Timing, kinematics, and the cerebellum: Tapping into differences between musicians and non-musicians

Musical performance relies on basic processes such as timing, and the synchronization of motor responses with environmental stimuli. The study of the effects of musical training on behaviour and the brain provides an opportunity to understand these processes and their neural correlates, particularly in relation to the cerebellum, a brain region implicated in timing. The first study presented here compared musicians and non-musicians on the standard sensorimotor synchronization task of finger tapping to a metronome, with and without tactile feedback. The results indicated that musicians differed from non-musicians in their use of kinematics and sensory information for synchronization. The second study focused on how musical training affects event-based and emergent timing in repetitive rhythmic tapping and drawing. Event-based timing has been shown to rely on an internal clock-like process that is independent of the motor response. Conversely, emergent timing establishes regular rhythmic movement by stabilizing kinematic parameters without reference to an explicit internal representation of time intervals. Musical training was associated with improved precision in event-based timing but not in emergent timing. For musicians only, the kinematic parameter of movement jerk was decoupled from timing variability in both event-based and emergent timing. These results support the dissociability of the two timing modes, highlight the limits of musical training, and show that the relationship between kinematics and timing is affected by musical expertise. The third study examined differences between musicians and non-musicians in a finger-tapping task, and in regional cerebellar volumes measured from magnetic resonance imaging data. Smaller volumes were associated with an earlier age of start of musical training, and with better timing performance. These findings are evidence for a sensitive period, before seven years, for initiation of musical training. Timing variability was associated with the volume of right Lobule VI, indicating localization of event-based timing to this region. The overall pattern of results suggests that musicians may be using sensory information to maintain timing in a more efficient and parsimonious manner compared to non-musicians. This is interpreted as evidence that musicians are using a top-down approach for many music-related tasks, in contrast to the bottom-up approach of non-musicians

Timing, kinematics, and the cerebellum: Tapping into differences between musicians and non-musicians

Musical performance relies on basic processes such as timing, and the synchronization of motor responses with environmental stimuli. The study of the effects of musical training on behaviour and the brain provides an opportunity to understand these processes and their neural correlates, particularly in relation to the cerebellum, a brain region implicated in timing. The first study presented here compared musicians and non-musicians on the standard sensorimotor synchronization task of finger tapping to a metronome, with and without tactile feedback. The results indicated that musicians differed from non-musicians in their use of kinematics and sensory information for synchronization. The second study focused on how musical training affects event-based and emergent timing in repetitive rhythmic tapping and drawing. Event-based timing has been shown to rely on an internal clock-like process that is independent of the motor response. Conversely, emergent timing establishes regular rhythmic movement by stabilizing kinematic parameters without reference to an explicit internal representation of time intervals. Musical training was associated with improved precision in event-based timing but not in emergent timing. For musicians only, the kinematic parameter of movement jerk was decoupled from timing variability in both event-based and emergent timing. These results support the dissociability of the two timing modes, highlight the limits of musical training, and show that the relationship between kinematics and timing is affected by musical expertise. The third study examined differences between musicians and non-musicians in a finger-tapping task, and in regional cerebellar volumes measured from magnetic resonance imaging data. Smaller volumes were associated with an earlier age of start of musical training, and with better timing performance. These findings are evidence for a sensitive period, before seven years, for initiation of musical training. Timing variability was associated with the volume of right Lobule VI, indicating localization of event-based timing to this region. The overall pattern of results suggests that musicians may be using sensory information to maintain timing in a more efficient and parsimonious manner compared to non-musicians. This is interpreted as evidence that musicians are using a top-down approach for many music-related tasks, in contrast to the bottom-up approach of non-musicians

A Multilepton signal for supersymmetric particles in Tevatron data?

