Four Streams Within the Prefrontal Cortex: Integrating Structural and Functional Connectivity.

Merging functional evidence derived from studies of autism spectrum disorder and attention-deficit/hyperactivity disorder converges in four neural streams of the prefrontal cortex, hence suggesting a model of information processing through four streams: motor through Brodmann area (BA) 8, emotion through BA 9, memory through BA 10, and emotional-related sensory through BA 11. A growing body of functional data has been supporting this model of information processing. Nevertheless, the underlying structural connectivity was only recently unveiled by a population-based high-definition tractography study with data from 1,065 individuals. This update provides a brief overview of recent evidence supporting the anatomofunctional integration of the four streams of the prefrontal cortex and reviews the white matter fiber tracts subserving the four streams.

The amygdala-insula-medial prefrontal cortex-lateral prefrontal cortex pathway and its disorders.

Smith and Lane have suggested a model of emotion processing with at least three stations: areas like the amygdala, which process discrete body features areas like the anterior insula, which process whole-body patterns and areas like the medial prefrontal cortex, which process emotion concepts. Ben Shalom and Bonneh have suggested a model of the prefrontal cortex, in which medial BA 9 integrates emotional states, and lateral BA 9 performs selection/inhibition on these states. Taken together, the current paper suggests a pathway for emotion processing with at least four stations: areas like the amygdala, which process discrete body features areas like the anterior insula, which process whole-body patterns, medial BA 9 which integrates emotion concepts, and lateral BA 9, which performs selection/inhibition on these concepts. Following the existing literature, it then suggest that there is a significant involvement of the amygdala in psychopathy (Blair), of the anterior insula in alexithymia (Bird), of the medial BA 9 in deficits in somatosensory discrimination (Ben Shalom), and of lateral BA 9 in emotional impulsivity (Ronel).

The functional significance of the P600: Some linguistic P600's do localize to language areas.

A recent paper in the journal Neuroreport suggested that, upon source localization, the semantic P600 localizes to executive function areas, that is, outside language. But is this true for all types of linguistic P600? We report a cross-sectional source localization study of a classical (agreement) syntactic paradigm.The results show a clear localization to the temporal lobe, in classical language areas.The P600 is probably not a unitary phenomenon in term of source localization, and the question whether it localizes within or outside the language system depends on the type of P600.

A Double Dissociation Between Inattentive and Impulsive Traits, on Tasks of Visual Processing and Emotion Regulation.

OBJECTIVE: To dissociate between inattentive and impulsive traits common in attention deficit hyperactivity disorder (ADHD) using a non-dichotomous measurment of these traits. METHOD: 120 university students who completed the Conner's adult ADHD rating scales (CAARS) were also tested on the Microgenesis task which requires visual attention and on the Cyber Cruiser task which requires emotion regulation. RESULTS: Results show that a measure of inattention was specifically related to a measure of effortful visual processing condition. In addition, a measure of impulsivity was specifically related to the tendency to fail in refueling one's car on time, although this relation was opposite to the predicted direction. Furthermore, by using exploratory and confirmatory factor analyses, the CAARS' factor structure was confirmed to be relevant to an Israeli population. CONCLUSION: The current experiment supports the idea that visual attention may play a part in inattentive symptoms, and that emotion regulation may play a part in impulsivity symptoms.

A quantitative measure of JS's memory.

JS is a highly able, well-educated 37 year old man with Asperger syndrome. A recent qualitative paper (Boucher, 2007) described his self-report of verbal and visual memory difficulties. The present paper used the WMS-III to compare the memory profile of JS to that of the adults with HFA in the Williams et al. (2005) WMS-III paper. Results show that JS's self-report of his memory difficulties can by and large be supported, that JS's memory performance is at the lower end of the group examined in the Williams et al. (2005) paper, and that, unlike the group profile in Williams et al. (2005), JS shows reduced performance on both verbal and visual measures of memory. A qualitative analysis of JS's performance raises the possibility that JS is using language to retain details he can generalize over, as a compensatory strategy for some reductions in episodic memory.

Memory in autism: review and synthesis.

Much research about memory in autism concerns the hypothesis that autism is similar to adult-onset amnesia. Initial support for the hypothesis came from post-mortem studies of individuals with autism showing abnormalities in the hippocampus and related brain structures, as well as behavioral studies finding contrasts between intact cued recall and impaired free recall and recognition in autism. The hypothesis was later brought into question by the finding of intact performance in individuals with autism on explicit memory tasks typically impaired in adult-onset amnesia. The present paper proposes a possible reconciliation of these contradictory findings, suggesting that there is selective damage to the limbic-prefrontal episodic memory system, sparing the limbic-only perceptual representation system, and the semantic memory system. This view is consistent with other evidence for early selective damage to other systems involving cooperation between the limbic system and the medial prefrontal cortex in autism.

The effect of spectral manipulations on the identification of affective and linguistic prosody.

We investigated the effect of various spectral manipulations on the identification of sentential prosody. Two main categories of prosody--affective (happy, angry, sad) and linguistic (statement, question, continuation)--were studied. Thirty-six subjects were presented with stimuli that were recorded by a female native speaker of American English. The stimuli were digitally manipulated to create synthesized, band-pass filtered (F0-range and F2/F3-range) and re-entrant (pitch only version of stimulus is convolved with a steady-state signal) conditions. Results of a forced-choice discrimination paradigm showed that, in general, performance is remarkably robust despite spectral manipulation, even when there is relatively little spectral information. However, performance was significantly degraded in the low band-pass and re-entrant conditions. These observations are discussed in light of the relevance of the fundamental frequency as well as syllabification for the analysis of prosodic information.