scholarly journals Choice-Related Activity during Visual Slant Discrimination in Macaque CIP but Not V3A

2018 ◽  
Author(s):  
L. Caitlin Elmore ◽  
Ari Rosenberg ◽  
Gregory C. DeAngelis ◽  
Dora E. Angelaki
Keyword(s):  
Visual Processing ◽  
Discrimination Task ◽  
Three Dimensional ◽  
Surface Orientation ◽  
Orientation Discrimination ◽  
Visual Orientation ◽  
Planar Surface ◽  
Related Activity ◽  
Planar Surfaces ◽  
3D Surface

AbstractCreating three-dimensional (3D) representations of the world from two-dimensional retinal images is fundamental to many visual guided behaviors including reaching and grasping. A critical component of this process is determining the 3D orientation of objects. Previous studies have shown that neurons in the caudal intraparietal area (CIP) of the macaque monkey represent 3D planar surface orientation (i.e., slant and tilt). Here we compare the responses of neurons in areas V3A (which is implicated in 3D visual processing and which precedes CIP in the visual hierarchy) and CIP to 3D oriented planar surfaces. We then examine whether activity in these areas correlates with perception during a fine slant discrimination task in which monkeys report if the top of a surface is slanted towards or away from them. Although we find that V3A and CIP neurons show similar sensitivity to planar surface orientation, significant choice-related activity during the slant discrimination task is rare in V3A but prominent in CIP. These results implicate both V3A and CIP in the representation of 3D surface orientation, and suggest a functional dissociation between the areas based on slant-related decision signals.Significance StatementSurface orientation perception is fundamental to visually guided behaviors such as reaching, grasping, and navigation. Previous studies implicate the caudal intraparietal area (CIP) in the representation of 3D surface orientation. Here we show that responses to 3D oriented planar surfaces are similar in CIP and V3A, which precedes CIP in the cortical hierarchy. However, we also find a qualitative distinction between the two areas: only CIP neurons show robust choice-related activity during a fine visual orientation discrimination task.

scholarly journals Investigating the Effects of tDCS on Visual Orientation Discrimination Task Performance: “the Possible Influence of Placebo”

2019 ◽  
Vol 4 (3) ◽  
pp. 235-249
Author(s):  
A. Bin Dawood ◽  
A. Dickinson ◽  
A. Aytemur ◽  
C. Howarth ◽  
E. Milne ◽  
...  
Keyword(s):  
Placebo Effect ◽  
Discrimination Task ◽  
Low Cost ◽  
Cortical Inhibition ◽  
Orientation Discrimination ◽  
Visual Orientation ◽  
Non Invasive ◽  
Clear Link ◽  
Cortical Modulation ◽  
Improved Performance

Abstract The non-invasive neuromodulation technique tDCS offers the promise of a low-cost tool for both research and clinical applications in psychology, psychiatry, and neuroscience. However, findings regarding its efficacy are often equivocal. A key issue is that the clinical and cognitive applications studied are often complex and thus effects of tDCS are difficult to predict given its known effects on the basic underlying neurophysiology, namely alterations in cortical inhibition-excitation balance. As such, it may be beneficial to assess the effects of tDCS in tasks whose performance has a clear link to cortical inhibition-excitation balance such as the visual orientation discrimination task (ODT). In prior studies in our laboratory, no practice effects were found during 2 consecutive runs of the ODT, thus in the current investigation, to examine the effects of tDCS, subjects received 10 min of 2 mA occipital tDCS (sham, anode, cathode) between a first and second run of ODT. Surprisingly, subjects’ performance significantly improved in the second run of ODT compared to the first one regardless of the tDCS stimulation type they received (anodal, cathodal, or sham-tDCS). Possible causes for such an improvement could have been due to either a generic “placebo” effect of tDCS (as all subjects received some form of tDCS) or an increased delay period between the two runs of ODT of the current study compared to our previous work (10-min duration required to administer tDCS as opposed to ~ 2 min in previous studies as a “break”). As such, we tested these two possibilities with a subsequent experiment in which subjects received 2-min or 10-min delay between the 2 runs (with no tDCS) or 10 min of sham-tDCS. Only sham-tDCS resulted in improved performance thus these data add to a growing literature suggesting that tDCS has powerful placebo effect that may occur even in the absence of active cortical modulation.