The CDF and D0 collaborations have both reported unusual events in the dilepton+jets sample with very high lepton and missing transverse energies. It is possible, but very unlikely, that these events originate from top quark pair production; however, they have characteristics that are better accounted for by decays of supersymmetric quarks with mass in the region of 300 GeV: $\widetilde q \to q \widetilde \chi$, $\widetilde\chi \to \nu\widetilde\ell$, $\widetilde\ell\rightarrow \ell \widetilde \chi_1^0$. Such a supersymmetric origin also leads to events with large transverse missing energy and either 0, 1, 2 same-sign, or 3 isolated leptons.Comment: 11 pages, 1 figure include

SUSY, the Third Generation and the LHC

We develop a bottom-up approach to studying SUSY with light stops and sbottoms, but with other squarks and sleptons heavy and beyond reach of the LHC. We discuss the range of squark, gaugino and Higgsino masses for which the electroweak scale is radiatively stable over the "little hierarchy" below ~ 10 TeV. We review and expand on indirect constraints on this scenario, in particular from flavor and CP tests. We emphasize that in this context, R-parity violation is very well motivated. The phenomenological differences between Majorana and Dirac gauginos are also discussed. Finally, we focus on the light subsystem of stops, sbottom and neutralino with R-parity, in order to probe the current collider bounds. We find that 1/fb LHC bounds are mild and large parts of the motivated parameter space remain open, while the 10/fb data can be much more decisive.Comment: 42 pages, 8 figures, 1 table. V2: minor corrections, references adde

Yukawa Unification and the Superpartner Mass Scale

Naturalness in supersymmetry (SUSY) is under siege by increasingly stringent LHC constraints, but natural electroweak symmetry breaking still remains the most powerful motivation for superpartner masses within experimental reach. If naturalness is the wrong criterion then what determines the mass scale of the superpartners? We motivate supersymmetry by (1) gauge coupling unification, (2) dark matter, and (3) precision b-tau Yukawa unification. We show that for an LSP that is a bino-Higgsino admixture, these three requirements lead to an upper-bound on the stop and sbottom masses in the several TeV regime because the threshold correction to the bottom mass at the superpartner scale is required to have a particular size. For tan beta about 50, which is needed for t-b-tau unification, the stops must be lighter than 2.8 TeV when A_t has the opposite sign of the gluino mass, as is favored by renormalization group scaling. For lower values of tan beta, the top and bottom squarks must be even lighter. Yukawa unification plus dark matter implies that superpartners are likely in reach of the LHC, after the upgrade to 14 (or 13) TeV, independent of any considerations of naturalness. We present a model-independent, bottom-up analysis of the SUSY parameter space that is simultaneously consistent with Yukawa unification and the hint for m_h = 125 GeV. We study the flavor and dark matter phenomenology that accompanies this Yukawa unification. A large portion of the parameter space predicts that the branching fraction for B_s to mu^+ mu^- will be observed to be significantly lower than the SM value.Comment: 34 pages plus appendices, 20 figure

New hadrons as ultra-high energy cosmic rays

Ultra-high energy cosmic ray (UHECR) protons produced by uniformly distributed astrophysical sources contradict the energy spectrum measured by both the AGASA and HiRes experiments, assuming the small scale clustering of UHECR observed by AGASA is caused by point-like sources. In that case, the small number of sources leads to a sharp exponential cutoff at the energy E<10^{20} eV in the UHECR spectrum. New hadrons with mass 1.5-3 GeV can solve this cutoff problem. For the first time we discuss the production of such hadrons in proton collisions with infrared/optical photons in astrophysical sources. This production mechanism, in contrast to proton-proton collisions, requires the acceleration of protons only to energies E<10^{21} eV. The diffuse gamma-ray and neutrino fluxes in this model obey all existing experimental limits. We predict large UHE neutrino fluxes well above the sensitivity of the next generation of high-energy neutrino experiments. As an example we study hadrons containing a light bottom squark. These models can be tested by accelerator experiments, UHECR observatories and neutrino telescopes.Comment: 17 pages, revtex style; v2: shortened, as to appear in PR

Mechanisms of Perceived Treatment Assignment and Subsequent Expectancy Effects in a Double Blind Placebo Controlled RCT of Major Depression

