It’s in the timing: reduced temporal precision in neural activity of schizophrenia

Abstract

Studies of perception and cognition in schizophrenia (SCZ) show neuronal background noise (ongoing activity) to intermittently overwhelm the processing of external stimuli. This increased noise, relative to the activity evoked by the stimulus, results in temporal imprecision and higher variability of behavioral responses. What, however, are the neural correlates of temporal imprecision in SCZ behavior? We first report a decrease in electroencephalography signal-to-noise ratio (SNR) in two SCZ datasets and tasks in the broadband (1–80 Hz), theta (4–8 Hz), and alpha (8–13 Hz) bands. SCZ participants also show lower inter-trial phase coherence (ITPC)—consistency over trials in the phase of the signal—in theta. From these ITPC results, we varied phase offsets in a computational simulation, which illustrated phase-based temporal desynchronization. This modeling also provided a necessary link to our results and showed decreased neural synchrony in SCZ in both datasets and tasks when compared with healthy controls. Finally, we showed that reduced SNR and ITPC are related and showed a relationship to temporal precision on the behavioral level, namely reaction times. In conclusion, we demonstrate how temporal imprecision in SCZ neural activity—reduced relative signal strength and phase coherence—mediates temporal imprecision on the behavioral level.

Toward naturalistic neuroscience: Mechanisms underlying the flattening of brain hierarchy in movie-watching compared to rest and task

“…This has led to a deeper understanding of how the brain solves complex psychological tasks such as, for example, working memory (11) and reward (12), but at the same time, this also led to the accidental discovery of a network of regions that are more active during rest than during task (13,14). Over time, this has grown into a burgeoning field, which has provided new insights into how spontaneous resting state activity recapitulates task activity (15)(16)(17)(18)(19)(20)(21)(22). However, it has also become clear that the field needs more realistic real-life stimuli where the brain is forced to integrate complex multimodal stimuli over longer time spans.…”

Prolonged Intrinsic Neural Timescales Dissociate from Phase Coherence in Schizophrenia

“…Schizophrenia patients show deficits with input processing [ 1 , 2 ]. One possible source of these deficits may stem from temporal imprecision on the neuronal level, which leads to problems with the temporal segregation of incoming information [ 3 , 4 ]. Temporal segregation requires temporal precision as the single input may be segregated from others through their distinct time points.…”

Characterization of local activation and network dynamics from electrical brain activity: application to schizophrenia, mild cognitive impairment and dementia due to Alzheimer's disease

“…Since it has been shown that theta band power overlaps with ERP peaks ), our results suggest that theta-band meta-states are also time-locked to the stimulus, with a midline network being associated with the ERP peak, and that this phenomenon is not found in patients with schizophrenia. Another possible explanation of this apparent lack of time-locked activation could be the previously observed temporal imprecision of patients with schizophrenia when processing external stimuli (Wolff et al (2021)). A higher variability of behavioral responses to the relevant stimuli, accompanied by an increase in background activity, could lead to temporal mismatches of the activation of meta-state 3 between trials, canceling out the time-locked response when visualizing the averaged behavior.…”

“…A reduction in metrics of task-related activity is therefore present across many domains, such as sensory, motor, cognitive, and affective ). Moreover, it has also been shown that the signal-to-noise ratio of EEG activity is decreased in the theta and alpha bands and inter-trial phase coherence is decreased in the theta band, suggesting that temporal imprecision in the processing of task is related to an increase in neuronal background activity (Wolff et al (2021)). Coupling measures have also been used to analyze functional brain interactions in schizophrenia during such tasks.…”

“…Schizophrenia-induced alterations in predictive coding have been associated with abnormal temporospatial dynamics of rest/task modulation of EEG activity ). Here, we hypothesized that patients with schizophrenia will fail to properly activate task-related meta-states with temporal precision (Wolff et al (2021)). Moreover, schizophrenia has been linked to reduced dynamism of brain activity, with patients displaying difficulty in the activation of the default mode network, after which it remains active for abnormally long periods (Kottaram et al (2019)).…”