1,721,003 research outputs found
Understanding Body Language Does Not Require Matching the Body's Egocentric Map to Body Posture: A Brain Activation fMRI Study
Full text linkBody language (BL) is a type of nonverbal communication in which the body communicates the message. We contrasted participants' cognitive processing of body representations or meanings versus body positions. Participants (N = 20) were shown pictures depicting body postures and were instructed to focus on their meaning (BL) or on the position of a body part relative to the position of another part (body structural description [BSD]). We examined activation in brain areas related to the two types of body representation—body schema and BSD—as modulated by the two tasks. We presumed that if understanding BL triggers embodiment of body posture, a matching procedure between the egocentric map coding the position of one's body segments in space and time should occur. We found that BL (vs. BSD) differentially activated the angular gyrus bilaterally, the anterior middle temporal gyrus, the temporal pole, and the right superior temporal gyrus, the inferior frontal gyrus, the superior medial gyrus, and the left superior frontal gyrus. BSD (vs. BL) differentially activated the superior parietal lobule (Area 7A) bilaterally, the posterior inferior temporal gyrus, the middle frontal gyrus, and the left precentral gyrus. Sensorimotor areas were differentially activated by BSD when compared with BL. Inclusive masking showed significant voxels in the superior colliculus and pulvinar, fusiform gyrus, inferior temporal gyrus, superior temporal gyrus, the intraparietal sulcus bilaterally, inferior frontal gyrus bilaterally, and precentral gyrus. These results indicate common brain networks for processing BL and BSD, for which some areas show differentially stronger or weaker processing of one task or the other, with the precuneus and the superior parietal lobule, the intraparietal sulcus, and sensorimotor areas most related to the BSD as activated by the BSD task. In contrast, the parietal operculum, an area related to the body schema, a representation crucial during embodiment of body postures, was not activated for implicit masking or for the differential contrasts
Anticipatory simulation of implied actions in the human motor system
No full textMemory for the final position or configuration of amoving object is distorted forward along its actual or implied path of motion representational momentum). This may allow humans to anticipate the forthcoming position of moving objects or creatures. By using single-pulse transcranial magnetic stimulation (TMS), we tested whether mirror motor facilitation is higher during extrapolation of dynamic information about forward than backward action paths. The results show that motor facilitation is specific for the observation of snapshots evoking ongoing but incomplete actions. This suggests that the motor cortico-spinal component of the observation-execution matching system is preferentially activated by the inner anticipatory simulation of the deployment of an action in the future
What do we know about intratumoral functional activity: a scoping review of imaging and intra-surgery results
Full text linkIntratumoral functional tissue represent a challenge in neurosurgery, as its resection may induce a permanent postoperative deficit. Only little is said in literature about this pattern. Currently this issue is receiving increased attention and in the last few years, the number of reports on intratumor functionality has increased. Aim of the current review was to provide a comprehensive overview of intratumoral area functionality patterns and of how much frequently this pattern is reported. PRISMA guidelines were followed. We identified 107 papers, but only 24 articles on 1220 patients were included for having reported intratumoral activation data. Within this framework, we aimed to shed light on some issues, including whether i) it is expressed only as fMRI activation within the mass, or whether it impacts on distant areas via functional connectivity, ii) it is found in slow growing tumors such as low grade glioma or also for fast infiltrative processes such as for high grade glioma, and iii) inhomogeneity of the tumor structure and morphological appearance or the tumor histology are key factors determining intratumoral area functionality. Key methods suitable for detecting intratumour function included MEG (in 7 studies), resting-state fMRI and task-active fMRI (in 8 studies) and intra-surgery direct cortical stimulation (in 8 studies). The type of patients were patients with astrocytoma (321 cases) and oligodendroglioma (255 cases) with tumor grade II (252 cases) and isocitrate dehydrogenase (IDH) mutation. Their mean tumor volume was 53.11 ± 19.23, and the affected hemisphere was mainly the left one (895 cases); lesion site most frequently involved the frontal cortex (435 cases). We discussed the clinical implications of these aspects, as a functional intratumoral area has a high impact on both planning and outcome, and we addressed the role of intra-surgery cognitive monitoring that should encompass a wide variety of functions
Relation Between Reading Performance and White-Matter Alteration and Reorganization in Neurosurgical Patients
No full textReading abilities and diffusion tensor imaging (DTI) parameters were retrospectively analyzed in a group of neurosurgical patients to investigate (Study 1) the role of white matter-in particular the arcuate fasciculus (AF)-in preserved vs. impaired reading; 4 months after surgery, we explored the plasticity processes (Study 2). Study 1 involved 40 patients with brain glioma (23 low-grade and 17 high-grade gliomas). We compared preoperative DTI parameters of language-related fascicles between patients who developed a reading impairment after surgery (n = 23) and patients with preserved reading (n = 17). Besides lower fractional anisotropy (FA), patients with impaired reading also displayed lower number and density of streamlines of a direct (i.e., directly connecting temporal and frontal lobes) AF segment. In Study 2, we longitudinally tested at follow-up-when reading performance had generally improved-13 patients diagnosed with low-grade glioma. The most relevant finding was a significant increase in length of streamlines of the direct AF segments in both hemispheres. From a neurosurgical perspective, our preliminary findings suggest the clinical importance of sparing direct AF segments for the involvement they showed in reading; however, the results also suggest the reorganization potential of these segments, possibly compensating of the right homologs as well
Effects of inhomogeneous radiofrequency power depositino on the apparent diffusion coefficient of the normal breast at 3.0 T.
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Test-retest reliability of diffusion tensor imaging of the liver at 3.0 T.
No full textPURPOSE: This study was done to evaluate test-retest reliability of liver diffusion tensor imaging (LDTI).
MATERIALS AND METHODS: Ten healthy volunteers (median age 23 years) underwent two LDTI scans on a 3.0 T magnet during two imaging sessions separated by 2 weeks (session-1/-2, respectively). Fifteen gradient directions and b values of 0-1,000 s/mm(2) were used. Two radiologists in consensus assessed liver apparent diffusion coefficient (ADC) and fraction of anisotropy (FA) values on ADC and FA maps at four reference levels, namely: right upper level (RUL), right lower level (RLL), left upper level (LUL) and left lower level (LLL). We then assessed (a) whether ADC and FA values overlapped when measured on different levels within the same imaging session or between different imaging sessions; (b) the degree of variability on an intra-session and inter-session basis, respectively, using the coefficient of variation (CV).
RESULTS: In sessions 1 and 2, the ADC/FA values were significantly larger in the left liver lobe (LUL/LLL) compared to right liver lobe (RUL/RLL) (p < 0.05/6). Intra-session CVs were 9.51 % (session 1) and 9.73 % (session 2) for ADC, and 12.93 % (session 1) and 11.82 % (session 2) for FA, respectively. When comparing RUL, RLL, LUL and LLL on an inter-session basis, CVs were 6.52, 8.20, 6.52 and 11.06 % for ADC, and 15.42, 15.80, 15.42 and 6.80 % for FA, respectively.
CONCLUSION: LDTI provides consistent and repeatable measurements. However, since larger left lobe ADC/FA values can be attributed to artefacts, right lobe values should be considered the most reliable measurements of water diffusivity within the live
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Variations on the Author
Full text link“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
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