PRECOG: Comprehensive Experimental Design and Stimuli Protocol for Investigating Depression and Suicidal Ideation

The Multimodal Integration of Neural and Biobehavioral Signals for Predicting Preconscious Responses (PRECOG) project investigated the neural and cognitive mechanisms underlying depression and suicidal ideation through a series of cognitive tasks paired with continuous multimodal physiological and neurophysiological recordings. A total of 160 college-aged participants, including healthy controls, individuals with depression without suicidal ideation, and individuals with depression and suicidal ideation, were recruited based on screening using the Patient Health Questionnaire-9 (PHQ-9) and the Suicide Ideation Scale (SIS).The experimental protocol included three primary cognitive tasks: (1) an emotional Stroop task to assess attentional biases toward affectively charged and suicide-related words, (2) a sentence processing task examining neural responses to self-referential statements varying in emotional and suicidal content, and (3) the Death-Brief Implicit Association Task (D-BIAT) to measure implicit associations with life and death. EEG and other physiological signals were recorded continuously throughout all tasks. Additionally, resting-state recordings (with eyes open and eyes closed) were obtained before, between, and after the emotional Stroop and sentence tasks.Neurophysiological data were acquired using 64-channel electroencephalography (EEG), electrooculography (EOG), electrocardiography (ECG), and galvanic skin response (GSR), and were supplemented with eye tracking and high-frame-rate facial video recordings. By integrating neural, behavioral, and physiological measures, the PRECOG study aimed to advance our understanding of cognitive and emotional processing in depression and suicidality, ultimately contributing to more precise risk assessment and targeted clinical intervention.