Exposure to physical movements in low back pain patients: restricted effects of generalization.

Whether the effects of exposure to 1 movement generalize to another dissimilar movement was investigated in 37 patients with low back pain (15 men, 22 women). Two movements were executed twice: bending forward while standing and lifting 1 leg while lying down. During each trial, baseline pain, expected pain, and experienced pain were recorded. Similar ratings for perceived harm were obtained. Analyses revealed an initial over prediction of pain, but after exposure the overprediction was readily corrected. This exposure effect did not generalize toward another dissimilar movement. These results were only characteristic for patients with catastrophic thinking about pain. Low pain catastrophizers did not overpredict pain. There were no effects of exposure on perceived harm. Exposure may profitably be conceived of as the learning of exceptions to a general rule.     

How Introspections Concerning Cloninger’s Concepts of Temperament and Character Influence Eysenckian Personality Structure

Two studies examine the consequences of distinguishing between self-report responses on the Eysenck Personality Profiler (Eysenck et al. The European Journal of Psychological Assessment 8: 109–117, 1992) in terms of Cloninger’s concepts of Temperament and Character (Cloninger et al. Archives of General Psychiatry 50: 975–990, 1993). Character is thought to reflect conscious, maturation-related influences on personality, while Temperament is thought to reflect instinctive, biologically-based influences. In Study one, one-hundred and thirty-three participants (76.6% female) classify primary scales of the Eysenck Personality Profiler as relating to Character or Temperament. Impulsiveness, Anxiety and Aggression are perceived as the most Temperament-based scales, while Responsibility, Manipulativeness and Assertiveness are perceived as the most Character-based scales. In Study two, one-hundred and seventy-seven participants (74.4% female) complete the Eysenck Personality Profiler using the standard response scale, while one-hundred and thirty-eight participants (62.3% female) complete the Eysenck Personality Profiler using a scale which distinguishes between Character and Temperament. Results demonstrate differences in the factor structure and concurrent validity of the Eysenck Personality Profiler when scoring distinguishes between Temperament and Character. We conclude that the concepts of Temperament and Character might usefully be applied to Eysenck’s personality taxonomy.

Is the medial amygdala part of the neural circuit modulating conditioned defeat in Syrian hamsters?

Conditioned defeat is a model wherein hamsters that have previously experienced a single social defeat subsequently exhibit heightened levels of avoidance and submission in response to a smaller, non-aggressive intruder. While we have previously demonstrated the critical involvement of the basolateral and central nuclei of the amygdala in the acquisition and expression of conditioned defeat, the role of the medial amygdala has yet to be investigated. In Experiment 1, muscimol, a GABA(A) receptor agonist, was infused bilaterally into the MeA prior to initial defeat training. Experiment 2 examined the effects of muscimol injections given prior to subsequent testing with a non-aggressive intruder. Finally, in Experiment 3, anisomycin was used to block protein synthesis in the medial and basolateral amygdala to examine the involvement of these nuclei in memory consolidation related to conditioned defeat. Submissive behavior was significantly reduced in animals that received muscimol prior to initial defeat training as well as in animals injected prior to testing with the non-aggressive intruder, indicating that the MeA is necessary for the acquisition and expression of conditioned defeat. In Experiment 3, however, anisomycin reduced conditioned defeat only when administered into the BLA, and not when injected into the MeA. The results of the present series of experiments suggest that, while the MeA may serve an important gateway for sensory information that is crucial for conditioned defeat, it does not appear to play a role in the plasticity including this behavioral response to social defeat.     

Being forward not backward: lexical limits to masked priming

This study investigated whether masked priming is mediated by existing memory representations by determining whether nonwords targets would show repetition priming. To avoid the potential confound that nonword repetition priming would be obscured by a familiarity response bias, the standard lexical decision and naming tasks were modified to make targets unfamiliar. Participants were required to read a target string from right to left (i.e., "ECAF" should be read as "FACE") and then make a response. To examine if priming was based on lexical representations, repetition primes consisted of words when read forwards or backwards (e.g., "face", "ecaf") and nonwords (e.g., "pame", "emap"). Forward and backward primes were used to test if task instruction affected prime encoding. The lexical decision and naming tasks showed the same pattern of results: priming only occurred for forward primes with word targets (e.g., "face-ECAF"). Additional experiments to test if response priming affected the LDT indicated that the lexical status of the prime per se did not affect target responses. These results showed that the encoding of masked primes was unaffected by the novel task instruction and support the view that masked priming is due to the automatic triggering of pre-established computational processes based on stored information.