Effects of Acute Stress or Centrally Injected Interleukin-1beta on Neuropeptide Expression in the Immune System

Acute stress stimulates the expression and release of corticotropin-releasing hormone (CRH) and arginine vasopressin (AVP) from the hypothalamus, and the pro-opiomelanocortin products beta-endorphin and ACTH from the anterior pituitary. These neuropeptides are also expressed in immune tissues, and it has been proposed that they may modulate immune responses to stress through paracrine mechanisms. We subjected rats to restraint stress or central injection of interleukin (IL)-1beta to determine whether these acute stimuli can alter the expression of neuropeptides in the spleen and thymus. Restraint stress significantly increased the contents of all these neuropeptides in thymic, but not splenic, extracts. A single icv injection of IL-1beta increased contents of CRH, AVP, ACTH and beta-endorphin in the spleens of both sham-operated and adrenalectomised (ADX) rats. IL-1beta increased thymic contents of CRH and ACTH in sham-operated rats but these increases were not observed in ADX rats. These results suggest that the effects of IL-1beta on neuropeptide expression in the spleen are independent of glucocorticoids, whereas IL-1beta stimulation of neuropeptide expression in the thymus is dependent on circulating glucocorticoids. There were significant correlations between increases in CRH, ACTH and beta-endorphin in the spleen, and between CRH and ACTH in the thymus, consistent with the suggestion that IL-1beta-induced increases in ACTH and beta-endorphin may be mediated through CRH. These results provide evidence that stressors can directly influence neuropeptide expression in immune tissues. Thus stress may influence immune functions through paracrine mechanisms involving locally synthesised neuropeptides as well as through activation of the hypothalamo-pituitary-adrenal axis.     

Evidence for syntactic alignment in children with autism

We report an experiment that examined whether children with Autistic Spectrum Disorder (ASD) spontaneously converge, or align, syntactic structure with a conversational partner. Children with ASD were more likely to produce a passive structure to describe a picture after hearing their interlocutor use a passive structure to describe an unrelated picture when playing a card game. Furthermore, they converged syntactic structure with their interlocutor to the same extent as did both chronological and verbal age-matched controls. These results suggest that the linguistic impairment that is characteristic of children with ASD, and in particular their difficulty with interactive language usage, cannot be explained in terms of a general deficit in linguistic imitation.     

Tasty non-words and neighbours: The cognitive roots of lexical-gustatory synaesthesia

For lexical-gustatory synaesthetes, words trigger automatic, associated food sensations (e.g., for JB, the word slope tastes of over-ripe melon). Our study tests two claims about this unusual condition: that synaesthetic tastes are associated with abstract levels of word representation (concepts/lemmas), and that the first tastes to crystallise in early development are those triggered by food-names (e.g., apple tastes of apple; Simner & Ward, 2006). This concept/lemma-based proposal is difficult to immediately reconcile with the finding that non-words may also generate tastes (Ward, Simner, & Auyeung, 2005), since non-words have no concept/lemma representations. We manipulated the characteristics of non-words to provide three types of evidence that non-word tastes in fact stem from real word neighbours: Non-words with neighbours (e.g., keach) are more likely to generate tastes than those with no neighbours (e.g., vilps); pseudo-homophone non-words that are orthographically close to real words (e.g., peeple) are more likely to generate tastes than those that are more distant (baybee); and finally, the tastes of non-words are less consistent, and less intense, than those of real words. Additionally, we test the hypothesis that synaesthetic tastes develop initially from food-names by showing that non-words are more intensely flavoured if they are homophonic with food-names (e.g., toffie) versus non-foods (e.g., peeple). From this we conclude that synaesthetic tastes develop from food-names, and that tasty non-words do not challenge a concept/lemma-based account of lexical-gustatory synaesthesia.     

The detection of malingering in criminal forensic groups: MMPI validity scales

Despite the value of the MMPI to the forensic assessment of malingering (exaggeration) of psychopathology, few studies have assessed the accuracy of the MMPI validity scales in criminal forensic populations. We administered the MMPI to 35 insanity defendants undergoing evaluation for fitness to stand trial and/or sanity at the time of the crime, who stood to benefit from being assessed as psychologically disturbed, and 39 subjects previously found not guilty by reason of insanity (NGRI), who did not stand to gain from such an assessment, Insanity defendants showed significantly more malingering than NGRI subjects, p less than .05. Racial differences did not affect the data. These findings support the efficacy of MMPI validity scales in assessing malingering within criminal forensic groups, and support the generalizability of the scales across race.     

Do speakers avoid ambiguities during dialogue?

What affects speakers' production of ambiguous utterances in dialogue? They might consider ease of production for themselves, or ease of comprehension for their addressees. Previous research has demonstrated that ease of production plays a role in speakers' syntactic choices, but that ease of comprehension does not. However, such studies have not employed dialogues that involve role swapping on a turn-by-turn basis. In our experiment, participants alternated in giving and following instructions to move objects around on a grid. They tended to repeat the syntactic form just used by their interlocutor, reflecting sensitivity to ease of production. More interestingly, they were more likely to disambiguate their utterances when the visual context was potentially ambiguous than when it was not, reflecting sensitivity to ease of comprehension. We conclude that speakers pay attention to their beliefs about their addressees' ease of comprehension, in addition to considering ease of production for themselves.