scholarly journals Optimal spatial frequencies for discrimination of motion direction in optic flow patterns

1999 ◽  
Vol 39 (19) ◽  
pp. 3175-3185 ◽  
Author(s):  
Jeounghoon Kim ◽  
Kathleen A Turano
Keyword(s):  
Optic Flow ◽  
Flow Patterns ◽  
Motion Direction ◽  
Spatial Frequencies

scholarly journals Neural selectivity for visual motion in macaque area V3A

2020 ◽  
Author(s):  
Nardin Nakhla ◽  
Yavar Korkian ◽  
Matthew R. Krause ◽  
Christopher C. Pack
Keyword(s):  
Visual Cortex ◽  
Optic Flow ◽  
Functional Role ◽  
Visual Motion ◽  
Flow Patterns ◽  
Brain Regions ◽  
Direction Selectivity ◽  
Motion Processing ◽  
Imaging Studies ◽  
Motion Direction

AbstractThe processing of visual motion is carried out by dedicated pathways in the primate brain. These pathways originate with populations of direction-selective neurons in the primary visual cortex, which project to dorsal structures like the middle temporal (MT) and medial superior temporal (MST) areas. Anatomical and imaging studies have suggested that area V3A might also be specialized for motion processing, but there have been very few studies of single-neuron direction selectivity in this area. We have therefore performed electrophysiological recordings from V3A neurons in two macaque monkeys (one male and one female) and measured responses to a large battery of motion stimuli that includes translation motion, as well as more complex optic flow patterns. For comparison, we simultaneously recorded the responses of MT neurons to the same stimuli. Surprisingly, we find that overall levels of direction selectivity are similar in V3A and MT and moreover that the population of V3A neurons exhibits somewhat greater selectivity for optic flow patterns. These results suggest that V3A should be considered as part of the motion processing machinery of the visual cortex, in both human and non-human primates.Significance statementAlthough area V3A is frequently the target of anatomy and imaging studies, little is known about its functional role in processing visual stimuli. Its contribution to motion processing has been particularly unclear, with different studies yielding different conclusions. We report a detailed study of direction selectivity in V3A. Our results show that single V3A neurons are, on average, as capable of representing motion direction as are neurons in well-known structures like MT. Moreover, we identify a possible specialization for V3A neurons in representing complex optic flow, which has previously been thought to emerge in higher-order brain regions. Thus it appears that V3A is well-suited to a functional role in motion processing.

Visual Motion Priors Differ for Infants and Mothers

2014 ◽  
Vol 26 (11) ◽  
pp. 2652-2668 ◽  
Author(s):  
Florian Raudies ◽  
Rick O. Gilmore
Keyword(s):  
Empirical Data ◽  
Optic Flow ◽  
Visual Motion ◽  
Motion Direction ◽  
Normal Distributions ◽  
Data Support

Visual motion direction ambiguities due to edge-aperture interaction might be resolved by speed priors, but scant empirical data support this hypothesis. We measured optic flow and gaze positions of walking mothers and the infants they carried. Empirically derived motion priors for infants are vertically elongated and shifted upward relative to mothers. Skewed normal distributions fitted to estimated retinal speeds peak at values above 20[Formula: see text]/sec.

scholarly journals Children's cortical responses to optic flow patterns show differential tuning by pattern type, speed, scalp location and age group

2012 ◽  
Vol 12 (9) ◽  
pp. 243-243
Author(s):  
A. Thomas ◽  
A. Mancino ◽  
H. Elnathan ◽  
J. Fesi ◽  
K. Hwang ◽  
...  
Keyword(s):  
Optic Flow ◽  
Flow Patterns ◽  
Age Group ◽  
Pattern Type ◽  
Cortical Responses ◽  
Differential Tuning ◽  
Scalp Location

Development of cortical responses to optic flow

2007 ◽  
Vol 24 (6) ◽  
pp. 845-856 ◽  
Author(s):  
RICK O. GILMORE ◽  
C. HOU ◽  
M.W. PETTET ◽  
A.M. NORCIA
Keyword(s):  
Optic Flow ◽  
Radial Flow ◽  
Brain Activity ◽  
Flow Patterns ◽  
Motion Processing ◽  
Uniform Motion ◽  
Brain Responses ◽  
Cortical Responses ◽  
Frequency Domains ◽  
Self Motion

Humans discriminate approaching objects from receding ones shortly after birth, and optic flow associated with self-motion may activate distinctive brain networks, including the human MT+ complex. We sought evidence for evoked brain activity that distinguished radial motion from other optic flow patterns, such as translation or rotation by recording steady-state visual evoked potentials (ssVEPs), in both adults and 4–6 month-old infants to direction-reversing optic flow patterns. In adults, radial flow evoked distinctive brain responses in both the time and frequency domains. Differences between expansion/contraction and both translation and rotation were especially strong in lateral channels (PO7 and PO8), and there was an asymmetry between responses to expansion and contraction. In contrast, infants' evoked response waveforms to all flow types were equivalent, and showed no evidence of the expansion/contraction asymmetry. Infants' responses were largest and most reliable for the translation patterns in which all dots moved in the same direction. This pattern of response is consistent with an account in which motion processing systems detecting locally uniform motion develop earlier than do systems specializing in complex, globally non-uniform patterns of motion, and with evidence suggesting that motion processing undergoes prolonged postnatal development.

