Preshanta Naicker1,2, Shailendra Anoopkumar-Dukie1,2, Gary D Grant1,2, Luca Modenese3,4, Justin J Kavanagh5,6. 1. Menzies Health Institute Queensland, Griffith University, Gold Coast, QLD, Australia. 2. School of Pharmacy, Griffith University, Gold Coast, QLD, Australia. 3. Institute for in silico Medicine, University of Sheffield, Sheffield, UK. 4. Department of Mechanical Engineering, University of Sheffield, Sheffield, UK. 5. Menzies Health Institute Queensland, Griffith University, Gold Coast, QLD, Australia. j.kavanagh@griffith.edu.au. 6. School of Allied Health Sciences, Griffith University, Gold Coast, QLD, Australia. j.kavanagh@griffith.edu.au.
Abstract
RATIONALE: Anticholinergic medications largely exert their effects due to actions on the muscarinic receptor, which mediates the functions of acetylcholine in the peripheral and central nervous systems. In the central nervous system, acetylcholine plays an important role in the modulation of movement. OBJECTIVE: This study investigated the effects of over-the-counter medications with varying degrees of central anticholinergic properties on fixation stability, saccadic response time and the dynamics associated with this eye movement during a temporally-cued visual reaction time task, in order to establish the significance of central cholinergic pathways in influencing eye movements during reaction time tasks. METHODS:Twenty-two participants were recruited into theplacebo-controlled, human double-blind, four-way crossover investigation. Eye tracking technology recorded eye movements while participants reacted to visual stimuli following temporally informative and uninformative cues. The task was performed pre-ingestion as well as 0.5 and 2 h post-ingestion of promethazine hydrochloride (strong centrally acting anticholinergic), hyoscine hydrobromide (moderate centrally acting anticholinergic), hyoscine butylbromide (anticholinergic devoid of central properties) and a placebo. RESULTS:Promethazine decreased fixation stability during the reaction time task. In addition, promethazine was the only drug to increase saccadic response time during temporally informative and uninformative cued trials, whereby effects on response time were more pronounced following temporally informative cues. Promethazine also decreased saccadic amplitude and increased saccadic duration during the temporally-cued reaction time task. CONCLUSION: Collectively, the results of the study highlight the significant role that central cholinergic pathways play in the control of eye movements during tasks that involve stimulus identification and motor responses following temporal cues.
RCT Entities:
RATIONALE: Anticholinergic medications largely exert their effects due to actions on the muscarinic receptor, which mediates the functions of acetylcholine in the peripheral and central nervous systems. In the central nervous system, acetylcholine plays an important role in the modulation of movement. OBJECTIVE: This study investigated the effects of over-the-counter medications with varying degrees of central anticholinergic properties on fixation stability, saccadic response time and the dynamics associated with this eye movement during a temporally-cued visual reaction time task, in order to establish the significance of central cholinergic pathways in influencing eye movements during reaction time tasks. METHODS: Twenty-two participants were recruited into the placebo-controlled, human double-blind, four-way crossover investigation. Eye tracking technology recorded eye movements while participants reacted to visual stimuli following temporally informative and uninformative cues. The task was performed pre-ingestion as well as 0.5 and 2 h post-ingestion of promethazine hydrochloride (strong centrally acting anticholinergic), hyoscine hydrobromide (moderate centrally acting anticholinergic), hyoscine butylbromide (anticholinergic devoid of central properties) and a placebo. RESULTS:Promethazine decreased fixation stability during the reaction time task. In addition, promethazine was the only drug to increase saccadic response time during temporally informative and uninformative cued trials, whereby effects on response time were more pronounced following temporally informative cues. Promethazine also decreased saccadic amplitude and increased saccadic duration during the temporally-cued reaction time task. CONCLUSION: Collectively, the results of the study highlight the significant role that central cholinergic pathways play in the control of eye movements during tasks that involve stimulus identification and motor responses following temporal cues.
Authors: Ellen Matthias; Peter Bublak; Hermann J Müller; Werner X Schneider; Joseph Krummenacher; Kathrin Finke Journal: J Exp Psychol Hum Percept Perform Date: 2010-02 Impact factor: 3.332