Accessory stimulation in the time course of visuomotor information processing: Stimulus intensity effects on reaction time and response force

2005 ◽  
Vol 120 (1) ◽  
pp. 1-18 ◽  
Author(s):  
Jutta Stahl ◽  
Thomas H. Rammsayer
Keyword(s):  
Information Processing ◽  
Reaction Time ◽  
Stimulus Intensity ◽  
Time Course ◽  
Response Force

A Clock Paradigm to Study the Relationship between Expectancy and Response Force

1993 ◽  
Vol 77 (1) ◽  
pp. 163-174 ◽  
Author(s):  
Piotr Jaskowski ◽  
Rolf Verleger
Keyword(s):  
Reaction Time ◽  
Stimulus Intensity ◽  
Response Force ◽  
Warning Stimulus ◽  
The Moment ◽  
The Relationship

It has recently been demonstrated that the force used by subjects to press a response key depends on stimulation conditions such as stimulus intensity, foreperiod, etc. We performed an experiment in which response force and reaction time were measured as a function of expectancy. In contrast to the paradigms used so far, we manipulated expectancy without using warning stimuli by applying a so-called “clock-paradigm.” It enabled us to avoid the possible arousing effect of the warning stimulus. Both reaction time and response force depended on expectancy. The results suggest that response force was not affected by arousal or activation but was affected by preparatory state at the moment of making a response.

Calcium Dynamics and Compartmentalization in Leech Neurons

2005 ◽  
Vol 94 (6) ◽  
pp. 4430-4440 ◽  
Author(s):  
Sofija Andjelic ◽  
Vincent Torre
Keyword(s):  
Information Processing ◽  
Action Potential ◽  
Action Potentials ◽  
Time Course ◽  
Ccd Camera ◽  
Calcium Dynamics ◽  
Single Action ◽  
Single Action Potential ◽  
Calcium Indicator ◽  
Mechanosensory Neurons

Calcium dynamics in leech neurons were studied using a fast CCD camera. Fluorescence changes (Δ F/ F) of the membrane impermeable calcium indicator Oregon Green were measured. The dye was pressure injected into the soma of neurons under investigation. Δ F/ F caused by a single action potential (AP) in mechanosensory neurons had approximately the same amplitude and time course in the soma and in distal processes. By contrast, in other neurons such as the Anterior Pagoda neuron, the Annulus Erector motoneuron, the L motoneuron, and other motoneurons, APs evoked by passing depolarizing current in the soma produced much larger fluorescence changes in distal processes than in the soma. When APs were evoked by stimulating one distal axon through the root, Δ F/ F was large in all distal processes but very small in the soma. Our results show a clear compartmentalization of calcium dynamics in most leech neurons in which the soma does not give propagating action potentials. In such cells, the soma, while not excitable, can affect information processing by modulating the sites of origin and conduction of AP propagation in distal excitable processes.

Quantitative studies of the reactions to horizontal angular accelerations in axolotls. I. The head-turning reflexes of normal animals

1977 ◽  
Vol 66 (1) ◽  
pp. 1-14
Author(s):  
K. Brandle
Keyword(s):  
Stimulus Intensity ◽  
Time Course ◽  
Maximum Velocity ◽  
Afferent Input ◽  
Head Turning ◽  
Mean Values ◽  
Quantitative Studies ◽  
The Mean ◽  
Negative Exponential ◽  
Total Angle

1. Artifically metamorphosed axolotls were exposed to both brief (impulse) and long-lasting horizontal angular accelerations on a turn-table. The animals responded with a head-turning reaction. 2. The general course of the reaction to impulse acceleration was independent of stimulus intensity. The velocity of the head movement first increased to a maximum exponentially and then decreased in a negative exponential manner. Stimulus intensity had a linear relationship to the mean maximum velocity and mean total angle covered by head-turning. The average velocity-time curves at various stimulus intensities differed only by a velocity factor. 3. During long-lasting constant accelerations the velocity of the head-turning increased to a maximum velocity in a sigmoid time-course and then decreased, first to a constant velocity, and then further. Mean values of the maximum velocity were correlated linearly with the stimulus intensity. 4. It was concluded that the head-turning reflexes in axolotls do not agree with the accepted movements of the vertebrate cupula and therefore are not a simple ‘copy’ of the afferent input. It is also suggested that the reaction threshold differes from that for the labyrinthine input.

