this possibility we presented stationary locusts with disks traveling along combinations of colliding (looming), noncolliding (translatory), and near-miss trajectories. Distinctly different responses to different trajectories and trajectory changes demonstrate that DCMD responds to complex aspects of local visual motion. DCMD peak firing rates associated with the time of collision remained relatively invariant after a trajectory change from translation to looming. Translatory motion initiated in the frontal visual field generated a larger peak firing rate relative to object motion initiated in the posterior visual field, and the peak varied with simulated distance from the eye. Transition from translation to looming produced a transient decrease in the firing rate, whereas transition away from looming produced a transient increase. The change in firing rate at the time of transition was strongly correlated with unique expansion parameters described by the instantaneous angular acceleration of the leading edge and subtense angle of the disk. However, response time remained invariant. While these results may reflect low spatial resolution of the compound eye, they also suggest that this motion-sensitive pathway may be capable of monitoring dynamic expansion properties of objects that change the trajectory of motion.

scholarly journals Local processing in neurites of VGluT3-expressing amacrine cells differentially organizes visual information

eLife ◽  
2017 ◽  
Vol 6 ◽  
Author(s):  
Jen-Chun Hsiang ◽  
Keith P Johnson ◽  
Linda Madisen ◽  
Hongkui Zeng ◽  
Daniel Kerschensteiner
Keyword(s):  
Visual Processing ◽  
Visual Information ◽  
Receptive Fields ◽  
Visual Space ◽  
Amacrine Cells ◽  
Object Motion ◽  
Image Motion ◽  
Local Processing ◽  
Mouse Retina ◽  
Population Activity

Neurons receive synaptic inputs on extensive neurite arbors. How information is organized across arbors and how local processing in neurites contributes to circuit function is mostly unknown. Here, we used two-photon Ca2+ imaging to study visual processing in VGluT3-expressing amacrine cells (VG3-ACs) in the mouse retina. Contrast preferences (ON vs. OFF) varied across VG3-AC arbors depending on the laminar position of neurites, with ON responses preferring larger stimuli than OFF responses. Although arbors of neighboring cells overlap extensively, imaging population activity revealed continuous topographic maps of visual space in the VG3-AC plexus. All VG3-AC neurites responded strongly to object motion, but remained silent during global image motion. Thus, VG3-AC arbors limit vertical and lateral integration of contrast and location information, respectively. We propose that this local processing enables the dense VG3-AC plexus to contribute precise object motion signals to diverse targets without distorting target-specific contrast preferences and spatial receptive fields.

scholarly journals Characterization of a reduced-eye mutant of the grasshopper, Melanoplus sanguinipes

Development ◽  
1984 ◽  
Vol 83 (1) ◽  
pp. 189-211
Author(s):  
D. J. Emery ◽  
K. A. Bell ◽  
W. Chapco ◽  
J. D. Steeves
Keyword(s):  
Compound Eye ◽  
Optic Lobe ◽  
Compound Eyes ◽  
Movement Detector ◽  
Melanoplus Sanguinipes ◽  
Optic Chiasma ◽  
Morphological Alterations ◽  
Tactile Stimuli ◽  
Normal Manner ◽  
Contralateral Movement

A reduced-eye (re) mutant grasshopper of Melanoplus sanguinipes has been characterized by small flat compound eyes lacking facets, no lateral ocelli and only a remnant of the median ocellus. The re grasshoppers walk, jump, fly and feed in a normal manner, but do not respond to visual and auditory stimuli, suggesting they may be blind and deaf. Extracellular recordings from the ventral nerve cord of re mutants verified the lack of neural activity in response to visual and auditory inputs, yet the mutants detected mechanical and tactile stimuli. Electroretinograms implied that a visual deficit may be within the photoreceptors of the compound eye. Histological examination of the compound eyes and ocelli indicated that the cells of the mutant compound eye incompletely differentiate. The optic lamina underlying the retina is missing, as is the outer optic chiasma. The medulla and lobula of the mutant optic lobe are present, however, the neuropil of the medulla lacks the characteristic axonal projection patterns of wild-type grasshoppers. The re grasshopper also lacks all ocellar nerves. Ocellar nerves are normally formed from processes of second order ocellar neurons (SONs), suggesting that if the mutant SONs are present within the protocerebrum, their morphology is drastically altered. Comparison of embryos and juvenile nymphs supports the suggestion that the alterations in the re visual system are the result of abnormal differentiation during development. Even though there is clear evidence of morphological alterations in second and third order optic lobe interneurons, one higher order visual interneuron of the midbrain, the descending contralateral movement detector (DCMD), has the same morphology as the DCMD in a wildtype brain. In this instance, the complete deprivation of the primary sensory input does not appear to alter cellular development.

