scholarly journals Time-dependent competition between habitual and goal-directed response preparation

2017 ◽  
Author(s):  
Robert M Hardwick ◽  
Alexander D Forrence ◽  
John W Krakauer ◽  
Adrian M Haith
Keyword(s):  
Time Course ◽  
Stimulus Presentation ◽  
Time Dependent ◽  
Response Preparation ◽  
Movement Initiation ◽  
Control Behavior ◽  
Association Task ◽  
Habitual Behavior ◽  
Human Participants ◽  
Habitual Responses

AbstractConverging evidence indicates that separate goal-directed and habitual systems compete to control behavior1. However, it has proven difficult to reliably induce habitual behavior in human participants2–4. We reasoned that habits may be present in the form of habitually prepared responses, but are overridden by goal-directed processes, preventing their overt expression. Here we show that latent habits can be unmasked by limiting the time participants have to respond to a stimulus. Participants trained for 4 days on a visuomotor association task. By continuously varying the time allowed to prepare responses, we found that the probability of expressing a learned habit followed a stereotyped time course, peaking 300-600ms after stimulus presentation. This time course was captured by a computational model of response preparation in which habitual responses are automatically prepared at short latency, but are replaced by goal-directed responses at longer latency. A more extensive period of practice (20 days) led to increased habit expression by reducing the average time of movement initiation. These findings refine our understanding of habits, and show that practice can influence habitual behavior in distinct ways: by promoting habit formation, and by modulating the likelihood of habit expression.

scholarly journals A comparison of visuomotor cue integration strategies for object placement and prehension

2009 ◽  
Vol 26 (1) ◽  
pp. 63-72 ◽  
Author(s):  
HAL S. GREENWALD ◽  
DAVID C. KNILL
Keyword(s):  
Motor Control ◽  
Visual Cues ◽  
Time Course ◽  
Three Dimensional ◽  
Stimulus Presentation ◽  
Task Demands ◽  
Cue Integration ◽  
Movement Initiation ◽  
Initial Stimulus ◽  
Integration Strategies

AbstractVisual cue integration strategies are known to depend on cue reliability and how rapidly the visual system processes incoming information. We investigated whether these strategies also depend on differences in the information demands for different natural tasks. Using two common goal-oriented tasks, prehension and object placement, we determined whether monocular and binocular information influence estimates of three-dimensional (3D) orientation differently depending on task demands. Both tasks rely on accurate 3D orientation estimates, but 3D position is potentially more important for grasping. Subjects placed an object on or picked up a disc in a virtual environment. On some trials, the monocular cues (aspect ratio and texture compression) and binocular cues (e.g., binocular disparity) suggested slightly different 3D orientations for the disc; these conflicts either were present upon initial stimulus presentation or were introduced after movement initiation, which allowed us to quantify how information from the cues accumulated over time. We analyzed the time-varying orientations of subjects’ fingers in the grasping task and those of the object in the object placement task to quantify how different visual cues influenced motor control. In the first experiment, different subjects performed each task, and those performing the grasping task relied on binocular information more when orienting their hands than those performing the object placement task. When subjects in the second experiment performed both tasks in interleaved sessions, binocular cues were still more influential during grasping than object placement, and the different cue integration strategies observed for each task in isolation were maintained. In both experiments, the temporal analyses showed that subjects processed binocular information faster than monocular information, but task demands did not affect the time course of cue processing. How one uses visual cues for motor control depends on the task being performed, although how quickly the information is processed appears to be task invariant.

Pulsatile Pressure and Flow in the Skeletal Muscle Microcirculation

1990 ◽  
Vol 112 (4) ◽  
pp. 437-443 ◽  
Author(s):  
Shou-Yan Lee ◽  
G. W. Schmid-Scho¨nbein
Keyword(s):  
Skeletal Muscle ◽  
Arterial Pressure ◽  
Time Course ◽  
Venous Pressure ◽  
Time Dependent ◽  
Physiological Importance ◽  
Pulsatile Pressure ◽  
Theoretical Predictions ◽  
Skeletal Muscle Microcirculation