Effects of Information Processing Requirements on Reaction Time of the Eye

1978 ◽  
Vol 22 (1) ◽  
pp. 287-291 ◽  
Author(s):  
Christine L. Nelson ◽  
Robert M. London ◽  
Gordon H. Robinson
Keyword(s):  
Information Processing ◽  
Reaction Time ◽  
Motor Response ◽  
Task Type ◽  
Head Movements ◽  
Central Control ◽  
Control Task ◽  
Target Direction ◽  
Response Systems ◽  
Subject Differences

This experiment measured eye reaction time as a function of presence or absence of a central control task, type of command, and knowledge of target direction prior to command. It was found that eye reaction time was greater when a subject was involved in a central tracking task than when he was not; it was greater when the command was symbolic than when it was spatial; and it was longer when the target direction was unknown prior to command. These variables also interacted, so that the effect of unknown target direction was greater with a symbolic command. Results of this experiment also showed that subjects sometimes used an initial compensatory pattern of eye-head movements. There were large inter-subject differences, but use of compensation generally increased with complexity of centrally located information which required processing. It thus appears that reaction time of the eye responds to information processing variables in a manner similar to other motor response systems.

Reduced information processing speed as primum movens for cognitive decline in MS

2014 ◽  
Vol 21 (1) ◽  
pp. 83-91 ◽  
Author(s):  
Jeroen Van Schependom ◽  
Marie B D’hooghe ◽  
Krista Cleynhens ◽  
Mieke D’hooge ◽  
Marie-Claire Haelewyck ◽  
...  
Keyword(s):  
Cognitive Impairment ◽  
Information Processing ◽  
Processing Speed ◽  
Time Course ◽  
Age At Onset ◽  
Memory Task ◽  
Cognitive Domain ◽  
Information Processing Speed ◽  
Survival Curves ◽  
Cross Sectional

Background: Cognitive impairment affects half of the multiple sclerosis (MS) patient population and is an important contributor to patients’ daily activities. Most cognitive impairment studies in MS are, however, cross-sectional or/and focused on the early disease stages. Objective: We aim to assess the time course of decline of different cognitive domains. Methods: We collected neuropsychological data on 514 MS patients to construct Kaplan-Meier survival curves of the tests included in the Neuropsychological Screening Battery for MS (NSBMS) and the Symbol Digit Modalities Test (SDMT). Cox-proportional hazard models were constructed to examine the influence of MS onset type, age at onset, gender, depression and level of education on the time course, expressed as age or disease. Results: Survival curves of tests focusing on information processing speed (IPS) declined significantly faster than tests with less specific demands of IPS. Median age for pathological decline was 56.2 years (95% CI: 54.4–58.2) on the SDMT and 63.9 years (95% CI: 60–66.9) on the CLTR, a memory task. Conclusion: In conclusion, IPS is the cognitive domain not only most widely affected by MS but it is also the first cognitive deficit to emerge in MS.

scholarly journals Systemic Effects of Selection History on Learned Ignoring

2021 ◽  
Author(s):  
Andy Jeesu Kim ◽  
Brian A. Anderson
Keyword(s):  
Eye Movements ◽  
Reaction Time ◽  
Young Adult ◽  
High Probability ◽  
Time Course ◽  
Systemic Effects ◽  
Reduced Frequency ◽  
Selection History ◽  
Adult Participants ◽  
Task Irrelevant

Despite our best intentions, physically salient but entirely task-irrelevant stimuli can sometimes capture our attention. With learning, it is possible to more efficiently ignore such stimuli, although specifically how the visual system accomplishes this remains to be clarified. Using a sample of young-adult participants, we examined the time course of eye movements to targets and distractors. We replicate a reduced frequency of eye movements to the distractor when appearing in a location at which distractors are frequently encountered. This reduction was observed even for the earliest saccades, when selection tends to be most stimulus-driven. When the distractor appeared at the high-probability location, saccadic reaction time was slowed specifically for distractor-going saccades, suggesting a slowing of priority accumulation at this location. In the event that the distractor was fixated, disengagement from the distractor was also faster when it appeared in the high-probability location. Both proactive and reactive mechanisms of distractor suppression work together to minimize attentional capture by frequently-encountered distractors.

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