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Using magnetoencephalography (MEG), we compared the processing of sinusoidal tones in the auditory cortex of 12 non-musicians, 12 professional musicians and 13 amateur musicians. We found neurophysiological and anatomical differences between groups. In professional musicians as compared to non-musicians, the activity evoked in primary auditory cortex 19-30 ms after stimulus onset was 102% larger, and the gray matter volume of the anteromedial portion of Heschl's gyrus was 130% larger. Both quantities were highly correlated with musical aptitude, as measured by psychometric evaluation. These results indicate that both the morphology and neurophysiology of Heschl's gyrus have an essential impact on musical aptitude.

This review is aimed to demonstrate the basics and use of formalism of gauge-invariant nonlocal correlators in nonabelian gauge theories. Many phenomenologically interesting nonperturbative aspects of gluodynamics and QCD can be described in terms of correlators of the nonabelian field strength tensors. It is explained how the properties of correlator ensemble encode the structure of QCD vacuum and determine different nonperturbative observables. It is argued that in gluodynamics and QCD the dominant role is played by the lowest nontrivial two-point correlator (Gaussian dominance). Lattice measurements of field correlators are discussed. Important for the formalism theoretical tools, such as nonabelian Stokes theorem, background perturbation theory, cluster expansion, as well as phenomenological applications to the heavy quarkonium dynamics and QCD phase transition are reviewed.Comment: LaTeX, 77 pages, 7 eps-figure

Total cross sections and logarithmic slopes of the elastic scattering cross sections for different hadronic processes are calculated in the framework of the model of the stochastic vacuum. The relevant parameters of this model, a correlation length and the gluon condensate, are determined from scattering data, and found to be in very good agreement with values coming from completely different sources of information. A parameter-free relation is given between total cross sections and slope parameters, which is shown to be remarkably valid up to the highest energies for which data exist.PACS number(s): 12.38.Lg. 13.85.Dz, 13.85.Lg @(a. w) = P exp -ig d a ( X -w),[ l1J P denotes path ordering, which is necessary in order togive to the exponential a well-defined meaning. In a nonperturbative way, this ordering is defined, for any operator 0 throughwith 0 < a1 < a 2 . . . < 1, Auk = C T~+~ -uk .The field strength tensor in Eq. (7) transforms with

The relative pitch of harmonic complex sounds, such as instrumental sounds, may be perceived by decoding either the fundamental pitch (f0) or the spectral pitch (fSP) of the stimuli. We classified a large cohort of 420 subjects including symphony orchestra musicians to be either f0 or fSP listeners, depending on the dominant perceptual mode. In a subgroup of 87 subjects, MRI (magnetic resonance imaging) and magnetoencephalography studies demonstrated a strong neural basis for both types of pitch perception irrespective of musical aptitude. Compared with f0 listeners, fSP listeners possessed a pronounced rightward, rather than leftward, asymmetry of gray matter volume and P50m activity within the pitch-sensitive lateral Heschl's gyrus. Our data link relative hemispheric lateralization with perceptual stimulus properties, whereas the absolute size of the Heschl's gyrus depends on musical aptitude.

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We derive sum rules for the leptonic decay constant of a heavy-light meson in the effective heavy quark theory. We show that the summation of logarithms in the heavy quark mass by the renormalization group technique enhances considerably radiative corrections. Our result for the decay constant in the static limit agrees well with recent lattice calculations. Finite quark mass corrections are estimated.I. In this paper we give a consistent framework for the construction of QCD sum rules [ 1 ] for heavy-light quark systems in the heavy quark limit (HQL), which in that approach has first been discussed by Shuryak [ 2 ] and has been further studied by several authors [ 3,4 ]. Although for the heavy quark mass mQ below 10 GeV both the logarithmic and nonlogarithmic contributions are numerically of the same size, for the consistent treatment of the limit mQ~oV it is necessary to sum all corrections of the type [as(mQ)lnmQ] n,In mQ ] n, etc. by the renormalization group technique. This "mass factorization" has become one of the most actively discussed topics in the literature, and we find it important to formulate the sum rule approach in such a way that all the scaling laws inherent to the heavy quark expansion (HQE) are automatically fulfilled. This task is interesting for several reasons. First, the sum rules formulated in this way exhibit explicit Isgur-Wise symmetries [ 5 ] and so do the physical quantities extracted as their output. Second, quantitative estimates can be made for the finite heavy quark mass corrections. In addition, such a formulation of sum rules facilitates the comparison to the results of lattice calculations [6,7 ].A convenient framework for systematically factorizing out the large-mass physics is provided by the effective field theory [ 5 ]. The key issue there is the introduction of a separate heavy quark and antiquark field h ~ for each four-velocity v in order to implement the velocity superselection rule: the velocity of the heavy quark cannot be changed by the radiation of gluons since it would correspond to infinitely large momentum transfers 8pu = m o ~v~. Hence, the part of the lagrangian associated with heavy quarks becomes 0370-2693/92/$ 05.00

We present a nonperturbative QCD calculation of diffractive vector meson production in virtual photon nucleon scattering at high energy. We use the nonperturbative model of the stochastic QCD vacuum which yields linear confinement and makes specific predictions for the dependence of high-energy scattering cross sections on the hadron size. Using light cone wave functions of the photon and vector mesons, we calculate electroproduction cross sections for ρ, ω, φ and J/ψ. We emphasize the behavior of specific observables such as the ratio of longitudinal to transverse production cross section and the t-dependence of the differential cross section.