Objective: It has been suggested that patients' perception of treatment assignment might serve to bias results of double blind randomized controlled trials (RCT). Most previous evidence on the effects of patients' perceptions and the mechanisms influencing these perceptions relies on cross-sectional associations. This re-analysis of a double blind, placebo controlled RCT of pharmacological treatment of major depression set out to gather longitudinal evidence on the mechanism and effects of patients' perceived treatment assignment in the pharmacological treatment of major depression.Methods: One-hundred eighty-nine outpatients with DSM-IV diagnosed major depression were randomized to SAMe 1,600–3,200 mg/d, escitalopram 10–20 mg/days, or placebo for 12 weeks. Data on depressive symptoms (17-item Hamilton Depression Scale; HDRS-17), adverse events and patients' perceived treatment assignment was collected at baseline, week 6, and week 12. The re-analysis focused on N = 166 (out of the originally included 189 participants) with available data on perceived treatment assignment.Results: As in the parent trial, depressive symptoms (HDRS-17) significantly decreased over the course of 12 weeks and there was no difference between placebo, SAMe or escitalopram. A significant number of patients changed their perceptions about treatment assignment throughout the trial, especially between baseline and week 6. Improvement in depressive symptoms, but not adverse events significantly predicted perceived treatment assignment at week 6. In turn, perceived treatment assignment at week 6, but not actual treatment, predicted further improvement in depressive symptoms at week 12.Conclusions: The current results provide longitudinal evidence that patients' perception of treatment assignment systematically change despite a double blind procedure and in turn might trigger expectancy effects with the potential to bias the validity of an RCT.Parent study grant number: R01 AT001638 Parent study ClinicalTrials. gov Identifier: NCT0010145

Communications Biophysics

Contains research objectives, summary of research and reports on three research projects.National Institutes of Health (Grant 5 PO1 GM14940-04)National Institutes of Health (Grant 5 TOl GM01555-04)National Aeronautics and Space Administration (Grant NGL 22-009-304

Burden of anemia in patients with osteoarthritis and rheumatoid arthritis in French secondary care

<p>Abstract</p> <p>Background</p> <p>Arthritic disorders can be the cause of hospitalizations, especially among individuals 60 years and older. The objective of this study is to investigate associations between health care resource utilization in arthritis patients with and without concomitant anemia in a secondary care setting in France.</p> <p>Methods</p> <p>This retrospective cohort study utilized data on secondary care activity in 2001 from the Programme de Médicalisation des Systèmes d'Information database. Two cohorts were defined using ICD-10 codes: patients with an arthritis diagnosis with a concomitant diagnosis of anemia; and arthritis patients without anemia. Health care resource utilization for both populations was analyzed separately in public and private hospitals. Study outcomes were compared between the cohorts using standard bivariate and multivariable methods.</p> <p>Results</p> <p>There were 300,865 hospitalizations for patients with arthritis only, and 2,744 for those with concomitant anemia. Over 70% of patients with concomitant anemia were in public hospitals, compared with 53.5% of arthritis-only patients. Arthritis patients without anemia were younger than those with concomitant anemia (mean age 66.7 vs 74.6, public hospitals; 67.1 vs 72.2, private hospitals). Patients with concomitant anemia/arthritis only had a mean length of stay of 11.91 (SD 14.07)/8.04 (SD 9.93) days in public hospitals, and 10.68 (SD 10.16)/9.83 (SD 7.76) days in private hospitals. After adjusting for confounders, the mean (95% CI) additional length of stay for arthritis patients with concomitant anemia, compared with those with arthritis only, was 1.56 (1.14-1.98) days in public and 0.69 (0.22-1.16) days in private hospitals. Costs per hospitalization were €;480 (227-734) greater for arthritis patients with anemia in public hospitals, and €;30 (-113-52) less in private hospitals, than for arthritis-only patients.</p> <p>Conclusions</p> <p>Arthritis patients with concomitant anemia have a longer length of stay, undergo more procedures, and have higher hospitalization costs than nonanemic arthritis patients in public hospitals in France. In private hospitals, concomitant anemia was associated with modest increases in length of stay and number of procedures; however, this did not translate into higher costs. Such evidence of anemia-related health care utilization and costs can be considered as a proxy for the clinical significance of anemia.</p