Although blood flow in the microcirculation of the rat skeletal muscle has negligible inertia forces with very low Reynolds number and Womersley parameter, time-dependent pressure and flow variations can be observed. Such phenomena include, for example, arterial flow overshoot following a step arterial pressure, a gradual arterial pressure reduction for a step flow, or hysteresis between pressure and flow when a pulsatile pressure is applied. Arterial and venous flows do not follow the same time course during such transients. A theoretical analysis is presented for these phenomena using a microvessel with distensible viscoelastic walls and purely viscous flow subject to time variant arterial pressures. The results indicate that the vessel distensibility plays an important role in such time-dependent microvascular flow and the effects are of central physiological importance during normal muscle perfusion. In-vivo whole organ pressure-flow data in the dilated rat gracilis muscle agree in the time course with the theoretical predictions. Hemodynamic impedances of the skeletal muscle microcirculation are investigated for small arterial and venous pressure amplitudes superimposed on an initial steady flow and pressure drop along the vessel.

Decoupling countermands nonselective response inhibition during selective stopping

2021 ◽  
Author(s):  
Corey George Wadsley ◽  
John Cirillo ◽  
Arne Nieuwenhuys ◽  
Winston D Byblow
Keyword(s):  
Response Inhibition ◽  
Interference Effect ◽  
Complex Form ◽  
Functional Coupling ◽  
Response Preparation ◽  
Response Delay ◽  
Healthy Human ◽  
Human Participants ◽  
Goal Directed Behavior ◽  
Effector Response

Response inhibition is essential for goal-directed behavior within dynamic environments. Selective stopping is a complex form of response inhibition where only part of a multi-effector response must be cancelled. A substantial response delay emerges on unstopped effectors when a cued effector is successfully stopped. This stopping-interference effect is indicative of nonselective response inhibition during selective stopping which may, in-part, be a consequence of functional coupling. The present study examined selective stopping of (de)coupled bimanual responses in healthy human participants of either sex. Participants performed synchronous and asynchronous versions of an anticipatory stop-signal paradigm across two sessions while mu (µ) and beta (β) rhythm were measured with electroencephalography. Results showed that responses were behaviorally decoupled during asynchronous go trials and the extent of response asynchrony was associated with lateralized sensorimotor µ and β desynchronization during response preparation. Selective stopping produced a stopping-interference effect and was marked by a nonselective increase and subsequent rebound in prefrontal and sensorimotor β. In support of the coupling account, stopping-interference was smaller during selective stopping of asynchronous responses, and negatively associated with the magnitude of decoupling. However, the increase in sensorimotor β during selective stopping was equivalent between the stopped and unstopped hand irrespective of response synchrony. Overall, the findings demonstrate that decoupling facilitates selective stopping after a global pause process and emphasizes the importance of considering the influence of both the go and stop context when investigating response inhibition.

Time-dependent progression of neurogenic lower urinary tract dysfunction after spinal cord injury in the mouse model

2021 ◽  
Author(s):  
Tetsuichi Saito ◽  
Daisuke Gotoh ◽  
Naoki Wada ◽  
Pradeep Tyagi ◽  
Tomonori Minagawa ◽  
...  
Keyword(s):  
Spinal Cord ◽  
Spinal Cord Injury ◽  
Time Course ◽  
Time Dependent ◽  
Lower Urinary Tract Dysfunction ◽  
Emg Activity ◽  
Mrna Levels ◽  
Mechanosensitive Channels ◽  
Reduction Time ◽  
Cord Injury

