Mind-wandering and Predictive Processes in Narcolepsy: a Putative Mechanism Through Covert REM Intrusions

Summary

Mind wandering is a state in which attention turns away from the external environment or current task to focus on internal thoughts (past experiences, future events, planned actions...). Humans are thought to spend at least one third of their waking lives in this state. Mind wandering can be assessed experimentally by investigating mental content during well-controlled tasks. In this case, task-unrelated thoughts likely to arise during tasks of varying cognitive demand are studied. Mind wandering (=task-unrelated thoughts) has a deleterious effect on cognitive performance in most paradigms, particularly those requiring sustained attention and executive control. However, this phenomenon could also have cognitive benefits, although knowledge on this issue remains limited. For example, it has been suggested that mind wandering could promote creativity, anticipation of future scenarios and prospective memory. In a recent behavioural study, we investigated the cost and benefit of mind wandering in an implicit visual-motor probabilistic learning task (ASRT - Alternating Serial Reaction Time Task). ASRT distinguishes between two fundamental processes: visuomotor performance and implicit statistical learning. While the former reflects visuo-spatial discrimination efficiency, the latter refers to the unintentional acquisition of probabilistic regularities of external inputs. Reduced visuo-spatial accuracy and faster but less accurate responses have been observed during periods of mind-wandering. On the other hand, mind-wandering was associated with enhanced statistical learning reflecting improved predictive processing.

Whereas the study of the neural correlates of mind-wandering is constantly growing, the mechanisms triggering mind-wandering are far from being unravelled, but may involve sleep pressure. Thus, the frequency of mind wandering tends to increase after sleep deprivation or during attention-demanding cognitive tasks, during which neurophysiological markers of local sleep appear. These markers of sleep during wakefulness are frequently observed in hypersomnolence disorders. They are generally defined by the appearance of slow waves (typical of slow wave sleep, SWS). Nevertheless, sleep intrusions during wakefulness may not be limited to non-rapid-eye-movement (NREM) sleep but also concern REM sleep. REM sleep is the sleep state when the most intense forms of dreaming occur, and could therefore be phenomenologically similar to the reverie of mind wandering. Thus, daytime mental wandering could be triggered by intrusions of REM sleep during wakefulness.

Patients with narcolepsy type 1 (NT1) exhibit frequent REM sleep onset during daytime wakefulness. The study of ASRT in this population therefore offers a unique opportunity to investigate the role of REM sleep intrusions in mind wandering. The hypothesis is that mind wandering would be observed more frequently during the ASRT task in NT1 patients (with REM sleep intrusions during wakefulness) than in patients with idiopathic hypersomnia (IH) (with NREM sleep intrusions during wakefulness) and patients with subjective hypersomnolence (little or no sleep intrusion). Furthermore, it could be possible that REM sleep-related mind wandering would be associated with impaired visuomotor performance in terms of accuracy, but improved predictive processing (probabilistic learning) compared to NREM sleep intrusions or no sleep intrusion during the task.

Conditions

• Narcolepsy Type 1
• Hypersomnolence
• Idiopathic Hypersomnia

Interventions

BEHAVIORAL

ASRT

The task involves the presentation of a visual stimulus in one of four horizontal locations on the screen, and participants are instructed to indicate the location of the target stimulus by pressing the corresponding key on the keyboard. In case of correct response, the target stimulus disappears, and after a 120 ms interstimulus interval, the next stimulus appears. In case of an incorrect response, the target stimulus remains in place until the first correct response. The stimuli follow a probabilistic eight-element sequence, with pattern and random elements alternating with each other. Each participant will be assigned to one of 24 possible sequences throughout the task. The ASRT task will be composed of 25 blocks, with each block containing ten repetitions of the eight-element sequence. After each block, participants will have to take a short break and answer the thought probes before continuing. All patients will perform the task one time.

BEHAVIORAL

Questionnaires

All patients will have to fill questionnaire at the beginning of the study * Spontaneous and Deliberate Mind Wandering Scales (SDMWS) * Epworth Sleepiness Scale * Narcolepsy Severity Index * Idiopathic Hypersomnia Severity Scale * Hospital Anxiety and Depression scale * Horne \& Ostberg questionnaire * Attention Deficit Hyperactivity Disorder (ADHD) auto-evaluation * Pittsburgh Sleep Quality Index * Insomnia Severity Index * Psychotic-like experiences scale

DEVICE

Electrophysiological recordings

A subset of patients in each arm will undergo polysomnography recording (EEG, EOG, EMG, ECG) during the ASRT

Sponsors & Collaborators

• Hospices Civils de Lyon

  lead OTHER

Principal Investigators

• Laure PETER-DEREX, Professor · Hospices Civils de Lyon

Study Design

Allocation

NON_RANDOMIZED

Purpose

BASIC_SCIENCE

Masking

NONE

Model

PARALLEL

Eligibility

Min Age

18 Years

Max Age

65 Years

Sex

ALL

Healthy Volunteers

No

Timeline & Regulatory

Start

2024-12-03

Primary Completion

2026-12-03

Completion

2026-12-03

Countries

• France

Study Locations