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Jeyarajan G, Ayaz A, Herold F, Zou L, Heath M. A single bout of aerobic exercise does not alter inhibitory control preparatory set cerebral hemodynamics: Evidence from the antisaccade task. Brain Cogn 2024; 179:106182. [PMID: 38824809 DOI: 10.1016/j.bandc.2024.106182] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2024] [Revised: 05/21/2024] [Accepted: 05/21/2024] [Indexed: 06/04/2024]
Abstract
A single bout of exercise improves executive function (EF) and is a benefit - in part -attributed to an exercise-mediated increase in cerebral blood flow enhancing neural efficiency. Limited work has used an event-related protocol to examine postexercise changes in preparatory phase cerebral hemodynamics for an EF task. This is salient given the neural efficiency hypothesis' assertion that improved EF is related to decreased brain activity. Here, event-related transcranial Doppler ultrasound was used to measure pro- (saccade to target) and antisaccades (saccade mirror-symmetrical target) preparatory phase middle cerebral artery velocity (MCAv) prior to and immediately after 15-min of aerobic exercise. Antisaccades produced longer reaction times (RT) and an increased preparatory phase MCAv than prosaccades - a result attributed to greater EF neural activity for antisaccades. Antisaccades selectively produced a postexercise RT reduction (ps < 0.01); however, antisaccade preparatory phase MCAv did not vary from pre- to postexercise (p=0.53) and did not correlate with the antisaccade RT benefit (p = 0.31). Accordingly, results provide no evidence that improved neural efficiency indexed via functional hyperemia is linked to a postexercise EF behavioural benefit. Instead, results support an evolving view that an EF benefit represents the additive interplay between interdependent exercise-mediated neurophysiological changes.
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Affiliation(s)
- Gianna Jeyarajan
- School of Kinesiology, University of Western Ontario, London, ON, Canada
| | - Azar Ayaz
- School of Kinesiology, University of Western Ontario, London, ON, Canada
| | - Fabian Herold
- Faculty of Health Sciences Brandenburg, University of Potsdam, Potsdam, Germany
| | - Liye Zou
- Body-Brain-Mind Laboratory, School of Psychology, Shenzhen University, Shenzhen, China
| | - Matthew Heath
- School of Kinesiology, University of Western Ontario, London, ON, Canada; Graduate Program in Neuroscience, Schulich School of Medicine & Dentistry, University of Western Ontario, London, ON, Canada; Canadian Centre for Activity and Aging, University of Western Ontario, London, ON, Canada.
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2
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Shirzad M, Van Riesen J, Behboodpour N, Heath M. 10-min exposure to a 2.5% hypercapnic environment increases cerebral blood blow but does not impact executive function. LIFE SCIENCES IN SPACE RESEARCH 2024; 40:143-150. [PMID: 38245339 DOI: 10.1016/j.lssr.2023.07.003] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/07/2023] [Revised: 07/19/2023] [Accepted: 07/20/2023] [Indexed: 01/22/2024]
Abstract
Space travel and exploration are associated with increased ambient CO2 (i.e., a hypercapnic environment). Some work reported that the physiological changes (e.g., increased cerebral blood flow [CBF]) associated with a chronic hypercapnic environment contributes to a "space fog" that adversely impacts cognition and psychomotor performance, whereas other work reported no change or a positive change. Here, we employed the antisaccade task to evaluate whether transient exposure to a hypercapnic environment influences top-down executive function (EF). Antisaccades require a goal-directed eye movement mirror-symmetrical to a target and are an ideal tool for identifying subtle EF changes. Healthy young adults (aged 19-25 years) performed blocks of antisaccade trials prior to (i.e., pre-intervention), during (i.e., concurrent) and after (i.e., post-intervention) 10-min of breathing factional inspired CO2 (FiCO2) of 2.5% (i.e., hypercapnic condition) and during a normocapnic (i.e., control) condition. In both conditions, CBF, ventilatory and cardiorespiratory responses were measured. Results showed that the hypercapnic condition increased CBF, ventilation and end-tidal CO2 and thus demonstrated an expected physiological adaptation to increased FiCO2. Notably, however, null hypothesis and equivalence tests indicated that concurrent and post-intervention antisaccade reaction times were refractory to the hypercapnic environment; that is, transient exposure to a FiCO2 of 2.5% did not produce a real-time or lingering influence on an oculomotor-based measure of EF. Accordingly, results provide a framework that - in part - establishes the FiCO2 percentage and timeline by which high-level EF can be maintained. Future work will explore CBF and EF dynamics during chronic hypercapnic exposure as more direct proxy for the challenges of space flight and exploration.
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Affiliation(s)
- Mustafa Shirzad
- School of Kinesiology, Faculty of Health Sciences, University of Western Ontario, 1151 Richmond St, London, ON N6A 3K7, Canada
| | - James Van Riesen
- Canadian Centre for Activity and Aging, University of Western Ontario, 1201 Western Rd, London, ON N6G 1H1, Canada
| | - Nikan Behboodpour
- School of Kinesiology, Faculty of Health Sciences, University of Western Ontario, 1151 Richmond St, London, ON N6A 3K7, Canada
| | - Matthew Heath
- School of Kinesiology, Faculty of Health Sciences, University of Western Ontario, 1151 Richmond St, London, ON N6A 3K7, Canada; Canadian Centre for Activity and Aging, University of Western Ontario, 1201 Western Rd, London, ON N6G 1H1, Canada; Graduate Program in Neuroscience, University of Western Ontario, 1151 Richmond St, London, ON N6A 3K7, Canada.
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3
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Yang C, He L, Liu Y, Lin Z, Luo L, Gao S. Anti-saccades reveal impaired attention control over negative social evaluation in individuals with depressive symptoms. J Psychiatr Res 2023; 165:64-69. [PMID: 37463539 DOI: 10.1016/j.jpsychires.2023.07.016] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/08/2023] [Revised: 07/10/2023] [Accepted: 07/12/2023] [Indexed: 07/20/2023]
Abstract
Depressed individuals are excessively sensitive to negative information but blunt to positive information, which has been considered as vulnerability to depression. Here, we focused on inhibitory control over attentional bias on social evaluation in individuals with depression. We engaged individuals with and without depressive symptoms (categorized by Beck Depression Inventory-II) in a novel attention control task using positive and negative evaluative adjectives as self-referential feedback given by social others. Participants were instructed to look at sudden onset feedback targets (pro-saccade) or the mirror location of the targets (anti-saccade) when correct saccade latencies and saccade errors were collected. The two indices showed that while both groups displayed longer latencies and more errors for anti-saccade relative to pro-saccade responses depressed individuals spent more time reacting correctly and made more errors than non-depressed individuals in the anti-saccade trials and such group differences were not observed in the pro-saccade trials. Although group differences in correct anti-saccade latencies were found for both positive and negative stimuli, depressed individuals spent more time making correct anti-saccade responses to negative social feedback than to positive ones whereas non-depressed individuals featured longer correct anti-saccade latencies for positive relative to negative evaluations. Our results suggest that depressed individuals feature an impaired ability in attention control for self-referential evaluations, notably those of negative valence, shedding new light on depression-distorted self-schema and corresponding social dysfunctions.
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Affiliation(s)
- Chaoqing Yang
- School of Foreign Languages, University of Electronic Science and Technology of China, Chengdu, China
| | - Linlin He
- School of Law, Southwest University of Science and Technology, Mianyang, China
| | - Yucheng Liu
- School of Foreign Languages, University of Electronic Science and Technology of China, Chengdu, China
| | - Ziyang Lin
- Pittsburgh Institute, Sichuan University, Chengdu, China
| | - Lizhu Luo
- Brian-Body Initiative, A*STAR Research Entities (ARES), Singapore; Singapore Institute for Clinical Sciences, A*STAR Research Entities, Singapore.
| | - Shan Gao
- School of Foreign Languages, University of Electronic Science and Technology of China, Chengdu, China; The Clinical Hospital of Chengdu Brain Science Institute, MOE Key Laboratory for Neuroinformation, University of Electronic Science and Technology of China, Chengdu, China.
