Temporal imprecision and phase instability in schizophrenia resting state EEG

Area of Science:

• Neuroscience
• Psychiatry
• Signal Processing

Background:

• Schizophrenia is linked to temporal processing deficits, typically studied during cognitive tasks.
• It remains unclear if these temporal irregularities manifest in spontaneous brain activity during rest.

Purpose of the Study:

• To investigate temporal precision and regularity of brain activity during resting state in schizophrenia and bipolar disorder.
• To determine if temporal imprecisions observed in task-related activity are also present in spontaneous neural activity.

Main Methods:

• Utilized electroencephalography (EEG) to record brain activity in healthy, schizophrenia, and bipolar disorder participants.
• Developed a novel method, nominal frequency phase stability (NFPS), to quantify phase angle stability over time.
• Applied sample entropy to analyze time-series of phase angles for temporal regularity.

Main Results:

• Schizophrenia patients exhibited increased temporal irregularities in theta activity (4-8 Hz) over frontocentral electrodes during rest.
• Bipolar disorder participants did not show similar significant temporal irregularities in theta activity.
• Findings suggest that temporal imprecision is a characteristic of spontaneous brain activity in schizophrenia.

Conclusions:

• Temporal imprecision and irregularity are present in the resting-state brain activity of individuals with schizophrenia.
• These findings extend the understanding of temporal deficits in schizophrenia beyond task-related performance.
• The novel NFPS method provides a tool for assessing temporal dynamics in neural oscillations.