scholarly journals Arousal Facilitates Collision Avoidance Mediated by a Looming Sensitive Visual Neuron in a Flying Locust

2008 ◽  
Vol 100 (2) ◽  
pp. 670-680 ◽  
Author(s):  
F. Claire Rind ◽  
Roger D. Santer ◽  
Geraldine A. Wright
Keyword(s):  
Visual Processing ◽  
Physiological State ◽  
Object Motion ◽  
Arousal State ◽  
Change Of State ◽  
Vision For Action ◽  
Octopamine Receptor ◽  
Movement Detectors ◽  
Contralateral Movement ◽  
Gregarious Locusts

Locusts have two large collision-detecting neurons, the descending contralateral movement detectors (DCMDs) that signal object approach and trigger evasive glides during flight. We sought to investigate whether vision for action, when the locust is in an aroused state rather than a passive viewer, significantly alters visual processing in this collision-detecting pathway. To do this we used two different approaches to determine how the arousal state of a locust affects the prolonged periods of high-frequency spikes typical of the DCMD response to approaching objects that trigger evasive glides. First, we manipulated arousal state in the locust by applying a brief mechanical stimulation to the hind leg; this type of change of state occurs when gregarious locusts accumulate in high-density swarms. Second, we examined DCMD responses during flight because flight produces a heightened physiological state of arousal in locusts. When arousal was induced by either method we found that the DCMD response recovered from a previously habituated state; that it followed object motion throughout approach; and—most important—that it was significantly more likely to generate the maintained spike frequencies capable of evoking gliding dives even with extremely short intervals (1.8 s) between approaches. Overall, tethered flying locusts responded to 41% of simulated approaching objects (sets of 6 with 1.8 s ISI). When we injected epinastine, the neuronal octopamine receptor antagonist, into the hemolymph responsiveness declined to 12%, suggesting that octopamine plays a significant role in maintaining responsiveness of the DCMD and the locust to visual stimuli during flight.

Plasticity in the Visual System Is Correlated With a Change in Lifestyle of Solitarious and Gregarious Locusts

2004 ◽  
Vol 91 (1) ◽  
pp. 1-12 ◽  
Author(s):  
Thomas Matheson ◽  
Stephen M. Rogers ◽  
Holger G. Krapp
Keyword(s):  
Visual System ◽  
Flight Control ◽  
Schistocerca Gregaria ◽  
Movement Detector ◽  
Time To Collision ◽  
Angular Extent ◽  
Behavioral Phase ◽  
Contralateral Movement ◽  
Gregarious Locusts ◽  
And Behavior

We demonstrate pronounced differences in the visual system of a polyphenic locust species that can change reversibly between two forms (phases), which vary in morphology and behavior. At low population densities, individuals of Schistocerca gregaria develop into the solitarious phase, are cryptic, and tend to avoid other locusts. At high densities, individuals develop instead into the swarm-forming gregarious phase. We analyzed in both phases the responses of an identified visual interneuron, the descending contralateral movement detector (DCMD), which responds to approaching objects. We demonstrate that habituation of DCMD is fivefold stronger in solitarious locusts. In both phases, the mean time of peak firing relative to the time to collision nevertheless occurs with a similar characteristic delay after an approaching object reaches a particular angular extent on the retina. Variation in the time of peak firing is greater in solitarious locusts, which have lower firing rates. Threshold angle and delay are therefore conserved despite changes in habituation or behavioral phase state. The different rates of habituation should contribute to different predator escape strategies or flight control for locusts living either in a swarm or as isolated individuals. For example, increased variability in the habituated responses of solitarious locusts should render their escape behaviors less predictable. Relative resistance to habituation in gregarious locusts should permit the continued responsiveness required to avoid colliding with other locusts in a swarm. These results will permit us to analyze neuronal plasticity in a model system with a well-defined and controllable behavioral context.

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 Spatial precision of population activity in primate area MT

2015 ◽  
Vol 114 (2) ◽  
pp. 869-878 ◽  
Author(s):  
Spencer C. Chen ◽  
John W. Morley ◽  
Samuel G. Solomon
Keyword(s):  
Neural Activity ◽  
Visual Processing ◽  
Receptive Fields ◽  
Object Motion ◽  
Spatial Position ◽  
Multielectrode Arrays ◽  
Visual World ◽  
Population Activity ◽  
Area Mt ◽  
Mt Neurons

The middle temporal (MT) area is a cortical area integral to the “where” pathway of primate visual processing, signaling the movement and position of objects in the visual world. The receptive field of a single MT neuron is sensitive to the direction of object motion but is too large to signal precise spatial position. Here, we asked if the activity of MT neurons could be combined to support the high spatial precision required in the where pathway. With the use of multielectrode arrays, we recorded simultaneously neural activity at 24–65 sites in area MT of anesthetized marmoset monkeys. We found that although individual receptive fields span more than 5° of the visual field, the combined population response can support fine spatial discriminations (<0.2°). This is because receptive fields at neighboring sites overlapped substantially, and changes in spatial position are therefore projected onto neural activity in a large ensemble of neurons. This fine spatial discrimination is supported primarily by neurons with receptive fields flanking the target locations. Population performance is degraded (by 13–22%) when correlations in neural activity are ignored, further reflecting the contribution of population neural interactions. Our results show that population signals can provide high spatial precision despite large receptive fields, allowing area MT to represent both the motion and the position of objects in the visual world.

