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1.
Schizophr Bull ; 45(5): 1060-1067, 2019 09 11.
Article in English | MEDLINE | ID: mdl-30551180

ABSTRACT

OBJECTIVE: Embodied emotions arise from interoceptive and somatosensory processes, and are essential to the development of a stable sense of self. Emotional embodiment is therefore inherently interwoven with our sense of bodily self-awareness, and allows us to navigate complex social situations. Given that the core feature of schizophrenia (SZ) is characterized by the presence of bodily self-disturbances and social-emotional deficits, we hypothesized that embodiment of emotion would be disrupted in SZ. METHOD: Twenty-six medicated individuals with SZ and 26 demographically matched controls used a computerized topographical mapping tool ("EmBODY") to indicate on a body outline where they felt bodily sensations while experiencing an emotion. There were 13 different emotions plus a neutral state. The resulting bodily maps of emotions were quantitatively compared between groups using linear discriminant analysis and similarity scores. RESULTS: Bodily maps of emotions were anomalous in SZ as indicated by indistinguishable maps across different emotions. Relative to the control group, patients reported less discrete and less clear bodily sensations across emotions. In particular, bodily maps for low-arousal emotions were atypical in comparison with healthy controls. CONCLUSIONS: Anomalous and undifferentiated mapping of embodied emotions in SZ could lead to deficits in linking bodily sensations to conceptual categories of emotions. Disrupted emotional embodiment could also contribute to poor social functioning. Abnormal bodily sensations of emotions might therefore be a promising target for future psychosocial interventions.


Subject(s)
Emotions , Interoception , Schizophrenia/physiopathology , Adult , Case-Control Studies , Discriminant Analysis , Female , Humans , Male , Middle Aged , Sensation
2.
ACM Trans Access Comput ; 11(4)2018 Nov.
Article in English | MEDLINE | ID: mdl-30627303

ABSTRACT

Emotion recognition impairment is a core feature of schizophrenia (SZ), present throughout all stages of this condition, and leads to poor social outcome. However, the underlying mechanisms that give rise to such deficits have not been elucidated and hence, it has been difficult to develop precisely targeted interventions. Evidence supports the use of methods designed to modify patterns of visual attention in individuals with SZ in order to effect meaningful improvements in social cognition. To date, however, attention-shaping systems have not fully utilized available technology (e.g., eye tracking) to achieve this goal. The current work consisted of the design and feasibility testing of a novel gaze-sensitive social skills intervention system called MASI-VR. Adults from an outpatient clinic with confirmed SZ diagnosis (n=10) and a comparison sample of neurotypical participants (n=10) were evaluated on measures of emotion recognition and visual attention at baseline assessment, and a pilot test of the intervention system was evaluated on the SZ sample following five training sessions over three weeks. Consistent with the literature, participants in the SZ group demonstrated lower recognition of faces showing medium intensity fear, spent more time deliberating about presented emotions, and had fewer fixations in comparison to neurotypical peers. Furthermore, participants in the SZ group showed significant improvement in the recognition of fearful faces post-training. Preliminary evidence supports the feasibility of a gaze-sensitive paradigm for use in assessment and training of emotion recognition and social attention in individuals with SZ, thus warranting further evaluation of the novel intervention.

3.
Article in English | MEDLINE | ID: mdl-24892593

ABSTRACT

The high-pressure structural behaviour of a series of binary thorium compounds ThX (X = C, N, P, As, Sb, Bi, S, Se, Te) is studied using the all-electron full potential linear muffin-tin orbital (FP-LMTO) method within the generalized gradient approximation (GGA) for the exchange and correlation potential. The calculated equlibrium lattice parameters and bulk moduli, as well as the equations of state agree well with experimental results. New experiments are reported for ThBi and ThN. Calculations are performed for the ThX compounds in the NaCl- and CsCl-type crystal structures, and structural phase transitions from NaCl to CsCl are found in ThP, ThAs, ThSb and ThSe at pressures of 26.1, 22.1, 8.1 and 23.2 GPa, respectively, in excellent agreement with experimental results. ThC, ThN and ThS are found to be stable in the NaCl structure, and ThBi and ThTe in the CsCl structure, for pressures below 50 GPa. The electronic structures of the ThX compounds are studied using the quasiparticle self-consistent GW method (G: Green function, W: dynamically screened interaction).

