Synaptic Reliability Correlates with Reduced Susceptibility to Synaptic Potentiation by Brain-Derived Neurotrophic Factor

Recent studies have implicated brain-derived neurotrophic factor (BDNF) in use-dependent modification of hippocampal synapses. BDNF can rapidly potentiate synaptic transmission at glutamatergic synapses by enhancing transmitter release. Using simultaneous perforated patch recording from pairs and triplets of glutamatergic hippocampal neurons, we have examined how the initial state of the glutamatergic synapse determines its susceptibility to synaptic modification by BDNF. We found that the degree of synaptic potentiation by BDNF depends on the initial reliability and strength of the synapse: Relatively weak connections were strongly potentiated, whereas the effect was markedly reduced at stronger synapses. The degree of BDNF-induced potentiation strongly correlated with the initial coefficient of variation (CV) of the amplitude of excitatory postsynaptic currents (EPSCs) and inversely correlated with the initial paired–pulse facilitation, suggesting that synapses with lower release probability (P_r) are more susceptible to the action of BDNF. To determine whether saturation of P_r could have masked the potentiation effect of BDNF in the stronger synapses, we lowered the initial P_r either by reducing the extracellular Ca²⁺ concentration ([Ca²⁺]_o) or by bath application of adenosine. Synapses that were initially strong remained unaffected by BDNF under these conditions of reduced P_r. Thus, the lack of BDNF effect on synaptic efficacy cannot simply be accounted for by saturation of P_r, but rather may be due to intrinsic changes associated with synaptic maturation that might covary with P_r. Finally, the dependence on initial synaptic strength was also found for divergent outputs of the same presynaptic neuron, suggesting that synaptic terminals with different degrees of responsiveness to BDNF can coexist within in the same neuron.     

Emotion and perception of one's own actions--a comment on Wilke, Synofzik and Lindner

Wilke et al. (2012) make significant headway in gaining a better understanding of the influence affect cues may have on action perception and judgement. In our view their account also brings up a row of important questions demanding further research. This concerns (a) the role of conceptual and non-conceptual content and (b) the different effects emotions of the same valence may play in the perception and judgement of action.     

A comparison of four approaches to account for method effects in latent state-trait analyses

Latent state-trait (LST) analysis is frequently applied in psychological research to determine the degree to which observed scores reflect stable person-specific effects, effects of situations and/or person-situation interactions, and random measurement error. Most LST applications use multiple repeatedly measured observed variables as indicators of latent trait and latent state residual factors. In practice, such indicators often show shared indicator-specific (or method) variance over time. In this article, the authors compare 4 approaches to account for such method effects in LST models and discuss the strengths and weaknesses of each approach based on theoretical considerations, simulations, and applications to actual data sets. The simulation study revealed that the LST model with indicator-specific traits (Eid, 1996) and the LST model with M - 1 correlated method factors (Eid, Schneider, & Schwenkmezger, 1999) performed well, whereas the model with M orthogonal method factors used in the early work of Steyer, Ferring, and Schmitt (1992) and the correlated uniqueness approach (Kenny, 1976) showed limitations under conditions of either low or high method-specificity. Recommendations for the choice of an appropriate model are provided.     

Out of our skulls: How the extended mind thesis can extend psychiatry

The thesis that mental states extend beyond the skull, otherwise known as the extended mind thesis (ExM), has attracted considerable philosophical attention and support. It has also been accused of lacking practical import. At the same time, the field of psychiatry has remained largely unacquainted with ExM, tending to rely instead upon what ExM proponents would consider to be outdated models of the mind. ExM and psychiatry, therefore, have much to offer one another, but the connection between the two has remained largely unexplored. Here, I consider what implications ExM may have for psychiatry and, in so doing, reveal how psychiatry may lend practical import to ExM. First, I detail the possibility of the extension of one mental state relevant to psychiatry. I augment this example by surveying other possibilities for extension in the context of psychiatric diagnoses. I then consider ways in which such extensions might alter psychiatric diagnosis and treatment. Overall, I argue that recognition of the truth of ExM could alter the diagnostic status of certain individuals by correcting both false positives and false negatives, re-conceptualize certain aspects of treatment, help us re-envision psychiatric research, and potentially increase empathy towards those individuals considered to be mentally disordered or mentally different.     

