scholarly journals IDENTIFICATION OF DIRECTIONALLY SELECTIVE MOTION-DETECTING NEURONES IN THE LOCUST LOBULA AND THEIR SYNAPTIC CONNECTIONS WITH AN IDENTIFIED DESCENDING NEURONE

1990 ◽  
Vol 149 (1) ◽  
pp. 21-43 ◽  
Author(s):  
F. CLAIRE RIND
Keyword(s):  
Preceding Paper ◽  
Apparent Movement ◽  
Single Step ◽  
Resting Membrane Potential ◽  
Null Direction ◽  
Excitatory Connection ◽  
Anatomy And Physiology ◽  
Preferred Direction ◽  
Presynaptic Spike ◽  
Postsynaptic Neurone

The anatomy and physiology of two directionally selective motion-detecting neurones in the locust are described. Both neurones had dendrites in the lobula, and projected to the ipsilateral protocerebrum. Their cell bodies were located on the posterio-dorsal junction of the optic lobe with the protocerebrum. The neurones were sensitive to horizontal motion of a visual stimulus. One neurone, LDSMD(F), had a preferred direction forwards over the ipsilateral eye, and a null direction backwards. The other neurone, LDSMD(B), had a preferred direction backwards over the ipsilateral eye 1. Motion in the preferred direction caused EPSPs and spikes in the LDSMD neurones. Motion in the null direction resulted in IPSPs 2. Both excitatory and inhibitory inputs were derived from the ipsilateral eye 3. The DSMD neurones responded to velocities of movement up to and beyond 270°s−1 4. The response of both LDSMD neurones showed no evidence of adaptation during maintained apparent or real movement 5. There was a delay of 60–80 ms between a single step of apparent movement, either the preferred or the null direction, and the start of the response 6. There was a monosynaptic, excitatory connection between the LDSMD(B) neurone and the protocerebral, descending DSMD neurone (PDDSMD) identified in the preceding paper (Rind, 1990). At resting membrane potential, a single presynaptic spike did not give rise to a spike in the postsynaptic neurone

A DIRECTIONALLY SELECTIVE MOTION-DETECTING NEURONE IN THE BRAIN OF THE LOCUST: PHYSIOLOGICAL AND MORPHOLOGICAL CHARACTERIZATION

1990 ◽  
Vol 149 (1) ◽  
pp. 1-19 ◽  
Author(s):  
F. CLAIRE RIND
Keyword(s):  
Cell Body ◽  
Morphological Characterization ◽  
Resting Membrane Potential ◽  
Anatomy And Physiology ◽  
Preferred Direction ◽  
Spatial Frequencies ◽  
Metathoracic Ganglion ◽  
Eye Motion ◽  
Contralateral Eye ◽  
The Brain

1. The anatomy and physiology of a directionally selective motion-detecting DSMD) neurone in the locust are described. The neurone was descending, with the cell body in the protocerebrum. The axon lay in the dorsolateral quadrant of the nerve cord and has been traced as far as the metathoracic ganglion. It arborized, ipsilateral to the cell body, from the dorsal intermediate tract (DIT) in the suboesophageal and thoracic ganglia 2. The neurone was binocular and sensitive to motion in the horizontal plane. It had a preferred direction backwards over the ipsilateral eye and forwards over the contralateral eye. Motion in the opposite direction suppressed the discharge, which had a frequency of 5–20 spikes s−1 at resting membrane potential 3. The neurone showed a clear directional response to stimuli with temporal frequencies between 0.7 and 44Hz, with a peak response at 11–22 Hz. It responded with spikes to light ON and light OFF 4. The neurone responded directionally to spatial frequencies of 0.28 cycles degree−1 (3.7° stripe period) to above 0.025 cycles degree−1 (40° stripe period). The maximum response was at around 0.035 cycles degree−1 (29° stripe period) 5. No evidence of adaptation was seen in the responses of the neurone to real or apparent continuous horizontal motion in either the preferred or the null direction

scholarly journals Substructure of Direction-Selective Receptive Fields in Macaque V1

