Significance?... Significance! Empirical, methodological, and theoretical connections between the late positive potential and P300 as neural responses to stimulus significance: An integrative review

There is abundant literature demonstrating that processing emotional stimuli modulates inhibitory control processes. However, the reverse effects, namely, how cognitive inhibition influences the processing of emotional stimuli, have been considerably neglected. This ERP study tries to fill this gap by studying the bidirectional interactions between emotional language and inhibitory processes. To this end, participants read emotional sentences, embedded in a cue‐based Go‐NoGo task. In Experiment 1, the critical emotional adjective preceded the Go‐NoGo visual cue. The ERPs showed a significant reduction in the inhibition‐related N2 component in NoGo trials when they were preceded by negative adjectives, compared to positive or neutral adjectives, indicating a priming‐like effect on inhibitory control. Consistently, the estimated source of this interaction was the dorsomedial PFC, a region associated with inhibitory and control processes. In Experiment 2, the Go‐NoGo cue preceded the emotional adjective, and the ERPs showed a sustained, broadly distributed LPP‐like positivity for NoGo negative trials, relative to all the other conditions. In this case, the presetting of an inhibition state modulated the processing of negatively charged words. Together, the two experiments suggest a mutual facilitation between inhibitory control and negative valence, supporting thereby recent integrative theories of cognition–emotion interactions.

It is well known that most people who think about suicide do not attempt or die by suicide. Capability for suicide, a construct proposed by Joiner (2005) within the interpersonal theory of suicide, was relatively novel in that it explained a potential mechanism by which individuals move from thinking about suicide to engaging in suicidal behavior. In this paper, we examine Joiner’s (2005) original conceptualization of the nature of capability for suicide, and review the evidence for and against this conceptualization. We examine the evidence for specific constructs that comprise capability for suicide, how capability for suicide develops, whether it can change, and possibilities regarding the functional neural correlates of capability for suicide. We then end our review proposing future directions in the study of capability for suicide, which include research across disciplines and countries.

Neurocognitive impairments commonly observed in depressive disorders are thought to be reflected in reduced P300 amplitudes. To date, depression‐related P300 amplitude reduction has mostly been demonstrated cross‐sectionally, while its clinical implication for the course of depression remains largely unclear. Moreover, the relationship between P300 and specific clinical characteristics of depression is uncertain. To shed light on the functional significance of the P300 in depression, we examined whether initial P300 amplitude prospectively predicted changes in depressive symptoms among a community sample of 58 adults (mean age = 38.86 years old, 81% female) with a current depressive disorder. This sample was assessed at two‐time points, separated by approximately nine months (range = 6.6–15.9). At the initial visit, participants completed clinical interviews, self‐report measures, and a flanker task, while EEG was recorded to derive P300 amplitude. At the follow‐up visit, participants again completed the same clinical interviews and self‐report measures. Results indicated that a reduced P300 amplitude at the initial visit was associated with higher total depressive symptoms at follow‐up, even after controlling for initial depressive symptoms. These data indicate the potential clinical utility for the P300 as a neural marker of disease course among adults with a current depressive disorder. Future research may target P300 in interventions to determine whether depression‐related outcomes can be improved.