Thinking sadly: In favor of an adverbial theory of emotions

Introspective as well as empirical evidence indicates that emotions shape our thinking in numerous ways. Yet, this modificatory aspect of emotions has received relatively little interest in the philosophy of emotion. I give a detailed account of this aspect. Drawing both on the work of William James and adverbialist conceptions of perception, I sketch a theory of emotions that takes these aspects into consideration and suggest that we should understand emotions as manners of thinking.     

Sex differences in regret: all for love or some for lust?

Few sex differences in regret or counterfactual thinking are evident in past research. The authors discovered a sex difference in regret that is both domain-specific (i.e., unique to romantic relationships) and interpretable within a convergence of theories of evolution and regulatory focus. Three studies showed that within romantic relationships, men emphasize regrets of inaction over action (which correspond to promotion vs. prevention goals, respectively), whereas women report regrets of inaction and action with equivalent frequency. Sex differences were not evident in other interpersonal regrets (friendship, parental, sibling interactions) and were not moderated by relationship status. Although the sex difference was evident in regrets centering on both sexual and nonsexual relationship aspects, it was substantially larger for sexual regrets. These findings underscore the utility of applying an evolutionary perspective to better understand goal-regulating, cognitive processes.     

Using the ASEBA to Screen for Callous Unemotional Traits in Early Childhood: Factor Structure,Temporal Stability,and Utility

This study evaluated a five-item screening measure of Callous Unemotional (CU) traits using items drawn from the Preschool Form of the Achenbach System of Empirically Based Assessment (ASEBA). Using data from the Durham Child Health and Development study (N = 178), confirmatory factor analyses demonstrated that CU items could be distinguished from Attention Deficit/Hyperactivity Disorder (ADHD) and Oppositional Defiant (ODD) items. The two-year stability (N = 137) of CU (ϕ = .84) was comparable to that of ADHD (ϕ = .79) and ODD (ϕ = .69). Three groups of children were selected based on parent-rated ODD and CU behaviors at the 36-month assessment (N = 37; ODD+CU, N = 7; ODD-only, N = 12; non-ODD, N = 18). Multiple measures of infant temperament predicted group membership with 84% accuracy. Consistent with Frick and Morris’ (Journal of Clinical Child and Adolescent Psychology 33(1):54–68, 2004) hypotheses, ODD+CU and ODD-only children exhibited temperamental profiles in infancy that were consistent with low fear and emotionally dysregulated pathways into conduct problems, respectively.     

The effects of token reinforcement on attending in a young child with autism

The benefits of token economies have been widely established, however there are very few empirical studies on the effects of token reinforcement on the behavior of young children with autism. The establishment of conditioned reinforcers such as tokens may be important in interventions for children with autism. Token reinforcement was used to increase the attending behavior of a young child with autism during discrete trials instruction for academic and communication skills. A reversal design showed that token reinforcement sustained attending only when the back‐up reinforcer was available and was accessed immediately. The results extend and corroborate findings on token reinforcement reported in other applied settings and are also consistent with findings from basic research on conditioned reinforcement. Copyright © 2006 John Wiley & Sons, Ltd.     

Collectively ill: a preliminary case that groups can have psychiatric disorders

Synthese - In the 2000s, several psychiatrists cited the lack of relational disorders (what I call “collective disorders”—disorders of groups rather than individuals) in the...     

Click location in sentences: A test of the linguistic competence of seven-year-old fluent and disfluent males

Ten fluent and ten disfluent 7-yr-old males were presented simple and complex fully grammatical, anomalous and scrambled sentences. A click (35-msec 1-kHz tone burst) had been superimposed within three positions to the right or left of the major syntactic boundary in each sentence. The subjects heard the sentence, repeated the sentence, and marked on a preprinted version of the sentence where they heard the click. It was expected that children with greater language facility would more probably locate the click veridically. By the same reasoning, less complex syntactic structures should be expected to influence click placement less than more complex utterances. The following results were obtained: (a) the disfluent group gave a greater number of correct responses than the fluent group; (b) more correct responses were observed for simple sentences than for complex sentences for both groups; and (c) fewer correct responses were observed for both simple and complex grammatical sentences than for anomalous and scrambled sentence types.