Cortex最新文献

Influential theories of complex behaviour invoke the notion of cognitive control modulated by conflict between counterfactual actions. Medial frontal cortex, notably the anterior cingulate cortex, has been variously posited as critical to such conflict detection, resolution, or monitoring, largely based on correlative data from functional imaging. Examining performance on the most widely used "conflict" task-Stroop-in a large cohort of patients with focal brain injury (N = 176), we compare anatomical patterns of lesion-inferred neural substrate dependence to those derived from functional imaging, meta-analytically summarised. Our results show that whereas performance is sensitive to the integrity of left lateral frontal regions implicated by functional imaging, it does not depend on medial frontal cortex, despite sampling adequate to reveal robust medial effects in the context of phonemic fluency. We suggest that medial frontal cortex is not critically invoked by Stroop and proceed to review the conceptual grounds for rejecting the core notion of conflict-driven cognitive control.

The neurological process of mirror generalization in memory, also known as mirror symmetrization, presents a real dilemma for typically developing 5- to 6-year-olds when learning to write characters (digits and letters). Should they write the digit 3 oriented to the left, that is correctly, or to the right, which leads to its mirror image ε? It has been anecdotally suggested that boys are more prone to mirror-writing than girls, but there is no scientific evidence for this idea. The present article gathers data from 691 children in the upper section of the French école maternelle (age between 5 and 6 ½), who each wrote the digits 0 to 9 four times under dictation and not necessarily in their natural order. Both simple and complex (mixed-effects linear regression) statistical comparisons on the percentages of digit reversal, show a substantial difference: girls produce more mirror reversals than boys. And yet the reversal curves as a function of the digits are quite similar between the two sexes (r = .97). It has been proposed that mirror reversal of characters results from the left orientation of some of them (e.g., 3, 7, J, Z), that is, in an orientation contrary to the direction of writing in our Western cultures. The present investigation shows that (1) this character orientation hypothesis (choosing to write characters in the same orientation as sentence writing) better explains reversals than the counterclockwise hypothesis (children are trained to draw circles counter-clockwise to prepare for attached cursive writing); (2) the study of the stability of reversals additionally supports the explanation of mirror writing by the left orientation of the digits (1, 2, 3, 7 and, less obviously, 9); but (3) neither of the preceding findings (left-right orientation and stability) provided a convincing explanation for the aforementioned gender difference.

Binding, a critical cognitive process likely mediated by attention, is essential for creating coherent object representations within a scene. This process is vulnerable in individuals with dementia, who exhibit deficits in visual working memory (VWM) binding, primarily tested using abstract arrays of standalone objects. To explore how binding operates in more realistic settings across the lifespan, we examined the impact of object saliency and semantic consistency on VWM binding and the role of overt attention. Using an eye-tracking change detection task, we compared younger adults, healthy older adults, and individuals with Mild Cognitive Impairment (MCI). Participants were presented with naturalistic scenes and asked to detect changes in the identity and/or location of objects that were either semantically consistent or inconsistent with their scene context. Across all age groups, semantically inconsistent objects were prioritised during encoding, leading to better change detection than consistent objects. Highly salient objects decreased the inconsistency advantage while being detrimental to detection accuracy when inspected at longer latencies to the first fixation. Longer fixation durations on the critical object were beneficial for recognition. In contrast, delayed initial inspection or frequent subsequent fixations on other objects were detrimental to detection, regardless of age or cognitive impairment. These findings challenge the notion of generalised semantic memory impairment in the prodromal stages of dementia and highlight the importance of efficient attentional control in supporting VWM binding, even in the face of cognitive decline. Overall, preserved low-level and high-level mechanisms of object-scene integration can compensate for age-related cognitive decline, enabling successful binding in naturalistic contexts.

Closing-in behavior (CIB) is characterized by the placement of the graphic copy near (Near CIB) or even on the top of (Overlap CIB) the stimulus to be reproduced. Although CIB has received little attention in the literature, Sergio Della Sala and colleagues made important contributions to the understanding of the phenomenon. They noted that CIB is often observed in Alzheimer's Disease but is also present in other forms of dementia and mild cognitive impairment and stroke; they argued that CIB may reflect a deficit in executive function, rather than working memory, and that the phenomenon occurs more frequently in dual task conditions. Importantly, they demonstrated that CIB may not be specific to copying but may instead reflect a general deficit in decoupling movement location from the focus of attention. In the present study, we explored these observations in a mixed sample of 106 participants (AD n = 37, frontal stroke n = 25, other forms of dementia n = 24, and normal controls n = 20). First, we confirmed that CIB is equally common in AD, other forms of dementia and frontal stroke. Second, we confirmed the association between CIB and executive function deficits. Third, we showed that individuals with CIB are more likely to exhibit the phenomenon in dual task situations, in which line-drawing is associated with an unrelated secondary task (tapping, counting, or counting backward). The present work supports and extends the contributions of Della Sala and colleagues demonstrating that CIB is enhanced when the general attentional load of the task increases.

We report a case of crossmodal bilingual aphasia-aphasia in two modalities, spoken and sign language-and dysgraphia in both writing and fingerspelling. The patient, Sunny, was a 42 year-old woman after a left temporo-parietal stroke, a speaker of Hebrew, Romanian, and English and an adult learner, daily user of Israeli Sign language (ISL). We assessed Sunny's spoken and sign languages using a comprehensive test battery of naming, reading, and repetition tasks, and also analysed her spontaneous-speech and sign. Her writing and fingerspelling were assessed using tasks of dictation, naming, and delayed copying. In spoken language production, Sunny showed a classical phonological output buffer (POB) impairment in naming, reading, repetition, and spontaneous production, with phonological errors (transpositions, substitutions, insertions, and omissions) in words and pseudo-words, and whole-unit errors in morphological affixes, function-words, and number-words, with a length effect. Importantly, her error pattern in ISL was remarkably similar in the parallel tasks, with phonological errors in signs and pseudo-signs, affecting all the phonological parameters of the sign (movement, handshape, location, and orientation), and whole-unit errors in morphemes, function-signs, and number-signs. Sunny's impairment was selective to the POB, without phonological input, semantic-conceptual, or syntactic deficits. This shows for the first time how POB impairment, a kind of conduction aphasia, manifests itself in a sign language, and indicates that the POB for sign-language has the same cognitive architecture as the one for spoken language. It may also indicate similar neural underpinnings for spoken and sign languages. In writing, Sunny forms the first case of a selective type of dysgraphia in fingerspelling, orthographic (graphemic) output buffer dysgraphia. In both writing and fingerspelling, she made letter errors (letter transpositions, substitutions, insertions, and omissions), as well as morphological errors and errors in function words, and showed length effect. Sunny's impairment was selective to the orthographic output buffer, whereas her reading, including orthographic input processing, was intact. This suggests that the orthographic output buffer is shared for writing and fingerspelling, at least in a late learner of sign language. The results shed further light on the architecture of phonological and orthographic production.