Speech-specific auditory processing: where is it?

Are speech-specific processes localized in dedicated cortical regions or do they emerge from developmental plasticity in the connections among non-dedicated regions? Here we claim that all the brain regions activated by the processing of auditory speech can be re-classified according to whether they respond to non-verbal environmental sounds, pitch changes, unfamiliar melodies, or conceptual processes. We therefore argue that speech-specific processing emerges from differential demands on auditory and conceptual processes that are shared by speech and non-speech stimuli. This has implications for domain- vs. process-specific cognitive models, and for the relative importance of segregation and integration in functional anatomy.     

Judging the urgency of nonvocal auditory warning signals: perceptual and cognitive processes

Previous research has identified acoustic properties modulating the perceived urgency of alarms. The authors conducted 3 experiments using a multidimensional approach in which participants made acoustic dissimilarity judgments and urgency dissimilarity judgments for pairs of sequences. Experiment 1 confirmed the validity of acoustic parameters in urgency perception of experimental alarms. Experiment 2 confirmed the role of these acoustic parameters with real alarms but suggested the importance of additional factors. Experiment 3 compared the relative degrees of urgency of alarms from Experiments 1 and 2, highlighting the role of both sequence structure and associated mental representation. The authors conclude that the design of alarms should not be based exclusively on acoustic factors but should also take into consideration the acquisition of an appropriate mental representation.     

Assessing the Approximate Number System: no relation between numerical comparison and estimation tasks

Whether our general numerical skills and the mathematical knowledge that we acquire at school are entwined is a debated issue, which many researchers are still striving to investigate. The findings reported in the literature are actually inconsistent; some studies emphasized the existence of a relationship between the acuity of the Approximate Number System (ANS) and arithmetic competence, while some others did not observe any significant correlation. One potential explanation of the discrepancy might stem from the evaluation of the ANS itself. In the present study, we correlated two measures used to index ANS acuity with arithmetic performance. These measures were the Weber fraction (w), computed from a numerical comparison task and the coefficient of variation (CV), computed from a numerical estimation task. Arithmetic performance correlated with estimation CV but not with comparison w. We further investigated the meaning of this result by taking the relationship between w and CV into account. We expected a tight relation as both these measures are believed to assess ANS acuity. Crucially, however, w and CV did not correlate with each other. Moreover, the value of w was modulated by the congruity of the relation between numerical magnitude and non-numerical visual cues, potentially accounting for the lack of correlation between the measures. Our findings thus challenge the overuse of w to assess ANS acuity and more generally put into question the relevance of correlating this measure with arithmetic without any deeper understanding of what they are really indexing.     

Functional connectivity changes in second language vocabulary learning

Functional connectivity changes in the language network (Price, 2010), and in a control network involved in second language (L2) processing (Abutalebi & Green, 2007) were examined in a group of Persian (L1) speakers learning French (L2) words. Measures of network integration that characterize the global integrative state of a network (Marrelec, Bellec et al., 2008) were gathered, in the shallow and consolidation phases of L2 vocabulary learning. Functional connectivity remained unchanged across learning phases for L1, whereas total, between- and within-network integration levels decreased as proficiency for L2 increased.The results of this study provide the first functional connectivity evidence regarding the dynamic role of the language processing and cognitive control networks in L2 learning (Abutalebi et al., 2005, Altarriba and Heredia, 2008, Leonard et al., 2011, Parker-Jones et al., 2011). Thus, increased proficiency results in a higher degree of automaticity and lower cognitive effort (Segalowitz & Hulstijn, 2005).