4.
J Phys Condens Matter ; 25(26): 265401, 2013 Jul 03.
Article in English | MEDLINE | ID: mdl-23751600

ABSTRACT

The structural behaviour under compression of different lanthanide (La, Gd, Ho, Yb) and actinide (Am) monochalcogenides is studied by means of in situ high-pressure x-ray diffraction. All the investigated compounds crystallize at ambient conditions within a cubic (B1) NaCl-type structure but show different behaviours at high pressures. LaTe and AmTe undergo B1 to B2 (CsCl-type structure) phase transitions, starting at 9 GPa and 12 GPa, respectively. The high-pressure phase of AmTe exhibits an electronic transition, identified by an anomaly in the compression curve which is accompanied by a sample colour change. The other three monochalcogenides studied here show clear evidence of decomposition and amorphization under pressure and are, to the best of our knowledge, the first in the LnTe series to show a pressure-induced amorphization. The bulk moduli of all B1-type structure compounds are calculated using the third-order Birch-Murnaghan equation of state.


Subject(s)
Actinoid Series Elements/chemistry , Chalcogens/chemistry , Lanthanoid Series Elements/chemistry , Tellurium/chemistry , Crystallization , Models, Molecular , Phase Transition , Pressure , Quantum Theory , Surface Properties , X-Ray Diffraction
5.
PLoS One ; 6(10): e27089, 2011.
Article in English | MEDLINE | ID: mdl-22073126

ABSTRACT

BACKGROUND: A weakened sense of self may contribute to psychotic experiences. Body ownership, one component of self-awareness, can be studied with the rubber hand illusion (RHI). Watching a rubber hand being stroked while one's unseen hand is stroked synchronously can lead to a sense of ownership over the rubber hand, a shift in perceived position of the real hand, and a limb-specific drop in stimulated hand temperature. We aimed to assess the RHI in schizophrenia using quantifiable measures: proprioceptive drift and stimulation-dependent changes in hand temperature. METHODS: The RHI was elicited in 24 schizophrenia patients and 21 matched controls by placing their unseen hand adjacent to a visible rubber hand and brushing real and rubber hands synchronously or asynchronously. Perceived finger location was measured before and after stimulation. Hand temperature was taken before and during stimulation. Subjective strength of the illusion was assessed by a questionnaire. RESULTS: Across groups, the RHI was stronger during synchronous stimulation, indicated by self-report and proprioceptive drift. Patients reported a stronger RHI than controls. Self-reported strength of RHI was associated with schizotypy in controls Proprioceptive drift was larger in patients, but only following synchronous stimulation. Further, we observed stimulation-dependent changes in skin temperature. During right hand stimulation, temperature dropped in the stimulated hand and rose in the unstimulated hand. Interestingly, induction of RHI led to an out-of-body experience in one patient, linking body disownership and psychotic experiences. CONCLUSIONS: The RHI is quantitatively and qualitatively stronger in schizophrenia. These findings suggest that patients have a more flexible body representation and weakened sense of self, and potentially indicate abnormalities in temporo-parietal networks implicated in body ownership. Further, results suggest that these body ownership disturbances might be at the heart of a subset of the pathognomonic delusions of passivity.


