Biology subjects

Alves, M. V.

Publications and source records attributed to Alves, M. V..

2 recordsLinked to original sources

bioRxiv2020

Cognitive Processing dissociation and Mental Effort manipulation in long demanding tasks

Individuals uses cognitive resources to modulate performance in demanding tasks and a non-invasive and reliable way of measuring mental effort is pupillometry. This study aimed to test the mental effort related to different processing systems in long tasks with controlled and automatic demands. We conducted two experiments with healthy subjects: in Experiment 1 (n=15), using a metronome to ensure control on task pace, participants performed a serial number generation task (Counting; little to no effort tasks), a random number generation (RNG; effortful tasks), and no task (Unfilled interval; no effort at all). In experiment 2, (n=15) participants performed counting tasks with or without additional intermediary beeps produced by a metronome to assess the effect of a possible increase in effort demanded by the distractors. Experiment 1 showed differences between unfilled interval, counting and RNG. Experiment 2 showed that the intermediate beep made the counting tasks more demanding than the normal counting tasks. Notable in both experiments was the tendency of participants to demand mental effort at the beginning of the trial. These results indicate that previously effortless automatic tasks can become controlled, or at least more demanding, with a simple experimental manipulation. They also reveal that tasks that require mental effort over a long period will demand more than automatic ones, but even so the peak of this demand is in the initial trial period. Moreover, they reveal the high sensitivity of pupillometry for the measurement of mental effort employing different processing systems and cognitive resource modulation.

neuroscience↗

bioRxiv2019

Haloperidol-induced impairment on working memory capacity affecting long term memory performance: the binding hypothesis

The dopaminergic system is implicated in several cognitive processes including memory, attention and executive functions. This study was a double-blind, placebo-randomized trial designed to investigate the effect of dopamine D2 receptor blockade on episodic and working memory and particularly the relationship between executive functions, working memory capacity and long-term memory (LTM). Subjects ingested a single oral dose (4 mg) of haloperidol, a dopamine D2 receptor antagonist or placebo. Multiple linear regression using generalized linear models and a generalized estimating equation were used for statistical analyses. The results demonstrated that haloperidol impaired episodic memory (free recall of words and prose recall), working memory capacity-WMC (operation span task-OSPAN) and highly demanding executive functions (random number generation - RNG). In addition, it demonstrated that despite the large impairment in the RNG task performance in the haloperidol group, it did not affect episodic memory. The OSPAN task is predictive of episodic memory impairment, suggesting that memory impairments produced by haloperidol could be due in part to the impairment of WMC. As WMC partly relies on the appropriate functioning of the medial temporal lobe, probably the haloperidol-induced impairment on episodic memory through the decrease in the performance of WMC may depend on the activation of this area of the brain. The present study is relevant because it provides data on dopaminergic modulation of memory systems; suggesting that the major cause of deficits in episodic memory may be due to hippocampal function and WMC impairments, the latter more specifically with regard to controlled search and binding.

neuroscience↗