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Biomedical subjects

B Ans

Publications and source records attributed to B Ans.

8 recordsLinked to original sources
PubMed2006

Polysyllabic pseudo-word processing in reading and lexical decision: converging evidence from behavioral data, connectionist simulations and functional MRI.

The cognitive mechanisms involved in polysyllabic pseudo-word processing -- and their neurobiological correlates -- were studied through the analysis of length effects on French words and pseudo-words in reading and lexical decision. Connectionist simulations conducted on the ACV98 network paralleled the behavioral data in showing a strong length effect on naming latencies for pseudo-words only and the absence of length effect for both words and pseudo-words in lexical decision. Length effects in reading were characterized at the neurobiological level by a significant and specific activity increase for pseudo-words as compared to words in the right lingual gyrus (BA 19), the left superior parietal lobule and precuneus (BA7), the left middle temporal gyrus (BA21) and the left cerebellum. The behavioral results suggest that polysyllabic pseudo-word reading mainly relies on an analytic procedure. At the biological level, additional activations in visual and visual attentional brain areas during long pseudo-word reading emphasize the role of visual and visual attentional processes in pseudo-word reading. The present findings place important constraints on theories of reading in suggesting the involvement of a serial mechanism based on visual attentional processing in pseudo-word reading.

Adult↗
PubMed1998

A connectionist multiple-trace memory model for polysyllabic word reading.

A connectionist feedforward network implementing a mapping from orthography to phonology is described. The model develops a view of the reading system that accounts for both irregular word and pseudoword reading without relying on any system of explicit or implicit conversion rules. The model assumes, however, that reading is supported by 2 procedures that work successively: a global procedure using knowledge about entire words and an analytic procedure based on the activation of word syllabic segments. The model provides an account of the basic effects that characterize human skilled reading performance including a frequency by consistency interaction and a position-of-irregularity effect. Furthermore, early in training, the network shows a performance similar to that of less skilled readers. It also offers a plausible account of the patterns of acquired phonological and surface dyslexia when lesioned in different ways.

Humans↗
PubMed1993

Propriomuscular coding of kinaesthetic sensation. Experimental approach and mathematical modelling.

The role of propriomuscular information in kinaesthetic sensation was studied. Experiments were carried out on human subjects in whom kinaesthetic illusions were induced by applying tendon vibration with a variable frequency. Six patterns of frequency modulation were used, four of which had an arbitrary form and the other two mimicked natural Ia discharges. The results show that the shape of the illusory movements recorded depended on the type of vibratory pattern used. A mathematical model for the propriomuscular information decoding process is proposed. It takes into account both the agonist and antagonist muscle spindle populations as sources of kinaesthetic information and is based on the assumption that position and velocity information are additively combined. The experimental data show a good fit with the theoretical data obtained by means of model simulation, thus validating our initial hypothesis. Various aspects of the experimental results and the hypotheses involved in the model are discussed.

Adult↗
PubMed1990

[Associative learning in a neuromimetic network with local competitions].

Presented here is a neuromimetic model for the learning of associations between activity patterns originating from recoding layers. These layers are described as networks of cellular clusters made up of competitive formal neurons. A rule of synaptic plasticity with improved neurobiological realism is proposed; it allows for fast learning of large sets of associations.

Association Learning↗
PubMed1990

[Neuromimetic model for storage and recall of temporal sequences].

A neuromimetic model is presented here for the storage and recall of temporal sequences, including two fundamental properties. First, recall of a sequence is not induced by the presentation of one of its parts, but evoked by the occurrence of a contextual item representing its identity; second, this reproduction can be driven according to a varying rhythm under the control of an attentional subsystem.

Memory↗
PubMed1984

[Neuronal network with modifiable synapses: decoding of composite sensory messages under unsupervised and permanent learning].

Afferent sensory fibers carry usually messages which combine several primitive entities. A model of neural structure under unsupervised and permanent learning is proposed, which can detect the primary independent entities mixed in the afferent message. The model is a network of neurons mutually interconnected by means of inhibitory modifiable synapses with efficacies locally controlled by a specific conjunction law of pre- and post-synaptic activities.

Learning↗
PubMed1983

[Simulation of neuronal networks (SIRENE). II. Hypothesis for decoding the message of movement carried by spindle afferences IA and II by a mechanism of synaptic plasticity].

The spindle message derived from passively stretched muscles during a movement, carries mixed information about the velocity and the position of the joint concerned. With the help of the program SIRENE, it is shown that a non-specialized neuron can decode this message, and it is able especially to extract from the mixture the pure velocity component, and that under a weak assumption on synaptic plasticity.

Ankle Joint↗