Egocentric Action in Early Infancy: Spatial Frames of Reference for Saccades

1997 ◽  
Vol 8 (3) ◽  
pp. 224-230 ◽  
Author(s):  
Rick O. Gilmore ◽  
Mark H. Johnson
Keyword(s):  
Spatial Information ◽  
Visual Space ◽  
Frames Of Reference ◽  
Saccade Target ◽  
Visually Guided ◽  
Retinal Position ◽  
Position Information ◽  
Visual Spatial ◽  
Visually Guided Action ◽  
Spatial Frames Of Reference

The extent to which infants combine visual (i e, retinal position) and nonvisual (eye or head position) spatial information in planning saccades relates to the issue of what spatial frame or frames of reference influence early visually guided action We explored this question by testing infants from 4 to 6 months of age on the double-step saccade paradigm, which has shown that adults combine visual and eye position information into an egocentric (head- or trunk-centered) representation of saccade target locations In contrast, our results imply that infants depend on a simple retinocentric representation at age 4 months, but by 6 months use egocentric representations more often to control saccade planning Shifts in the representation of visual space for this simple sensorimotor behavior may index maturation in cortical circuitry devoted to visual spatial processing in general

Adaptation in the Auditory Space Map of the Barn Owl

2006 ◽  
Vol 96 (2) ◽  
pp. 813-825 ◽  
Author(s):  
Yoram Gutfreund ◽  
Eric I. Knudsen
Keyword(s):  
Inferior Colliculus ◽  
Spatial Information ◽  
Short Term Memory ◽  
Threshold Level ◽  
Central Nucleus ◽  
Visually Guided ◽  
Auditory Space ◽  
Visual Spatial ◽  
Stimulus Offset ◽  
A Site

Auditory neurons in the owl’s external nucleus of the inferior colliculus (ICX) integrate information across frequency channels to create a map of auditory space. This study describes a powerful, sound-driven adaptation of unit responsiveness in the ICX and explores the implications of this adaptation for sensory processing. Adaptation in the ICX was analyzed by presenting lightly anesthetized owls with sequential pairs of dichotic noise bursts. Adaptation occurred in response even to weak, threshold-level sounds and remained strong for more than 100 ms after stimulus offset. Stimulation by one range of sound frequencies caused adaptation that generalized across the entire broad range of frequencies to which these units responded. Identical stimuli were used to test adaptation in the lateral shell of the central nucleus of the inferior colliculus (ICCls), which provides input directly to the ICX. Compared with ICX adaptation, adaptation in the ICCls was substantially weaker, shorter lasting, and far more frequency specific, suggesting that part of the adaptation observed in the ICX was attributable to processes resident to the ICX. The sharp tuning of ICX neurons to space, along with their broad tuning to frequency, allows ICX adaptation to preserve a representation of stimulus location, regardless of the frequency content of the sound. The ICX is known to be a site of visually guided auditory map plasticity. ICX adaptation could play a role in this cross-modal plasticity by providing a short-term memory of the representation of auditory localization cues that could be compared with later-arriving, visual–spatial information from bimodal stimuli.

The Main Sequence of Human Optokinetic Afternystagmus (OKAN)

2009 ◽  
Vol 101 (6) ◽  
pp. 2889-2897 ◽  
Author(s):  
Andre Kaminiarz ◽  
Kerstin Königs ◽  
Frank Bremmer
Keyword(s):  
Neural Networks ◽  
Eye Movements ◽  
Main Sequence ◽  
Critical Role ◽  
Saccade Target ◽  
Control Mechanisms ◽  
Visually Guided ◽  
Background Characteristics ◽  
Optokinetic Afternystagmus

Different types of fast eye movements, including saccades and fast phases of optokinetic nystagmus (OKN) and optokinetic afternystagmus (OKAN), are coded by only partially overlapping neural networks. This is a likely cause for the differences that have been reported for the dynamic parameters of fast eye movements. The dependence of two of these parameters—peak velocity and duration—on saccadic amplitude has been termed “main sequence.” The main sequence of OKAN fast phases has not yet been analyzed. These eye movements are unique in that they are generated by purely subcortical control mechanisms and that they occur in complete darkness. In this study, we recorded fast phases of OKAN and OKN as well as visually guided and spontaneous saccades under identical background conditions because background characteristics have been reported to influence the main sequence of saccades. Our data clearly show that fast phases of OKAN and OKN differ with respect to their main sequence. OKAN fast phases were characterized by their lower peak velocities and longer durations compared with those of OKN fast phases. Furthermore we found that the main sequence of spontaneous saccades depends heavily on background characteristics, with saccades in darkness being slower and lasting longer. On the contrary, the main sequence of visually guided saccades depended on background characteristics only very slightly. This implies that the existence of a visual saccade target largely cancels out the effect of background luminance. Our data underline the critical role of environmental conditions (light vs. darkness), behavioral tasks (e.g., spontaneous vs. visually guided), and the underlying neural networks for the exact spatiotemporal characteristics of fast eye movements.

