Enhanced cholinergic suppression of previously strengthened synapses enables the formation of self-organized representations in olfactory cortex

Computational modeling assists in analyzing the specific functional role of the cellular effects of acetylcholine within cortical structures. In particular, acetylcholine may regulate the dynamics of encoding and retrieval of information by regulating the magnitude of synaptic transmission at excitatory recurrent connections. Many abstract models of associative memory function ignore the influence of changes in synaptic strength during the storage process and apply the effect of these changes only during a so-called recall-phase. Efforts to ensure stable activity with more realistic, continuous updating of the synaptic strength during the storage process have shown that the memory capacity of a realistic cortical network can be greatly enhanced if cholinergic modulation blocks transmission at synaptic connections of the association fibers during the learning process. We here present experimental data from an olfactory cortex brain slice preparation showing that previously potentiated fibers show significantly greater suppression (presynaptic inhibition) by the cholinergic agonist carbachol than unpotentiated fibers. We conclude that low suppression of non-potentiated fibers during the learning process ensures the formation of self-organized representations in the neural network while the higher suppression of previously potentiated fibers minimizes interference between overlapping patterns. We show in a computational model of olfactory cortex, that, together, these two phenomena reduce the overlap between patterns that are stored within the same neural network structure. These results further demonstrate the contribution of acetylcholine to mechanisms of cortical plasticity. The results are consistent with the extensive evidence supporting a role for acetylcholine in encoding of new memories and enhancement of response to salient sensory stimuli.     

Predicting Quality of Life After Lumbar Spondylodesis

Quality of life after spondylodesis was predicted by pretreatment psychological variables and findings in a standardized physical examination. Four quality-of-life criteria were used: functional capacity, vocational rehabilitation, satisfaction with the outcome of the operation, and pain intensity recorded in a pain diary. Those of six presurgery variables that proved to be associated with the outcome 9 months postsurgery, by means of a multiple stepwise regression procedure, were selected for discriminant analyses. The sample consisted of 50 consecutive patients who underwent either ventral (n = 10) or posterolateral (n = 40) spondylodesis with or without posterior instrumentation. Their average age was 44.9 years (SD = 12.9) with an average duration of pain of 8.6 years (SD = 8.8). Nearly half of the patients had had previous spine surgery. Follow-up data indicate that about half of the patients show a beneficial outcome in terms of quality-of-life measures. Discriminant analyses suggest that poor presurgical functional capacity and an unclear finding in the physical examination before surgery contribute to our knowledge about patients who are likely to show continuous pain and poor functional capacity after surgery.     

How much could we boost scholastic achievement and IQ scores? A direct answer from a French adoption study

We observed 32 subjects whose biological parents were both unskilled workers. Abandoned at birth, the subjects had been placed at approximately 4 months of age into families spanning the top 13% of the socio-professional scale. The effects of this change in social class were estimated by comparisons with groups of children of unskilled workers observed in two large scale studies. An internal control group was also available for 20 of the 32 subjects: the biological half-siblings who had been reared in their ‘natural’ environment. The effects observed are an increase of 14 IQ points in the mean IQ score estimated with 2 tests and a reduction by a factor of 4 in the probability of repeating a grade. These are significant despite the small number of subjects; we have shown that the bulk of these effects cannot be attributed to methodological biases. Our observations thus provide a direct quantitative answer to the question posed by Jensen in 1969.     

Gender stereotypes in education: Development,consequences, and interventions

Despite many efforts to increase gender fairness in education in recent years, the issue has not yet become obsolete: Gender discrimination still exists and finds expression in unused chances and limited action repertoires for both sexes. This article gives an overview on existing gender differences across the lifespan before providing explanations for these differences from a developmental perspective. We present psychological theories of development dealing with the adoption of gender typical preferences and behaviors in children, and draw the connection to the role parents’ and teachers’ gender stereotypes play in this process. The mechanisms contributing to the perpetuation of gender differences are illustrated via empirical studies. Finally, we offer starting points for interventions to prevent the development of these gender differences, and introduce the REFLECT program which enhances gender competence in secondary school teachers and their students, and a training program for kindergarten teachers as concrete examples of such interventions.     

