Biology subjects

van Schouwenburg, M. R.

Publications and source records attributed to van Schouwenburg, M. R..

3 recordsLinked to original sources

bioRxiv2022

Conscious perception and the role of the basal ganglia: preliminary findings from a deep brain stimulation study

Conscious perception is thought to depend on global amplification of sensory input. In recent years, the basal ganglia have been implicated in gating conscious access due to their consistent involvement in thalamocortical loops. However, much of the evidence implicating the basal ganglia in these processes in humans is correlational. The current study is a preliminary investigation in four patients to explore whether deep brain stimulation (DBS) in the basal ganglia might improve conscious perception. In our study, treatment-resistant obsessive-compulsive disorder (OCD) patients with a striatal DBS implant completed two canonical conscious perception tasks: emotion-induced blindness and backward masking. We found preliminary evidence in support of a role played by the basal ganglia in conscious perception at the behavioral level: patients performed better when stimulation was active, but we could not establish neural effects corresponding to these behavioral findings, possibly due to our small sample size. We discuss the potential implications and limitations of our study and delineate avenues for future research.

neuroscience↗

bioRxiv2020

Conscious perception and the modulatory role of dopamine: no effect of the dopamine D2 agonist cabergoline on visual masking, the attentional blink, and probabilistic discrimination

RationaleConscious perception is thought to depend on global amplification of sensory input. In recent years, striatal dopamine has been proposed to be involved in gating information and conscious access, due to its modulatory influence on thalamocortical connectivity. ObjectivesSince much of the evidence that implicates striatal dopamine is correlational, we conducted a double-blind crossover pharmacological study in which we administered cabergoline - a dopamine D2 agonist - and placebo to 30 healthy participants. Under both conditions, we subjected participants to several well-established experimental conscious-perception paradigms, such as backward masking and the attentional blink task. ResultsWe found no evidence in support of an effect of cabergoline on conscious perception: key behavioral and event-related potential (ERP) findings associated with each of these tasks were unaffected by cabergoline. ConclusionsOur results cast doubt on a causal role for dopamine in visual perception. It remains an open possibility that dopamine has causal effects in other tasks, perhaps where perceptual uncertainty is more prominent.

neuroscience↗

bioRxiv2019

Effects of mid-frontal brain stimulation on sustained attention

Sustained attention is defined as the ability to maintain attention over longer periods of time, which typically declines with time on task (i.e., the vigilance decrement). Previous studies have suggested an important role for the dorsomedial prefrontal cortex (mPFC) in sustained attention. In two experiments, we aimed to enhance sustained attention by applying transcranial electrical current stimulation over the mPFC during a sustained attention task. In the first experiment, we applied transcranial direct current stimulation (tDCS) in a between-subject design (n=97): participants received either anodal, cathodal, or sham stimulation. Contrary to our prediction, we found no effect of stimulation on the vigilance decrement. In the second experiment, participants received theta and alpha transcranial alternating current stimulation (tACS) in two separate sessions (n=47, within-subject design). Here, we found a frequency-dependent effect on the vigilance decrement, such that contrary to our expectation, participants performance over time became worse after theta compared to alpha stimulation. However, this result needs to be interpreted with caution given that this effect could be driven by differential side effects between the two stimulation frequencies. To conclude, across two studies, we were not able to reduce the vigilant decrement using tDCS or theta tACS.

neuroscience↗