Formulating State Space Models in R with Focus on Longitudinal Regression Models

We provide a language for formulating a range of state space models with response densities within the exponential family. The described methodology is implemented in the R-package sspir. A state space model is specified similarly to a generalized linear model in R, and then the time-varying terms are marked in the formula. Special functions for specifying polynomial time trends, harmonic seasonal patterns, unstructured seasonal patterns and time-varying covariates can be used in the formula. The model is fitted to data using iterated extended Kalman filtering, but the formulation of models does not depend on the implemented method of inference. The package is demonstrated on three datasets.

Surround inhibition in the primary motor cortex is task-specifically modulated in non-professional musicians but not in healthy controls during real piano playing

Research has indicated that at the onset of a finger movement, unwanted contractions of adjacent muscles are prevented by inhibiting the cortical areas representing these muscles. This so-called surround inhibition (SI) seems relevant for the performance of selective finger movements but may not be necessary for tasks involving functional coupling between different finger muscles. Therefore, the present study compared SI between isolated finger movement and complex selective finger movements while playing a three-finger sequence on the piano in nine non-professional musicians and 10 untrained control participants. Transcranial magnetic stimulation (TMS) was applied to the contralateral motor cortex to assess SI in the first dorsal interosseous (FDI), abductor pollicis brevis (APB) and abductor digiti minimi (ADM) during the movement preparation and the late phasic phases. The results reveal stronger SI during the preparation phase than during the phasic phase (30.6% vs. 10.7%; P   0.05). Thus, musicians were able to modulate SI between conditions whereas control participants revealed constant levels of SI. Therefore, it may be assumed that long-term training as observed in skilled musicians is accompanied by task-specific effects on SI modulation potentially relating to the ability to perform selective and complex finger movements

Hvem var de? En lokalhistorisk undersøgelse af de tidligste private gymnastik- og idrætstiltag i Århus og Randers

Resultater fra Lundbyes speciale og lokalhistorisk forsknings relevans for den samlede idrætshistoriske opfattelse.Steen Rosenvinge Lundbye: Who were they? A Local historical study of the earliest private gymnastic and sports initiatives in Århus and RandersWhy did people become members of a gymnastic or sport association at the end of the 19th century? If we study exclusively the professional groups to which members of Denmark’s earliest gymnastic and sports associations belonged, it becomes clear that business and office occupations represented a large majority. This has been interpreted as evidence for the fact that professional affiliations were a prerequisite for admission and membership of these associations. However, as the present article attempts to demonstrate, an overrepresentation of this kind does not necessarily mean that everything depended on professional relations. A detailed local historical study of the earliest members of Århus Gynmastic Association in 1880 and of Randers Gynmastic Association of 1872, focusing especially on members’ social and residential relations, shows that other factors can be indicated that might also have had considerable significance. In this way it appears that a large number of members had other features in common besides their profession. A very large proportion of them had addresses on the same land registry title, a situation which becomes particularly evident when all members addresses are drawn in on a land registry map. These results lead to the logical conclusion that an incoming member’s social circle had just as much influence on the chance of he or she becoming a member or not. In spite of the simplicity of this thesis, it has until now been bypassed by Danish researchers into sporting history, and it could be a benefit if other associations’ members could be studied in the similar way. Only by that means can we achieve clear answers to these questions

Repetitive Activation of the Corticospinal Pathway by Means of rTMS may Reduce the Efficiency of Corticomotoneuronal Synapses

Low-frequency rTMS applied to the primary motor cortex (M1) may produce depression of motor-evoked potentials (MEPs). This depression is commonly assumed to reflect changes in cortical circuits. However, little is known about rTMS-induced effects on subcortical circuits. Therefore, the present study aimed to clarify whether rTMS influences corticospinal transmission by altering the efficiency of corticomotoneuronal (CM) synapses. The corticospinal transmission to soleus α-motoneurons was evaluated through conditioning of the soleus H-reflex by magnetic stimulation of either M1 (M1-conditioning) or the cervicomedullary junction (CMS-conditioning). The first facilitation of the H-reflex (early facilitation) was determined after M1- and CMS-conditioning. Comparison of the early facilitation before and after 20-min low-frequency (1 Hz) rTMS revealed suppression with M1- (−17 ± 4%; P = 0.001) and CMS-conditioning (−6 ± 2%; P = 0.04). The same rTMS protocol caused a significant depression of compound MEPs, whereas amplitudes of H-reflex and M-wave remained unaffected, indicating a steady level of motoneuronal excitability. Thus, the effects of rTMS are likely to occur at a premotoneuronal site—either at M1 and/or the CM synapse. As the early facilitation reflects activation of direct CM projections, the most likely site of action is the synapse of the CM neurons onto spinal motoneuron