Recent studies have suggested that the degree of on-frequency peripheral auditory compression is similar for apical and basal cochlear sites and that compression extends to a wider range of frequencies in apical than in basal sites. These conclusions were drawn from the analysis of the slopes of temporal masking curves (TMCs) on the assumption that forward masking decays at the same rate for all probe and masker frequencies. The aim here was to verify this conclusion using a different assumption. TMCs for normal hearing listeners were measured for probe frequencies (f(P)) of 500 and 4000 Hz and for masker frequencies (f(M)) of 0.4, 0.55, and 1.0 times the probe frequency. TMCs were measured for probes of 9 and 15 dB sensation level. The assumption was that given a 6 dB increase in probe level, linear cochlear responses to the maskers should lead to a 6 dB vertical shift of the corresponding TMCs, while compressive responses should lead to bigger shifts. Results were consistent with the conclusions from earlier studies. It is argued that this supports the assumptions of the standard TMC method for inferring compression, at least in normal-hearing listeners.

Highlights► Signal detection theory was applied to ferrets’ behaviour-detecting tones in noise. ► Sensory acuity was stable but the decisions depended on the set of stimuli. ► Decisions also depended on responses and rewards in previous trials. ► Computer simulations accounted for the data quantitatively. ► Behaviour reflects a stable sensory representation with a dynamic decision process.

Psychophysical forward masking is an increase in threshold of detection of a sound (probe) when it is preceded by another sound (masker). This is reminiscent of the reduction in neuronal responses to a sound following prior stimulation. Studies in the auditory nerve and cochlear nucleus using signal detection theory techniques to derive neuronal thresholds showed that in centrally projecting neurons, increases in masked thresholds were significantly smaller than the changes measured psychophysically. Larger threshold shifts have been reported in the inferior colliculus of awake marmoset. The present study investigated the magnitude of forward masking in primary auditory cortical neurons of anaesthetised guinea-pigs. Responses of cortical neurons to unmasked and forward masked tones were measured and probe detection thresholds estimated using signal detection theory methods. Threshold shifts were larger than in the auditory nerve, cochlear nucleus and inferior colliculus. The larger threshold shifts suggest that central, and probably cortical, processes contribute to forward masking. However, although methodological differences make comparisons difficult, the threshold shifts in cortical neurons were, in contrast to subcortical nuclei, actually larger than those observed psychophysically. Masking was largely attributable to a reduction in the responses to the probe, rather than either a persistence of the masker responses or an increase in the variability of probe responses.

Playing a musical instrument demands the integration of sensory and perceptual information with motor processes in order to produce a harmonic musical piece. The diversity of brain mechanisms involved and the joyful character of playing an instrument make musical instrument training a potential vehicle for neurorehabilitation of motor skills in patients with cerebral palsy (CP). This clinical condition is characterized by motor impairments that can affect, among others, manual function, and limit severely the execution of basic daily activities. In this study, adolescents and adult patients with CP, as well as a group of typically developing children learned to play piano for 4 consecutive weeks, having completed a total of 8 hours of training. For ten of the participants, learning was supported by a special technical system aimed at helping people with sensorimotor deficits to better discriminate fingers and orient themselves along the piano keyboard. Potential effects of piano training were assessed with tests of finger tapping at the piano and tests of perception of vibratory stimulation of fingers, and by measuring neuronal correlates of motor learning in the absence of and after piano training. Results were highly variable especially among participants with CP. Nevertheless, a significant effect of training on the ability to perceive the localization of vibrations over fingers was found. No effects of training on the performance of simple finger tapping sequences at the piano or on motor-associated brain responses were registered. Longer periods of training are likely required to produce detectable changes.

Impaired cerebral autoregulation leads to fluctuations in cerebral blood flow, which can be especially dangerous for immature brain of preterm newborns. In this paper, two mathematical models of cerebral autoregulation are discussed. The first one is an enhancement of a vascular model proposed by Piechnik et al. We extend this model by adding a polynomial dependence of the vascular radius on the arterial blood pressure and adjusting the polynomial coefficients to experimental data to gain the autoregulation behavior. Moreover, the inclusion of a Preisach hysteresis operator, simulating a hysteretic dependence of the cerebral blood flow on the arterial pressure, is tested. The second model couples the blood vessel system model by Piechnik et al. with an ordinary differential equation model of cerebral autoregulation by Ursino and Lodi. An optimal control setting is proposed for a simplified variant of this coupled model. The objective of the control is the maintenance of the autoregulatory function for a wider range of the arterial pressure. The control can be interpreted as the effect of a medicament changing the cerebral blood flow by, for example, dilation of blood vessels. Advanced numerical methods developed by the authors are applied for the numerical treatment of the control problem.

Purpose. Children with neurological disorders, such as cerebral palsy (CP), have a high risk of developing scoliosis during growth. The fast progression of scoliosis implies in several cases frequent clinical and X-ray examinations. We present an ionizing radiation-free, noncontacting method to estimate the trajectory of the vertebral column and to potentially facilitate medical diagnosis in cases where an X-ray examination is not indicated. Methods. A body scanner and corresponding analysis software tools have been developed to get 3D surface scans of patient torsos and to analyze their spinal curvatures. The trajectory of the vertebral column has been deduced from the body contours at different transverse sectional planes along the vertical torso axis. In order to verify the present methods, we have analyzed twenty-five torso contours, extracted from computer tomography (CT) images of patients who had a CT scan for other medical reasons, but incidentally also showed a scoliosis. The software tools therefore process data from the body scanner as well as X-ray or CT images. Results. The methods presented show good results in the estimations of the lateral deviation of the spine for mild and moderate scoliosis. The partial mismatch for severe cases is associated with a less accurate estimation of the rotation of the vertebrae around the vertical body axis in these cases. In addition, distinct torso contour shapes, in the transverse sections, have been characterized according to the severity of the scoliosis. Conclusion. The hardware and software tools are a first step towards an ionizing radiation-free analysis of progression of scoliosis. However, further improvements of the analysis methods and tests on a larger number of data sets with diverse types of scoliosis are necessary, before its introduction into clinical application as a supplementary tool to conventional examinations.

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Damage to the developing brain may lead to impairment of the hand motor function and negatively impact on patients’ quality of life. Development of manual dexterity and finger and hand motor function may be promoted by learning to play the piano. The latter brings together music with the intensive training of hand coordination and fine finger mobility. We investigated if learning to play the piano helped to improve hand motor skills in 18 youths with hand motor disorders resulting from damage during early brain development. Participants trained 35–40 minutes twice a week for 18 months with a professional piano teacher. With the use of a Musical Instrument Digital Interface piano, the uniformity of finger strokes could be objectively assessed from the timing of keystrokes. The analysis showed a significant improvement in the uniformity of keystrokes during the training. Furthermore, the youths showed strong motivation and engagement during the study. This is nevertheless an open study, and further studies remain needed to exclude effects of growth and concomitant therapies on the improvements observed and clarify which patients will more likely benefit from learning to play the piano.