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 Local processing of visual information in neurites of VGluT3-expressing amacrine cells

2017 ◽  
Author(s):  
Jen-Chun Hsiang ◽  
Keith Johnson ◽  
Linda Madisen ◽  
Hongkui Zeng ◽  
Daniel Kerschensteiner
Keyword(s):  
Visual Processing ◽  
Visual Information ◽  
Plexiform Layer ◽  
Amacrine Cells ◽  
Object Motion ◽  
Image Motion ◽  
Inner Plexiform Layer ◽  
Two Photon ◽  
Size Contrast ◽  
Preferred Stimulus

AbstractSynaptic inputs to neurons are distributed across extensive neurite arborizations. To what extent arbors process inputs locally or integrate them globally is, for most neurons, unknown. This question is particularly relevant for amacrine cells, a diverse class of retinal interneurons, which receive input and provide output through the same neurites. Here, we used two-photon Ca2+ imaging to analyze visual processing in VGluT3-expressing amacrine cells (VG3-ACs), an important component of object motion sensitive circuits in the retina. VG3-AC neurites differed in their preferred stimulus contrast (ON vs. OFF); and ON and OFF responses varied in transience and preferred stimulus size. Contrast preference changed predictably with the laminar position of neurites in the inner plexiform layer. Yet, neurites at all depths were strongly activated by local but not by global image motion. Thus, VG3-AC neurites process visual information locally, exhibiting diverse responses to contrast steps, but uniform object motion selectivity.

scholarly journals Visual Processing of Impending Collision: Differential Processing of Object Motion and Self-motion

2012 ◽  
Vol 12 (9) ◽  
pp. 246-246
Author(s):  
J.-J. Yan ◽  
B. Lorv ◽  
H. Li ◽  
H.-J. Sun
Keyword(s):  
Visual Processing ◽  
Object Motion ◽  
Differential Processing ◽  
Self Motion

Background complexity affects response of a looming-sensitive neuron to object motion

2015 ◽  
Vol 113 (1) ◽  
pp. 218-231 ◽  
Author(s):  
Ana C. Silva ◽  
Glyn A. McMillan ◽  
Cristina P. Santos ◽  
John R. Gray
Keyword(s):  
Flow Field ◽  
Locusta Migratoria ◽  
Three Dimensional ◽  
Object Motion ◽  
Stimulus Complexity ◽  
Movement Detector ◽  
Behavioral Context ◽  
Firing Rates ◽  
Moving Stimulus ◽  
Contralateral Movement

An increasing number of studies show how stimulus complexity affects the responses of looming-sensitive neurons across multiple animal taxa. Locusts contain a well-described, descending motion-sensitive pathway that is preferentially looming sensitive. However, the lobula giant movement detector/descending contralateral movement detector (LGMD/DCMD) pathway responds to more than simple objects approaching at constant, predictable trajectories. In this study, we presented Locusta migratoria with a series of complex three-dimensional visual stimuli presented while simultaneously recording DCMD activity extracellularly. In addition to a frontal looming stimulus, we used a combination of compound trajectories (nonlooming transitioning to looming) presented at different velocities and onto a simple, scattered, or progressive flow field background. Regardless of stimulus background, DCMD responses to looming were characteristic and related to previously described effects of azimuthal approach angle and velocity of object expansion. However, increasing background complexity caused reduced firing rates, delayed peaks, shorter rise phases, and longer fall phases. DCMD responded to transitions to looming with a characteristic drop in a firing rate that was relatively invariant across most stimulus combinations and occurred regardless of stimulus background. Spike numbers were higher in the presence of the scattered background and reduced in the flow field background. We show that DCMD response time to a transition depends on unique expansion parameters of the moving stimulus irrespective of background complexity. Our results show how background complexity shapes DCMD responses to looming stimuli, which is explained within a behavioral context.

Virtually the same? How impaired sensory information in virtual reality may disrupt visually-guided action.