Contextual Modulation of Central Thalamic Delay-Period Activity: Representation of Visual and Saccadic Goals

2004 ◽  
Vol 91 (6) ◽  
pp. 2628-2648 ◽  
Author(s):  
Melanie T. Wyder ◽  
Dino P. Massoglia ◽  
Terrence R. Stanford
Keyword(s):  
Spatial Information ◽  
Delay Period ◽  
Visually Guided ◽  
Physical Stimulus ◽  
Behavioral Context ◽  
Thalamic Neurons ◽  
Contextual Modulation ◽  
Sensory Stimuli ◽  
Central Thalamus ◽  
Combine Information

This study examines the influence of behavioral context on the activity of visuomotor neurons in primate central thalamus. Neurons that combine information about sensory stimuli and their behavioral relevance are thought to contribute to the decision mechanisms that link specific stimuli to specific responses. We reported in a previous study that neurons in central thalamus carry spatial information throughout the instructed delay period of a visually guided delayed saccade task. The goal of the current study was to determine whether the delay-period activity of thalamic neurons is modulated by behavioral context. Single neurons were evaluated during performance of visually guided and memory-guided variants of a saccadic choice task in which a cue designated the response field stimulus as the target of a rewarded saccade or as an irrelevant distracter. The relative influence of the physical stimulus and context on delay-period activity suggested a minimum of 3 neural groups. Some neurons signaled the locations of visible stimuli regardless of behavioral relevance. Other neurons preferentially signaled the locations of current saccadic goals and did so even in the absence of the physical stimulus. A third group signaled only the locations of currently visible saccadic goals. For the latter 2 groups, activity was the product of both stimulus and context, suggesting that central thalamic neurons play a role in the context-dependent linkage of sensory signals and saccadic commands. More generally, these data suggest that the anatomical substrate of sensorimotor decision making may include the cortico-subcortical loops for which central thalamus serves as the penultimate synapse.

Functional properties of monkey caudate neurons. III. Activities related to expectation of target and reward

1989 ◽  
Vol 61 (4) ◽  
pp. 814-832 ◽  
Author(s):  
O. Hikosaka ◽  
M. Sakamoto ◽  
S. Usui
Keyword(s):  
Spatial Information ◽  
Target Location ◽  
Hand Movement ◽  
Visual Fixation ◽  
Saccade Target ◽  
Tonic Activity ◽  
Sustained Activity ◽  
Neural Activities ◽  
Reward Expectancy ◽  
Mouth Movement

1. The present paper reports complex neural activities in the monkey caudate nucleus that precede and anticipate visual stimuli and reward in learned visuomotor paradigms. These activities were revealed typically in the delayed saccade task in which memory and anticipation were required. We classified these activities according to their relationships to the task. 2. Activity related to expectation of a cue (n = 46) preceded the presentation of a spot of light (target cue) that signified the future location of saccade target. When the target cue was delayed, the activity was prolonged accordingly. The same spot of light was preceded by no activity if it acted as a distracting stimulus. 3. The sustained activity (n = 80) was a tonic discharge starting after the target cue as if holding the spatial information. 4. The activity related to expectation of target (n = 109) preceded the appearance of the target whose location was cued previously. It started with or after a saccade to the cued target location and ended with the appearance of the target. The activity was greater when the target was expected to appear in the contralateral visual field. 5. The activity related to expectation of reward (n = 57) preceded a task-specific reward. It started with the appearance of the final target and ended with the reward. In most cases, the activity was nonselective for how the monkey obtained the reward, i.e., by visual fixation only, by a saccade, or by a hand movement. The activity was dependent partly on visual fixation. 6. A few neurons showed tonic activity selectively before lever release and are thus considered to be related to the preparation of hand movements. 7. The activity related to breaking fixation (n = 33) occurred phasically if the monkey broke fixation, aborting the trial. 8. Activity related to reward (n = 104) was a phasic discharge that occurred before or after a reward of water was delivered. The activity was not simply related to a specific movement involved in the reward-obtaining behavior (eye, hand, or mouth movement). 9. Fixation-related activity (n = 72) was tonic activity continuing as long as the monkey attentively fixated a spot of light. It was dependent on reward expectancy in most cases. 10. The present results, together with those in the preceding papers, indicate that the activities of individual caudate neurons--sensory, motor, or cognitive--are dependent on specific contexts of learned behavior.(ABSTRACT TRUNCATED AT 400 WORDS)

scholarly journals Non-communicable disease surveillance in India using Geographical Information System-An experience from Punjab

2021 ◽  
Vol 33 (3) ◽  
pp. 506-511
Author(s):  
Sheikh Mohd Saleem ◽  
Chaitnya Aggarwal ◽  
Om Prakash Bera ◽  
Radhika Rana ◽  
Gurmandeep Singh ◽  
...  
Keyword(s):  
Information System ◽  
Spatial Information ◽  
Communicable Diseases ◽  
Project Planning ◽  
Geographical Information ◽  
Non Communicable Diseases ◽  
Visual Spatial ◽  
Catchment Areas ◽  
Health Related ◽  
Space Data