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Morava A, Tari B, Ahn J, Shirzad M, Heath M, Prapavessis H. Acute stress imparts a transient benefit to task-switching that is not modulated following a single bout of exercise. Front Psychol 2023; 14:1157644. [PMID: 37533726 PMCID: PMC10391836 DOI: 10.3389/fpsyg.2023.1157644] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2023] [Accepted: 06/29/2023] [Indexed: 08/04/2023] Open
Abstract
Introduction Cognitive flexibility represents a core component of executive function that promotes the ability to efficiently alternate-or "switch"-between different tasks. Literature suggests that acute stress negatively impacts cognitive flexibility, whereas a single bout of aerobic exercise supports a postexercise improvement in cognitive flexibility. Here, we examined whether a single bout of aerobic exercise attenuates a stress-induced decrement in task-switching. Materials and Methods Forty participants (age range = 19-30) completed the Trier Social Stress Test (TSST) and were randomized into separate Exercise or Rest groups entailing 20-min sessions of heavy intensity exercise (80% of heart rate maximum via cycle ergometer) or rest, respectively. Stress induction was confirmed via state anxiety and heart rate. Task-switching was assessed prior to the TSST (i.e., pre-TSST), following the TSST (i.e., post-TSST), and following Exercise and Rest interventions (i.e., post-intervention) via pro- (i.e., saccade to veridical target location) and antisaccades (i.e., saccade mirror-symmetrical to target location) arranged in an AABB task-switching paradigm. The underlying principle of the AABB paradigm suggests that when prosaccades are preceded by antisaccades (i.e., task-switch trials), the reaction times are longer compared to their task-repeat counterparts (i.e., unidirectional prosaccade switch-cost). Results As expected, the pre-TSST assessment yielded a prosaccade switch cost. Notably, post-TSST physiological measures indicated a reliable stress response and at this assessment a null prosaccade switch-cost was observed. In turn, post-intervention assessments revealed a switch-cost independent of Exercise and Rest groups. Conclusion Accordingly, the immediate effects of acute stress supported improved task-switching in young adults; however, these benefits were not modulated by a single bout of aerobic exercise.
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Affiliation(s)
- Anisa Morava
- Faculty of Health Sciences, School of Kinesiology, University of Western Ontario, London, ON, Canada
| | - Benjamin Tari
- Faculty of Health Sciences, School of Kinesiology, University of Western Ontario, London, ON, Canada
- Department of Psychiatry, University of Oxford, Oxford, United Kingdom
| | - Joshua Ahn
- Faculty of Health Sciences, School of Kinesiology, University of Western Ontario, London, ON, Canada
| | - Mustafa Shirzad
- Faculty of Health Sciences, School of Kinesiology, University of Western Ontario, London, ON, Canada
| | - Matthew Heath
- Faculty of Health Sciences, School of Kinesiology, University of Western Ontario, London, ON, Canada
- Canadian Centre for Activity and Aging, University of Western Ontario, London, ON, Canada
- Graduate Program in Neuroscience, University of Western Ontario, London, ON, Canada
| | - Harry Prapavessis
- Faculty of Health Sciences, School of Kinesiology, University of Western Ontario, London, ON, Canada
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Ahn J, Tari B, Morava A, Prapavessis H, Heath M. A single bout of passive exercise mitigates a mental fatigue-induced inhibitory control deficit. Exp Brain Res 2023:10.1007/s00221-023-06640-7. [PMID: 37256338 DOI: 10.1007/s00221-023-06640-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2023] [Accepted: 05/15/2023] [Indexed: 06/01/2023]
Abstract
Sustained cognitive effort associated with the psychomotor vigilance task (PVT) increases objective and subjective measures of mental fatigue and elicits a post-PVT inhibitory control deficit. In contrast, passive exercise wherein an individual's limbs are moved via an external force (i.e., mechanically driven cycle ergometer flywheel) provides a postexercise inhibitory control benefit linked to an exercise-based increase in cerebral blood flow. Here, we examined whether passive exercise performed concurrently with the PVT 'blunts' an inhibitory control deficit. On separate days, participants (N = 27) completed a 20 min PVT protocol (control condition) and same duration PVT protocol paired with passive cycle ergometry (passive exercise condition). Prior to (i.e., baseline), immediately after and 30 min after each condition inhibitory control was assessed via the antisaccade task. Antisaccades require a goal-directed eye movement (i.e., saccade) mirror-symmetrical to a target and provide an ideal tool for evaluating task-based changes in inhibitory control. PVT results showed that vigilance (as assessed via reaction time: RT) during control and passive exercise conditions decreased from the first to last 5 min of the protocol and increased subjective ratings of mental fatigue. As well, in the control condition, immediate (but not 30-min) post-intervention antisaccade RTs were longer than their baseline counterparts-a result evincing a transient mental fatigue-based inhibitory control deficit. For the passive exercise condition, immediate and 30-min post-intervention antisaccade RTs were shorter than their baseline counterparts and this result was linked to decreased subjective ratings of mental fatigue. Thus, passive exercise ameliorated the selective inhibitory control deficit associated with PVT-induced mental fatigue and thus provides a potential framework to reduce executive dysfunction in vigilance-demanding occupations.
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Affiliation(s)
- Joshua Ahn
- School of Kinesiology, Faculty of Health Sciences, University of Western Ontario, 1151 Richmond St, London, ON, N6A 3K7, Canada
| | - Benjamin Tari
- School of Kinesiology, Faculty of Health Sciences, University of Western Ontario, 1151 Richmond St, London, ON, N6A 3K7, Canada
| | - Anisa Morava
- School of Kinesiology, Faculty of Health Sciences, University of Western Ontario, 1151 Richmond St, London, ON, N6A 3K7, Canada
| | - Harry Prapavessis
- School of Kinesiology, Faculty of Health Sciences, University of Western Ontario, 1151 Richmond St, London, ON, N6A 3K7, Canada
| | - Matthew Heath
- School of Kinesiology, Faculty of Health Sciences, University of Western Ontario, 1151 Richmond St, London, ON, N6A 3K7, Canada.
- Canadian Centre for Activity and Aging, University of Western Ontario, 1201 Western Rd, London, ON, N6G 1H1, Canada.
- Graduate Program in Neuroscience, University of Western Ontario, 1151 Richmond St, London, ON, N6A 3K7, Canada.
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Shukla D, Heath M. A Single Bout of Exercise Provides a Persistent Benefit to Cognitive Flexibility. RESEARCH QUARTERLY FOR EXERCISE AND SPORT 2022; 93:516-527. [PMID: 34663200 DOI: 10.1080/02701367.2021.1873902] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/15/2020] [Accepted: 01/06/2021] [Indexed: 06/13/2023]
Abstract
Purpose: A single bout of exercise enhances activity within the cortical networks that support executive function. It is, however, unclear whether exercise improves each core component of executive function and for how long a putative benefit might persist. Method: In Experiment 1, participants completed 20-min of aerobic exercise (via cycle ergometer) and cognitive flexibility-a core component of executive function-was examined pre-exercise, and at immediate, 30- and 60-min post-exercise assessments. Experiment 2 entailed a non-exercise control (i.e., participants sat on the ergometer without exercising) involving the same timeline of cognitive flexibility assessment. Cognitive flexibility was measured via stimulus-driven (SD) and minimally delayed (MD) saccades arranged in an AABB paradigm. SD and MD saccades require a response at target onset and after target offset, respectively, with the latter requiring executive control. Work has shown that reaction times for a SD saccade preceded by a MD saccade are longer than when a SD saccade is preceded by its same task-type, whereas the converse switch does not influence performance (i.e., the unidirectional switch-cost). Results: Experiment 1 showed a unidirectional switch-cost at each assessment; however, the switch-cost magnitude was decreased at immediate and 30-min assessments compared to the pre- and 60-min assessments. In contrast, Experiment 2 did not elicit a change in switch-cost magnitude across the different assessments. Discussion/Conclusion: Thus, a single-bout of exercise benefitted the cognitive flexibility component of executive function in the immediate and 30-min post-exercise assessments.
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Tari B, Edgar C, Persaud P, Dalton C, Heath M. The unidirectional prosaccade switch-cost: no evidence for the passive dissipation of an oculomotor task-set inertia. Exp Brain Res 2022; 240:2061-2071. [PMID: 35727365 PMCID: PMC9211787 DOI: 10.1007/s00221-022-06394-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2022] [Accepted: 05/28/2022] [Indexed: 11/30/2022]
Abstract
Cognitive flexibility is a core component of executive function and supports the ability to ‘switch’ between different tasks. Our group has examined the cost associated with switching between a prosaccade (i.e., a standard task requiring a saccade to veridical target location) and an antisaccade (i.e., a non-standard task requiring a saccade mirror-symmetrical to veridical target) in predictable (i.e., AABB) and unpredictable (e.g., AABAB…) switching paradigms. Results have shown that reaction times (RTs) for a prosaccade preceded by an antisaccade (i.e., task-switch trial) are longer than when preceded by its same task-type (i.e., task-repeat trial), whereas RTs for antisaccade task-switch and task-repeat trials do not differ. The asymmetrical switch-cost has been attributed to an antisaccade task-set inertia that proactively delays a subsequent prosaccade (i.e., the unidirectional prosaccade switch-cost). A salient question arising from previous work is whether the antisaccade task-set inertia passively dissipates or persistently influences prosaccade RTs. Accordingly, participants completed separate AABB (i.e., A = prosaccade, B = antisaccade) task-switching conditions wherein the preparation interval for each trial was ‘short’ (1000–2000 ms; i.e., the timeframe used in previous work), ‘medium’ (3000–4000 ms) and ‘long’ (5000–6000 ms). Results demonstrated a reliable prosaccade switch-cost for each condition (ps < 0.02) and two one-sided test statistics indicated that switch cost magnitudes were within an equivalence boundary (ps < 0.05). Hence, null and equivalence tests demonstrate that an antisaccade task-set inertia does not passively dissipate and represents a temporally persistent feature of oculomotor control.