Postembryonic development of the visual system of Periplaneta americana

Development ◽  
1981 ◽  
Vol 66 (1) ◽  
pp. 235-255
Author(s):  
Robert J. Stark ◽  
Michael I. Mote
Keyword(s):  
Developmental Stage ◽  
Periplaneta Americana ◽  
Compound Eye ◽  
Optic Lobe ◽  
Postembryonic Development ◽  
Structural Differentiation ◽  
Eye Growth ◽  
Body Tissues ◽  
Optic Fibre ◽  
Cell Growth And Proliferation

The compound eyes of Periplaneta americana are connected by optic fibre tracts to an optic lobe composed of three sequential ganglia, the lamina, the medulla and the lobula respectively. The eyes and optic ganglia are organized into repeating sub-units arranged in a regular pattern. During postembryonic development, the number of subunits in the eye (ommatidia) increases from between 50 and 60 to over 2000, with a concomitant increase in the size of the optic lobe ganglia. The patterns of cell growth and proliferation were examined in serial section autoradiagraphs prepared following long and short exposures to [3H]thymidine during each developmental stage. Aspects of structural differentiation were examined in reduced silver-stained sections of nymphs at each developmental stage. Growth of the eye and optic ganglia resulted from the continuous proliferation of new cells throughout postembryonic development. Unlike other body tissues, growth of this system was independent of the moulting cycle. The pattern of growth observed in the optic ganglia directly reflected the growth of the eye. Growth of the compound eye occurs from a special zone of proliferation and differentiation located along all but its posterior margin. The lamina and medulla both grow by cell proliferation from a single neuroblast region located at the apex of the angle subtended by them. Cells which proliferate distally from this region differentiate into lamina neurons, while those that proliferate proximally differentiate into medulla neurons. Axons growing from these two adjacent regions meet at and add new new fibres to the distal end of the medulla neuropil. Specificity of the interneuronal connexions appears to result from a precise temporospatial sequencing of growth with the formation of the optic ganglia dependent on retinal development.

scholarly journals Influence of Electrotonic Structure and Synaptic Mapping on the Receptive Field Properties of a Collision-Detecting Neuron

2007 ◽  
Vol 97 (1) ◽  
pp. 159-177 ◽  
Author(s):  
Simon P. Peron ◽  
Holger G. Krapp ◽  
Fabrizio Gabbiani
Keyword(s):  
Receptive Field ◽  
Compound Eye ◽  
Escape Behavior ◽  
Visual Stimulation ◽  
Visual Space ◽  
Equal Weight ◽  
Movement Detector ◽  
Local Motion ◽  
Dendritic Field ◽  
Receptive Field Properties

The lobula giant movement detector (LGMD) is a visual interneuron of Orthopteran insects involved in collision avoidance and escape behavior. The LGMD possesses a large dendritic field thought to receive excitatory, retinotopic projections from the entire compound eye. We investigated whether the LGMD's receptive field for local motion stimuli can be explained by its electrotonic structure and the eye's anisotropic sampling of visual space. Five locust ( Schistocerca americana) LGMD neurons were stained and reconstructed. We show that the excitatory dendritic field and eye can be fitted by ellipsoids having similar geometries. A passive compartmental model fit to electrophysiological data was used to demonstrate that the LGMD is not electrotonically compact. We derived a spike rate to membrane potential transform using intracellular recordings under visual stimulation, allowing direct comparison between experimental and simulated receptive field properties. By assuming a retinotopic mapping giving equal weight to each ommatidium and equally spaced synapses, the model reproduced the experimental data along the eye equator, though it failed to reproduce the receptive field along the ventral-dorsal axis. Our results illustrate how interactions between the distribution of synaptic inputs and the electrotonic properties of neurons contribute to shaping their receptive fields.

scholarly journals The neuroplasticity of division of labor: worker polymorphism, compound eye structure and brain organization in the leafcutter ant Atta cephalotes

2020 ◽  
Author(s):  
Sara Arganda ◽  
Andrew P. Hoadley ◽  
Evan S. Razdan ◽  
Isabella B. Muratore ◽  
James F. A. Traniello
Keyword(s):  
Division Of Labor ◽  
Compound Eye ◽  
Optic Lobe ◽  
Light Availability ◽  
Visual Sensitivity ◽  
Atta Cephalotes ◽  
Brain Organization ◽  
Functional Neuroplasticity ◽  
Parameter Values ◽  
Peripheral Sensory

AbstractOur understanding of how the design of peripheral sensory structures is coupled with neural processing capacity to adaptively support division of labor is limited. Workers of the remarkably polymorphic fungus-growing ant Atta cephalotes are behaviorally specialized by size: the smallest workers (minims) tend fungi in dark subterranean chambers while larger workers perform tasks mainly outside the nest. These strong differences in worksite light conditions are predicted to influence sensory and processing requirements for vision. We found that eye structure and visual neuropils have been be selected to maximize task performance according to light availability. Minim eyes had few ommatidia, large interommatidial angles and eye parameter values, suggesting selection for visual sensitivity over acuity. Large workers had larger eyes with disproportionally more and larger ommatidia, and smaller interommatidial angles and eye parameter values, reflecting peripheral sensory adaptation to ambient rainforest light. Additionally, optic lobe and mushroom body collar volumes were disproportionately small in minims, and within the optic lobe, lamina and lobula relative volumes increased with worker size whereas the medulla decreased. Visual system phenotypes thus correspond to task specializations in dark or light environments and reflect a functional neuroplasticity underpinning division of labor in this socially complex agricultural ant.

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