This study evaluated the time-course changes in bladder and external urinary sphincter (EUS) activity as well as the expression of mechanosensitive channels in lumbosacral dorsal root ganglia (DRG) after spinal cord injury (SCI). Female C57BL/6N mice in the SCI group underwent transection of the Th8/9 spinal cord. Spinal intact mice and SCI mice at 2, 4 and 6 weeks post SCI were evaluated by single-filling cystometry and EUS-electromyography (EMG). In another set of mice, the bladder and L6-S1 DRG were harvested for protein and mRNA analyses. In SCI mice, non-voiding contractions was confirmed at 2 weeks post-SCI, and did not increase over time to 6 weeks. In 2-weeks SCI mice, EUS-EMG measurements revealed detrusor-sphincter dyssynergia (DSD), but periodic EMG reductions during bladder contraction were hardly observed. At 4 weeks, SCI mice showed increases of EMG activity reduction time with increased voiding efficiency (VE). At 6 weeks, SCI mice exhibited a further increase in EMG reduction time. RT-PCR of L6-S1 DRG showed increased mRNA levels of TRPV1 and ASIC1-3 in SCI mice with a decrease of ASIC2-3 at 6 weeks compared to 4 weeks whereas Piezo2 showed a slow increase at 6 weeks. Protein assay showed the SCI-induced overexpression of bladder BDNF with a time-dependent decrease post SCI. These results indicate that detrusor overactivity is established in the early phase whereas DSD is completed later at 4 weeks with an improvement at 6 weeks post SCI, and that mechanosensitive channels may be involved in the time-dependent changes.

Modulation of medial temporal lobe activity in epilepsy patients with hippocampal sclerosis during verbal working memory

2009 ◽  
Vol 15 (4) ◽  
pp. 536-546 ◽  
Author(s):  
PABLO CAMPO ◽  
FERNANDO MAESTÚ ◽  
IRENE GARCÍA-MORALES ◽  
ANTONIO GIL-NAGEL ◽  
BRYAN STRANGE ◽  
...  
Keyword(s):  
Working Memory ◽  
Episodic Memory ◽  
Temporal Lobe ◽  
Medial Temporal Lobe ◽  
Time Course ◽  
Hippocampal Sclerosis ◽  
Stimulus Presentation ◽  
Verbal Working Memory ◽  
Compelling Evidence ◽  
Electrophysiological Studies

AbstractIt has been traditionally assumed that medial temporal lobe (MTL) is not required for working memory (WM). However, animal lesion and electrophysiological studies and human neuropsychological and neuroimaging studies have provided increasing evidences of a critical involvement of MTL in WM. Based on previous findings, the central aim of this study was to investigate the contribution of the MTL to verbal WM encoding. Here, we used magnetoencephalography (MEG) to compare the patterns of MTL activation of 9 epilepsy patients suffering from left hippocampal sclerosis with those of 10 healthy matched controls while they performed a verbal WM task. MEG recordings allow detailed tracking of the time course of MTL activation. We observed impaired WM performance associated with changes in the dynamics of MTL activity in epilepsy patients. Specifically, whereas patients showed decreased activity in damaged MTL, activity in the contralateral MTL was enhanced, an effect that became significant in the 600- to 700-ms interval after stimulus presentation. These findings strongly support the crucial contribution of MTL to verbal WM encoding and provide compelling evidence for the proposal that MTL contributes to both episodic memory and WM. Whether this pattern is signaling reorganization or a normal use of a damaged structure is discussed. (JINS, 2009, 15, 536–546.)

Time-dependent platelet-vessel wall interactions induced by intestinal ischemia-reperfusion

2003 ◽  
Vol 284 (6) ◽  
pp. G1027-G1033 ◽  
Author(s):  
Dianne Cooper ◽  
Keith D. Chitman ◽  
Matthew C. Williams ◽  
D. Neil Granger
Keyword(s):  
Time Course ◽  
Platelet Adhesion ◽  
Ischemia Reperfusion ◽  
Time Dependent ◽  
Wild Type ◽  
Blocking Antibody ◽  
Low Levels ◽  
Intestinal Ischemia Reperfusion ◽  
Deficient Mice ◽  
Platelet Depletion