Subject(s)
Body Image , Hand/physiology , Illusions/physiology , Proprioception/physiology , Schizophrenia/physiopathology , Visual Perception/physiology , Adult , Female , Human Body , Humans , Male , Middle Aged , Rubber
6.
J Phys Condens Matter ; 22(27): 275603, 2010 Jul 14.
Article in English | MEDLINE | ID: mdl-21399262

ABSTRACT

High-pressure techniques were used to determine the structural behaviour of the superconducting ferromagnet UCoGe up to 30 GPa enabling us to determine the link between the effect of pressure on the material magnetic properties and crystal structure. The TiNiSi type structure of UCoGe was preserved up to the highest pressure. The a direction, equivalent to the shortest U-U links, was identified as the critical soft direction. The data are compared with the structural variations in UCoGe α-hydride, which becomes non-magnetic and non-superconducting despite a volume expansion. We show that at least in this case, but probably more generally, the structure impact of hydrogenation is definitely not equivalent to negative pressure.

7.
Science ; 309(5731): 110-3, 2005 Jul 01.
Article in English | MEDLINE | ID: mdl-15994550

ABSTRACT

Curium lies at the center of the actinide series and has a half-filled shell with seven 5f electrons spatially residing inside its radon core. As a function of pressure, curium exhibits five different crystallographic phases up to 100 gigapascals, of which all but one are also found in the preceding element, americium. We describe here a structure in curium, Cm III, with monoclinic symmetry, space group C2/c, found at intermediate pressures (between 37 and 56 gigapascals). Ab initio electronic structure calculations agree with the observed sequence of structures and establish that it is the spin polarization of curium's 5f electrons that stabilizes Cm III. The results reveal that curium is one of a few elements that has a lattice structure stabilized by magnetism.

8.
Phys Rev Lett ; 85(14): 2961-4, 2000 Oct 02.
Article in English | MEDLINE | ID: mdl-11005978

ABSTRACT

Americium occupies a pivotal position in the actinide series with regard to the behavior of 5f electrons. High-pressure techniques together with synchrotron radiation have been used to determine the structural behavior up to 100 GPa. We have resolved earlier controversial findings regarding americium and find that our experimental results are in discord with recent theoretical predictions. We have two new findings: (1) that there exists a critical, new structural link between americium under pressure and its near neighbor, plutonium; and (2) that the 5f electron delocalization in americium occurs in two rather than one step.

10.
EMBO J ; 12(5): 1781-95, 1993 May.
Article in English | MEDLINE | ID: mdl-8491171

ABSTRACT

The crystal structure of EcoRV endonuclease has been determined at 2.5 A resolution and that of its complexes with the cognate DNA decamer GGGATATCCC (recognition sequence underlined) and the non-cognate DNA octamer CGAGCTCG at 3.0 A resolution. Two octamer duplexes of the non-cognate DNA, stacked end-to-end, are bound to the dimeric enzyme in B-DNA-like conformations. The protein--DNA interactions of this complex are prototypic for non-specific DNA binding. In contrast, only one cognate decamer duplex is bound and deviates considerably from canonical B-form DNA. Most notably, a kink of approximately 50 degrees is observed at the central TA step with a concomitant compression of the major groove. Base-specific hydrogen bonds between the enzyme and the recognition base pairs occur exclusively in the major groove. These interactions appear highly co-operative as they are all made through one short surface loop comprising residues 182-186. Numerous contacts with the sugar phosphate backbone extending beyond the recognition sequence are observed in both types of complex. However, the total surface area buried on complex formation is > 1800 A2 larger in the case of cognate DNA binding. Two acidic side chains, Asp74 and Asp90, are close to the reactive phosphodiester group in the cognate complex and most probably provide oxygen ligands for binding the essential cofactor Mg2+. An important role is also indicated for Lys92, which together with the two acidic functions appears to be conserved in the otherwise unrelated structure of EcoRI endonuclease. The structural results give new insight into the physical basis of the remarkable sequence specificity of this enzyme.


Subject(s)
DNA/chemistry , Deoxyribonucleases, Type II Site-Specific/chemistry , Amino Acid Sequence , Base Sequence , Binding Sites , Computer Simulation , Models, Molecular , Molecular Sequence Data , Nucleic Acid Conformation , Protein Conformation , X-Ray Diffraction
11.
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