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Affiliation(s)
- Benjamin Tari
- School of Kinesiology, Faculty of Health Sciences, The University of Western Ontario, 1151 Richmond St, London, ON, N6A 3K7, Canada
| | - Chloe Edgar
- School of Kinesiology, Faculty of Health Sciences, The University of Western Ontario, 1151 Richmond St, London, ON, N6A 3K7, Canada
| | - Priyanka Persaud
- School of Kinesiology, Faculty of Health Sciences, The University of Western Ontario, 1151 Richmond St, London, ON, N6A 3K7, Canada
| | - Connor Dalton
- School of Kinesiology, Faculty of Health Sciences, The University of Western Ontario, 1151 Richmond St, London, ON, N6A 3K7, Canada
| | - Matthew Heath
- School of Kinesiology, Faculty of Health Sciences, The University of Western Ontario, 1151 Richmond St, London, ON, N6A 3K7, Canada. .,Canadian Centre for Activity and Aging, The University of Western Ontario, 1201 Western Rd, London, ON, N6G 1H1, Canada. .,Graduate Program in Neuroscience, The University of Western Ontario, 1151 Richmond St, London, ON, N6A 3K7, Canada.
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8
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Tsai CL, Chang YC, Pan CY, Wang TC, Ukropec J, Ukropcová B. Acute Effects of Different Exercise Intensities on Executive Function and Oculomotor Performance in Middle-Aged and Older Adults: Moderate-Intensity Continuous Exercise vs. High-Intensity Interval Exercise. Front Aging Neurosci 2021; 13:743479. [PMID: 34720993 PMCID: PMC8548419 DOI: 10.3389/fnagi.2021.743479] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2021] [Accepted: 09/23/2021] [Indexed: 12/02/2022] Open
Abstract
A wealth of evidence has shown that a single bout of aerobic exercise can facilitate executive function. However, none of current studies on this topic have addressed whether the magnitude of the acute-exercise benefit on executive function and oculomotor performance is influenced by different aerobic exercise modes. The present study was thus aimed toward an investigation of the acute effects of high-intensity interval exercise (HIIE) vs. moderate-intensity continuous exercise (MICE) on executive-related oculomotor performance in healthy late middle-aged and older adults. Using a within-subject design, twenty-two participants completed a single bout of 30 min of HIIE, MICE, or a non-exercise-intervention (REST) session in a counterbalanced order. The behavioral [e.g., reaction times (RTs), coefficient of variation (CV) of the RT], and oculomotor (e.g., saccade amplitude, saccade latency, and saccadic peak velocity) indices were measured when participants performed antisaccade and prosaccade tasks prior to and after an intervention mode. The results showed that a 30-min single-bout of HIIE and MICE interventions shortened the RTs in the antisaccade task, with the null effect on the CV of the RT in the late middle-aged and older adults. In terms of oculomotor metrics, although the two exercise modes could not modify the performance in terms of saccade amplitudes and saccade latencies, the participants’ saccadic peak velocities while performing the oculomotor paradigm were significantly altered only following an acute HIIE intervention. The present findings suggested that a 30-min single-bout of HIIE and MICE interventions modulated post-exercise antisaccade control on behavioral performance (e.g., RTs). Nevertheless, the HIIE relative MICE mode appears to be a more effective aerobic exercise in terms of oculomotor control (e.g., saccadic peak velocities) in late middle-aged and older adults.
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Affiliation(s)
- Chia-Liang Tsai
- Institute of Physical Education, Health and Leisure Studies, National Cheng Kung University, Tainan, Taiwan
| | - Yu-Chuan Chang
- Institute of Physical Education, Health and Leisure Studies, National Cheng Kung University, Tainan, Taiwan
| | - Chien-Yu Pan
- Department of Physical Education, National Kaohsiung Normal University, Kaohsiung, Taiwan
| | - Tsai-Chiao Wang
- Institute of Physical Education, Health and Leisure Studies, National Cheng Kung University, Tainan, Taiwan
| | - Jozef Ukropec
- Biomedical Research Center, Institute of Experimental Endocrinology, Slovak Academy of Sciences, Bratislava, Slovakia
| | - Barbara Ukropcová
- Biomedical Research Center, Institute of Experimental Endocrinology, Slovak Academy of Sciences, Bratislava, Slovakia.,Faculty of Medicine, Institute of Pathological Physiology, Comenius University, Bratislava, Slovakia
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9
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Tari B, Shirzad M, Badcock NA, Belfry GR, Heath M. 'Delaying' a saccade: Preparatory phase cortical hemodynamics evince the neural cost of response inhibition. Brain Cogn 2021; 154:105808. [PMID: 34634572 DOI: 10.1016/j.bandc.2021.105808] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2021] [Revised: 08/12/2021] [Accepted: 09/26/2021] [Indexed: 11/30/2022]
Abstract
Minimally delayed (MD) saccades require inhibition of a prepotent response until a target is extinguished, and unlike the more extensively studied antisaccade task, do not require the additional cognitive component of vector inversion (i.e., 180° target spatial transposition). Here, participants completed separate blocks of MD and prepotent stimulus-driven saccades (i.e., respond at target onset) while cortical hemodynamics were measured via functional transcranial Doppler ultrasound. MD saccades produced longer and more variable reaction times (RT). In turn, MD and stimulus-driven saccade preparatory phase cortical hemodynamics increased and decreased, respectively, relative to baseline and the two conditions differed from one another throughout the preparatory phase. The longer RTs and increased cortical hemodynamics of MD saccades is taken to evince response complexity and the increased neural activity to accommodate response inhibition. To our knowledge, such findings provide the first work to examine the neural foundations of MD saccades.
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Affiliation(s)
- Benjamin Tari
- School of Kinesiology, Faculty of Health Sciences, University of Western Ontario, 1151 Richmond St, London, ON N6A 3K7, Canada
| | - Mustafa Shirzad
- School of Kinesiology, Faculty of Health Sciences, University of Western Ontario, 1151 Richmond St, London, ON N6A 3K7, Canada
| | - Nicholas A Badcock
- School of Psychological Science, University of Western Australia, 35 Stirling Hwy, Crawley, WA 6009, Australia
| | - Glen R Belfry
- School of Kinesiology, Faculty of Health Sciences, University of Western Ontario, 1151 Richmond St, London, ON N6A 3K7, Canada; Canadian Centre for Activity and Aging, University of Western Ontario, 1201 Western Rd, London, ON N6G 1H1, Canada
| | - Matthew Heath
- School of Kinesiology, Faculty of Health Sciences, University of Western Ontario, 1151 Richmond St, London, ON N6A 3K7, Canada; Canadian Centre for Activity and Aging, University of Western Ontario, 1201 Western Rd, London, ON N6G 1H1, Canada; Graduate Program in Neuroscience, University of Western Ontario, 1151 Richmond St, London, ON N6A 3K7, Canada.
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10
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Hamidi M, Giuffre L, Heath M. A summary statistical representation influences perceptions but not visually or memory-guided grasping. Hum Mov Sci 2020; 75:102739. [PMID: 33310378 DOI: 10.1016/j.humov.2020.102739] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2020] [Revised: 10/21/2020] [Accepted: 11/26/2020] [Indexed: 11/29/2022]
Abstract
A statistical summary representation (SSR) is a phenomenon wherein a target property (e.g., size) is encoded based on the average of the stimulus-set to which it belongs. An SSR has been demonstrated in obligatory judgment tasks; however, to our knowledge no work has examined whether it influences grasps to 3D targets. Here, participants completed a method of adjustment task, and visually and memory-guided grasps in conditions wherein differently sized 3D targets (widths: 20, 30 and 40 mm; height and depth = 10 mm) were presented with equal frequency (i.e., control) and when the smallest (i.e., 20-mm: small-target) and largest (i.e., 40-mm: large-target) targets were presented five times as often as the other targets in the stimulus-set. In the method of adjustment task, responses for the small- and large-target weighting conditions were smaller and larger than the control condition, respectively. In other words, an SSR biased perceptions in the direction of the most frequently presented target in the stimulus-set - a result consistent with the view that perceptions are supported by relative visual information laid down by the ventral visual pathway. In contrast, grip apertures were refractory to target-weighting and was a finding independent of the presence (i.e., visually guided) or absence (i.e., memory-guided) of visual feedback. Furthermore, two one-sided tests showed that peak grip apertures for the different target weighting conditions were within an equivalence boundary. Accordingly, an SSR does not influence 3D grasps and is a finding adding to a growing literature reporting that actions are supported by the absolute visuomotor networks of the dorsal visual pathway.
