Dopaminergic stimulation enhances confidence and accuracy in seeing rapidly presented words

Abstract

Liberal acceptance, overconfidence, and increased activity of the neurotransmitter dopamine have been proposed to account for abnormal sensory experiences, for instance, hallucinations in schizophrenia. In normal subjects, increased sensory experience in Yoga Nidra meditation is linked to striatal dopamine release. We therefore hypothesize that the neurotransmitter dopamine may function as a regulator of subjective confidence of visual perception in the normal brain. Although much is known about the effect of stimulation by neurotransmitters on cognitive functions, their effect on subjective confidence of perception has never been recorded experimentally before. In a controlled study of 24 normal, healthy female university students with the dopamine agonist pergolide given orally, we show that dopaminergic activation increases confidence in seeing rapidly presented words. It also improves performance in a forced-choice word recognition task. These results demonstrate neurotransmitter regulation of subjective conscious experience of perception and provide evidence for a crucial role of dopamine.

Cognitive Neurostimulation: Learning to Volitionally Sustain Ventral Tegmental Area Activation

“…The range of behaviors dependent on dopamine neuromodulation is broad and far reaching (Alcaro et al, 2007). Potential benefits of learning to sustain dopamine release include increased perceptual signal to noise (Lou et al, 2011; Pessoa and Engelmann, 2010), invigoration of motor responses (Beierholm et al, 2013; Niv et al, 2007), improved attention (Volkow et al, 2009), working memory (Cools and D’Esposito, 2011; Goldman-Rakic, 1997), and long-term memory encoding (Lisman et al, 2011; Shohamy and Adcock, 2010). Cognitive neurostimulation could achieve some of these benefits with greater temporal precision and fewer side effects than chronic pharmacotherapy or deep brain stimulation, suggesting the potential for safer, more efficient interventions.…”

The Importance of Metamemory Functioning to the Pathogenesis of Psychosis

“…Patients were currently untreated regarding antipsychotics and had never been treated for longer than 4 weeks before. Since it has been shown that dopaminergic treatment can influence confidence of judgments (Lou et al, 2011; Andreou et al, 2013) this exclusion of antipsychotic medication is very important for the pathogenic research. All in all, investigations in the early psychosis demonstrated that memory monitoring biases exist in and contribute to this illness phase and are not merely the consequence of long-term illness-related variables (see Figure 2).…”

“…A “large amount” of evidence indicates that metamemory biases are also associated with deficient dopaminergic processes. For example, Lou et al (2011) administered pergolide, a dopaminergic agonist, to healthy participants in order to construct a model of psychosis-like awareness. They found that pergolide led to increases in confidence.…”

Eluding the illusion? Schizophrenia, dopamine and the McGurk effect

“…This pathological firing can explain reduced susceptibility to illusory multisensory stimuli in schizophrenia since inconsistent dopamine-coded, event-specific precision (Friston, 2005) potentially reduces the likelihood of appropriately binding encountered stimuli from discrete modalities. Relatedly, it has been shown that dopamine agonists facilitate visual discriminative performance and enhance perceived sensory acuity; and that this improvement is associated with greater subjective feelings of event-related confidence (Fillmore et al, 2005; Lou et al, 2011). The investigation of the relationship between multisensory integration and metacognitive confidence judgments in schizophrenia provides an accessible means of increasing our understanding of the associated role of dopaminergic dysregulation.…”