"Geographic information system (GIS) collects various kinds of data based on the geographic relationship across space." Data in GIS is stored to visualize, analyze, and interpret geographic data to learn about an area, an ongoing project, site planning, business, health economics and health-related surveys and information. GIS has evolved from ancient disease maps to 3D digital maps and continues to grow even today. The visual-spatial mapping of the data has given us an insight into different diseases ranging from diarrhea, pneumonia to non-communicable diseases like diabetes mellitus, hypertension, cardiovascular diseases, or risk factors like obesity, being overweight, etc. All in a while, this information has highlighted health-related issues and knowledge about these in a contemporary manner worldwide. Researchers, scientists, and administrators use GIS for research project planning, execution, and disease management. Cases of diseases in a specific area or region, the number of hospitals, roads, waterways, and health catchment areas are examples of spatially referenced data that can be captured and easily presented using GIS. Currently, we are facing an epidemic of non-communicable diseases, and a powerful tool like GIS can be used efficiently in such a situation. GIS can provide a powerful and robust framework for effectively monitoring and identifying the leading cause behind such diseases.  GIS, which provides a spatial viewpoint regarding the disease spectrum, pattern, and distribution, is of particular importance in this area and helps better understand disease transmission dynamics and spatial determinants. The use of GIS in public health will be a practical approach for surveillance, monitoring, planning, optimization, and service delivery of health resources to the people at large. The GIS platform can link environmental and spatial information with the disease itself, which makes it an asset in disease control progression all over the globe.

No evidence for visuomotor priming in a visually guided action task

2005 ◽  
Vol 43 (2) ◽  
pp. 216-226 ◽  
Author(s):  
Jonathan S. Cant ◽  
David A. Westwood ◽  
Kenneth F. Valyear ◽  
Melvyn A. Goodale
Keyword(s):  
Visually Guided ◽  
Visually Guided Action

Quantitative Assessment of the Timing and Tuning of Visual-Related, Saccade-Related, and Delay Period Activity in Primate Central Thalamus

2003 ◽  
Vol 90 (3) ◽  
pp. 2029-2052 ◽  
Author(s):  
Melanie T. Wyder ◽  
Dino P. Massoglia ◽  
Terrence R. Stanford
Keyword(s):  
Posterior Parietal Cortex ◽  
Spatial Information ◽  
Delay Period ◽  
Population Variation ◽  
Visually Guided ◽  
Directed Movement ◽  
Posterior Parietal ◽  
Saccade Task ◽  
Behavioral Requirement ◽  
Central Thalamus

This study investigates the visuomotor properties of several nuclei within primate central thalamus. These nuclei, which might be considered components of an oculomotor thalamus (OcTh), are found within and at the borders of the internal medullary lamina. These nuclei have extensive anatomical links to numerous cortical and subcortical visuomotor areas including the frontal eye fields, supplementary eye fields, prefrontal cortex, posterior parietal cortex, caudate, and substantia nigra pars reticulata. Previous single-unit recordings have shown that neurons in OcTh respond during self-paced spontaneous saccades and to visual stimuli in the absence of any specific behavioral requirement, but a thorough account of the activity of these areas in association with voluntary, goal-directed movement is lacking. We recorded activity from single neurons in primate central thalamus during performance of a visually guided delayed saccade task. The sample consisted primarily of neurons from the centrolateral and paracentral intralaminar nuclei and paralaminar regions of the ventral anterior and ventral lateral nuclei. Neurons responsive to sensory, delay, and motor phases of the task were observed in each region, with many neurons modulated during multiple task periods. Across the population, variation in the quality and timing of saccade-contingent activity suggested participation in functions ranging from generating a saccade (presaccadic) to registering its consequences (e.g., efference copy). Finally, many neurons were found to carry spatial information during the delay period, suggesting a role for central thalamus in higher-order aspects of visuomotor control.

scholarly journals Parallel updating and weighting of multiple spatial maps for visual stability during whole body motion

2015 ◽  
Vol 114 (6) ◽  
pp. 3211-3219 ◽  
Author(s):  
J. J. Tramper ◽  
W. P. Medendorp
Keyword(s):  
Reference Frame ◽  
Reference Frames ◽  
Spatial Information ◽  
Target Location ◽  
Visual Space ◽  
Body Motion ◽  
Whole Body ◽  
Spatial Representations ◽  
Integration Model ◽  
The Brain

It is known that the brain uses multiple reference frames to code spatial information, including eye-centered and body-centered frames. When we move our body in space, these internal representations are no longer in register with external space, unless they are actively updated. Whether the brain updates multiple spatial representations in parallel, or whether it restricts its updating mechanisms to a single reference frame from which other representations are constructed, remains an open question. We developed an optimal integration model to simulate the updating of visual space across body motion in multiple or single reference frames. To test this model, we designed an experiment in which participants had to remember the location of a briefly presented target while being translated sideways. The behavioral responses were in agreement with a model that uses a combination of eye- and body-centered representations, weighted according to the reliability in which the target location is stored and updated in each reference frame. Our findings suggest that the brain simultaneously updates multiple spatial representations across body motion. Because both representations are kept in sync, they can be optimally combined to provide a more precise estimate of visual locations in space than based on single-frame updating mechanisms.

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