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Affiliation(s)
- Maryam Hamidi
- Graduate Program in Neuroscience, University of Western Ontario, London, ON N6A 3K7, Canada
| | - Lauren Giuffre
- School of Kinesiology, University of Western Ontario, London, ON N6A 3K7, Canada
| | - Matthew Heath
- Graduate Program in Neuroscience, University of Western Ontario, London, ON N6A 3K7, Canada; School of Kinesiology, University of Western Ontario, London, ON N6A 3K7, Canada; Canadian Centre for Activity and Aging, University of Western Ontario, London, ON N6A 3K7, Canada.
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11
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Visually guided saccades and acoustic distractors: no evidence for the remote distractor effect or global effect. Exp Brain Res 2020; 239:59-66. [PMID: 33098653 DOI: 10.1007/s00221-020-05959-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2020] [Accepted: 10/13/2020] [Indexed: 10/23/2022]
Abstract
A remote visual distractor increases saccade reaction time (RT) to a visual target and may reflect the time required to resolve conflict between target- and distractor-related information within a common retinotopic representation in the superior colliculus (SC) (i.e., the remote distractor effect: RDE). Notably, because the SC serves as a sensorimotor interface it is possible that the RDE may be associated with the pairing of an acoustic distractor with a visual target; that is, the conflict related to saccade generation signals may be sensory-independent. To address that issue, we employed a traditional RDE experiment involving a visual target and visual proximal and remote distractors (Experiment 1) and an experiment wherein a visual target was presented with acoustic proximal and remote distractors (Experiment 2). As well, Experiments 1 and 2 employed no-distractor trials. Experiment 1 RTs elicited a reliable RDE, whereas Experiment 2 RTs for proximal and remote distractors were shorter than their no distractor counterparts. Accordingly, findings demonstrate that the RDE is sensory specific and arises from conflicting visual signals within a common retinotopic map. As well, Experiment 2 findings indicate that an acoustic distractor supports an intersensory facilitation that optimizes oculomotor planning.
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12
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Shukla D, Al-Shamil Z, Belfry G, Heath M. A single bout of moderate intensity exercise improves cognitive flexibility: evidence from task-switching. Exp Brain Res 2020; 238:2333-2346. [PMID: 32743687 DOI: 10.1007/s00221-020-05885-w] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2019] [Accepted: 07/16/2020] [Indexed: 12/12/2022]
Abstract
Executive function entails the core components of response inhibition, working memory and cognitive flexibility. An accumulating literature has shown that a single bout of exercise improves the response inhibition and working memory components of executive function; however, limited work has examined a putative exercise-related improvement to cognitive flexibility. To address this limitation, Experiment 1 entailed a 20-min session of moderate intensity aerobic exercise (via cycle ergometer), and pre- and post-exercise cognitive flexibility was examined via a task-switching paradigm involving alternating pro- and antisaccades (AABB: A = prosaccade, B = antisaccade). In Experiment 2, participants sat on the cycle ergometer without exercising (i.e., rest break) and the same AABB paradigm was examined pre- and post-break. We used an AABB pro- and antisaccade paradigm because previous work has shown that a prosaccade preceded by an antisaccade exhibits a reliable-and large magnitude-increase in reaction time, whereas the converse switch does not (i.e., the unidirectional prosaccade switch-cost). Experiment 1 showed a unidirectional prosaccade switch-cost pre-exercise (p = .012)-but not post-exercise (p = .30), and a two one-sided t test indicated that the latter comparison was within an equivalence boundary (p < .01). In contrast, Experiment 2 revealed a unidirectional prosaccade switch-cost at pre- and post-break assessments (ps < .01). Accordingly, our results indicate that a single bout of exercise improves cognitive flexibility and provides convergent evidence that exercise improves global components of executive function.
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Affiliation(s)
- Diksha Shukla
- School of Kinesiology, University of Western Ontario, London, ON, N6A 3K7, Canada
| | - Zain Al-Shamil
- School of Kinesiology, University of Western Ontario, London, ON, N6A 3K7, Canada
| | - Glen Belfry
- School of Kinesiology, University of Western Ontario, London, ON, N6A 3K7, Canada
- Canadian Centre for Activity and Aging, Faculty of Health Sciences, University of Western Ontario, London, ON, Canada
| | - Matthew Heath
- School of Kinesiology, University of Western Ontario, London, ON, N6A 3K7, Canada.
- Canadian Centre for Activity and Aging, Faculty of Health Sciences, University of Western Ontario, London, ON, Canada.
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13
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Ayala N, Heath M. Executive Dysfunction after a Sport-Related Concussion Is Independent of Task-Based Symptom Burden. J Neurotrauma 2020; 37:2558-2568. [PMID: 32438897 DOI: 10.1089/neu.2019.6865] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
A sport-related concussion (SRC) results in short- and long-term deficits in oculomotor control; however, it is unclear whether this change reflects executive dysfunction and/or a performance decrement caused by an increase in task-based symptom burden. Here, individuals with a SRC - and age- and sex-matched controls - completed an antisaccade task (i.e., saccade mirror-symmetrical to a target) during the early (initial assessment ≤12 days) and later (follow-up assessment <30 days) stages of recovery. Antisaccades were used because they require top-down executive control and exhibit performance decrements following an SRC. Reaction time (RT) and directional errors were included with pupillometry, because pupil size in the antisaccade task has been shown to provide a neural proxy for executive control. In addition, the Sport-Concussion Assessment Tool (SCAT-5) symptom checklist was completed prior to and after each oculomotor assessment to identify a possible task-based increase in symptomology. The SRC group yielded longer initial assessment RTs, more directional errors, and larger task-evoked pupil dilations (TEPD) than the control group. At the follow-up assessment, RTs for the SRC and control group did not reliably differ; however, the former demonstrated more directional errors and larger TEPDs. SCAT-5 symptom severity scores did not vary from the pre- to post-oculomotor evaluation for either initial or follow-up assessments. Accordingly, an SRC imparts a persistent executive dysfunction to oculomotor planning independent of a task-based increase in symptom burden. These findings evince that antisaccades serve as an effective tool to identify subtle executive deficits during the early and later stages of SRC recovery.
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Affiliation(s)
- Naila Ayala
- School of Kinesiology, University of Western Ontario, London, Ontario, Canada.,Graduate Program in Neuroscience, University of Western Ontario, London, Ontario, Canada
| | - Matthew Heath
- School of Kinesiology, University of Western Ontario, London, Ontario, Canada.,Graduate Program in Neuroscience, University of Western Ontario, London, Ontario, Canada
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14
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Tari B, Heath M. Pro- and antisaccade task-switching: response suppression-and not vector inversion-contributes to a task-set inertia. Exp Brain Res 2019; 237:3475-3484. [PMID: 31741001 DOI: 10.1007/s00221-019-05686-w] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2019] [Accepted: 11/07/2019] [Indexed: 11/25/2022]
Abstract
Alternating between different tasks represents an executive function essential to activities of daily living. In the oculomotor literature, reaction times (RT) for a 'standard' and stimulus-driven (SD) prosaccade (i.e., saccade to target at target onset) are increased when preceded by a 'non-standard' antisaccade (i.e., saccade mirror-symmetrical to target at target onset), whereas the converse switch does not elicit an RT cost. The prosaccade switch-cost has been attributed to lingering neural activity-or task-set inertia-related to the antisaccade executive demands of response suppression and vector inversion. It is, however, unclear whether response suppression and/or vector inversion contribute to the prosaccade switch-cost. Experiment 1 of the present work had participants alternate (i.e., AABB paradigm) between minimally delayed (MD) pro- and antisaccades. MD saccades require a response after target extinction and necessitate response suppression for both pro- and antisaccades-a paradigm providing a framework to determine whether vector inversion contributes to a task-set inertia. In Experiment 2, participants alternated between SD pro- and MD antisaccades-a paradigm designed to determine if a switch-cost is selectively imparted when a SD and standard response is preceded by a non-standard response. Experiment 1 showed that RTs for MD pro- and antisaccades were refractory to the preceding trial-type; that is, vector inversion did not engender a switch-cost. Experiment 2 indicated that RTs for SD prosaccades were increased when preceded by an MD antisaccade. Accordingly, response suppression engenders a task-set inertia but only for a subsequent stimulus-driven and standard response (i.e., SD prosaccade). Such a result is in line with the view that response suppression is a hallmark feature of executive function.
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Affiliation(s)
- Benjamin Tari
- School of Kinesiology, The University of Western Ontario, London, ON, N6A 3K7, Canada
| | - Matthew Heath
- School of Kinesiology, The University of Western Ontario, London, ON, N6A 3K7, Canada.
