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Biomedical subjects

G Florian

Publications and source records attributed to G Florian.

7 recordsLinked to original sources
PubMed1998

Do changes in coherence always reflect changes in functional coupling?

It is well known that the rhythmic activity within the alpha band in the central area may be composed of two different types of rhythms: (i) the Rolandic mu rhythm, representing the intrinsic activity of the sensorimotor area, and (ii) rhythmic activity believed to be generated within parieto-occipital areas and to extend into central regions through volume conduction (the 'classical alpha rhythm'). In this paper we clearly demonstrate that this second type of rhythmic activity is not due to volume conduction from parieto-occipital areas. We also demonstrate the significant impact of the coexistence of these two types of rhythms on the interpretation of interhemispheric coherence measurements.

Alpha Rhythm↗
PubMed1998

Cardiac response induced by voluntary self-paced finger movement.

Cardiac responses induced by slow and brisk voluntary self-paced index finger movements of the dominant and non-dominant hand were investigated in a group of 12 right-handed subjects. Since subjects synchronised movement and respiration, initiating movement preferably during inspiration, a novel method of evaluating the movement-induced cardiac response was used. This method allows one to distinguish the differential effects on the cardiac response due to movement and respiration. The effect of type of movements (slow vs. brisk) and hand (right vs. left) were analysed. Slow movements induced a monophasic cardiac response, consisting of cardiac deceleration preceding and accompanying movement. Brisk movements induced a biphasic cardiac response, consisting of preparatory deceleration followed by slight post-movement cardiac acceleration. Hand-dominance did not influence the movement-induced cardiac response. The results suggest that neocortical structures involved in planning and execution of voluntary movement impinge upon brainstem cardiovascular nuclei. Vagal cardiac outflow is affected and gives rise to movement-induced changes in cardiac chronotropism.

Adult↗
PubMed1995

Dynamic spectral analysis of event-related EEG data.

A method for analysing the time course of power spectra of event-related EEG data is presented. A sequence of autoregressive models is fitted to segments of the EEG within which the data exhibit local stationarity. For parameter estimation a method involving ensemble averages is introduced. Besides investigating the evolution of power spectra, time courses of peak frequency, bandwidth and power of alpha (mu) and beta rhythms are traced. The method is applied to EEG recorded over the primary motor area during self-paced finger movements.

Electroencephalography↗
PubMed1985

[Tissue polypeptide antigen: significance and prospective use in the clinical laboratory].

Sequential determination of tissue polypeptide antigen were carried out in patients with neoplastic diseases. Blood specimens were taken before surgery and one week, one month and every months after the operation. The values obtained were compared with those of a control group of blood donors and those of a control group of healthy persons. The values obtained in control groups suggest that alcohol could cause significant increase of tissue polypeptide antigen values.

Adult↗
PubMedDate not supplied

[Elimination of respiratory effects on motion-induced changes in heart rate].

As part of a comprehensive movement study, the cardiac response induced by voluntary movement of the right and left index fingers was analysed. Since subjects synchronised movement and respiration, a special method that permitted the differentiation of movement-induced from respiratory-related effects was employed. This method is described, and its advantages over the standard method of estimating stimulus-induced cardiac responses are discussed. The results obtained in three subjects are presented, and the impact of the synchronisation of movement and respiration on the induced cardiac response demonstrated.

Artifacts↗