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Biomedical subjects

E Biondi

Publications and source records attributed to E Biondi.

At least 19 recordsLinked to original sources

A model for the auditory evoked brainstem responses.

The present research was undertaken to approach the formation of the Brainstem Evoked Response (BSER) by means of modelling techniques similar to those previously successfully adopted to interpret the generation of the Auditory Nerve Action Potential. The definition of a model intended to reproduce the compound electrical response of a given ensemble of neural units, firing after stimulation, is taken as the basic constituent for the formulation of the complete model. The activity of the primary auditory neurons is assumed to be the input to the BSER model; then, a simplified structure for the connections among the neural complexes contributing to the BSER is proposed to account for monaurally evoked, homolaterally recorded responses. Computer simulations of the model show a satisfactory degree of approximation between the experimental data taken as reference and the final output, in spite of the rather small number of parameters and the simplicity of the structure used. Even though this work has to be considered as preliminary in character, at least in certain respects, some applicative implications of the present approach can be outlined.

Brain Stem

Electrocochleography by mathematical modelling.

The aim of this work is to critically review some of the classical electrocochleographic methods in accordance with the systems theory: (a) in describing, by means of mathematical models, the different parts of the auditory system concerned in the generation of stimulus-evoked signals; and: (b) in comparing the outputs of these models with the measurements of the cochlear potentials. It must be stated clearly that we realise that many of the conclusions drawn could be criticised, it is hoped that future research in the field with be stimulated by this work.

Adaptation, Physiological

Do efferent fibres to hair cells intervene in acoustic stimulus peripheral coding?

The functional roles suggested for Olivo-Cochlear Bundle (OCB) fibres innervating auditory receptors never received a fully convincing demonstration. Assuming that efferent fibres effects, at the level of hair cells, are inhibitory with regard to single auditory nerve fibre activity, a mathematical model of the peripheral auditory system is proposed in which the presence of the descending pathway is taken into account. Computer simulation of the model accounts for most of the salient features of the patterns of activity of single cochlear nerve fibres. In the light of the model predictions, the influence of OCB fibres on peripheral receptors is assumed to act in the direction of improving the signal-to-noise ratio, as a first step of information processing.

Acoustic Stimulation

Compound action potential and single acoustic nerve fibres activity generation: an equivalent neuron approach.

The peripheral acoustic system can be easily subdivided into three distinct subsystems: a mechanical one (middle ear and basilar membrane), the set of mechanical-to-neural transducers (the inner and outer hair cells) and the neural part. The functional behaviour of the external and middle ear is well known, but the processes concerned with the transduction of mechanical motion into neural activity are still under investigation. Actually the mechanism of transmission of information concerning acoustic stimuli to the central nervous pathways is not clearly known. On the basis of physiological knowledge, a mathematical model reproducing the pattern of activity of the acoustic nerve, in response to the most typical acoustic stimuli, is proposed. This has been simulated on a digital computer.

Action Potentials