Surface Orientation Discrimination Activates Caudal and Anterior Intraparietal Sulcus in Humans: An Event-Related fMRI Study

2001 ◽  
Vol 85 (3) ◽  
pp. 1309-1314 ◽  
Author(s):  
Elisa Shikata ◽  
Farsin Hamzei ◽  
Volkmar Glauche ◽  
René Knab ◽  
Christian Dettmers ◽  
...  
Keyword(s):  
Discrimination Task ◽  
Parietal Lobe ◽  
Functional Neuroimaging ◽  
3D Structure ◽  
Color Discrimination ◽  
Surface Orientation ◽  
Linear Perspective ◽  
Orientation Discrimination ◽  
Intraparietal Sulcus ◽  
Functional Neuroanatomy

Perception of surface orientation is an essential step for the reconstruction of the three-dimensional (3D) structure of an object. Human lesion and functional neuroimaging studies have demonstrated the importance of the parietal lobe in this task. In primate single-unit studies, neurons in the caudal part of the intraparietal sulcus (CIP) were found to be active during the extraction of surface orientation through monocular (two-dimensional) cues such as texture gradients and linear perspective as well as binocular (3D) cues such as disparity gradient and orientation disparity. We used event-related fMRI to study the functional neuroanatomy of surface orientation discrimination using stimuli with monocular depth cues in six volunteers. Both posterior (CIP) and anterior (AIP) areas within the intraparietal sulcus showed a stronger activation during surface orientation as compared with a control (color discrimination) task using identical stimuli. Furthermore, the signal changes in CIP showed a greater performance effect than those in AIP, suggesting that CIP is tightly linked to the discrimination task.

P199 tES effects on a visual orientation discrimination task: Noise induction in a non-linear system

2017 ◽  
Vol 128 (3) ◽  
pp. e111-e112
Author(s):  
A. Zazio ◽  
M. Bortoletto ◽  
A. Fertonani ◽  
C. Pirulli ◽  
C. Miniussi
Keyword(s):  
Linear System ◽  
Discrimination Task ◽  
Orientation Discrimination ◽  
Visual Orientation ◽  
Non Linear ◽  
Non Linear System

3D Laser Scanning at Church Hole, Creswell Crags

2007 ◽  
Author(s):  
Alistair Carty
Keyword(s):  
Laser Scanning ◽  
Three Dimensional ◽  
Point Of View ◽  
3D Laser Scanning ◽  
Natural Processes ◽  
Planar Surfaces ◽  
3D Surface ◽  
Third Dimension ◽  
Visualization Techniques

The process of recording in situ archaeological art can be a time-consuming and complex task, especially on inaccessible and non-planar surfaces such as those found in Church Hole, Creswell Crags. There are considerable challenges to the recorder, including the accurate positioning and fixing of survey frames, the physical discomfort of sitting, crouching, or even lying down for long periods of time in cramped surroundings, and, ultimately, the difficulty in interpreting the panels to enable accurate recording. Furthermore, the more accurate forms of traditional recording include the taking of rubbings of the carvings, a process known to increase the potential of damage to already fragile artworks. 3D laser scanning offers solutions to most of these problems by quickly producing a highly dense fully three-dimensional surface map of the art which can be studied in more conducive circumstances by researchers at a later date. Furthermore, powerful visualization techniques can be applied to the 3D surface map to extract and enhance detail that might be virtually invisible to the naked eye. Over-arching the visualization and interpretational aspects of 3D laser scanning is the potential to use the acquired 3D surface map to monitor any change in the surface through repeated scanning over a period of time. This technique is suitable for detecting minute differences in the surface over time, including both erosion due to natural processes or vandalism and accretion through build-up of deposits on the surface of the art. The most complex aspect of three-dimensional recording, no matter what the subject matter, is that of the third dimension. People have an almost schizophrenic way of looking at the world. For example, if you were to place two identical objects a distance apart, it is simple to state that one object is further away than the other due to our perception of depth and the ability to walk around the two objects. However, if you were to take a photograph or make a drawing of the scene from one point of view, it becomes difficult to tell whether two identical objects are placed some distance apart, or if two differently sized objects sit beside one another. The three-dimensionality of the scene is now lost and is available by inference only.

