Cortex; a journal devoted to the study of the nervous system and behavior
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Attentional dyslexia is a reading deficit in which letters migrate between neighboring words, but are correctly identified and keep their correct relative position within the word. Thus, for example, fig tree can be read as fig free or even tie free. This study reports on 10 Hebrew-speaking individuals with developmental attentional dyslexia and explores in detail the characteristics of their between-word errors. ⋯ More migrations occurred when the result of migration was an existing word. Similarity between words in a pair did not increase error rates, and more migrations occurred when the words shared fewer letters. The between-word errors included the classic errors of migration of a letter between words, but also omission of one instance of a letter that appeared in the same position in the two words, an error that constituted a considerable percentage of the between-word errors, and intrusion of a letter from one word to the corresponding position in the neighboring word without erasing the original letter in the same position.
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Previous studies have reported a dissociation between social behavioral impairments after severe traumatic brain injury (TBI) and relatively preserved performances in traditional tasks that investigate cognitive abilities. Theory of mind (ToM) refers to the ability to make inferences about other's mental states and use them to understand and predict others' behavior. We tested a group of 15 patients with severe TBI and 15 matched controls on a series of four verbal and non-verbal ToM tasks: the faux pas test, the first-order and second-order false belief task, the character intention task and the Reading the Mind in the Eyes Test. ⋯ Subjects with TBI performed worse than control subjects on all ToM tasks, except the first-order false belief task. The findings converge with previous evidence for ToM deficit in TBI and dissociation between ToM and executive functions. We show that ToM deficit is probably distinct from other aspects of social cognition like empathy and pragmatic communication skills.
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Despite electrostimulation studies of the white matter pathways, supporting the role of the inferior fronto-occipital fasciculus (IFOF) in semantic processing, little is known about the precise anatomical course of this fascicle, especially regarding its exact cortical terminations. Here, in the lights of these new functional data, we dissected 14 post-mortem human hemispheres using the Klingler fiber dissection technique, to study the IFOF fibers and to identify their actual cortical terminations in the parietal, occipital and temporal lobes. ⋯ Thus, our results are in line with the hypothesis of the functional role of the IFOF in the semantic system, by showing that it is mainly connected with two areas involved in semantics: the occipital associative extrastriate cortex and the temporo-basal region. Further combined anatomical (dissection and Diffusion Tensor Imaging) and functional (intraoperative subcortical stimulation) studies are needed, to clarify the exact participation of each IFOF subcomponent in semantic processing.
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Aging is associated with decrements in both spatial and temporal context retrieval. Functional neuroimaging studies of young adults suggest that there are differences in left versus right lateral prefrontal cortex (PFC) contributions to spatial versus temporal source (recency) retrieval, respectively. The goal of the current study was to determine if age-related decreases in temporal and spatial context retrieval are due to common or distinct changes in PFC function. ⋯ Our behavioural results indicated that older adults did not differ on recognition performance, but did exhibit a deficit in both context retrieval tasks, compared to young adults. The fMRI results suggest that age-related deficits in both spatial and temporal context retrieval may be linked to functional changes in right dorsolateral and left medial anterior PFC (APFC) function. In addition, based on brain-behaviour correlations in older adults, our results imply that older adults attempt to compensate for these deficits by engaging left dorsolateral PFC during spatial context retrieval and right APFC during temporal context retrieval.
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Although the substrates that mediate singing abilities in the human brain are not well understood, invasive brain mapping techniques used for clinical decision making such as intracranial electro-cortical testing and Wada testing offer a rare opportunity to examine music-related function in a select group of subjects, affording exceptional spatial and temporal specificity. ⋯ Despite inherent limitations with respect to strictly research objectives, invasive clinical techniques offer a rare opportunity to probe musical and language cognitive processes of the brain in a select group of patients.