2003 ◽  
Vol 89 (5) ◽  
pp. 2743-2759 ◽  
Author(s):  
Margaret S. Livingstone ◽  
Bevil R. Conway
Keyword(s):  
Receptive Fields ◽  
Direction Selectivity ◽  
Positive Interactions ◽  
Null Direction ◽  
Simple Cells ◽  
Complex Cells ◽  
Preferred Direction ◽  
Orientation Axis ◽  
Interaction Regions ◽  
Simple And Complex Cells

We used two-dimensional (2-D) sparse noise to map simultaneous and sequential two-spot interactions in simple and complex direction-selective cells in macaque V1. Sequential-interaction maps for both simple and complex cells showed preferred-direction facilitation and null-direction suppression for same-contrast stimulus sequences and the reverse for inverting-contrast sequences, although the magnitudes of the interactions were weaker for the simple cells. Contrast-sign selectivity in complex cells indicates that direction-selective interactions in these cells must occur in antecedent simple cells or in simple-cell-like dendritic compartments. Our maps suggest that direction selectivity, and on andoff segregation perpendicular to the orientation axis, can occur prior to receptive-field elongation along the orientation axis. 2-D interaction maps for some complex cells showed elongated alternating facilitatory and suppressive interactions as predicted if their inputs were orientation-selective simple cells. The negative interactions, however, were less elongated than the positive interactions, and there was an inflection at the origin in the positive interactions, so the interactions were chevron-shaped rather than band-like. Other complex cells showed only two round interaction regions, one negative and one positive. Several explanations for the map shapes are considered, including the possibility that directional interactions are generated directly from unoriented inputs.

scholarly journals An Optimization framework for Nonspiking Neuronal Networks and Aided Discovery of a Model for the Elementary Motion Detector

2019 ◽  
Author(s):  
Arunava Banerjee
Keyword(s):  
Optic Lobe ◽  
Optimization Procedure ◽  
Theoretical Models ◽  
Direction Selectivity ◽  
Recurrent Networks ◽  
Motion Detector ◽  
Null Direction ◽  
Optimization Framework ◽  
Preferred Direction ◽  
Low Pass

AbstractWe present a general optimization procedure that given a parameterized network of nonspiking conductance based compartmentally modeled neurons, tunes the parameters to elicit a desired network behavior. Armed with this tool, we address the elementary motion detector problem. Central to established theoretical models, the Hassenstein-Reichardt and Barlow-Levick detectors, are delay lines whose outputs from spatially separated locations are prescribed to be nonlinearly integrated with the direct outputs to engender direction selectivity. The neural implementation of the delays—which are substantial as stipulated by interomatidial angles—has remained elusive although there is consensus regarding the neurons that constitute the network. Assisted by the optimization procedure, we identify parameter settings consistent with the connectivity architecture and physiology of the Drosophila optic lobe, that demonstrates that the requisite delay and the concomitant direction selectivity can emerge from the nonlinear dynamics of small recurrent networks of neurons with simple tonically active synapses. Additionally, although the temporally extended responses of the neurons permit simple synaptic integration of their signals to be sufficient to induce direction selectivity, both preferred direction enhancement and null direction suppression is necessary to abridge the overall response. Finally, the characteristics of the response to drifting sinusoidal gratings are readily explained by the charging-up of the recurrent networks and their low-pass nature.

scholarly journals Subthreshold Membrane Conductances Enhance Directional Selectivity in Vertebrate Sensory Neurons

2010 ◽  
Vol 104 (1) ◽  
pp. 449-462 ◽  
Author(s):  
Maurice J. Chacron ◽  
Eric S. Fortune
Keyword(s):  
Directional Selectivity ◽  
Null Direction ◽  
Directional Bias ◽  
Membrane Conductances ◽  
Preferred Direction ◽  
Receptor Array ◽  
Central Nervous Systems ◽  
Direction Of Movement ◽  
Nonlinear Integration

Directional selectivity, in which neurons respond preferentially to one “preferred” direction of movement over the opposite “null” direction, is a critical computation that is found in the central nervous systems of many animals. Such responses are generated using two mechanisms: spatiotemporal convergence via pathways that differ in the timing of information from different locations on the receptor array and the nonlinear integration of this information. Previous studies have showed that various mechanisms may act as nonlinear integrators by suppressing the response in the null direction. Here we show, through a combination of mathematical modeling and in vivo intracellular recordings, that subthreshold membrane conductances can act as a nonlinear integrator by increasing the response in the preferred direction of motion only, thereby enhancing the directional bias. Such subthreshold conductances are ubiquitous in the CNS and therefore may be used in a wide array of computations that involve the enhancement of an existing bias arising from differential spatiotemporal filtering.

