Human perceptual learning is delayed by the N-methyl-D-aspartate receptor partial agonist D-cycloserine

Background: The optimisation of learning has long been a focus of scientific research, particularly in relation to improving psychological treatment and recovery of brain function. Previously, partial N-methyl-D-aspartate agonists have been shown to augment reward learning, procedural learning and psychological therapy, but many studies also report no impact of these compounds on the same processes. Aims: Here we investigate whether administration of an N-methyl-D-aspartate partial agonist (D-cycloserine) modulates a previously unexplored process – tactile perceptual learning. Further, we use a longitudinal design to investigate whether N-methyl-D-aspartate-related learning effects vary with time, thereby providing a potentially simple explanation for apparent mixed effects in previous research. Methods: Thirty-four volunteers were randomised to receive one dose of 250 mg D-cycloserine or placebo 2 h before tactile sensitivity training. Tactile perception was measured using psychophysical methods before and after training, and 24/48 h later. Results: The placebo group showed immediate within-day tactile perception gains, but no further improvements between-days. In contrast, tactile perception remained at baseline on day one in the D-cycloserine group (no within-day learning), but showed significant overnight gains on day two. Both groups were equivalent in tactile perception by the final testing – indicating N-methyl-D-aspartate effects changed the timing, but not the overall amount of tactile learning. Conclusions: In sum, we provide first evidence for modulation of perceptual learning by administration of a partial N-methyl-D-aspartate agonist. Resolving how the effects of such compounds become apparent over time will assist the optimisation of testing schedules, and may help resolve discrepancies across the learning and cognition domains

Investigating the effect of proactive interference control training on intrusive memories = Investigando el efecto del entrenamiento de control de interferencias proactivas en las memorias intrusivas = 研究主动干扰控制训练对闯入性记忆的影响

Intrusive re-experiencing is a hallmark symptom of Posttraumatic Stress Disorder (PTSD). According to prominent models of intrusive phenomena, intrusive memories may result from impairments in the efficiency of working memory capacity (WMC), more specifically proactive interference control. Yet, experimental research is scarce. Therefore, the present study aimed to investigate experimentally the role of proactive interference control in intrusive memories. We randomly assigned 57 healthy participants to either receive a high interference control training or a low interference control training. Participants were then exposed to highly distressing film clips. WMC was assessed before and after the training. Intrusion symptoms were assessed directly post-training and after one week using an Intrusion Provocation Task (IPT), a one-week intrusions diary, and the retrospective intrusion subscale of the Impact of Event Sale – Revised (IES-R). Results indicated that both groups reported improvements in WMC and fewer intrusions on the second IPT post-training, with no differences between groups. Similarly, no group differences on intrusions were found at one-week follow-up (i.e., intrusion diary and IES-R). To conclude, these data are not consistent with the hypothesis that WMC plays a role in intrusive re-experiencing. Implications for future research are discussed. / La re-experiencia intrusiva es un síntoma distintivo del trastorno por estrés postraumático (TEPT). De acuerdo con los prominentes modelos de fenómenos intrusivos, las memorias intrusivas pueden resultar en deterioros en la eficiencia de la capacidad de memoria de trabajo (CMT), más específicamente del control proactivo de interferencias. Sin embargo, la investigación experimental a este respecto es escasa. Por lo tanto, el presente estudio tuvo como objetivo investigar experimentalmente el papel del control proactivo de interferencias en las memorias intrusivas. Asignamos aleatoriamente 57 participantes sanos a recibir, ya sea, un entrenamiento de control de alta interferencia o un entrenamiento de control de baja interferencia. Luego, los participantes fueron expuestos a videoclips de películas altamente angustiantes. La CMT fue evaluada antes y después del entrenamiento. Los síntomas de intrusión se evaluaron directamente después del entrenamiento y después de una semana utilizando una Tarea de Provocación de Intrusión (IPT), registro diario de intrusiones (por una semana), y la subescala de intrusión retrospectiva de la Escala del Impacto del Evento - Revisada (IES-R). Los resultados indicaron que ambos grupos experimentaron mejoras en la CMT y reducción de intrusiones en la segunda IPT posterior al entrenamiento, sin diferencias entre los grupos. De manera similar, no se encontraron diferencias de grupo en las intrusiones en el seguimiento de una semana (es decir, en el diario de intrusiones y la IES-R). Para concluir, estos datos no son consistentes con la hipótesis de que la CMT desempeña un papel en la re-experiencia intrusiva. Se discuten las implicaciones para futuras investigaciones. / 闯入性再体验是创伤后应激障碍（PTSD）的标志性症状。根据闯入现象的经典模型，闯入性记忆可能是由工作记忆容量（WMC）效率的损害引起的，更具体地说是主动干扰控制。然而，这方面实验研究很少。因此，本研究通过实验研究主动干扰控制在闯入性记忆中的作用。我们随机分配了57名健康被试，以接受高干扰控制训练或低干扰控制训练。然后被试接触到令人非常痛苦的电影片段。在训练前后对WMC进行了评估。在训练后和一周后随访使用闯入激发任务（IPT），一周闯入症状日记以及事件影响量表修订版（IES－R）的回顾性闯入子量表直接评估闯入症状。结果表明，两组均报告WMC改善，第二次IPT训练后闯入较少，两组间无差异。同样，在一周的随访中没有发现闯入的群体差异（即闯入日记和IES-R）。总之，这些数据与WMC在闯入性再体验中发挥作用的假设不一致。文中讨论了对未来研究的启示