Platelets roll and adhere in venules exposed to ischemia-reperfusion (I/R). This platelet-endothelial adhesion may influence leukocyte trafficking because platelet depletion decreases I/R-induced leukocyte emigration. The objectives of this study were 1) to assess the time course of platelet adhesion in the small bowel after I/R and 2) to determine the roles of endothelial and/or platelet P-selectin and P-selectin glycoprotein ligand-1 (PSGL-1) in this adhesion. The adhesion of fluorescently labeled platelets was monitored by intravital microscopy in postcapillary venules exposed to 45 min of ischemia and up to 8 h of reperfusion. Peak platelet adhesion was observed at 4 h of reperfusion. To assess the contributions of platelet and endothelial cell P-selectin, platelets from P-selectin-deficient and wild-type mice were infused into wild-type and P-selectin-deficient mice, respectively. Platelets deficient in P-selectin exhibited low levels of adhesion comparable to that in sham-treated animals. In the absence of endothelial P-selectin, platelet adhesion was reduced by 65%. Treatment with a blocking antibody against PSGL-1 reduced adhesion by 57%. These results indicate that I/R induces a time-dependent platelet-endothelial adhesion response in postcapillary venules via a mechanism that involves PSGL-1 and both platelet and endothelial P-selectin, with platelet P-selectin playing a greater role.

scholarly journals Binding of Delta1, Jagged1, and Jagged2 to Notch2 Rapidly Induces Cleavage, Nuclear Translocation, and Hyperphosphorylation of Notch2

2000 ◽  
Vol 20 (18) ◽  
pp. 6913-6922 ◽  
Author(s):  
Kiyoshi Shimizu ◽  
Shigeru Chiba ◽  
Noriko Hosoya ◽  
Keiki Kumano ◽  
Toshiki Saito ◽  
...  
Keyword(s):  
Ligand Binding ◽  
Notch Signaling ◽  
Time Course ◽  
Nuclear Translocation ◽  
Reporter Genes ◽  
Time Dependent ◽  
Dependent Manner ◽  
Notch Receptors ◽  
Notch Protein ◽  
Membrane Spanning

ABSTRACT Delta1, Jagged1, and Jagged2, commonly designated Delta/Serrate/LAG-2 (DSL) proteins, are known to be ligands for Notch1. However, it has been less understood whether they are ligands for Notch receptors other than Notch1. Meanwhile, ligand-induced cleavage and nuclear translocation of the Notch protein are considered to be fundamental for Notch signaling, yet direct observation of the behavior of the Notch molecule after ligand binding, including cleavage and nuclear translocation, has been lacking. In this report, we investigated these issues for Notch2. All of the three DSL proteins bound to endogenous Notch2 on the surface of BaF3 cells, although characteristics of Jagged2 for binding to Notch2 apparently differed from that of Delta1 and Jagged1. After binding, the three DSL proteins induced cleavage of the membrane-spanning subunit of Notch2 (Notch2TM), which occurred within 15 min. In a simultaneous time course, the cleaved fragment of Notch2TMwas translocated into the nucleus. Interestingly, the cleaved Notch2 fragment was hyperphosphorylated also in a time-dependent manner. Finally, binding of DSL proteins to Notch2 also activated the transcription of reporter genes driven by the RBP-Jκ-responsive promoter. Together, these data indicate that all of these DSL proteins function as ligands for Notch2. Moreover, the findings of rapid cleavage, nuclear translocation, and phosphorylation of Notch2 after ligand binding facilitate the understanding of the Notch signaling.

Trajectory-Based Tissue Engineering for Cartilage Repair: Correlation Between Maturation Rate and Integration Capacity

2013 ◽  
Author(s):  
Matthew B. Fisher ◽  
Nicole Söegaard ◽  
David R. Steinberg ◽  
Robert L. Mauck
Keyword(s):  
Tissue Engineering ◽  
Time Course ◽  
Biomechanical Properties ◽  
Time Dependent ◽  
In Vivo Studies ◽  
Surgical Approaches ◽  
General Hypothesis ◽  
Vitro Assay