Delay-Period Activity in Visual, Visuomovement, and Movement Neurons in the Frontal Eye Field

2005 ◽  
Vol 94 (2) ◽  
pp. 1498-1508 ◽  
Author(s):  
Bonnie M. Lawrence ◽  
Robert L. White ◽  
Lawrence H. Snyder
Keyword(s):  
Spatial Information ◽  
Delay Period ◽  
Frontal Eye Field ◽  
Significant Delay ◽  
Related Activity ◽  
Null Direction ◽  
Preferred Direction ◽  
Canonical Neurons ◽  
Eye Field ◽  
Saccade Direction

In the present study, we examined the role of frontal eye field neurons in the maintenance of spatial information in a delayed-saccade paradigm. We found that visual, visuomovement, and movement neurons conveyed roughly equal amounts of spatial information during the delay period. Although there was significant delay-period activity in individual movement neurons, there was no significant delay-period activity in the averaged population of movement neurons. These contradictory results were reconciled by the finding that the population of movement neurons with memory activity consisted of two subclasses of neurons, the combination of which resulted in the cancellation of delay-period activity in the population of movement neurons. One subclass consisted of neurons with significantly greater delay activity in the preferred than in the null direction (“canonical”), whereas the other subclass consisted of neurons with significantly greater delay activity in the null direction than in the preferred direction (“paradoxical”). Preferred direction was defined by the saccade direction that evoked the greatest movement-related activity. Interestingly, the peak saccade-related activity of canonical neurons occurred before the onset of the saccade, whereas the peak saccade-related activity of paradoxical neurons occurred after the onset of the saccade. This suggests that the former, but not the latter, are directly involved in triggering saccades. We speculate that paradoxical neurons provide a mechanism by which spatial information can be maintained in a saccade-generating circuit without prematurely triggering a saccade.

The receptive field of the primate P retinal ganglion cell, II: Nonlinear dynamics

1997 ◽  
Vol 14 (1) ◽  
pp. 187-205 ◽  
Author(s):  
Ethan A. Benardete ◽  
Ehud Kaplan
Keyword(s):  
Receptive Field ◽  
Visual Processing ◽  
Ganglion Cells ◽  
Preceding Paper ◽  
Retinal Ganglion ◽  
First Order ◽  
Anatomy And Physiology ◽  
Series Of Experiments ◽  
A New Technique ◽  
P Cells

AbstractThe receptive-field properties of retinal ganglion cells (RGCs) provide information about early visual processing. In the primate retina, P cells form the largest class of RGCs (Rodieck, 1988). A detailed exploration of the dynamics of the two subdivisions of the P-cell receptive field—the center and the surround—was undertaken. In the preceding paper (Benardete & Kaplan, 1996), the first-order responses of the center and the surround of P cells were described, which were obtained with a new technique, the multiple m-sequence stimulus (Benardete & Victor, 1994). In this paper, the investigation of P-cell responses measured as S-potentials in the lateral geniculate nucleus (LGN) is continued, and significant nonlinear, second-order responses from the center and the surround are described. These responses are quantified by fitting a mathematical model, the linear-nonlinear-linear (LNL) model (Korenberg, 1973; Korenberg & Hunter, 1986; Victor, 1988) to the data. In a second series of experiments, demonstration that steady illumination of the surround modifies the gain of the center to contrast signals (see also Kaplan & Shapley, 1989) is made. In P ON cells, increasing the steady illumination of the surround decreases the gain and speeds up the center's first-order response. In P OFF cells, increasing the steady illumination of the surround increases the gain of the center while speeding up the response. The results of both sets of experiments are related to the known anatomy and physiology of the P cell.

