scholarly journals Spatiotemporal coding in the macaque supplementary eye fields: landmark influence in the target-to-gaze transformation

2020 ◽  
Author(s):  
Vishal Bharmauria ◽  
Amirsaman Sajad ◽  
Xiaogang Yan ◽  
Hongying Wang ◽  
John Douglas Crawford
Keyword(s):  
Motor Neurons ◽  
Visual Signals ◽  
Visual Response ◽  
The Gaze ◽  
Directed Action ◽  
Visual Motor ◽  
Integrated Response ◽  
High Level ◽  
Supplementary Eye Fields ◽  
Gaze Position

ABSTRACTEye-centered (egocentric) and landmark-centered (allocentric) visual signals influence spatial cognition, navigation and goal-directed action, but the neural mechanisms that integrate these signals for motor control are poorly understood. A likely candidate for ego / allocentric integration in the gaze control system is the supplementary eye fields (SEF), a mediofrontal structure with high-level ‘executive’ functions, spatially tuned visual / motor response fields, and reciprocal projections with the frontal eye fields (FEF). To test this hypothesis, we trained two head-unrestrained animals to saccade toward a remembered visual target in the presence of a visual landmark that shifted during the delay, causing gaze end points to shift partially in the same direction. 256 SEF neurons were recorded, including 68 with spatially tuned response fields. Model fits to the latter established that, like the FEF and superior colliculus, spatially tuned SEF responses primarily showed an egocentric (eye-centered) target-to-gaze position transformation. However, the landmark shift influenced this default egocentric transformation: during the delay, motor neurons (with no visual response) showed a transient but unintegrated shift (i.e., not correlated with the target-to-gaze transformation), whereas during the saccade-related burst visuomotor neurons showed an integrated shift (i.e., correlated with the target-to-gaze transformation). This differed from our simultaneous FEF recordings (Bharmauria et al., 2020), which showed a transient shift in visuomotor neurons, followed by an integrated response in all motor responses. Based on these findings and past literature, we propose that prefrontal cortex incorporates landmark-centered information into a distributed, eye-centered target-to-gaze transformation through a reciprocal prefrontal circuit.

scholarly journals Landmark-Centered Coding in Frontal Cortex Visual Responses

2020 ◽  
Author(s):  
Adrian Schütz ◽  
Vishal Bharmauria ◽  
Xiaogang Yan ◽  
Hongying Wang ◽  
Frank Bremmer ◽  
...  
Keyword(s):  
Frontal Cortex ◽  
Visual Space ◽  
List Type ◽  
Visual Response ◽  
Visual Responses ◽  
Visual Landmarks ◽  
Specific Target ◽  
Visual Coding ◽  
The Gaze ◽  
Landmark Configuration

SummaryVisual landmarks influence spatial cognition [1–3], navigation [4,5] and goal-directed behavior [6–8], but their influence on visual coding in sensorimotor systems is poorly understood [6,9–11]. We hypothesized that visual responses in frontal cortex control gaze areas encode potential targets in an intermediate gaze-centered / landmark-centered reference frame that might depend on specific target-landmark configurations rather than a global mechanism. We tested this hypothesis by recording neural activity in the frontal eye fields (FEF) and supplementary eye fields (SEF) while head-unrestrained macaques engaged in a memory-delay gaze task. Visual response fields (the area of visual space where targets modulate activity) were tested for each neuron in the presence of a background landmark placed at one of four oblique configurations relative to the target stimulus. 102 of 312 FEF and 43 of 256 SEF neurons showed spatially tuned response fields in this task. We then fit these data against a mathematical continuum between a gaze-centered model and a landmark-centered model. When we pooled data across the entire dataset for each neuron, our response field fits did not deviate significantly from the gaze-centered model. However, when we fit response fields separately for each target-landmark configuration, the best fits shifted (mean 37% / 40%) toward landmark-centered coding in FEF / SEF respectively. This confirmed an intermediate gaze / landmark-centered mechanism dependent on local (configuration-dependent) interactions. Overall, these data show that external landmarks influence prefrontal visual responses, likely helping to stabilize gaze goals in the presence of variable eye and head orientations.HighlightsPrefrontal visual responses recorded in the presence of visual landmarksResponse fields showed intermediate gaze / landmark-centered organizationThis influence depended on specific target-landmark configurations

scholarly journals Visual-motor transformations at the Neuronal Level in the Gaze System

2017 ◽  
Vol 17 (10) ◽  
pp. 378
Author(s):  
J. Douglas Crawford
Keyword(s):  
The Gaze ◽  
Visual Motor

scholarly journals Nuclear Phospho-SOD1 Protects DNA from Oxidative Stress Damage in Amyotrophic Lateral Sclerosis