Simply imagining sunshine, lollipops and rainbows will not budge the bias: The role of ambiguity in interpretive bias modification

Imagery-based interpretive bias modification (CBM-I) involves repeatedly imagining scenarios that are initially ambiguous before being resolved as either positive or negative in the last word/s. While the presence of such ambiguity is assumed to be important to achieve change in selective interpretation, it is also possible that the act of repeatedly imagining positive or negative events could produce such change in the absence of ambiguity. The present study sought to examine whether the ambiguity in imagery-based CBM-I is necessary to elicit change in interpretive bias, or, if the emotional content of the imagined scenarios is sufficient to produce such change. An imagery-based CBM-I task was delivered to participants in one of four conditions, where the valence of imagined scenarios were either positive or negative, and the ambiguity of the scenario was either present (until the last word/s) or the ambiguity was absent (emotional valence was evident from the start). Results indicate that only those who received scenarios in which the ambiguity was present acquired an interpretive bias consistent with the emotional valence of the scenarios, suggesting that the act of imagining positive or negative events will only influence patterns of interpretation when the emotional ambiguity is a consistent feature

Approach and Avoidance Tendencies in Spider Fearful Children: The Approach-Avoidance Task

Fear in children is associated with the tendency to avoid situations related to the fear. In this study, the Approach-Avoidance Task (AAT) was evaluated as a test of automatic behavioral avoidance tendencies in children. A sample of 195 children aged between 9 and 12 years completed an AAT, a Behavioral Assessment Task (BAT), and two spider fear questionnaires. The results indicate that all children showed an automatic avoidance tendency in response to spider pictures, but not pictures of butterflies or neutral pictures. Girls who reported more fear of spiders on the self-reports and behaved more anxiously during the BAT also showed a greater avoidance tendency in the AAT. These relationships were absent in boys

Assessment of automatic associations with bodily sensations and agoraphobic situations in panic disorder

Background and Objectives One of the central assumptions of cognitive models of Panic Disorder (PD) is that automatic panic-related associations are a core feature of PD. However, empirical findings are mixed and inconsistent, rendering it difficult to evaluate the role of panic-related associations adequately, particularly in relation to the relevant theories. The present study aimed to further advance our understanding of automatic associations in PD, and therefore applied a paradigm novel in this context, namely an Extrinsic Affective Simon Task (EAST). Methods Participants involved treatment seeking, unmedicated panic patients (n=45) and healthy controls (n=38). The EAST was applied prior to treatment. It included the following stimuli as targets: panic-related bodily sensations and agoraphobia-related situations, and as attributes: pleasant versus unpleasant, fear-related words. Results Contrary to our expectations, panic patients did not show stronger negative than positive automatic associations for either panic-related symptoms or agoraphobia-related situations, compared to healthy controls. Moreover, EAST effects did not correlate with panic-related self-report measures. Limitations Although the present study involved patients who were actively seeking treatment, panic-related associations might not have been activated sufficiently. Hence, a brief activation procedure (e.g., hyperventilation) might have been needed to optimize the assessment condition. Conclusions The present findings do not support contemporary theories of panic-related associations. Therefore, follow-up work is needed to disentangle their functional and operational properties more thoroughly. </p

Assessment of automatic associations with bodily sensations and agoraphobic situations in panic disorder

Background and Objectives One of the central assumptions of cognitive models of Panic Disorder (PD) is that automatic panic-related associations are a core feature of PD. However, empirical findings are mixed and inconsistent, rendering it difficult to evaluate the role of panic-related associations adequately, particularly in relation to the relevant theories. The present study aimed to further advance our understanding of automatic associations in PD, and therefore applied a paradigm novel in this context, namely an Extrinsic Affective Simon Task (EAST). Methods Participants involved treatment seeking, unmedicated panic patients (n=45) and healthy controls (n=38). The EAST was applied prior to treatment. It included the following stimuli as targets: panic-related bodily sensations and agoraphobia-related situations, and as attributes: pleasant versus unpleasant, fear-related words. Results Contrary to our expectations, panic patients did not show stronger negative than positive automatic associations for either panic-related symptoms or agoraphobia-related situations, compared to healthy controls. Moreover, EAST effects did not correlate with panic-related self-report measures. Limitations Although the present study involved patients who were actively seeking treatment, panic-related associations might not have been activated sufficiently. Hence, a brief activation procedure (e.g., hyperventilation) might have been needed to optimize the assessment condition. Conclusions The present findings do not support contemporary theories of panic-related associations. Therefore, follow-up work is needed to disentangle their functional and operational properties more thoroughly. </p