scholarly journals Complementary mechanisms create direction selectivity in the fly

eLife ◽  
2016 ◽  
Vol 5 ◽  
Author(s):  
Juergen Haag ◽  
Alexander Arenz ◽  
Etienne Serbe ◽  
Fabrizio Gabbiani ◽  
Alexander Borst
Keyword(s):  
Motion Detection ◽  
Visual Motion ◽  
Optic Lobe ◽  
Direction Selectivity ◽  
Neural Computation ◽  
Directional Selectivity ◽  
Motion Sensing ◽  
Null Direction ◽  
Preferred Direction ◽  
High Degree

How neurons become sensitive to the direction of visual motion represents a classic example of neural computation. Two alternative mechanisms have been discussed in the literature so far: preferred direction enhancement, by which responses are amplified when stimuli move along the preferred direction of the cell, and null direction suppression, where one signal inhibits the response to the subsequent one when stimuli move along the opposite, i.e. null direction. Along the processing chain in the Drosophila optic lobe, directional responses first appear in T4 and T5 cells. Visually stimulating sequences of individual columns in the optic lobe with a telescope while recording from single T4 neurons, we find both mechanisms at work implemented in different sub-regions of the receptive field. This finding explains the high degree of directional selectivity found already in the fly’s primary motion-sensing neurons and marks an important step in our understanding of elementary motion detection.

scholarly journals Directional selective neurons in the awake LGN: response properties and modulation by brain state

2014 ◽  
Vol 112 (2) ◽  
pp. 362-373 ◽  
Author(s):  
Xiaojuan Hei (黑晓娟) ◽  
Carl R. Stoelzel ◽  
Jun Zhuang (庄骏) ◽  
Yulia Bereshpolova ◽  
Joseph M. Huff ◽  
...  
Keyword(s):  
Receptive Fields ◽  
Harmonic Component ◽  
Brain State ◽  
Visual Response ◽  
Null Direction ◽  
Simple Cells ◽  
Response Properties ◽  
Strongly Nonlinear ◽  
Preferred Direction ◽  
Layer 4

Directionally selective (DS) neurons are found in the retina and lateral geniculate nucleus (LGN) of rabbits and rodents, and in rabbits, LGN DS cells project to primary visual cortex. Here, we compare visual response properties of LGN DS neurons with those of layer 4 simple cells, most of which show strong direction/orientation selectivity. These populations differed dramatically, suggesting that DS cells may not contribute significantly to the synthesis of simple receptive fields: 1) whereas the first harmonic component (F1)-to-mean firing rate (F0) ratios of LGN DS cells are strongly nonlinear, those of simple cells are strongly linear; 2) whereas LGN DS cells have overlapped ON/OFF subfields, simple cells have either a single ON or OFF subfield or two spatially separate subfields; and 3) whereas the preferred directions of LGN DS cells are closely tied to the four cardinal directions, the directional preferences of simple cells are more evenly distributed. We further show that directional selectivity in LGN DS neurons is strongly enhanced by alertness via two mechanisms, 1) an increase in responses to stimulation in the preferred direction, and 2) an enhanced suppression of responses to stimuli moving in the null direction. Finally, our simulations show that these two consequences of alertness could each serve, in a vector-based population code, to hasten the computation of stimulus direction when rabbits become alert.

Effects of Ca2+ channel blockers on directional selectivity of rabbit retinal ganglion cells

1995 ◽  
Vol 74 (1) ◽  
pp. 12-23 ◽  
Author(s):  
R. J. Jensen
Keyword(s):  
Retinal Ganglion Cells ◽  
Ganglion Cells ◽  
Leading Edge ◽  
Channel Blockers ◽  
Directional Selectivity ◽  
Retinal Ganglion ◽  
Null Direction ◽  
Trailing Edge ◽  
Preferred Direction ◽  
Ca2 Channels

