Abnormal Perceptual Sensitivity in Body-Focused Repetitive Behaviors

Objective Several compulsive grooming habits such as hair pulling, skin picking, and nail biting are collectively known as body-focused repetitive behaviors (BFRBs). Although subclinical BFRBs are common and benign, more severe and damaging manifestations exist that are difficult to manage. Researchers have suggested that BFRBs are maintained by various cognitive, affective, and sensory contingencies. Although the involvement of cognitive and affective processes in BFRBs has been studied, there is a paucity of research on sensory processes. Methods The current study tested whether adults with subclinical or clinical BFRBs would report abnormal patterns of sensory processing as compared to a healthy control sample. Results Adults with clinical BFRBs (n = 26) reported increased sensory sensitivity as compared to persons with subclinical BFRBs (n = 48) and healthy individuals (n = 33). Elevations in sensation avoidance differentiated persons with clinical versus subclinical BFRBs. Sensation seeking patterns were not different between groups. Unexpectedly, BFRB severity was associated with lower registration of sensory stimuli, but this finding may be due to high psychiatric comorbidity rates in the BFRB groups. Conclusions These findings suggest that several sensory abnormalities may underlie BFRBs. Implications for the etiology and treatment of BFRBs are discussed

The Internet's unexploited path diversity

The connectivity of the Internet at the Autonomous System level is influenced by the network operator policies implemented. These in turn impose a direction to the announcement of address advertisements and, consequently, to the paths that can be used to reach back such destinations. We propose to use directed graphs to properly represent how destinations propagate through the Internet and the number of arc-disjoint paths to quantify this network's path diversity. Moreover, in order to understand the effects that policies have on the connectivity of the Internet, numerical analyses of the resulting directed graphs were conducted. Results demonstrate that, even after policies have been applied, there is still path diversity which the Border Gateway Protocol cannot currently exploit.Comment: Submitted to IEEE Communications Letter

Emotion Regulation Deficits in Persons with Body-Focused Repetitive Behavior Disorders

Background Conceptualizations of emotion dysregulation (ED) and body-focused repetitive behavior disorders (BFRBDs) imply that ED may be a central component of BFRBDs as well as a factor that distinguishes BFRBDs from non-impairing, subclinical body-focused repetitive behaviors (BFRBs). The current study empirically tested these observations. Methods One hundred thirty-eight undergraduates (of 1900 who completed a screening survey) completed self-report measures assessing four emotion regulation (ER) deficits hypothesized to underlie ED (alexithymia, maladaptive emotional reactivity, experiential avoidance, and response inhibition when distressed); 34 of these participants had BFRBDs, 64 had subclinical BFRBs, and 42 were unaffected by BFRBs. Results Results indicated that participants with BFRBDs reported higher levels of maladaptive emotional reactivity, experiential avoidance, and response inhibition when distressed than participants with subclinical BFRBs and participants unaffected by BFRBs. These results held even when controlling for comorbidity and total number of reported BFRBs. Participants did not differ on alexithymia. Limitations Limitations of the current study include the BFRB groups’ different distributions of BFRB types (e.g., hair pulling versus skin picking), the sample\u27s demographic uniformity, and the fact that negative affectivity was not controlled when exploring BFRB group differences on ER deficits. Future research should improve on these limitations. Conclusions The current results suggest that ED is a factor that differentiates BFRBDs from subclinical BFRBs. Such results may be useful for generating hypotheses regarding mechanisms responsible for BFRBs’ development into BFRBDs. Furthermore, these results may provide insight into factors that explain the efficacy of more contemporary behavioral treatments for BFRBDs

OPA1 processing controls mitochondrial fusion and is regulated by mRNA splicing, membrane potential, and Yme1L

OPA1, a dynamin-related guanosine triphosphatase mutated in dominant optic atrophy, is required for the fusion of mitochondria. Proteolytic cleavage by the mitochondrial processing peptidase generates long isoforms from eight messenger RNA (mRNA) splice forms, whereas further cleavages at protease sites S1 and S2 generate short forms. Using OPA1-null cells, we developed a cellular system to study how individual OPA1 splice forms function in mitochondrial fusion. Only mRNA splice forms that generate a long isoform in addition to one or more short isoforms support substantial mitochondrial fusion activity. On their own, long and short OPA1 isoforms have little activity, but, when coexpressed, they functionally complement each other. Loss of mitochondrial membrane potential destabilizes the long isoforms and enhances the cleavage of OPA1 at S1 but not S2. Cleavage at S2 is regulated by the i-AAA protease Yme1L. Our results suggest that mammalian cells have multiple pathways to control mitochondrial fusion through regulation of the spectrum of OPA1 isoforms