2019 ◽  
Vol 8 (5) ◽  
pp. 729 ◽  
Author(s):  
Matteo Bordoni ◽  
Orietta Pansarasa ◽  
Michela Dell’Orco ◽  
Valeria Crippa ◽  
Stella Gagliardi ◽  
...  
Keyword(s):  
Oxidative Stress ◽  
Dna Damage ◽  
Amyotrophic Lateral Sclerosis ◽  
Oxidative Damage ◽  
Motor Neurons ◽  
Mononuclear Cells ◽  
Sporadic Amyotrophic Lateral Sclerosis ◽  
Peripheral Blood Mononuclear ◽  
High Level ◽  
Lateral Sclerosis

We already demonstrated that in peripheral blood mononuclear cells (PBMCs) of sporadic amyotrophic lateral sclerosis (sALS) patients, superoxide dismutase 1 (SOD1) was present in an aggregated form in the cytoplasmic compartment. Here, we investigated the possible effect of soluble SOD1 decrease and its consequent aggregation. We found an increase in DNA damage in patients PBMCs characterized by a high level of aggregated SOD1, while we found no DNA damage in PBMCs with normal soluble SOD1. We found an activation of ataxia-telangiectasia-mutated (ATM)/Chk2 and ATM and Rad3-related (ATR)/Chk1 DNA damage response pathways, which lead to phosphorylation of SOD1. Moreover, data showed that phosphorylation allows SOD1 to shift from the cytoplasm to the nucleus, protecting DNA from oxidative damage. Such pathway was finally confirmed in our cellular model. Our data lead us to suppose that in a sub-group of patients this physiologic pathway is non-functional, leading to an accumulation of DNA damage that causes the death of particularly susceptible cells, like motor neurons. In conclusion, during oxidative stress SOD1 is phosphorylated by Chk2 leading to its translocation in the nuclear compartment, in which SOD1 protects DNA from oxidative damage. This pathway, inefficient in sALS patients, could represent an innovative therapeutic target.

An Enquiry into the Determinants of a Differentiation between Elderly “Organic” and “Non-Organic” Psychiatric Patients on the Bender Gestalt Test

1957 ◽  
Vol 103 (431) ◽  
pp. 364-374 ◽  
Author(s):  
M. B. Shapiro ◽  
Jack Field ◽  
F. Post
Keyword(s):  
Psychiatric Patients ◽  
General Purpose ◽  
The Other ◽  
Level Of Confidence ◽  
Visual Motor ◽  
High Level ◽  
Bender Gestalt Test ◽  
And Control

In a previous study, Shapiro, Post, Lofving and Inglis (10) found that a modified version of the Bender Visual-Motor Gestalt Test differentiated, at a high level of confidence, three groups of elderly psychiatric patients: brain-damaged patients, functionals and a group of doubtful diagnosis. This level of confidence was far higher than that of any of the other 24 tests used. Furthermore, a number of recent studies have shown that the Bender test differentiated Organic from non-Organic subjects (2, 4, 6, 7, 8). In our own Department Yates (13) found significant differences on measures of the reproductions of other designs between Organics and Functionals. In view of these findings we decided to investigate our own results further. Our general purpose was to measure and control some of the variables appearing relevant in the performance of the task and in this way make possible testable explanations for the results.

Contribution of Head Movement to Gaze Command Coding in Monkey Frontal Cortex and Superior Colliculus

2003 ◽  
Vol 90 (4) ◽  
pp. 2770-2776 ◽  
Author(s):  
Julio C. Martinez-Trujillo ◽  
Eliana M. Klier ◽  
Hongying Wang ◽  
J. Douglas Crawford
Keyword(s):  
Superior Colliculus ◽  
Neural Control ◽  
Significant Contribution ◽  
Head Movements ◽  
Vector Model ◽  
Gaze Control ◽  
Gaze Shift ◽  
Visual Model ◽  
The Gaze ◽  
Supplementary Eye Fields

