Art for reward's sake: visual art recruits the ventral striatum

A recent study showed that people evaluate products more positively when they are physically associated with art images than similar non-art images. Neuroimaging studies of visual art have investigated artistic style and esthetic preference but not brain responses attributable specifically to the artistic status of images. Here we tested the hypothesis that the artistic status of images engages reward circuitry, using event-related functional magnetic resonance imaging (fMRI) during viewing of art and non-art images matched for content. Subjects made animacy judgments in response to each image. Relative to non-art images, art images activated, on both subject- and item-wise analyses, reward-related regions: the ventral striatum, hypothalamus and orbitofrontal cortex. Neither response times nor ratings of familiarity or esthetic preference for art images correlated significantly with activity that was selective for art images, suggesting that these variables were not responsible for the art-selective activations. Investigation of effective connectivity, using time-varying, wavelet-based, correlation-purged Granger causality analyses, further showed that the ventral striatum was driven by visual cortical regions when viewing art images but not non-art images, and was not driven by regions that correlated with esthetic preference for either art or non-art images. These findings are consistent with our hypothesis, leading us to propose that the appeal of visual art involves activation of reward circuitry based on artistic status alone and independently of its hedonic value.     

Dual pathways for haptic and visual perception of spatial and texture information

Segregation of information flow along a dorsally directed pathway for processing object location and a ventrally directed pathway for processing object identity is well established in the visual and auditory systems, but is less clear in the somatosensory system. We hypothesized that segregation of location vs. identity information in touch would be evident if texture is the relevant property for stimulus identity, given the salience of texture for touch. Here, we used functional magnetic resonance imaging (fMRI) to investigate whether the pathways for haptic and visual processing of location and texture are segregated, and the extent of bisensory convergence. Haptic texture-selectivity was found in the parietal operculum and posterior visual cortex bilaterally, and in parts of left inferior frontal cortex. There was bisensory texture-selectivity at some of these sites in posterior visual and left inferior frontal cortex. Connectivity analyses demonstrated, in each modality, flow of information from unisensory non-selective areas to modality-specific texture-selective areas and further to bisensory texture-selective areas. Location-selectivity was mostly bisensory, occurring in dorsal areas, including the frontal eye fields and multiple regions around the intraparietal sulcus bilaterally. Many of these regions received input from unisensory areas in both modalities. Together with earlier studies, the activation and connectivity analyses of the present study establish that somatosensory processing flows into segregated pathways for location and object identity information. The location-selective somatosensory pathway converges with its visual counterpart in dorsal frontoparietal cortex, while the texture-selective somatosensory pathway runs through the parietal operculum before converging with its visual counterpart in visual and frontal cortex. Both segregation of sensory processing according to object property and multisensory convergence appear to be universal organizing principles.     

Integrated local correlation: a new measure of local coherence in fMRI data

This article introduces the measure of integrated local correlation (ILC) for assessing local coherence in the brain using functional magnetic resonance imaging (fMRI) data and characterizes the measure in terms of reproducibility, the effect of physiological noise, and the dependence on image resolution. The coupling of local neuronal processes influences coherence in a voxel's neighborhood. ILC is defined, for each voxel, as the integration of its spatial correlation function. This integrated measure does not require the specification of a neighborhood and, as demonstrated by experimental data, is effectively independent of image resolution. Respiratory and cardiac fluctuations do not considerably alter the ILC value except in isolated areas in and surrounding large vessels. With resting-state fMRI data, ILC was demonstrated to be tissue-specific, higher in gray matter than white matter, and reproducible across consecutive runs in healthy individuals. Within the gray matter, ILC was found to be higher in the default mode network, particularly the posterior and anterior cingulate cortices. Comparing ILC maps obtained from resting state and continuous motor task data, we observed reduced local coherence in the default mode network during the task. Finally, we compared ILC and regional homogeneity by examining their ability to discriminate between gray and white matters in resting state data and found ILC to be more sensitive.     

Early life trauma and directional brain connectivity within major depression

Objective: Early life trauma (ELT) is a significant risk factor for the onset of depression. Emerging findings indicate ELT is associated with enhanced amygdala reactivity to aversive stimuli in never‐depressed healthy controls as well as those with acute depression but may be absent in non‐ELT exposed depressed. The precise mechanism mediating these differences in amygdala reactivity remains unclear. Method: The authors used Granger causality methods to evaluate task‐based directional connectivity between medial or lateral prefrontal cortex (PFC) and amygdala in 20 unmedicated patients with current major depressive disorder (MDD) and 19 healthy matched controls while participants engaged in an affective variant of the flanker task comparing response to sad and neutral faces. These data were correlated with childhood trauma history. Results: Exposure to ELT was associated with failure of inhibition within the MDD group based on medial PFC–amygdala connectivity. In contrast, non‐ELT exposed MDD was associated with a negative causal pathway from medial prefrontal cortex to amygdala, despite reduced dorsolateral PFC input in comparison to healthy controls. Neither MDD group demonstrated significant lateral PFC–amygdala connectivity in comparison to healthy controls. Conclusions: Failure of the circuit implicated in emotion regulation was associated with a significant history of ELT but not with MDD more broadly. Non‐ELT related depression was associated with intact regulation of emotion despite the absence of difference in severity of illness. These findings indicate opposing system‐level differences within depression relative to ELT are expressed as differential amygdala reactivity. Hum Brain Mapp 35:4815–4826, 2014. © 2014 Wiley Periodicals, Inc .     