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15
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Aponte EA, Stephan KE, Heinzle J. Switch costs in inhibitory control and voluntary behaviour: A computational study of the antisaccade task. Eur J Neurosci 2019; 50:3205-3220. [PMID: 31081574 DOI: 10.1111/ejn.14435] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2018] [Revised: 03/25/2019] [Accepted: 05/06/2019] [Indexed: 11/28/2022]
Abstract
An integral aspect of human cognition is the ability to inhibit stimulus-driven, habitual responses, in favour of complex, voluntary actions. In addition, humans can also alternate between different tasks. This comes at the cost of degraded performance when compared to repeating the same task, a phenomenon called the "task-switch cost." While task switching and inhibitory control have been studied extensively, the interaction between them has received relatively little attention. Here, we used the SERIA model, a computational model of antisaccade behaviour, to draw a bridge between them. We investigated task switching in two versions of the mixed antisaccade task, in which participants are cued to saccade either in the same or in the opposite direction to a peripheral stimulus. SERIA revealed that stopping a habitual action leads to increased inhibitory control that persists onto the next trial, independently of the upcoming trial type. Moreover, switching between tasks induces slower and less accurate voluntary responses compared to repeat trials. However, this only occurs when participants lack the time to prepare the correct response. Altogether, SERIA demonstrates that there is a reconfiguration cost associated with switching between voluntary actions. In addition, the enhanced inhibition that follows antisaccade but not prosaccade trials explains asymmetric switch costs. In conclusion, SERIA offers a novel model of task switching that unifies previous theoretical accounts by distinguishing between inhibitory control and voluntary action generation and could help explain similar phenomena in paradigms beyond the antisaccade task.
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Affiliation(s)
- Eduardo A Aponte
- Translational Neuromodeling Unit (TNU), Institute for Biomedical Engineering, University of Zurich and ETH Zurich, Zurich, Switzerland
| | - Klaas E Stephan
- Translational Neuromodeling Unit (TNU), Institute for Biomedical Engineering, University of Zurich and ETH Zurich, Zurich, Switzerland.,Wellcome Centre for Human Neuroimaging, University College London, London, UK.,Max Planck Institute for Metabolism Research, Cologne, Germany
| | - Jakob Heinzle
- Translational Neuromodeling Unit (TNU), Institute for Biomedical Engineering, University of Zurich and ETH Zurich, Zurich, Switzerland
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16
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Tari B, Fadel MA, Heath M. Response suppression produces a switch-cost for spatially compatible saccades. Exp Brain Res 2019; 237:1195-1203. [PMID: 30809706 DOI: 10.1007/s00221-019-05497-z] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2018] [Accepted: 02/19/2019] [Indexed: 11/29/2022]
Abstract
Executive function supports the rapid alternation between tasks for online reconfiguration of attentional and motor goals. The oculomotor literature has found that a prosaccade (i.e., saccade to veridical target location) preceded by an antisaccade (i.e., saccade mirror symmetrical to a target) elicits an increase in reaction time (RT), whereas the converse switch does not. This switch-cost has been attributed to the antisaccade task's requirement of inhibiting a prosaccade (i.e., response suppression) and transforming a target's coordinate (i.e., vector inversion)-executive processes thought to contribute to a task-set inertia that proactively interferes with the planning of a subsequent prosaccade. It is, however, unclear whether response suppression and vector inversion contribute to a task-set inertia or whether the phenomenon relates to a unitary component (e.g., response suppression). Here, the same stimulus-driven (SD) prosaccades (i.e., respond at target onset) as used in previous work were used with minimally delayed (MD) prosaccades (i.e., respond at target offset) and arranged in an AABB paradigm (i.e., A = SD prosaccade, B = MD prosaccade). MD prosaccades provide the same response suppression as antisaccades without the need for vector inversion. RTs for SD task-switch trials were longer and more variable than their task-repeat counterparts, whereas values for MD task-switch and task-repeat trials did not reliably differ. Moreover, SD task-repeat and task-switch movement times and amplitudes did not vary and thus demonstrate that a switch-cost is unrelated to a speed accuracy trade-off. Accordingly, results suggest the executive demands of response suppression is sufficient to engender the persistent activation of a non-standard task-set that selectively delays the planning of a subsequent SD prosaccade.
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Affiliation(s)
- Benjamin Tari
- School of Kinesiology, The University of Western Ontario, London, ON, N6A 3K7, Canada
| | - Mohammed A Fadel
- School of Kinesiology, The University of Western Ontario, London, ON, N6A 3K7, Canada
| | - Matthew Heath
- School of Kinesiology, The University of Western Ontario, London, ON, N6A 3K7, Canada.
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17
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Aponte EA, Tschan DG, Stephan KE, Heinzle J. Inhibition failures and late errors in the antisaccade task: influence of cue delay. J Neurophysiol 2018; 120:3001-3016. [PMID: 30110237 DOI: 10.1152/jn.00240.2018] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
In the antisaccade task participants are required to saccade in the opposite direction of a peripheral visual cue (PVC). This paradigm is often used to investigate inhibition of reflexive responses as well as voluntary response generation. However, it is not clear to what extent different versions of this task probe the same underlying processes. Here, we explored with the Stochastic Early Reaction, Inhibition, and late Action (SERIA) model how the delay between task cue and PVC affects reaction time (RT) and error rate (ER) when pro- and antisaccade trials are randomly interleaved. Specifically, we contrasted a condition in which the task cue was presented before the PVC with a condition in which the PVC served also as task cue. Summary statistics indicate that ERs and RTs are reduced and contextual effects largely removed when the task is signaled before the PVC appears. The SERIA model accounts for RT and ER in both conditions and better so than other candidate models. Modeling demonstrates that voluntary pro- and antisaccades are frequent in both conditions. Moreover, early task cue presentation results in better control of reflexive saccades, leading to fewer fast antisaccade errors and more rapid correct prosaccades. Finally, high-latency errors are shown to be prevalent in both conditions. In summary, SERIA provides an explanation for the differences in the delayed and nondelayed antisaccade task. NEW & NOTEWORTHY In this article, we use a computational model to study the mixed antisaccade task. We contrast two conditions in which the task cue is presented either before or concurrently with the saccadic target. Modeling provides a highly accurate account of participants' behavior and demonstrates that a significant number of prosaccades are voluntary actions. Moreover, we provide a detailed quantitative analysis of the types of error that occur in pro- and antisaccade trials.
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Affiliation(s)
- Eduardo A Aponte
- Translational Neuromodeling Unit, Institute for Biomedical Engineering, University of Zurich and ETH Zurich . Zurich , Switzerland
| | - Dominic G Tschan
- Translational Neuromodeling Unit, Institute for Biomedical Engineering, University of Zurich and ETH Zurich . Zurich , Switzerland
| | - Klaas E Stephan
- Translational Neuromodeling Unit, Institute for Biomedical Engineering, University of Zurich and ETH Zurich . Zurich , Switzerland.,Wellcome Centre for Human Neuroimaging, University College London . London , United Kingdom.,Max Planck Institute for Metabolism Research, Cologne, Germany
| | - Jakob Heinzle
- Translational Neuromodeling Unit, Institute for Biomedical Engineering, University of Zurich and ETH Zurich . Zurich , Switzerland
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18
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Clough M, Foletta P, Frohman AN, Sears D, Ternes A, White OB, Fielding J. Multiple sclerosis: Executive dysfunction, task switching and the role of attention. Mult Scler J Exp Transl Clin 2018; 4:2055217318771781. [PMID: 29707228 PMCID: PMC5912274 DOI: 10.1177/2055217318771781] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2018] [Revised: 02/27/2018] [Accepted: 03/20/2018] [Indexed: 11/25/2022] Open
Abstract
Background It has been suggested that switching ability might not be affected in multiple sclerosis (MS) as previously thought; however, whether this is true under more ‘real-world’ conditions when asymmetry in task difficulty is present has not been ascertained. Objective The objective of this paper is to examine the impact of task difficulty asymmetry on task switching ability in MS. Method An ocular motor (OM) paradigm that interleaves the simple task of looking towards a target (prosaccade, PS) with the cognitively more difficult task of looking away from a target (antisaccade, PS) was used. Two switching conditions: (1) PS switch cost, switching to a simple task from a difficult task (PS switch), relative to performing two simple tasks concurrently (PS repeat); (2) AS switch cost, switching to a difficult task from a simple task (AS switch) relative to performing two difficult tasks concurrently (AS repeat). Forty-five relapsing–remitting MS patients and 30 control individuals were compared. Results Controls and patients produced a similar magnitude PS switch cost, suggesting that task difficulty asymmetry does not detrimentally impact MS patients when transitioning from a more difficult task to a simpler task. However, MS patients alone found switching from the simpler PS trial to the more difficult AS trial easier (shorter latency and reduced error) than performing two AS trials consecutively (AS switch benefit). Further, MS patients performed significantly more errors than controls when required to repeat the same trial consecutively. Conclusion MS patients appear to find the maintenance of task-relevant processes difficult not switching per se, with deficits exacerbated under increased attentional demands.
