Inhibition of PKA anchoring to A-kinase anchoring proteins impairs consolidation and facilitates extinction of contextual fear memories

Both genetic and pharmacological studies demonstrated that contextual fear conditioning is critically regulated by cyclic AMP-dependent protein kinase (PKA). Since PKA is a broad range protein kinase, a mechanism for confining its activity is required. It has been shown that intracellular spatial compartmentalization of PKA signaling is mediated by A-kinase anchoring proteins (AKAPs). Here, we investigated the role of PKA anchoring to AKAPs in different stages of the memory process (acquisition, consolidation, retrieval and extinction) using contextual fear conditioning, a hippocampus-dependent learning task. Mice were injected intracerebroventricularly or intrahippocampally with the membrane permeable PKA anchoring disrupting peptides St-Ht31 or St-superAKAP-IS at different time points during the memory process. Blocking PKA anchoring to AKAPs resulted in an impairment of fear memory consolidation. Moreover, disrupted PKA anchoring promoted contextual fear extinction in the mouse hippocampus. We conclude that the temporal and spatial compartmentalization of hippocampal PKA signaling pathways, as achieved by anchoring of PKA to AKAPs, is specifically instrumental in long-term contextual fear memory consolidation and extinction, but not in acquisition and retrieval.     

Electrophysiological evidence for size invariance in masked picture repetition priming

This experiment examined invariance in object representations through measuring event-related potentials (ERPs) to pictures in a masked repetition priming paradigm. Pairs of pictures were presented where the prime was either the same size or half the size of the target object and the target was either presented in a normal orientation or was a normal sized mirror reflection of the prime object. Previous masked repetition priming studies have found a cascade of priming effect sensitive to perceptual (N190/P190) and semantic (N400) properties of the stimulus. This experiment found that both early (N190/P190 effects) and later effects (N400) were invariant to size, whereas only the N190/P190 effect was invariant to mirror reflection. The combination of a small prime and a mirror reflected target led to no significant priming effects. Taken together, the results of this set of experiments suggests that object recognition, more specifically, activating an object representation, occurs in a hierarchical fashion where overlapping perceptual information between the prime and target is necessary, although not always sufficient, to activate a higher level semantic representation.     

Eating disorder pathology among overweight treatment-seeking youth: clinical correlates and cross-sectional risk modeling

Preliminary research suggests that pediatric overweight is associated with increased eating disorder pathology, however, little is known about which overweight youth are most vulnerable to eating disorder pathology. We therefore investigated 122 overweight treatment-seeking youth to describe eating disorder pathology and mental health correlates, and to identify psychopathological constructs that may place overweight youth at increased risk for eating disorder pathology. Youth participated in a comprehensive assessment of eating disorders, mood and anxiety disorders, general psychopathology, and risk variables involving semi-structured clinical interviews and self- and parent-report questionnaires prior to the initiation of weight-loss treatment. Ten youth met criteria for an eating disorder, and over one-third endorsed recent binge eating. Eating disorder pathology was associated with depressive and anxious symptoms (p's<0.001). Structural equation modeling indicated increased negative affect, teasing experience, and thin-ideal internalization, and decreased perfectionism were associated with increased eating disorder pathology. Findings corroborate earlier work indicating that eating disorder pathology is elevated and clinically significant in overweight treatment-seeking youth, bolstering the need for mental health assessment of such individuals. Cross-sectional modeling proposed key variables that relate to eating disorder pathology in overweight treatment-seeking youth, which following prospective replication, may inform the development of effective interventions for overweight and eating disorders.     

Semantic similarity dissociates short- from long-term recency effects: Testing a neurocomputational model of list memory

The finding that recency effects can occur not only in immediate free recall (i.e., short-term recency) but also in the continuous-distractor task (ie., long-term recency) has led many theorists to reject the distinction between short- and long-term memory stores. Recently, we have argued that long-term recency effects do not undermine the concept of a short-term store, and we have presented a neurocomputational model that accounts for both short- and long-term recency and for a series of dissociations between these two effects. Here, we present a new dissociation between short- and long-term recency based on semantic similarity, which is predicted by our model. This dissociation is due to the mutual support between associated items in the short-term store, which takes place in immediate free recall and delayed free recall but not in continuous-distractor free recall.     