Integration of Perspective and Disparity Cues in Surface-Orientation–Selective Neurons of Area CIP

2001 ◽  
Vol 86 (6) ◽  
pp. 2856-2867 ◽  
Author(s):  
Ken-Ichiro Tsutsui ◽  
Min Jiang ◽  
Kazuo Yara ◽  
Hideo Sakata ◽  
Masato Taira
Keyword(s):  
Single Unit ◽  
Binocular Disparity ◽  
Three Dimensional ◽  
Surface Orientation ◽  
Linear Perspective ◽  
Orientation Tuning ◽  
Single Unit Recording ◽  
Unit Recording ◽  
Depth Cues ◽  
3D Surface

We investigated the effects of linear perspective and binocular disparity, as monocular and binocular depth cues, respectively, on the response of surface-orientation–selective (SOS) neurons in the caudal part of the lateral bank of the intraparietal sulcus (area CIP). During the single-unit recording, monkeys were required to perform the delayed-matching-to-sample (successive same/different discrimination) of discriminating surface orientation in stereoscopic computer graphics. Of 211 visually responsive neurons, 66 were intensively tested using the solid-figure stereogram (SFS) of a square plate with both disparity and perspective cues (D+P condition), and 62 of these were identified as SOS neurons for responding selectively to the orientation of stimuli. All these neurons were further tested using a solid figure with perspective cues alone (P-only condition), and 58% (36/62) of these showed selective response to the orientation of the stimuli. Of the 62 SOS neurons, 35 neurons were also tested using SFS with disparity cues alone (D-only condition) in addition to the D+P and P-only conditions. We classified these 35 neurons into four groups by comparing the response selectivity under the P-only and D-only conditions. More than one-half of these (19/35) were sensitive to both perspective and disparity cues (DP neurons), and nearly one-third (11/35) of these were sensitive to disparity cues alone (D neurons), but a few (2/35) were sensitive to perspective cues alone (P neurons). The remaining (3/35) neurons exhibited orientation selectivity only when both cues were present. In DP neurons, the preferred orientation under the D+P condition was correlated to those under the D-only and P-only conditions, and the response magnitude under the D+P condition was greater than those under the D-only and P-only conditions, suggesting the integration of both cues for the perception of surface orientation. However, in these neurons, the orientation tuning sharpness under the D+P and D-only conditions was higher than that under the P-only condition, suggesting the dominance of disparity cues. After the single-unit recording experiments, muscimol was microinjected into the recording site to temporarily inactivate its function. In all three effective cases out of six microinjection experiments, discrimination of a three-dimensional (3D) surface orientation was impaired when disparity cues alone were present. In only one effective case, when a relatively large amount of muscimol was microinjected, discrimination of a 3D surface orientation was impaired even when both disparity and perspective cues were present. These results suggest that linear perspective is an important cue for representations of a 3D surface of SOS neurons in area CIP, although it is less effective than binocular disparity, and that both of these depth cues may be integrated in area CIP for the perception of surface orientation in depth.

scholarly journals Representation of 3-D surface orientation by velocity and disparity gradient cues in area MT

2012 ◽  
Vol 107 (8) ◽  
pp. 2109-2122 ◽  
Author(s):  
Takahisa M. Sanada ◽  
Jerry D. Nguyenkim ◽  
Gregory C. DeAngelis
Keyword(s):  
Neural Coding ◽  
Three Dimensional ◽  
Surface Orientation ◽  
Intermediate Step ◽  
Single Neurons ◽  
Area Mt ◽  
Integration Rule ◽  
Spatial Gradients ◽  
Planar Surfaces ◽  
The Individual

