Tameness of pseudovariety joins involving R

2000 Mathematics Subject Classification: 20M07 (primary); 20M05, 20M35, 68Q70 (secondary).In this paper, we establish several decidability results for pseudovariety joins of the form VvW, where V is a subpseudovariety of J or the pseudovariety R. Here, J (resp. R) denotes the pseudovariety of all J-trivial (resp. R-trivial) semigroups. In particular, we show that the pseudovariety VvW is (completely) kappa-tame when V is a subpseudovariety of J with decidable kappa-word problem and W is (completely) kappa-tame. Moreover, if W is a kappa-tame pseudovariety which satisfies the pseudoidentity x_1...x_ry^{\omega+1}zt^\omega = x_1... x_ryzt^\omega, then we prove that RvW is also kappa-tame. In particular the joins RvAb, RvG, RvOCR, and RvCR are decidable.União Europeia (UE). Fundo Europeu de Desenvolvimento Regional (FEDER) - POCTI/32817/MAT/2000.International Association for the Promotion of Co-operation with Scientists from the New Independent States (NIS) of the Former Soviet Union (INTAS) - project 99-1224.Fundação para a Ciência e a Tecnologia (FCT)

Spatially dissociated intracerebral maps for face- and house-selective activity in the human ventral occipito-temporal cortex

We report a comprehensive mapping of the human ventral occipito-temporal cortex (VOTC) for selective responses to frequency-tagged faces or landmarks (houses) presented in rapid periodic trains of objects, with intracerebral recordings in a large sample (Nn=n75). Face-selective contacts are three times more numerous than house-selective contacts and show a larger amplitude, with a right hemisphere advantage for faces. Most importantly, these category-selective contacts are spatially dissociated along the lateral-to-medial VOTC axis, respectively, consistent with neuroimaging evidence. At the minority of "overlap" contacts responding selectively to both faces and houses, response amplitude to the two categories is not correlated, suggesting a contribution of distinct populations of neurons responding selectively to each category. The medio-lateral dissociation also extends into the underexplored anterior temporal lobe (ATL). In this region, a relatively high number of intracerebral recording contacts show category-exclusive responses (i.e., without any response to baseline visual objects) to faces but rarely to houses, in line with the proposed role of this region in processing people-related semantic information. Altogether, these observations shed novel insight on the neural basis of human visual recognition and strengthen the validity of the frequency-tagging approach coupled with intracerebral recordings in epileptic patients to understand human brain function

Dissociated face- and word-selective intracerebral responses in the human ventral occipito-temporal cortex

Item does not contain fulltextThe extent to which faces and written words share neural circuitry in the human brain is actively debated. We provide an original contribution to this debate by comparing face-selective and word-selective responses in a large group of patients (N=37) implanted with intracerebral electrodes in the ventral occipito-temporal cortex (VOTC). Both face-selective (i.e., significantly different responses to faces vs. nonface objects) and word-selective (i.e., significantly different responses to words vs. pseudofonts) neural activity is isolated through frequency-tagging (Jonas et al., 2016; Lochy et al., 2018, respectively). Critically, this approach allows disentangling category-selective neural responses from general visual responses. Overall, we find that 69.26% of significant contacts show either face- or word-selectivity, with the expected right and left hemispheric dominance, respectively (Fig.1A,B). Moreover, the center of mass for word-contacts is more lateral than for face-contacts, with no differences in postero-anterior axis (Fig.2A). Spatial dissociations are also found within core regions of face and word processing, with a medio-lateral dissociation in the fusiform gyrus (FG) and surrounding sulci (FG+sulci;Fig.2B), while a postero-anterior dissociation is found in the inferior occipital gyrus (IOG;Fig.2C). Despite their spatial dissociations in the FG+sulci and IOG, most overlap in category-selective responses is found in these regions (Fig.1C). Critically, in the overlap-contacts, across the whole brain or specifically in the FG+sulci, between-category (word-face) selective-amplitudes showed no-to-weak correlations, despite strong correlations for within-category (face-face, word-word) selective-amplitudes (Fig.3A), and a strong correlation in non-selective general-amplitudes to words-faces. Moreover, substantial overlap and no-to-weak correlations were observed between faces and a control category (houses) known to be functionally dissociated from faces. Overall, we conclude that category-selectivity for faces and words is largely dissociated in the human VOTC, with a limited spatial overlap likely due to the distant recording of dissociated populations of neurons rather than to shared category-selective representations.1 p

Occipital nerve stimulation improves the quality of life in medically-intractable chronic cluster headache: Results of an observational prospective study.

Background Occipital nerve stimulation (ONS) has been proposed to treat chronic medically-intractable cluster headache (iCCH) in small series of cases without evaluation of its functional and emotional impacts. Methods We report the multidimensional outcome of a large observational study of iCCH patients, treated by ONS within a nationwide multidisciplinary network ( https://clinicaltrials.gov NCT01842763), with a one-year follow-up. Prospective evaluation was performed before surgery, then three and 12 months after. Results One year after ONS, the attack frequency per week was decreased >30% in 64% and >50% in 59% of the 44 patients. Mean (Standard Deviation) weekly attack frequency decreased from 21.5 (16.3) to 10.7 (13.8) ( p = 0.0002). About 70% of the patients responded to ONS, 47.8% being excellent responders. Prophylactic treatments could be decreased in 40% of patients. Functional (HIT-6 and MIDAS scales) and emotional (HAD scale) impacts were significantly improved, as well as the health-related quality of life (EQ-5D). The mean (SD) EQ-5D visual analogic scale score increased from 35.2 (23.6) to 51.9 (25.7) ( p = 0.0037). Surgical minor complications were observed in 33% of the patients. Conclusion ONS significantly reduced the attack frequency per week, as well as the functional and emotional headache impacts in iCCH patients, and dramatically improved the health-related quality of life of responders