No abstract

The late positive potential (LPP) is larger for emotional than neutral stimuli, and reflects increased attention to motivationally salient stimuli. Recent studies have shown that the LPP can also be modulated by stimulus meaning and task relevance. The present studies sought to determine whether the magnitude of the LPP can be manipulated by directing attention to more or less arousing aspects within an emotional stimulus. To this end, trials included a passive viewing and directed attention portion. In both Studies 1 and 2, unpleasant compared to neutral images were associated with an increased LPP during passive viewing; additionally, directing attention to non-arousing compared to highly arousing areas of unpleasant images resulted in a decreased LPP. Results are discussed in terms of the utility of using the LPP to understand emotion-cognition interactions, especially with regard to directed visual attention as an emotion regulation strategy.

No animal models replicate the complexity of human depression. However, a number of behavioral tests in rodents are sensitive to antidepressants and may thus tap important underlying biological factors. Such models may also offer the best opportunity to discover novel treatments. Here, we used several of these models to test the hypothesis that the acid-sensing ion channel-1a (ASIC1a) might be targeted to reduce depression. Genetically disrupting ASIC1a in mice produced antidepressant-like effects in the forced swim test, the tail suspension test, and following unpredictable mild stress. Pharmacologically inhibiting ASIC1a also had antidepressant-like effects in the forced swim test. The effects of ASIC1a disruption in the forced swim test were independent of and additive to those of several commonly used antidepressants. Furthermore, ASIC1a disruption interfered with an important biochemical marker of depression, the ability of stress to reduce BDNF in the hippocampus. Restoring ASIC1a to the amygdala of ASIC1a Ϫ/Ϫ mice with a viral vector reversed the forced swim test effects, suggesting that the amygdala is a key site of ASIC1a action in depression-related behavior. These data are consistent with clinical studies emphasizing the importance of the amygdala in mood regulation, and suggest that ASIC1a antagonists may effectively combat depression.

Event-related potentials (ERPs) are a direct measure of neural activity and are ideally suited to study the time-course of attentional engagement with emotional and drug-related stimuli in addiction. In particular, the late positive potential (LPP) appears enhanced following cocainerelated compared to neutral stimuli in individuals with cocaine use disorders (CUD). However, previous studies have not directly compared cocaine-related to emotional stimuli while examining potential differences between abstinent and current cocaine users. The present study examined ERPs in 55 CUD (27 abstinent and 28 current users) and 29 matched healthy controls while they passively viewed pleasant, unpleasant, neutral, and cocaine-related pictures. To examine the timecourse of attention to these stimuli, we analyzed both an early and later window in the LPP as well as the early posterior negativity (EPN), established in assessing motivated attention. Cocaine pictures elicited increased electrocortical measures of motivated attention in ways similar to affectively pleasant and unpleasant pictures in all CUD, an effect that was no longer discernible during the late LPP window for the current users. This group also exhibited deficient processing of the other emotional stimuli (early LPP window: pleasant pictures; late LPP window: pleasant and unpleasant pictures). Results were unique to the LPP and not EPN. Taken together, results support a relatively early attention bias to cocaine stimuli in cocaine addicted individuals further suggesting that recent cocaine use decreases such attention bias during later stages of processing but at the expense of deficient processing of other emotional stimuli. KeywordsCocaine addiction; motivated attention; emotional processing; late positive potential Drug-related compared to neutral stimuli elicit increases in physiological reactivity in drug addicted individuals (Carter & Tiffany, 1999). Similar research demonstrates unique reactions to emotional compared to neutral stimuli in healthy individuals (Lang et al., 1997;Vuilleumier, 2005;Schupp et al., 2007). Termed 'motivated attention', it is hypothesized that motivational systems automatically allocate attention to, and enhance the salience of, emotional stimuli (Lang et al., 1997). Two event-related potentials (ERP), the early posterior negativity (EPN) and the late positive potential (LPP), are larger for both pleasant and unpleasant compared to neutral visual stimuli, interpreted as reflecting increased * Corresponding Author: Rita Z. Goldstein, Medical Research, Brookhaven National Laboratory, 30 Bell Ave., Bldg. 490, Upton, NY, 11973-5000; tel. (631) 344-2657; fax (631) Schupp et al., 2000;Schupp et al., 2003a;2004b;Hajcak et al., 2007;Hajcak & Olvet, 2008;Foti et al., 2009). These ERPs capture different stages within emotional processing; specifically, the EPN reflects early selective attentional processing, while the LPP reflects continued processing of motivationally significant stimuli. Also, evidence suggests that the LPP is...

Background-Individuals with cocaine use disorder (CUD) chose cocaine over non-drug rewards. In two newly designed laboratory tasks with pictures, we document this modified choice outside of a cocaine administration paradigm.

The late positive potential (LPP) is an event-related potential that is enhanced when viewing arousing (pleasant and unpleasant) pictures compared to neutral pictures. The affective modulation of the LPP is believed to reflect the increased attention to, and perceptual processing of, emotional stimuli. The present study examined whether concurrent task difficulty (performing mathematics) would modulate the LPP while participants viewed emotionally arousing stimuli. Results indicated that the LPP was larger following pleasant and unpleasant stimuli than it was following neutral stimuli; moreover, the magnitude of this increase was not influenced by concurrent task difficulty. This finding suggests that the affective modulation of neural activity during picture viewing is relatively automatic and is insusceptible to competing task demands. Results are further discussed in terms of the LPP's role in motivated attention and implications for research on emotion regulation.

Event-related potential studies have reported error-related negativity following both error commission and feedback indicating errors or monetary loss. The present study examined whether error-related negativities could be elicited by a predictive cue presented prior to both the decision and subsequent feedback in a gambling task. Participants were presented with a cue that indicated the probability of reward on the upcoming trial (0, 50, and 100%). Results showed a negative deflection in the event-related potential in response to loss cues compared with win cues; this waveform shared a similar latency and morphology with the traditional feedback error-related negativity.

Learning can be guided by unexpected success or failure, signaled via dopaminergic positive reward prediction error (ϩRPE) and negative reward-prediction error (ϪRPE) signals, respectively. Despite conflicting empirical evidence, RPE signaling is thought to be impaired in drug addiction. To resolve this outstanding question, we studied as a measure of RPE the feedback negativity (FN) that is sensitive to both reward and the violation of expectation. We examined FN in 25 healthy controls; 25 individuals with cocaine-use disorder (CUD) who tested positive for cocaine on the study day (CUDϩ), indicating cocaine use within the past 72 h; and in 25 individuals with CUD who tested negative for cocaine (CUDϪ). EEG was acquired while the participants performed a gambling task predicting whether they would win or lose money on each trial given three known win probabilities (25, 50, or 75%). FN was scored for the period in each trial when the actual outcome (win or loss) was revealed. A significant interaction between prediction, outcome, and group revealed that controls showed increased FN to unpredicted compared with predicted wins (i.e., intact ϩRPE) and decreased FN to unpredicted compared with predicted losses (i.e., intact ϪRPE). However, neither CUD subgroup showed FN modulation to loss (i.e., impaired ϪRPE), and unlike CUDϩ individuals, CUDϪ individuals also did not show FN modulation to win (i.e., impaired ϩRPE). Thus, using FN, the current study directly documents ϪRPE deficits in CUD individuals. The mechanisms underlying ϪRPE signaling impairments in addiction may contribute to the disadvantageous nature of excessive drug use, which can persist despite repeated unfavorable life experiences (e.g., frequent incarcerations).