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Affiliation(s)
- M Clough
- Department of Neurosciences, Central Clinical School, Monash University, Alfred Hospital, Australia.,School of Psychological Sciences and Monash Institute of Cognitive and Clinical Neurosciences, Monash University, Australia
| | - P Foletta
- Department of Neurosciences, Central Clinical School, Monash University, Alfred Hospital, Australia.,School of Psychological Sciences and Monash Institute of Cognitive and Clinical Neurosciences, Monash University, Australia
| | - A N Frohman
- Departments of Neurology and Neurotherapeutics, University of Texas Southwestern School of Medicine, USA
| | - D Sears
- Departments of Neurology and Neurotherapeutics, University of Texas Southwestern School of Medicine, USA
| | - A Ternes
- School of Psychological Sciences and Monash Institute of Cognitive and Clinical Neurosciences, Monash University, Australia
| | - O B White
- Department of Neurosciences, Central Clinical School, Monash University, Alfred Hospital, Australia
| | - J Fielding
- Department of Neurosciences, Central Clinical School, Monash University, Alfred Hospital, Australia.,School of Psychological Sciences and Monash Institute of Cognitive and Clinical Neurosciences, Monash University, Australia
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19
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Clough M, Mutimer S, Wright DK, Tsang A, Costello DM, Gardner AJ, Stanwell P, Mychasiuk R, Sun M, Brady RD, McDonald SJ, Webster KM, Johnstone MR, Semple BD, Agoston DV, White OB, Frayne R, Fielding J, O'Brien TJ, Shultz SR. Oculomotor Cognitive Control Abnormalities in Australian Rules Football Players with a History of Concussion. J Neurotrauma 2018; 35:730-738. [DOI: 10.1089/neu.2017.5204] [Citation(s) in RCA: 26] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Affiliation(s)
- Meaghan Clough
- School of Psychological Sciences, Monash University, Clayton, Victoria, Australia
| | - Steven Mutimer
- The Department of Medicine, The University of Melbourne, Parkville, Victoria, Australia
| | - David K. Wright
- The Florey Institute of Neuroscience and Mental Health, Parkville, Victoria, Australia
| | - Adrian Tsang
- The Department of Radiology, The University of Calgary, Calgary, Alberta, Canada
- Seaman Family MR Research Center, Foothills Medical Center, Calgary, Alberta, Canada
| | - Daniel M. Costello
- The Department of Medicine, The University of Melbourne, Parkville, Victoria, Australia
| | - Andrew J. Gardner
- School of Medicine and Public Health, The University of Newcastle, Callaghan, New South Wales, Australia
| | - Peter Stanwell
- School of Health Sciences, The University of Newcastle, Callaghan, New South Wales, Australia
| | - Richelle Mychasiuk
- The Department of Psychology, The University of Calgary, Calgary, Alberta, Canada
| | - Mujun Sun
- The Department of Medicine, The University of Melbourne, Parkville, Victoria, Australia
| | - Rhys D. Brady
- The Department of Medicine, The University of Melbourne, Parkville, Victoria, Australia
| | - Stuart J. McDonald
- Physiology, Anatomy & Microbiology, La Trobe University, Bundoora, Victoria, Australia
| | - Kyria M. Webster
- The Department of Medicine, The University of Melbourne, Parkville, Victoria, Australia
| | - Maddison R. Johnstone
- Physiology, Anatomy & Microbiology, La Trobe University, Bundoora, Victoria, Australia
| | - Bridgette D. Semple
- The Department of Medicine, The University of Melbourne, Parkville, Victoria, Australia
| | - Denes V. Agoston
- Anatomy, Physiology & Genetics, Uniformed Services University, Bethesda, Maryland
| | - Owen B. White
- The Department of Medicine, The University of Melbourne, Parkville, Victoria, Australia
| | - Richard Frayne
- The Department of Radiology, The University of Calgary, Calgary, Alberta, Canada
- Seaman Family MR Research Center, Foothills Medical Center, Calgary, Alberta, Canada
| | - Joanne Fielding
- School of Psychological Sciences, Monash University, Clayton, Victoria, Australia
| | - Terence J. O'Brien
- The Department of Medicine, The University of Melbourne, Parkville, Victoria, Australia
- Department of Neuroscience, Central Clinical School, Monash University, Melbourne, Victoria, Australia
| | - Sandy R. Shultz
- The Department of Medicine, The University of Melbourne, Parkville, Victoria, Australia
- Department of Neuroscience, Central Clinical School, Monash University, Melbourne, Victoria, Australia
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20
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Heath M, Shellington E, Titheridge S, Gill DP, Petrella RJ. A 24-Week Multi-Modality Exercise Program Improves Executive Control in Older Adults with a Self-Reported Cognitive Complaint: Evidence from the Antisaccade Task. J Alzheimers Dis 2018; 56:167-183. [PMID: 27911298 DOI: 10.3233/jad-160627] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
Exercise programs involving aerobic and resistance training (i.e., multiple-modality) have shown promise in improving cognition and executive control in older adults at risk, or experiencing, cognitive decline. It is, however, unclear whether cognitive training within a multiple-modality program elicits an additive benefit to executive/cognitive processes. This is an important question to resolve in order to identify optimal training programs that delay, or ameliorate, executive deficits in persons at risk for further cognitive decline. In the present study, individuals with a self-reported cognitive complaint (SCC) participated in a 24-week multiple-modality (i.e., the M2 group) exercise intervention program. In addition, a separate group of individuals with a SCC completed the same aerobic and resistance training as the M2 group but also completed a cognitive-based stepping task (i.e., multiple-modality, mind-motor intervention: M4 group). Notably, pre- and post-intervention executive control was examined via the antisaccade task (i.e., eye movement mirror-symmetrical to a target). Antisaccades are an ideal tool for the study of individuals with subtle executive deficits because of its hands- and language-free nature and because the task's neural mechanisms are linked to neuropathology in cognitive decline (i.e., prefrontal cortex). Results showed that M2 and M4 group antisaccade reaction times reliably decreased from pre- to post-intervention and the magnitude of the decrease was consistent across groups. Thus, multi-modality exercise training improved executive performance in persons with a SCC independent of mind-motor training. Accordingly, we propose that multiple-modality training provides a sufficient intervention to improve executive control in persons with a SCC.
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Affiliation(s)
- Matthew Heath
- School of Kinesiology, University of Western Ontario, London, ON, Canada.,Graduate Program in Neuroscience, University of Western Ontario, London, ON, Canada
| | - Erin Shellington
- School of Kinesiology, University of Western Ontario, London, ON, Canada.,Lawson Health Research Institute, London, ON, Canada
| | - Sam Titheridge
- School of Kinesiology, University of Western Ontario, London, ON, Canada.,Lawson Health Research Institute, London, ON, Canada
| | - Dawn P Gill
- Lawson Health Research Institute, London, ON, Canada.,School of Health Studies, University of Western Ontario, London, ON, Canada.,Department of Epidemiology, University of Washington, Seattle, WA, USA
| | - Robert J Petrella
- School of Kinesiology, University of Western Ontario, London, ON, Canada.,Lawson Health Research Institute, London, ON, Canada.,Department of Family Medicine, University of Western Ontario, London, ON, Canada.,Canadian Centre for Activity and Aging, University of Western Ontario, London, ON, Canada
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21
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Heath M, Weiler J, Gregory MA, Gill DP, Petrella RJ. A Six-Month Cognitive-Motor and Aerobic Exercise Program Improves Executive Function in Persons with an Objective Cognitive Impairment: A Pilot Investigation Using the Antisaccade Task. J Alzheimers Dis 2018; 54:923-931. [PMID: 27567829 DOI: 10.3233/jad-160288] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
Persons with an objective cognitive impairment (OCI) are at increased risk for progression to Alzheimer's disease and related dementias. The present pilot project sought to examine whether participation in a long-term exercise program involving cognitive-motor (CM) dual-task gait training and aerobic exercise training improves executive function in persons with an OCI. To accomplish our objective, individuals with an OCI (n = 12) as determined by a Montreal Cognitive Assessment (MoCA) score of less than 26 and older adults (n = 11) deemed to be cognitively healthy (i.e., control group: MoCA score ≥26) completed a six-month moderate-to-high intensity (65-85% maximum heart rate) treadmill-based CM and aerobic exercise training program wherein pre- and post-intervention executive control was examined via the antisaccade task. Notably, antisaccades require a goal-directed eye-movement mirror-symmetrical to a target and represent an ideal tool for the study of executive deficits because of its hands- and language-free nature. As well, the cortical networks mediating antisaccades represent regions associated with neuropathology in cognitive decline and dementia (e.g., dorsolateral prefrontal cortex). Results showed that antisaccade reaction times for the OCI group reliably decreased by 30 ms from pre- to post-intervention, whereas the control group did not produce a reliable pre- to post-intervention change in reaction time (i.e., 6 ms). Thus, we propose that in persons with OCI long-term CM and aerobic training improves the efficiency and effectiveness of the executive mechanisms mediating high-level oculomotor control.
