Ethan Weed

Social cognition and neurocognitive deficits in first-episode schizophrenia

BACKGROUND Recent research has shown a significant impact of social cognitive domains on real world functioning and prognosis in schizophrenia. However, the correlations between specific aspects of social cognition, neurocognition, IQ and clinical symptoms remain unclear in first-episode schizophrenia. Researchers have speculated about social cognitive subgroups since patients with schizophrenia appear to be a very heterogeneous group. METHODS Patients with a recent diagnosis of first-episode schizophrenia were tested regarding theory of mind, social perception, neurocognition, IQ, and clinical symptoms. RESULTS Data from 36 first-episode schizophrenia patients and 36 one to one matched healthy controls were analysed. Principal component analysis in the patient group was used to examine the variance contributed by different aspects of social cognition, neurocognition, and clinical symptoms. CONCLUSIONS Complex aspects of social cognition explained 24% of the variance in the patient group. The other principal components consisted mainly of aspects of simple perception of theory of mind. Neurocognition and clinical symptoms only explained a minor proportion of the variance in the patient group. The results imply that social cognitive deficits in first-episode schizophrenia come in two distinct versions where one is a complex, cognitive demanding form linked with IQ. The other version is related to simpler forms of social cognition and independent of IQ. These two forms are comparable to the implicit and explicit mentalising discussed in the developmental literature. The two forms of social cognitive deficits are likely to require quite different social cognitive interventions.

Accessing the Mental Space—Spatial Working Memory Processes for Language and Vision Overlap in Precuneus

The “overlapping systems” theory of language function argues that linguistic meaning construction crucially relies on contextual information provided by “nonlinguistic” cognitive systems, such as perception and memory. This study examines whether linguistic processing of spatial relations established by reading sentences call on the same posterior parietal neural system involved in processing spatial relations set up through visual input. Subjects read simple sentences, which presented two agents in relation to each other, and were subsequently asked to evaluate spatial (e.g., “Was he turned towards her?”) and equally concrete nonspatial content (e.g., “Was he older than her?”). We found that recall of the spatial content relative to the nonspatial content resulted in higher BOLD response in a dorsoposterior network of brain regions, most significantly in precuneus, strikingly overlapping a network previously shown to be involved in recall of spatial aspects of images depicting similar scenarios. This supports a neurocognitive model of language function, where sentences establish meaning by interacting with the perceptual and working memory networks of the brain. Hum Brain Mapp 2008.

Brain responses to musical feature changes in adolescent cochlear implant users

Cochlear implants (CIs) are primarily designed to assist deaf individuals in perception of speech, although possibilities for music fruition have also been documented. Previous studies have indicated the existence of neural correlates of residual music skills in postlingually deaf adults and children. However, little is known about the behavioral and neural correlates of music perception in the new generation of prelingually deaf adolescents who grew up with CIs. With electroencephalography (EEG), we recorded the mismatch negativity (MMN) of the auditory event-related potential to changes in musical features in adolescent CI users and in normal-hearing (NH) age mates. EEG recordings and behavioral testing were carried out before (T1) and after (T2) a 2-week music training program for the CI users and in two sessions equally separated in time for NH controls. We found significant MMNs in adolescent CI users for deviations in timbre, intensity, and rhythm, indicating residual neural prerequisites for musical feature processing. By contrast, only one of the two pitch deviants elicited an MMN in CI users. This pitch discrimination deficit was supported by behavioral measures, in which CI users scored significantly below the NH level. Overall, MMN amplitudes were significantly smaller in CI users than in NH controls, suggesting poorer music discrimination ability. Despite compliance from the CI participants, we found no effect of the music training, likely resulting from the brevity of the program. This is the first study showing significant brain responses to musical feature changes in prelingually deaf adolescent CI users and their associations with behavioral measures, implying neural predispositions for at least some aspects of music processing. Future studies should test any beneficial effects of a longer lasting music intervention in adolescent CI users.

A Verbal Illusion: Now in Three Languages

The so-called depth charge sentences (e.g., no head injury is too trivial to be ignored) were investigated in a comprehension experiment measuring both whether participants understood the stimuli and how certain they were of their interpretation. The experiment revealed that three factors influence the difficulty of depth charge type sentences: the number of negations, the plausibility of the relation between the subject and the verb, and finally the logic of the relation between the adjective and the verb. When a sentence is maximally complex (i.e., when there are multiple negations, the relation between subject and verb is implausible, and the relation between adjective and verb is illogical) participants misunderstood the sentence, but were at the same time certain of their answers. The experiment supports the idea that depth charge sentences create a verbal illusion—the sentences mean one thing, but people systematically understand them to mean the opposite.