1. Extracellular recordings were made from ON-OFF directionally selective ganglion cells in superfused rabbit retinas in order to examine the effects of voltage-activated Ca2+ channel blockers on the response of these ganglion cells to a moving bar of light. 2. Bath application of Cd2+ (67-110 microM) abolished directional selectivity in the ganglion cells. That is, the cells gave nearly equal responses to the leading and trailing edges of a bar of light moved in the preferred and null directions. This effect of Cd2+ was rapidly reversible. 3. Directional selectivity in the ganglion cells was not affected by Ni2+ (120-440 microM), Co2+ (180-690 microM), or the L-type Ca2+ channel blockers nicardipine (7-29 microM) and methoxyverapamil (18-60 microM). These blockers did, however, reduce the responses of the ganglion cells to a bar of light moved in the preferred direction. 4. omega-Conotoxin MVIIC (130 nM-1.9 microM), which potently blocks N-type and Q-type Ca2+ channels, abolished directional selectivity in the ganglion cells. omega-Conotoxin MVIIC not only brought out large leading and trailing edge responses to movement of a bar of light in the null direction, but it also increased the leading and trailing edge responses to movement of the bar of light in the preferred direction. The effect of omega-conotoxin MVIIC was slowly reversible. 5. The N-type Ca2+ channel blocker omega-conotoxin GVIA (1.4-6.3 microM) did not abolish directional selectivity in the ganglion cells. This blocker did, however, bring out some response to the leading edge of a bar of a light moved in the null direction. This effect of omega-conotoxin GVIA appeared to be irreversible. 6. omega-Agatoxin IVA, a potent blocker of P-type Ca2+ channels, when bath applied at low concentrations (66-83 nM), increased the responses to movement of a bar of light in the preferred direction but brought out only small responses to movement of the bar of light in the null direction. At high concentrations (250-280 nM) that reportedly block Q-type Ca2+ channels by > or = 50%, omega-agatoxin IVA nearly abolished directional selectivity. This effect of omega-agatoxin IVA was slowly reversible. 7. These results indicate that omega-conotoxin MVIIC- and omega-agatoxin IVA-sensitive Ca2+ channels (possibly Q-type channels) play an important role in the generation of directional selectivity in rabbit retinal ganglion cells.

scholarly journals Spatially displaced excitation contributes to the encoding of interrupted motion by the retinal direction-selective circuit

2020 ◽  
Author(s):  
Jennifer Ding ◽  
Albert Chen ◽  
Janet Chung ◽  
Hector Acaron Ledesma ◽  
David M. Berson ◽  
...  
Keyword(s):  
Ganglion Cells ◽  
Spatial Location ◽  
Direction Selectivity ◽  
Natural Scenes ◽  
Visual Response ◽  
Null Direction ◽  
Motion Trajectories ◽  
Preferred Direction ◽  
Synchronous Firing ◽  
Spatially Distributed

AbstractSpatially distributed excitation and inhibition collectively shape a visual neuron’s receptive field (RF) properties. In the direction-selective circuit of the mammalian retina, the effects of strong null-direction inhibition of On-Off direction-selective ganglion cells (ON-OFF DSGCs) on their direction selectivity are well-studied. However, how excitatory inputs influence the On-Off DSGC’s visual response is underexplored. Here, we report that the glutamatergic excitation of On-Off DSGCs shows a spatial displacement to the side where preferred-direction motion stimuli approach the soma (the ‘preferred side’). Underlying this displacement is a non-uniform distribution of excitatory conductance across the dendritic span of the DSGC on the preferred-null motion axis. The skewed excitatory RF contributes to robust null-direction spiking during RF activation limited to the preferred side, a potential ethologically relevant signal to encode interrupted or discontinuous motion trajectories abundant in natural scenes. Theoretical analysis indicates that such differential firing patterns of On-Off DSGCs to continuous and interrupted motion stimuli may help leverage synchronous firing to signal the spatial location of a moving object in complex, naturalistic visual environments. Our study highlights that visual circuitry, even the well-defined direction-selective circuit, exploits different sets of neural mechanisms under different stimulus conditions to generate context-dependent neural representations of visual features.

Sign in / Sign up

Export Citation Format

Share Document