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Affiliation(s)
- Matthew Heath
- School of Kinesiology, University of Western Ontario, London, ON, Canada.,Graduate Program in Neuroscience, University of Western Ontario, London, ON, Canada
| | - Jeffrey Weiler
- School of Kinesiology, University of Western Ontario, London, ON, Canada
| | - Michael A Gregory
- Health and Rehabilitation Sciences, University of Western Ontario, London, ON, Canada.,Lawson Health Research Institute, London, ON, Canada
| | - Dawn P Gill
- Health and Rehabilitation Sciences, University of Western Ontario, London, ON, Canada.,Department of Family Medicine, University of Western Ontario, London, ON, Canada.,Department of Epidemiology, University of Washington, Seattle, WA, USA
| | - Robert J Petrella
- School of Kinesiology, University of Western Ontario, London, ON, Canada.,Health and Rehabilitation Sciences, University of Western Ontario, London, ON, Canada.,Lawson Health Research Institute, London, ON, Canada.,Department of Family Medicine, University of Western Ontario, London, ON, Canada.,Canadian Centre for Activity and Aging, University of Western University, London, ON, Canada
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22
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Samani A, Heath M. Executive-related oculomotor control is improved following a 10-min single-bout of aerobic exercise: Evidence from the antisaccade task. Neuropsychologia 2017; 108:73-81. [PMID: 29191783 DOI: 10.1016/j.neuropsychologia.2017.11.029] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2017] [Revised: 11/01/2017] [Accepted: 11/23/2017] [Indexed: 11/30/2022]
Abstract
Previous work has shown that a single-bout of moderate-to-vigorous intensity exercise improves task-specific activity within frontoparietal networks and produces a short-term 'boost' to executive-related cognitive control - an effect in healthy young adults that is reported to be selective to exercise durations of 20min or greater. The present study sought to determine whether such a 'boost' extends to an exercise duration as brief as 10min. Healthy young adults performed a 10-min single-bout of moderate-to-vigorous intensity aerobic exercise (i.e., via a cycle ergometer) and pre- and post-exercise executive control was examined via the antisaccade task. Antisaccades are an executive task requiring a goal-directed eye movement (i.e., a saccade) mirror-symmetrical to a visual stimulus. The hands- and language-free nature of antisaccades coupled with the temporal precision of eye-tracking technology make it an ideal tool for identifying executive performance changes. Moreover, an extensive literature has shown that antisaccades are mediated via frontoparietal networks that are modulated following single-bout and chronic exercise training. Results showed that antisaccade reaction time (RT) reliably decreased by 27ms from pre- to post-exercise assessments. Further, the percentage of antisaccade directional errors did not reliably vary from the pre- (13%) to post-exercise (9%) assessments - a result indicating that the RT improvement was unrelated to a speed-accuracy trade-off. A follow-up experiment involving antisaccade sessions separated by a non-exercise interval did not show a similar RT modulation. Thus, a 10-min bout of moderate-to-vigorous intensity aerobic exercise benefits executive-related oculomotor control, and is a finding we attribute to an exercise-based increase in attention/arousal and/or improved task-specific activity within the frontoparietal networks supporting antisaccades.
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Affiliation(s)
- Ashna Samani
- School of Kinesiology and Graduate Program in Neuroscience, The University of Western Ontario, London, Ontario, Canada N6A 3K7
| | - Matthew Heath
- School of Kinesiology and Graduate Program in Neuroscience, The University of Western Ontario, London, Ontario, Canada N6A 3K7.
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23
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Chan JL, Koval MJ, Johnston K, Everling S. Neural correlates for task switching in the macaque superior colliculus. J Neurophysiol 2017; 118:2156-2170. [PMID: 28794192 DOI: 10.1152/jn.00139.2017] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2017] [Revised: 07/25/2017] [Accepted: 07/25/2017] [Indexed: 11/22/2022] Open
Abstract
Successful task switching requires a network of brain areas to select, maintain, implement, and execute the appropriate task. Although frontoparietal brain areas are thought to play a critical role in task switching by selecting and encoding task rules and exerting top-down control, how brain areas closer to the execution of tasks participate in task switching is unclear. The superior colliculus (SC) integrates information from various brain areas to generate saccades and is likely influenced by task switching. Here, we investigated switch costs in nonhuman primates and their neural correlates in the activity of SC saccade-related neurons in monkeys performing cued, randomly interleaved pro- and anti-saccade trials. We predicted that behavioral switch costs would be associated with differential modulations of SC activity in trials on which the task was switched vs. repeated, with activity on the current trial resembling that associated with the task set of the previous trial when a switch occurred. We observed both error rate and reaction time switch costs and changes in the discharge rate and timing of activity in SC neurons between switch and repeat trials. These changes were present later in the task only after fixation on the cue stimuli but before saccade onset. These results further establish switch costs in macaque monkeys and suggest that SC activity is modulated by task-switching processes in a manner inconsistent with the concept of task set inertia.NEW & NOTEWORTHY Task-switching behavior and superior colliculus (SC) activity were investigated in nonhuman primates performing randomly interleaved pro- and anti-saccade tasks. Here, we report error rate and reaction time switch costs in macaque monkeys and associated differences in stimulus-related activity of saccade-related neurons in the SC. These results provide a neural correlate for task switching and suggest that the SC is modulated by task-switching processes and may reflect the completion of task set reconfiguration.
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Affiliation(s)
- Jason L Chan
- Graduate Program in Neuroscience, University of Western Ontario, London, Ontario, Canada
| | - Michael J Koval
- Graduate Program in Neuroscience, University of Western Ontario, London, Ontario, Canada
| | - Kevin Johnston
- Graduate Program in Neuroscience, University of Western Ontario, London, Ontario, Canada.,Department of Physiology and Pharmacology, University of Western Ontario, London, Ontario, Canada; and
| | - Stefan Everling
- Graduate Program in Neuroscience, University of Western Ontario, London, Ontario, Canada; .,Department of Physiology and Pharmacology, University of Western Ontario, London, Ontario, Canada; and.,Robarts Research Institute, London, Ontario, Canada
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24
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Terao Y, Fukuda H, Tokushige SI, Inomata-Terada S, Ugawa Y. How Saccade Intrusions Affect Subsequent Motor and Oculomotor Actions. Front Neurosci 2017; 10:608. [PMID: 28127274 PMCID: PMC5226964 DOI: 10.3389/fnins.2016.00608] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2016] [Accepted: 12/21/2016] [Indexed: 11/25/2022] Open
Abstract
In daily activities, there is a close spatial and temporal coupling between eye and hand movements that enables human beings to perform actions smoothly and accurately. If this coupling is disrupted by inadvertent saccade intrusions, subsequent motor actions suffer from delays, and lack of coordination. To examine how saccade intrusions affect subsequent voluntary actions, we used two tasks that require subjects to make motor/oculomotor actions in response to a visual cue. One was the memory guided saccade (MGS) task, and the other the hand reaction time (RT) task. The MGS task required subjects to initiate a voluntary saccade to a memorized target location, which is indicated shortly before by a briefly presented cue. The RT task required subjects to release a button on detection of a visual target, while foveating on a central fixation point. In normal subjects of various ages, inadvertent saccade intrusions delayed subsequent voluntary motor, and oculomotor actions. We also studied patients with Parkinson's disease (PD), who are impaired not only in initiating voluntary saccades but also in suppressing unwanted reflexive saccades. Saccade intrusions also delayed hand RT in PD patients. However, MGS was affected by the saccade intrusion differently. Saccade intrusion did not delay MGS latency in PD patients who could perform MGS with a relatively normal latency. In contrast, in PD patients who were unable to initiate MGS within the normal time range, we observed slightly decreased MGS latency after saccade intrusions. What explains this paradoxical phenomenon? It is known that motor actions slow down when switching between controlled and automatic behavior. We discuss how the effect of saccade intrusions on subsequent voluntary motor/oculomotor actions may reflect a similar switching cost between automatic and controlled behavior and a cost for switching between different motor effectors. In contrast, PD patients were unable to initiate internally guided MGS in the absence of visual target and could perform only automatic visually guided saccades, and did not have to switch between automatic and controlled behavior. This lack of switching may explain the shortening of MGS latency by the saccade intrusion in PD patients.