2019 ◽  
Author(s):  
David Harris ◽  
Gavin Buckingham ◽  
Mark Wilson ◽  
Samuel James Vine
Keyword(s):  
Virtual Reality ◽  
Visual Processing ◽  
Haptic Feedback ◽  
Sensory Information ◽  
Dorsal Stream ◽  
Depth Information ◽  
Haptic Information ◽  
Promising Tool ◽  
Vision For Action ◽  
Optic Array

Virtual reality (VR) is a promising tool for expanding the possibilities of psychological experimentation and implementing immersive training applications. Despite a recent surge in interest, there remains an inadequate understanding of how VR impacts basic cognitive processes. Due to the artificial presentation of egocentric distance cues in virtual environments, a number of cues to depth in the optic array are impaired or placed in conflict with each other. Moreover, realistic haptic information is all but absent from current VR systems. The resulting conflicts could impact not only the execution of motor skills in VR but raises deeper concerns about basic visual processing, and the extent to which virtual objects elicit neural and behavioural responses representative of real objects. In this brief review we outline how the novel perceptual environment of VR may affect vision for action, by shifting users away from a dorsal mode of control. Fewer binocular cues to depth, conflicting depth information and limited haptic feedback may all impair the specialised, efficient, online control of action characteristic of the dorsal stream. A shift from dorsal to ventral control of action may create a fundamental disparity between virtual and real-world skills that has important consequences for how we understand perception and action in the virtual world.

Spatiotemporal stimulus properties modulate responses to trajectory changes in a locust looming-sensitive pathway

2014 ◽  
Vol 111 (9) ◽  
pp. 1736-1745 ◽  
Author(s):  
Paul C. Dick ◽  
John R. Gray
Keyword(s):  
Visual Field ◽  
Firing Rate ◽  
Translational Motion ◽  
Object Motion ◽  
Movement Detector ◽  
Natural Conditions ◽  
Avoidance Behaviors ◽  
Contralateral Movement ◽  
Direct Collision ◽  
Low Amplitude

The lobula giant movement detector (LGMD) and descending contralateral movement detector (DCMD) constitute one motion-sensitive pathway in the locust visual system that is implicated in collision-avoidance behaviors. While this pathway is thought to respond preferentially to objects approaching on a direct collision course, emerging studies suggest the firing rate is able to monitor more complicated movements that would occur under natural conditions. While previous studies have compared the response of the DCMD to objects on collision courses that travel at different speeds, velocity has not been manipulated for other simple or compound trajectories. Here we test the possibility that the LGMD/DCMD pathway is capable of responding uniquely to complex aspects of object motion, including translation and trajectory changes at different velocities. We found that the response of the DCMD to translational motion initiated in the caudal visual field was a low-amplitude peak in firing rate that occurred before the object crossed 90° azimuth that was invariant to different object velocities. Direct looms at different velocities resulted in peak firing rates that occurred later in time and with greater amplitude for higher velocities. In response to transitions from translational motion to a collision course, the firing rate change depended on both the location within the visual field and the velocity. These results suggest that this pathway is capable of conveying information about multiple properties of a moving object's trajectory.

scholarly journals Local synaptic integration enables ON-OFF asymmetric and layer-specific visual information processing in vGluT3 amacrine cell dendrites

2017 ◽  
Vol 114 (43) ◽  
pp. 11518-11523 ◽  
Author(s):  
Minggang Chen ◽  
Seunghoon Lee ◽  
Z. Jimmy Zhou
Keyword(s):  
Receptive Field ◽  
Visual Processing ◽  
Amacrine Cell ◽  
Amacrine Cells ◽  
Object Motion ◽  
Field Size ◽  
Inner Plexiform Layer ◽  
Small Object ◽  
Synaptic Inhibition ◽  
Small Field

A basic scheme of neuronal organization in the mammalian retina is the segregation of ON and OFF pathways in the inner plexiform layer (IPL), where glutamate is released from ON and OFF bipolar cell terminals in separate inner (ON) and outer (OFF) sublayers in response to light intensity increments and decrements, respectively. However, recent studies have found that vGluT3-expressing glutamatergic amacrine cells (GACs) generate ON-OFF somatic responses and release glutamate onto both ON and OFF ganglion cell types, raising the possibility of crossover excitation in violation of the canonical ON-OFF segregation scheme. To test this possibility, we recorded light-evoked Ca2+ responses from dendrites of individual GACs infected with GCaMP6s in mouse. Under two-photon imaging, a single GAC generated rectified local dendritic responses, showing ON-dominant responses in ON sublayers and OFF-dominant responses in OFF sublayers. This unexpected ON-OFF segregation within a small-field amacrine cell arose from local synaptic processing, mediated predominantly by synaptic inhibition. Multiple forms of synaptic inhibition compartmentalized the GAC dendritic tree and endowed all dendritic varicosities with a small-center, strong-surround receptive field, which varied in receptive field size and degree of ON-OFF asymmetry with IPL depth. The results reveal a form of short-range dendritic autonomy that enables a small-field, dual-transmitter amacrine cell to process diverse dendritic functions in a stratification level- and postsynaptic target-specific manner, while preserving the fundamental ON-OFF segregation scheme for parallel visual processing and high spatial resolution for small object motion and uniformity detection.

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