Most of what we know about the neural control of gaze comes from experiments in head-fixed animals, but several “head-free” studies have suggested that fixing the head dramatically alters the apparent gaze command. We directly investigated this issue by quantitatively comparing head-fixed and head-free gaze trajectories evoked by electrically stimulating 52 sites in the superior colliculus (SC) of two monkeys and 23 sites in the supplementary eye fields (SEF) of two other monkeys. We found that head movements made a significant contribution to gaze shifts evoked from both neural structures. In the majority of the stimulated sites, average gaze amplitude was significantly larger and individual gaze trajectories were significantly less convergent in space with the head free to move. Our results are consistent with the hypothesis that head-fixed stimulation only reveals the oculomotor component of the gaze shift, not the true, planned goal of the movement. One implication of this finding is that when comparing stimulation data against popular gaze control models, freeing the head shifts the apparent coding of gaze away from a “spatial code” toward a simpler visual model in the SC and toward an eye-centered or fixed-vector model representation in the SEF.

scholarly journals A neural locus for spatial-frequency specific saccadic suppression in visual-motor neurons of the primate superior colliculus

2017 ◽  
Vol 117 (4) ◽  
pp. 1657-1673 ◽  
Author(s):  
Chih-Yang Chen ◽  
Ziad M. Hafed
Keyword(s):  
Spatial Frequency ◽  
Superior Colliculus ◽  
Motor Neurons ◽  
Motor Command ◽  
Visual Sensitivity ◽  
Saccadic Suppression ◽  
Behavioral Measure ◽  
Visual Responses ◽  
Spatial Frequencies ◽  
Visual Motor

Saccades cause rapid retinal-image shifts that go perceptually unnoticed several times per second. The mechanisms for saccadic suppression have been controversial, in part because of sparse understanding of neural substrates. In this study we uncovered an unexpectedly specific neural locus for spatial frequency-specific saccadic suppression in the superior colliculus (SC). We first developed a sensitive behavioral measure of suppression in two macaque monkeys, demonstrating selectivity to low spatial frequencies similar to that observed in earlier behavioral studies. We then investigated visual responses in either purely visual SC neurons or anatomically deeper visual motor neurons, which are also involved in saccade generation commands. Surprisingly, visual motor neurons showed the strongest visual suppression, and the suppression was dependent on spatial frequency, as in behavior. Most importantly, suppression selectivity for spatial frequency in visual motor neurons was highly predictive of behavioral suppression effects in each individual animal, with our recorded population explaining up to ~74% of behavioral variance even on completely different experimental sessions. Visual SC neurons had mild suppression, which was unselective for spatial frequency and thus only explained up to ~48% of behavioral variance. In terms of spatial frequency-specific saccadic suppression, our results run contrary to predictions that may be associated with a hypothesized SC saccadic suppression mechanism, in which a motor command in the visual motor and motor neurons is first relayed to the more superficial purely visual neurons, to suppress them and to then potentially be fed back to cortex. Instead, an extraretinal modulatory signal mediating spatial-frequency-specific suppression may already be established in visual motor neurons. NEW & NOTEWORTHY Saccades, which repeatedly realign the line of sight, introduce spurious signals in retinal images that normally go unnoticed. In part, this happens because of perisaccadic suppression of visual sensitivity, which is known to depend on spatial frequency. We discovered that a specific subtype of superior colliculus (SC) neurons demonstrates spatial-frequency-dependent suppression. Curiously, it is the neurons that help mediate the saccadic command itself that exhibit such suppression, and not the purely visual ones.

Visual and motor functions in graphically gifted savants

1994 ◽  
Vol 24 (3) ◽  
pp. 673-680 ◽  
Author(s):  
B. Hermelin ◽  
L. Pring ◽  
L. Heavey
Keyword(s):  
Motor Skills ◽  
Building Blocks ◽  
Intellectual Impairment ◽  
Motor Functions ◽  
Mental Handicap ◽  
Visual Motor ◽  
Motor Operation ◽  
High Level ◽  
The Relationship ◽  
Perceptual Motor Skills

SynopsisSavant artists represent a conundrum to our understanding of the nature of high level specific talents as well as to the concept of general intellectual impairment. In the present paper, we are particularly concerned with the relationship between general perceptual-motor functions in relation to drawing aptitude. Drawing is by definition a perceptual-motor operation, yet mental handicap tends to be associated with some degree of impairment in this area. The following study seeks to isolate such aspects of performance on general perceptual-motor skills that might be associated with drawing ability, and may thus be regarded as building blocks underlying the manifestation of graphic talent. The results are discussed in terms of the relationships between graphic talent, non-verbal intelligence and visual-motor functions.