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Affiliation(s)
- Yasuo Terao
- Department of Neurology, University of TokyoTokyo, Japan; Department of Cell Physiology, Kyorin UniversityTokyo, Japan
| | - Hideki Fukuda
- Segawa Neurological Clinic for Children Tokyo, Japan
| | | | | | - Yoshikazu Ugawa
- Department of Neurology, School of Medicine, Fukushima Medical UniversityFukushima, Japan; Fukushima Global Medical Science Center, Advanced Clinical Research Center, Fukushima Medical UniversityFukushima, Japan
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25
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Heath M, Samani A, Tremblay L, Elliott D. Fitts’ Theorem in Oculomotor Control: Dissociable Movement Times for Amplitude and Width Manipulations. J Mot Behav 2016; 48:489-499. [DOI: 10.1080/00222895.2015.1134436] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
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26
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Alternating between pro- and antisaccades: switch-costs manifest via decoupling the spatial relations between stimulus and response. Exp Brain Res 2015; 234:853-65. [PMID: 26661337 DOI: 10.1007/s00221-015-4510-7] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2015] [Accepted: 11/19/2015] [Indexed: 10/22/2022]
Abstract
Antisaccades are a nonstandard task requiring a response mirror-symmetrical to the location of a target. The completion of an antisaccade has been shown to delay the reaction time (RT) of a subsequent prosaccade, whereas the converse switch elicits a null RT cost (i.e., the unidirectional prosaccade switch-cost). The present study sought to determine whether the prosaccade switch-cost arises from low-level interference specific to the sensory features of a target (i.e., modality-dependent) or manifests via the high-level demands of dissociating the spatial relations between stimulus and response (i.e., modality-independent). Participants alternated between pro- and antisaccades wherein the target associated with the response alternated between visual and auditory modalities. Thus, the present design involved task-switch (i.e., switching from a pro- to antisaccade and vice versa) and modality-switch (i.e., switching from a visual to auditory target and vice versa) trials as well as their task- and modality-repetition counterparts. RTs were longer for modality-switch than modality-repetition trials. Notably, however, modality-switch trials did not nullify or lessen the unidirectional prosaccade switch-cost; that is, the magnitude of the RT cost for task-switch prosaccades was equivalent across modality-switch and modality-repetition trials. Thus, competitive interference within a sensory modality does not contribute to the unidirectional prosaccade switch-cost. Instead, the modality-independent findings evince that dissociating the spatial relations between stimulus and response instantiates a high-level and inertially persistent nonstandard task-set that impedes the planning of a subsequent prosaccade.
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27
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Heath M, Hassall CD, MacLean S, Krigolson OE. Event-related brain potentials during the visuomotor mental rotation task: The contingent negative variation scales to angle of rotation. Neuroscience 2015; 311:153-65. [PMID: 26477986 DOI: 10.1016/j.neuroscience.2015.10.018] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2015] [Revised: 10/07/2015] [Accepted: 10/09/2015] [Indexed: 11/16/2022]
Abstract
Perceptual judgments about the angular disparity of a character from its standard upright (i.e., mental rotation task) result in a concurrent increase in reaction time (RT) and modulation of the amplitude of the P300 event-related brain potential (ERP). It has therefore been proposed that the P300 represents the neural processes associated with a visual rotation. In turn, the visuomotor mental rotation (VMR) task requires reaching to a location that deviates from a target by a predetermined angle. Although the VMR task exhibits a linear increase in RT with increasing oblique angles of rotation, work has not examined whether the task is supported via a visual rotation analogous to its mental rotation task counterpart. This represents a notable issue because seminal work involving non-human primates has ascribed VMR performance to the motor-related rotation of directionally tuned neurons in the primary motor cortex. Here we examined the concurrent behavioral and ERP characteristics of a standard reaching task and VMR tasks of 35°, 70°, and 105° of rotation. Results showed that the P300 amplitude was larger for the standard compared to each VMR task--an effect independent of the angle of rotation. In turn, the amplitude of the contingent negative variation (CNV)--an ERP related to cognitive and visuomotor integration for movement preparation--was systematically modulated with angle of rotation. Thus, we propose that the CNV represents an ERP correlate related to the cognitive and/or visuomotor transformation demands of increasing the angular separation between a stimulus and a movement goal.
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Affiliation(s)
- M Heath
- School of Kinesiology, University of Western Ontario, London, ON, Canada; Graduate Program in Neuroscience, University of Western Ontario, London, ON, Canada.
| | - C D Hassall
- Faculty of Education, University of Victoria, Victoria, BC, Canada
| | - S MacLean
- Department of Psychology and Neuroscience, Dalhousie University, Halifax, NS, Canada
| | - O E Krigolson
- Faculty of Education, University of Victoria, Victoria, BC, Canada; Division of Medical Sciences, University of Victoria, Victoria, BC, Canada
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28
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Pantomime-grasping: the ‘return’ of haptic feedback supports the absolute specification of object size. Exp Brain Res 2015; 233:2029-40. [DOI: 10.1007/s00221-015-4274-0] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2014] [Accepted: 04/03/2015] [Indexed: 11/25/2022]
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29
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DeSimone JC, Everling S, Heath M. The antisaccade task: visual distractors elicit a location-independent planning 'cost'. PLoS One 2015; 10:e0122345. [PMID: 25830383 PMCID: PMC4382315 DOI: 10.1371/journal.pone.0122345] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2014] [Accepted: 02/13/2015] [Indexed: 11/24/2022] Open
Abstract
The presentation of a remote – but not proximal – distractor concurrent with target onset increases prosaccade reaction times (RT) (i.e., the remote distractor effect: RDE). The competitive integration model asserts that the RDE represents the time required to resolve the conflict for a common saccade threshold between target- and distractor-related saccade generating commands in the superior colliculus. To our knowledge however, no previous research has examined whether remote and proximal distractors differentially influence antisaccade RTs. This represents a notable question because antisaccades require decoupling of the spatial relations between stimulus and response (SR) and therefore provide a basis for determining whether the sensory- and/or motor-related features of a distractor influence response planning. Participants completed pro- and antisaccades in a target-only condition and conditions wherein the target was concurrently presented with a proximal or remote distractor. As expected, prosaccade RTs elicited a reliable RDE. In contrast, antisaccade RTs were increased independent of the distractor’s spatial location and the magnitude of the effect was comparable across each distractor location. Thus, distractor-related antisaccade RT costs are not accounted for by a competitive integration between conflicting saccade generating commands. Instead, we propose that a visual distractor increases uncertainty related to the evocation of the response-selection rule necessary for decoupling SR relations.
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Affiliation(s)
- Jesse C. DeSimone
- School of Kinesiology, University of Western Ontario, London, ON, Canada
| | - Stefan Everling
- Department of Physiology and Pharmacology, Department of Psychology, Robarts Research Institute, and Graduate Program in Neuroscience, University of Western Ontario, London, ON, Canada
| | - Matthew Heath
- School of Kinesiology and Graduate Program in Neuroscience, University of Western Ontario, London, ON, Canada
- * E-mail:
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30
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Weiler J, Hassall CD, Krigolson OE, Heath M. The unidirectional prosaccade switch-cost: Electroencephalographic evidence of task-set inertia in oculomotor control. Behav Brain Res 2015; 278:323-9. [DOI: 10.1016/j.bbr.2014.10.012] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2014] [Revised: 10/05/2014] [Accepted: 10/11/2014] [Indexed: 11/25/2022]
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31
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Heath M, Starrs F, Macpherson E, Weiler J. Task-switching effects for visual and auditory pro- and antisaccades: evidence for a task-set inertia. J Mot Behav 2015; 47:319-27. [PMID: 25584657 DOI: 10.1080/00222895.2014.982068] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
Abstract
The completion of an antisaccade delays the reaction time (RT) of a subsequent prosaccade; however, the converse switch does not influence RT. In accounting for this result, the task-set inertia hypothesis contends that antisaccades engender a persistent nonstandard task-set that delays the planning of a subsequent prosaccade. In contrast, the coordinate system transformation hypothesis asserts that the transformation required to construct a mirror-symmetrical target representation persistently inhibits prosaccade planning. The authors tested the latter hypothesis by examining switch-costs for pro- and antisaccades directed to visual (i.e., the stimuli used in previous work) and auditory targets. Notably, auditory cues are specified in a head-centered frame of reference prior to their conversion into the retinocentric coordinates necessary for saccade output. Thus, if the coordinate system transformation hypothesis is correct then auditory pro- and antisaccades should elicit a bidirectional switch-cost because each requires a coordinate transformation. RTs for visual and auditory modalities showed a reliable--and equivalent magnitude--prosaccade switch-cost. Moreover, performance (e.g., movement time) and kinematic (e.g., velocity) variables indicated the switch-cost was restricted to response planning. As such, results are incompatible with the coordinate system transformation hypothesis and therefore provide convergent evidence that a task-set inertia contributes to the prosaccade switch-cost.
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Affiliation(s)
- Matthew Heath
- a School of Kinesiology, The University of Western Ontario , London , Canada
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32
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Gillen C, Heath M. Target frequency influences antisaccade endpoint bias: Evidence for perceptual averaging. Vision Res 2014; 105:151-8. [DOI: 10.1016/j.visres.2014.10.010] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2014] [Revised: 10/10/2014] [Accepted: 10/14/2014] [Indexed: 11/29/2022]
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