Imagination inflation: a statistical artifact of regression toward the mean

In the imagination inflation procedure of Garry, Manning, Loftus, and Sherman (1996), subjects rated a list of events in terms of how likely each was to have occurred in their childhood. Two weeks later, some of the events were imagined; control events were not. The subjects then rated the likelihood of occurrence for each event a second time. Garry et al. (1996) reported that the act of imagining the target events led to increased ratings of likelihood. This finding has been interpreted as indicating that false events can be suggestively planted in memory by simply having people imagine them. The present study tests and confirms the hypothesis that the results that have been attributed to imagination inflation are simply a statistical artifact of regression toward the mean. The experiment of Garry et al. (1996) was reproduced (with some procedural changes), using younger and older adults. The results of Garry et al. (1996) were replicated; likelihood ratings for events initially rated low in likelihood did increase from Time 1 to Time 2. However, ratings for events initially rated high in likelihood decreased under the same conditions, and these results were consistent with the imagined target events, the target events not imagined, and the nontarget events.     

The influence of significant others on attitudes, subjective norms and intentions regarding dietary supplement use among adolescent athletes

Dietary supplement use has increased significantly over the past decade. The use of supplements among adolescents seems to be influenced by their beliefs and attitudes. The influence of coaches, parents, and athletic trainers also may be important. The purpose of this study was (1) to determine whether attitudes are a better predictor of adolescents' intentions to use dietary supplements than are subjective norms, and (2) to assess the influence of significant others (coaches, parents, and trainers) on attitudes, subjective norms, and intentions among adolescent athletes. Adolescents (N = 1,626) who were enrolled in grades six through twelve in nine public schools completed a self-report questionnaire that measured attitudes, subjective norms, and intentions regarding dietary supplement use. Results indicated that attitudes were a better predictor of intentions to use dietary supplements than were subjective norms. It was also found that trainers had more influence on the attitudes, subjective norms, and intentions of adolescents regarding supplement use than did parents and coaches. Implications for prevention are addressed.     

Explaining Away Incompatibilist Intuitions

The debate between compatibilists and incompatibilists depends in large part on what ordinary people mean by ‘free will’, a matter on which previous experimental philosophy studies have yielded conflicting results. In Nahmias, Morris, Nadelhoffer, and Turner (2005, 2006) , most participants judged that agents in deterministic scenarios could have free will and be morally responsible. Nichols and Knobe (2007) , though, suggest that these apparent compatibilist responses are performance errors produced by using concrete scenarios, and that their abstract scenarios reveal the folk theory of free will for what it actually is—incompatibilist. Here, we argue that the results of two new studies suggest just the opposite. Most participants only give apparent incompatibilist judgments when they mistakenly interpret determinism to imply that agents’ mental states are bypassed in the causal chains that lead to their behavior. Determinism does not entail bypassing, so these responses do not reflect genuine incompatibilist intuitions. When participants understand what determinism does mean, the vast majority take it to be compatible with free will. Further results indicate that most people’s concepts of choice and the ability to do otherwise do not commit them to incompatibilism, either, putting pressure on incompatibilist arguments that rely on transfer principles, such as the Consequence Argument. We discuss the implications of these findings for philosophical debates about free will, and suggest that incompatibilism appears to be either false, or else a thesis about something other than what most people mean by ‘free will’.     

“I think you did it!”: Examining the effect of presuming guilt on the verbal output of innocent suspects during brief interviews

Innocent suspects interviewed by a guilt‐presumptive versus innocence‐presumptive or neutral interviewer may tend more to display non‐verbal behaviours which neutral judges consider indicative of guilt. We examined the effects of interviewer's presumption of guilt on innocent mock suspects' alibis. Participants (N = 90) provided an alibi to convince an interviewer of their innocence of a theft after she implied that she believed that they were guilty or innocent or that she had no belief about their veracity. On the basis of existing conflicting findings for suspects' verbal behaviour during accusatory interviews, we predicted that alibis in the guilt‐belief condition would contain the highest or lowest number of correct details with overall higher or poorer accuracy rates, respectively. Although participants perceived the interviewer's presumptive approach, the number of correct details provided and accuracy rates of alibis did not differ significantly between conditions. We propose explanations to these findings and future research paths.