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Luigi Cattaneo

Publications and source records attributed to Luigi Cattaneo.

5 recordsLinked to original sources
PubMed2005

Automatic audiovisual integration in speech perception.

Two experiments aimed to determine whether features of both the visual and acoustical inputs are always merged into the perceived representation of speech and whether this audiovisual integration is based on either cross-modal binding functions or on imitation. In a McGurk paradigm, observers were required to repeat aloud a string of phonemes uttered by an actor (acoustical presentation of phonemic string) whose mouth, in contrast, mimicked pronunciation of a different string (visual presentation). In a control experiment participants read the same printed strings of letters. This condition aimed to analyze the pattern of voice and the lip kinematics controlling for imitation. In the control experiment and in the congruent audiovisual presentation, i.e. when the articulation mouth gestures were congruent with the emission of the string of phones, the voice spectrum and the lip kinematics varied according to the pronounced strings of phonemes. In the McGurk paradigm the participants were unaware of the incongruence between visual and acoustical stimuli. The acoustical analysis of the participants' spoken responses showed three distinct patterns: the fusion of the two stimuli (the McGurk effect), repetition of the acoustically presented string of phonemes, and, less frequently, of the string of phonemes corresponding to the mouth gestures mimicked by the actor. However, the analysis of the latter two responses showed that the formant 2 of the participants' voice spectra always differed from the value recorded in the congruent audiovisual presentation. It approached the value of the formant 2 of the string of phonemes presented in the other modality, which was apparently ignored. The lip kinematics of the participants repeating the string of phonemes acoustically presented were influenced by the observation of the lip movements mimicked by the actor, but only when pronouncing a labial consonant. The data are discussed in favor of the hypothesis that features of both the visual and acoustical inputs always contribute to the representation of a string of phonemes and that cross-modal integration occurs by extracting mouth articulation features peculiar for the pronunciation of that string of phonemes.

Acoustic Stimulation↗
PubMed2005

Bell's palsy-induced blepharospasm relieved by passive eyelid closure and responsive to apomorphine.

OBJECTIVE: We describe the case of a woman with Bell's Palsy-induced blepharospasm (BPIB) of the right eye that appeared simultaneously with a complete left facial nerve palsy. The involuntary spasm was relieved by passive lowering of the upper eyelid on the paretic side. METHODS: The recovery curve of the blink reflex was evaluated on the non-paretic side in baseline conditions, after subcutaneous apomorphine and placebo administration and 8 months later, at recovery from the palsy. RESULTS: We found increased recovery of the test-R2 responses at short interstimulus intervals at baseline, which was normalised by apomorphine but not by placebo. At recovery the blink reflex R2 recovery curve returned to normal. CONCLUSIONS: This report demonstrates for the first time a response of BPIB to a dopamine agonist. SIGNIFICANCE: Our findings are in agreement with an animal model of blepharospasm that suggests a combined role of weakness of the orbicularis oculi muscle and a dysfunction of the dopaminergic system in the pathogenesis of this disorder.

Apomorphine↗
PubMed2005

Covert speech arrest induced by rTMS over both motor and nonmotor left hemisphere frontal sites.

Blocking the capacity to speak aloud (overt speech arrest, SA) may be induced by repetitive transcranial magnetic stimulation (rTMS). The possibility, however, of blocking internal speech (covert SA) has not been explored. To investigate this issue, we conducted two rTMS experiments. In the first experiment, we stimulated two left frontal lobe sites. The first was a motor site (left posterior site) and the second was a nonmotor site located in correspondence to the posterior part of the inferior frontal gyrus (IFG) (left anterior site). The corresponding right hemisphere nonmotor SA site was stimulated as a control. In the second experiment, we focused on the right hemisphere and stimulated a right hemisphere motor site (right posterior site), and, as control sites, a right hemisphere nonmotor site corresponding to the IFG (right anterior site) and a left hemisphere anteromedial site (left control). For both experiments, participants performed a syllable counting task both covertly and overtly for each stimulation site. Longer latencies in this task imply the occurrence of an overt and/or covert SA. All participants showed significantly longer latencies when stimulation was either over the left posterior or the left anterior site, as compared with the right hemisphere site (Experiment 1). This result was observed for the overt and covert speech task alike. During stimulation of the posterior right hemisphere site, a dissociation for overt and covert speech was observed. An overt SA was observed but there was no evidence for a covert SA (Experiment 2). Taken together, the results show that rTMS can induce a covert SA when applied to areas over the brain that are pertinent to language. Furthermore, both the left posterior/motor site and the left anterior/IFG site appear to be essential to language elaboration even when motor output is not required.

Adult↗
PubMed2003

Trigemino-facial inhibitory reflexes in idiopathic hemifacial spasm.

We investigated trigemino-facial excitatory and inhibitory responses in perioral muscles in hemifacial spasm (HFS). We examined 15 patients affected with idiopathic HFS and 8 healthy controls. Five patients had spasms mostly limited to the periocular region and 10 had spasms also involving the perioral muscles. Responses were recorded from the resting orbicularis oculi (OOc), levator labii superioris (LLS) and orbicularis oris (OOr) muscles, after supraorbital (SO) nerve stimulation and during isolated voluntary contraction of LLS muscle. Eight patients showed complete or partial preservation of the late silent period (SP2) in activated LLS muscle. The remaining 7 patients showed absence of SP2. Early and late excitatory responses were variably present in LLS muscle at rest. Patients with HFS clinically restricted to periocular muscles had at least partial preservation of the SP2. In conclusion, in HFS patients inhibitory trigemino-facial reflexes are impaired and excitatory trigemino-facial responses are elicited in perioral muscles. These two phenomena seem to develop independently; the degree of trigemino-facial reflex impairment parallels the extension of involuntary movements to the lower facial muscles.

Adult↗