Communicating attention

1995 ◽  
Vol 3 (2) ◽  
pp. 199-223 ◽  
Author(s):  
Boris M. Velichkovsky
Keyword(s):  
Eye Movements ◽  
Problem Solving ◽  
Data Transfer ◽  
Visual Environment ◽  
The Gaze ◽  
Working Space ◽  
Eye Fixations ◽  
Distributed Problem Solving ◽  
Position Data ◽  
Gaze Position

The results of two experiments, in which participants solved constructive tasks of the puzzle type, are reported. The tasks were solved by two partners who shared the same visual environment hut whose knowledge of the situation and ability to change it to reach a solution were different. One of the partners — the "expert" — knew the solution in detail but had no means of acting on this information. The second partner — the "novice " — could act to achieve the goal, but knew very little about the solution. The partners were free to communicate verbally. In one third of the trials of the first experiment, in addition to verbal communication, the eye fixations of the expert were projected onto the working space of the novice. In another condition the expert could use a mouse to show the novice relevant parts of the task configuration. Both methods of facilitating the 'joint attention' state of the partners improved their performance. The nature of the dialogues as well as the parameters of the eye movements changed. In the second experiment the direction of the gaze-position data transfer was reversed, from the novice to the expert. This also led to a significant increase in the efficiency of the distributed problem solving.

scholarly journals Habits as action sequences: hierarchical action control and changes in outcome value

2014 ◽  
Vol 369 (1655) ◽  
pp. 20130482 ◽  
Author(s):  
Amir Dezfouli ◽  
Nura W. Lingawi ◽  
Bernard W. Balleine
Keyword(s):  
Decision Making ◽  
Real Life ◽  
Neural Structure ◽  
Action Sequence ◽  
Action Sequences ◽  
Directed Action ◽  
Sequence Boundaries ◽  
High Level ◽  
Step Over ◽  
Two Sides

Goal-directed action involves making high-level choices that are implemented using previously acquired action sequences to attain desired goals. Such a hierarchical schema is necessary for goal-directed actions to be scalable to real-life situations, but results in decision-making that is less flexible than when action sequences are unfolded and the decision-maker deliberates step-by-step over the outcome of each individual action. In particular, from this perspective, the offline revaluation of any outcomes that fall within action sequence boundaries will be invisible to the high-level planner resulting in decisions that are insensitive to such changes. Here, within the context of a two-stage decision-making task, we demonstrate that this property can explain the emergence of habits. Next, we show how this hierarchical account explains the insensitivity of over-trained actions to changes in outcome value. Finally, we provide new data that show that, under extended extinction conditions, habitual behaviour can revert to goal-directed control, presumably as a consequence of decomposing action sequences into single actions. This hierarchical view suggests that the development of action sequences and the insensitivity of actions to changes in outcome value are essentially two sides of the same coin, explaining why these two aspects of automatic behaviour involve a shared neural structure.

scholarly journals Visual Spatial Summation in Macaque Geniculocortical Afferents

2006 ◽  
Vol 96 (6) ◽  
pp. 3474-3484 ◽  
Author(s):  
Michael P. Sceniak ◽  
Soumya Chatterjee ◽  
Edward M. Callaway
Keyword(s):  
Spatial Summation ◽  
Afferent Input ◽  
Visual Signals ◽  
Spatial Extent ◽  
Visual Response ◽  
Surround Suppression ◽  
Spatial Spread ◽  
Cortical Input ◽  
Visual Spatial ◽  
Spread Of Excitation

The spatial summation properties of visual signals were analyzed for geniculocortical afferents in the primary visual cortex (V1) of anesthetized paralyzed macaque monkeys. Afferent input responses were recorded extracellularly during cortical inactivation through superfusion of the cortex with muscimol, allowing investigation of lateral geniculate nucleus of the thalamus (LGN) cell properties in the absence of cortical feedback. Responses from afferent inputs were classified as magno-, parvo-, or koniocellular based on anatomical organization within the cortex, established through histological reconstructions, and visual response wavelength sensitivity. More than 80% of afferents showed strong surround suppression [suppression index (SI) >0.5] and 14% showed negligible surround suppression (SI < 0.2). Afferent responses with weak and strong surround suppression were found throughout cortical input layers 4C and 4A. High-contrast estimates of the spatial extent of the classical surround were similar to the nonclassical surround. The classical and nonclassical surrounds were, on average, 1.5-fold larger than the excitatory center. Unlike neurons within V1, the spatial extent of excitatory summation for geniculocortical afferents was contrast invariant. Nonclassical surround suppression showed slight contrast dependency with estimates larger (20%) at lower contrasts and stronger at higher contrasts (13%). Surround suppression is inherent in cortical input responses and likely derives from lateral inhibition in either the LGN or retina. Although surround suppression within afferent responses increases slightly with contrast, the spatial spread of excitation remains fixed with contrast. This argues for distinct mechanisms of action for contrast-dependent modulation in cortical and subcortical responses.

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