Fronto-parietal regulation of media violence exposure in adolescents: a multi-method study

Adolescents spend a significant part of their leisure time watching TV programs and movies that portray violence. It is unknown, however, how the extent of violent media use and the severity of aggression displayed affect adolescents' brain function. We investigated skin conductance responses, brain activation and functional brain connectivity to media violence in healthy adolescents. In an event-related functional magnetic resonance imaging experiment, subjects repeatedly viewed normed videos that displayed different degrees of aggressive behavior. We found a downward linear adaptation in skin conductance responses with increasing aggression and desensitization towards more aggressive videos. Our results further revealed adaptation in a fronto-parietal network including the left lateral orbitofrontal cortex (lOFC), right precuneus and bilateral inferior parietal lobules, again showing downward linear adaptations and desensitization towards more aggressive videos. Granger causality mapping analyses revealed attenuation in the left lOFC, indicating that activation during viewing aggressive media is driven by input from parietal regions that decreased over time, for more aggressive videos. We conclude that aggressive media activates an emotion-attention network that has the capability to blunt emotional responses through reduced attention with repeated viewing of aggressive media contents, which may restrict the linking of the consequences of aggression with an emotional response, and therefore potentially promotes aggressive attitudes and behavior.     

Rare presentation of osteoarticular tuberculosis

The varied clinical presentation of osteoarticular tuberculosis makes the diagnosis an enigma. This report underlines the fact that osteoarticular tuberculosis can present in the most atypical pattern. It also emphasises the need for a high index of clinical suspicion and the low threshold for tissue biopsy for establishing the diagnosis.     

Coronal sealing ability of three sectional obturation techniques--SimpliFill, Thermafil and warm vertical compaction--compared with cold lateral condensation and post space preparation

The purpose of this study was to evaluate the effect post space preparation has on the coronal seal of root canals obturated with cold lateral condensation of gutta-percha compared with the corsonal sealing ability of three sectional obturation techniques not requiring post space preparation. Sixty-eight human maxillary central incisors were divided equally into four groups: cold lateral condensation (Group I), SimpliFill (Group II), Thermafil (Group III) and warm vertical compaction (Group IV). After coronal flaring, all four groups were cleaned and shaped with Lightspeed rotary instruments to a size 60 master apical rotary. After obturation Peeso Reamers were used to create a post space for Group I, while Groups 2, 3 and 4 incorporated the post space in the obturation (sectional technique) and did not require making a post space after obturation. The teeth were then stored in 100% humidity for 1 week and then kept in rhodamine B fluorescent dye for 3 weeks. The teeth were then split open, and the linear dye penetration from a coronal to apical direction (coronal seal) was evaluated with a fluorescent light microscope. Statistical analysis showed that Group I (cold lateral condensation followed by post space made with Peeso Reamers) leaked significantly more (P < 0.05) than the remaining three sectional obturation groups. It was concluded that stresses generated during post space preparation might be detrimental to the seal obtained by the obturation. Sectional obturations with their superior sealing ability offer a viable alternative.     

Evaluation of the effect of MTAD in comparison with EDTA when employed as the final rinse on the shear bond strength of three endodontic sealers to dentine

The purpose of the study was to evaluate the effect of MTAD in comparison with EDTA as a final rinse on the shear bond strength of Kerr, Apexit and AH plus. Dentine surfaces of 135 extracted human non-carious maxillary premolars were divided into three groups (n = 45). Groups I and II were conditioned with 1.3% NaOCl for 20 min, followed by a final rinse of 17% EDTA for 1 min and MTAD for 5 min respectively. Group III was treated with distilled water. Each group was further divided into three subgroups (n = 15). Subgroup 1: Kerr, Subgroup 2: Apexit and Subgroup 3: AH plus. Three-millimetre-long sections of polyethylene tubes were filled with freshly mixed sealer and placed on the dentine surfaces. The bonding between the sealer and dentine surface was evaluated using shear bond testing. The values were statistically evaluated using one way anova followed by Tukey's test. Significant difference was found among the bond strength of the sealers and irrigating regimes. AH plus showed superior bond strength among the tested sealers, when EDTA was employed as the final rinse (P < 0.05). MTAD as a final rinse affected the bond strength of AH plus and Apexit, which were significantly lower than the control group.     

Positional ventricular tachycardia from a fractured mediport catheter with right ventricular migration--a case report

The totally implantable catheter system has gained popularity as venous access when prolonged treatment is needed. Despite its frequent use, intravascular fracture and embolization of catheter fragments from implantable venous port-catheter systems present a rare but potentially life-threatening complication. Any implanted catheters should therefore be removed after completion of the treatment or the system's integrity should be monitored on a regular basis. This report illustrates such a case, which presented with ventricular tachycardia triggered by changes in body position from a fractured Mediport catheter with cardiac migration. A 34-year-old woman had a venous port catheter (Mediport) implanted into the right subclavian vein for neoadjuvant radio-chemotherapy for Hodgkin's lymphoma. Owing to the patient's difficult venous access the catheter was left in situ after treatment. Three years after insertion of the Mediport she presented with shortness of breath and palpitations when lying in the left lateral position. Physical examination revealed no abnormalities. An electrocardiogram was within normal rhythm. An outpatient Holter monitor revealed multiple episodes of nonsustained and sustained ventricular tachycardia triggered by lying in the left lateral position. A chest radiograph showed a normal location of the port-system, but the distal fragment of the catheter had embolized into the right ventricle. The embolized fragment was extracted with a gooseneck snare technique and the reservoir of the system was removed under local anesthesia without any complications. The patient was free of symptoms at 7 seven months follow-up.