scholarly journals The A-Effect and Global Motion

Vision ◽  
2019 ◽  
Vol 3 (2) ◽  
pp. 13
Author(s):  
Pearl Guterman ◽  
Robert Allison
Keyword(s):  
Optic Flow ◽  
Object Motion ◽  
The Body ◽  
Body Tilt ◽  
Whole Body ◽  
Global Motion ◽  
Motion Direction ◽  
And Shifts ◽  
Self Motion ◽  
Gravitational Vertical

When the head is tilted, an objectively vertical line viewed in isolation is typically perceived as tilted. We explored whether this shift also occurs when viewing global motion displays perceived as either object-motion or self-motion. Observers stood and lay left side down while viewing (1) a static line, (2) a random-dot display of 2-D (planar) motion or (3) a random-dot display of 3-D (volumetric) global motion. On each trial, the line orientation or motion direction were tilted from the gravitational vertical and observers indicated whether the tilt was clockwise or counter-clockwise from the perceived vertical. Psychometric functions were fit to the data and shifts in the point of subjective verticality (PSV) were measured. When the whole body was tilted, the perceived tilt of both a static line and the direction of optic flow were biased in the direction of the body tilt, demonstrating the so-called A-effect. However, we found significantly larger shifts for the static line than volumetric global motion as well as larger shifts for volumetric displays than planar displays. The A-effect was larger when the motion was experienced as self-motion compared to when it was experienced as object-motion. Discrimination thresholds were also more precise in the self-motion compared to object-motion conditions. Different magnitude A-effects for the line and motion conditions—and for object and self-motion—may be due to differences in combining of idiotropic (body) and vestibular signals, particularly so in the case of vection which occurs despite visual-vestibular conflict.

Low-level processing deficits underlying poor contrast sensitivity for moving plaids in anisometropic amblyopia

2012 ◽  
Vol 29 (6) ◽  
pp. 315-323 ◽  
Author(s):  
YONG TANG ◽  
LINYI CHEN ◽  
ZHONGJIAN LIU ◽  
CAIYUAN LIU ◽  
YIFENG ZHOU
Keyword(s):  
Contrast Sensitivity ◽  
Significant Loss ◽  
Extrastriate Cortex ◽  
Motion Processing ◽  
Motion Direction ◽  
Temporal Area ◽  
Anisometropic Amblyopia ◽  
Low Level ◽  
Spatial Frequencies ◽  
Processing Deficits

AbstractMany studies using random dot kinematograms have indicated a global motion processing deficit originated from extrastriate cortex, specifically middle temporal area (MT) and media superior temporal area (MST), in patients with amblyopia. However, the nature of this deficit remains unclear. To explore whether the ability of motion integration is impaired in amblyopia, contrast sensitivity for moving plaids and their corresponding component gratings were measured over a range of stimulus durations and spatial and temporal frequencies in 10 control subjects and 13 anisometropic amblyopes by using a motion direction discrimination task. The results indicated a significant loss of contrast sensitivity for moving plaids as well as for moving gratings at intermediate and high spatial frequencies in amblyopic eyes (AEs). Additionally, we found that the loss of contrast sensitivity for moving plaids was statistically equivalent to that for moving component gratings in AEs, that is, the former could be almost completely accounted for by the latter. These results suggest that the integration of motion information conveyed by component gratings of moving plaids may be intact in anisometropic amblyopia, and that the apparent deficits in contrast sensitivity for moving plaids in anisometropic amblyopia can be almost completely attributed to those for gratings, that is, low-level processing deficits.

Receptive-field structure of optic flow responsive Purkinje cells in the vestibulocerebellum of pigeons

2006 ◽  
Vol 23 (1) ◽  
pp. 115-126 ◽  
Author(s):  
IAN R. WINSHIP ◽  
DOUGLAS R.W. WYLIE
Keyword(s):  
Receptive Field ◽  
Purkinje Cells ◽  
Optic Flow ◽  
Flow Patterns ◽  
Field Structure ◽  
Local Motion ◽  
Cortical Areas ◽  
Invertebrate Species ◽  
Visual Cortical ◽  
Complex Computer

Neurons sensitive to optic flow patterns have been recorded in the the olivo-vestibulocerebellar pathway and extrastriate visual cortical areas in vertebrates, and in the visual neuropile of invertebrates. The complex spike activity (CSA) of Purkinje cells in the vestibulocerebellum (VbC) responds best to patterns of optic flow that result from either self-rotation or self-translation. Previous studies have suggested that these neurons have a receptive-field (RF) structure that “approximates” the preferred optic flowfield with a “bipartite” organization. Contrasting this, studies in invertebrate species indicate that optic flow sensitive neurons are precisely tuned to their preferred flowfield, such that the local motion sensitivities and local preferred directions within their RFs precisely match the local motion in that region of the preferred flowfield. In this study, CSA in the VbC of pigeons was recorded in response to a set of complex computer-generated optic flow stimuli, similar to those used in previous studies of optic flow neurons in primate extrastriate visual cortex, to test whether the receptive field was of a precise or bipartite organization. We found that these RFs were not precisely tuned to optic flow patterns. Rather, we conclude that these neurons have a bipartite RF structure that approximates the preferred optic flowfield by pooling motion subunits of only a few different direction preferences.

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