What's in an accent? General spontaneous biases against nonnative accents: An investigation with conceptual and auditory IATs

Nonnative accents are prevalent in our globalized world and constitute highly salient cues in social perception. Whereas previous literature has commonly assumed that they cue specific social group stereotypes, we propose that nonnative accents generally trigger spontaneous negatively biased associations (due to a general nonnative accent category and perceptual influences). Accordingly, Study 1 demonstrates negative biases with conceptual IATs, targeting the general concepts of accent versus native speech, on the dimensions affect, trust, and competence, but not on sociability. Study 2 attests to negative, largely enhanced biases on all dimensions with auditory IATs comprising matched native–nonnative speaker pairs for four accent types. Biases emerged irrespective of the accent types that differed in attractiveness, recognizability of origin, and origin‐linked national associations. Study 3 replicates general IAT biases with an affect IAT and a conventional evaluative IAT. These findings corroborate our hypotheses and assist in understanding general negativity toward nonnative accents.     

Mechanisms underlying heightened risk taking in adolescents as compared with adults

Self-report surveys and behavioral tasks indicate greater risk-taking behavior in adolescents as compared with adults. However, the underlying causes of these behavioral differences remain unclear. The present study examined the possibility that adolescents may be more susceptible to immediate positive and negative outcomes than adults. We compared the behavior of adolescents and adults on a modified version of the Balloon Analogue Risk Task (Lejuez et al., 2002). The task required that participants press a button to "inflate" a series of balloons on a computer screen. Balloons inflated until either the participant released the button ("saved" balloons) or the balloon "burst." Accumulated points increased as the duration of the buttonpress increased; however, simultaneously, the likelihood that the balloon would burst also increased. Adolescents inflated balloons to a larger size prior to saving them than adults did, suggesting relatively higher levels of risk taking, although the adolescents' behavior was not uniformly risk prone. Further, in comparison with adults, behavior in adolescents was more influenced by whether a balloon was saved or had burst on the preceding trial, suggesting that sensitivity to immediate consequences is one mechanism that underlies the observed difference in risk taking.     

Odor enrichment increases interneurons responsiveness in spatially defined regions of the olfactory bulb correlated with perception

Odor enrichment enhances rats’ ability to discriminate between chemically similar odorants. We show here that this modulation of olfactory perception is accompanied by increases in the density of local inhibitory interneuron expressing Zif268 in response to olfactory stimuli. These changes depend on the overlap of the olfactory bulb activation patterns induced by the enrichment odorants with those induced by the testing odorants, in a manner similar to changes in perception. Moreover, we show that enrichment leads to an alteration of the pattern of Zif268 expression, dependent on the odors used for the enrichment indicating a restructuring of odor representation in the olfactory bulb.     

Anticipation of interoceptive threat in highly anxiety sensitive persons

Anticipatory anxiety plays a major role in the etiology of panic disorder. Although anticipatory anxiety elicited by expectation of interoceptive cues is specifically relevant for panic patients, it has rarely been studied. Using a population analogue in high fear of such interoceptive arousal sensations (highly anxiety sensitive persons) we evaluated a new experimental paradigm to assess anticipatory anxiety during anticipation of interoceptive (somatic sensations evoked by hyperventilation) and exteroceptive (electric shock) threat. Symptom reports, autonomic arousal, and defensive response mobilization (startle eyeblink response) were monitored during threat and matched safe conditions in 26 highly anxiety sensitive persons and 22 controls. The anticipation of exteroceptive threat led to a defensive and autonomic mobilization as indexed by a potentiation of the startle response and an increase in skin conductance level in both experimental groups. During interoceptive threat, however, only highly anxiety sensitive persons but not the controls exhibited a startle response potentiation as well as autonomic activation. The anticipation of a hyperventilation procedure thus seems a valid paradigm to investigate anticipatory anxiety elicited by interoceptive cues in the clinical context.