Neural coding of the three-dimensional (3-D) orientation of planar surface patches may be an important intermediate step in constructing representations of complex 3-D surface structure. Spatial gradients of binocular disparity, image velocity, and texture provide potent cues to the 3-D orientation (tilt and slant) of planar surfaces. Previous studies have described neurons in both dorsal and ventral stream areas that are selective for surface tilt based on one or more of these gradient cues. However, relatively little is known about whether single neurons provide consistent information about surface orientation from multiple gradient cues. Moreover, it is unclear how neural responses to combinations of surface orientation cues are related to responses to the individual cues. We measured responses of middle temporal (MT) neurons to random dot stimuli that simulated planar surfaces at a variety of tilts and slants. Four cue conditions were tested: disparity, velocity, and texture gradients alone, as well as all three gradient cues combined. Many neurons showed robust tuning for surface tilt based on disparity and velocity gradients, with relatively little selectivity for texture gradients. Some neurons showed consistent tilt preferences for disparity and velocity cues, whereas others showed large discrepancies. Responses to the combined stimulus were generally well described as a weighted linear sum of responses to the individual cues, even when disparity and velocity preferences were discrepant. These findings suggest that area MT contains a rudimentary representation of 3-D surface orientation based on multiple cues, with single neurons implementing a simple cue integration rule.

scholarly journals Functional links between sensory representations, choice activity, and sensorimotor associations in parietal cortex

eLife ◽  
2020 ◽  
Vol 9 ◽  
Author(s):  
Ting-Yu Chang ◽  
Raymond Doudlah ◽  
Byounghoon Kim ◽  
Adhira Sunkara ◽  
Lowell W Thompson ◽  
...  
Keyword(s):  
Parietal Cortex ◽  
Three Dimensional ◽  
Visual Representations ◽  
Orientation Discrimination ◽  
Object Representations ◽  
Visually Guided ◽  
Related Activity ◽  
Sensorimotor Transformations ◽  
Saccade Direction ◽  
3D Representations

Three-dimensional (3D) representations of the environment are often critical for selecting actions that achieve desired goals. The success of these goal-directed actions relies on 3D sensorimotor transformations that are experience-dependent. Here we investigated the relationships between the robustness of 3D visual representations, choice-related activity, and motor-related activity in parietal cortex. Macaque monkeys performed an eight-alternative 3D orientation discrimination task and a visually guided saccade task while we recorded from the caudal intraparietal area using laminar probes. We found that neurons with more robust 3D visual representations preferentially carried choice-related activity. Following the onset of choice-related activity, the robustness of the 3D representations further increased for those neurons. We additionally found that 3D orientation and saccade direction preferences aligned, particularly for neurons with choice-related activity, reflecting an experience-dependent sensorimotor association. These findings reveal previously unrecognized links between the fidelity of ecologically relevant object representations, choice-related activity, and motor-related activity.

scholarly journals Choice activity stabilizes sensory representations and mediates sensorimotor associations in parietal cortex

2020 ◽  
Author(s):  
Ting-Yu Chang ◽  
Raymond Doudlah ◽  
Byounghoon Kim ◽  
Adhira Sunkara ◽  
Meghan Lowe ◽  
...  
Keyword(s):  
Parietal Cortex ◽  
Three Dimensional ◽  
Orientation Discrimination ◽  
Object Representations ◽  
Visually Guided ◽  
Related Activity ◽  
Spatial Features ◽  
Saccade Direction ◽  
Saccade Task ◽  
3D Representations

AbstractSelecting actions which achieve desired goals often requires three-dimensional (3D) representations of the environment. Because the sensory epithelia cannot directly encode the world’s 3D spatial features, sensory signals must be converted into 3D representations. Here we investigated the relationships between the quality of 3D visual representations, choice-related activity, and motor-related activity in the parietal cortex of macaque monkeys using an eight-alternative 3D orientation discrimination task, visually guided saccade task, and laminar probe recordings. We found that choice activity was preferentially carried by caudal intraparietal area neurons with more robust 3D representations. Choice activity further stabilized the 3D representations, rather than attenuating information not directly relevant to the behavioral task (nuisance variables). An experience-dependent, sensorimotor association additionally aligned sensory and saccade direction preferences, particularly for neurons with choice activity. These findings reveal novel roles for choice activity in improving the fidelity of ecologically relevant object representations and mediating sensorimotor associations.

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