Given the limitations of current surgical approaches to treat articular cartilage injuries, tissue engineering (TE) approaches have been aggressively pursued over the past two decades. Although biochemical and biomechanical properties on the order of the native tissue have been achieved (1–5), several in-vitro and in-vivo studies indicate that increased tissue maturity may limit the ability of engineered constructs to remodel and integrate with surrounding cartilage, although results are highly variable (2, 6–8). Thus, “static” measures of construct maturity (e.g. compressive modulus) upon implantation may not be the best indicators of in-vivo success, which likely requires implanted TE constructs to mature, remodel, and integrate with the host over time to achieve optimal results. We recently introduced the concept of “trajectory-based” tissue engineering (TB-TE), which is based on the general hypothesis that time-dependent increases in construct maturation in-vitro prior to implantation (i.e. positive rates) may provide a better predictor of in-vivo success (9). As a first step in evaluating this concept, in the current study we hypothesized that time-dependent increases in equilibrium modulus (a metric of growth) would be correlated to ability of constructs to integrate to cartilage using an in-vitro assay. To test this hypothesis, the current objective was to determine and model the time course of maturation of TE constructs during in-vitro culture and to assess the ability of these constructs to integrate to cartilage at various points during their maturation.

Time-dependent systolic and diastolic function in mice overexpressing calcineurin

2003 ◽  
Vol 284 (2) ◽  
pp. H425-H430 ◽  
Author(s):  
L. M. Semeniuk ◽  
D. L. Severson ◽  
A. J. Kryski ◽  
S. L. Swirp ◽  
J. D. Molkentin ◽  
...  
Keyword(s):  
Sudden Death ◽  
Diastolic Dysfunction ◽  
Cardiac Death ◽  
Time Course ◽  
Left Ventricular ◽  
Time Dependent ◽  
Wild Type ◽  
Lv Mass ◽  
Age Dependent ◽  
Systolic And Diastolic Function

Echocardiograms have been assessed only at 56 days in mice overexpressing calcineurin (CN mice). Age-dependent echocardiographic changes were evaluated because the development of sudden death is time dependent. Because cyclosporin A (CsA) reverses hypertrophy in CN mice, its effects on the time course of the development of sudden death and cardiac dysfunction were assessed. In wild-type (WT) mice, the left ventricular (LV) internal end-diastolic dimension (LVIDd) increased and the LV mass index (LVMI) decreased with age. In CN mice, two distinct phases of pathophysiology were found. After 14 days, in CN mice, the LVIDd and LVMI were significantly increased, but sudden death had not occurred. After 28 days, in CN mice, relative dilation of the left ventricle occurred, whereas the LVMI decreased. Sudden death developed during progressive dilation associated with systolic and diastolic dysfunction. CsA treatment reversed hypertrophy in CN mice but did not reverse systolic and diastolic dysfunction and exaggerated sudden death. Sudden cardiac death was associated with systolic and diastolic dysfunction but was not related to isolated cardiac hypertrophy in CN mice.

Children's Cognitive Representations of Musical Pitch

1994 ◽  
Vol 12 (1) ◽  
pp. 27-55 ◽  
Author(s):  
Alexandra Lamont ◽  
Ian Cross
Keyword(s):  
Time Course ◽  
The Other ◽  
Time Dependent ◽  
Age Group ◽  
Cognitive Representations ◽  
Single Sex ◽  
Musical Pitch ◽  
Temporal Factors ◽  
Tonal Hierarchy

Several recent investigations of children's cognition of musical pitch have examined the nature of children's sensitivity to the "tonal hierarchy" identified by Krumhansl (1990a). These studies presented children with musical "contexts," asking them to make judgments about subsequent pitches, and have produced strikingly divergent results. Factors of age and of type of "musical material used in context" appear to play significant roles in determining subjects' sensitivities. This paper describes two experiments that examine the time course of the development of children's cognitive representations of pitch relations, taking into account the contributions made to such representations by structural and by temporal factors (following West & Fryer, 1990). A probetone technique was used with two contrasting context types, one being a "typical" cadential sequence and the other consisting of different randomizations of the diatonic collection. This experiment was conducted on 285 children ranging between 6 and 11 years old, from two different single-sex schools. The results were further investigated in a gameplaying experiment—using chime bars— with children from each age group represented in the first experiment. These experiments appear to indicate that children's early representations of pitch relations are remarkably stable and that development may take the form of an increasing sensitivity to time-dependent characteristics of the musical surface leading to an internalization of the tonal hierarchy. Despite the different methodologies used here, results are broadly in line with those suggested by Krumhansl and Keil ( 1982), although children's representations of musical pitch as exhibited here appear to be more sophisticated than would be implied in that study.

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