Biomedical subjects

Paolo Bernardis

Publications and source records attributed to Paolo Bernardis.

6 recordsLinked to original sources

PubMed2006

Imitation during phoneme production.

Does listening to and observing the speaking interlocutor influence phoneme production? In two experiments female participants were required to recognize and, then, to repeat the string-of-phonemes /aba/ presented by actors visually, acoustically and audiovisually. In experiment 1 a male actor presented the string-of-phonemes and the participants' lip kinematics and voice spectra were compared with those of a reading control condition. In experiment 2 female and male actors presented the string-of-phonemes and the lip kinematics and the voice spectra of the participants' responses to the male actors were compared with those to the female actors (control condition). In both experiments 1 and 2, the lip kinematics in the visual presentations and the voice spectra in the acoustical presentations changed in the comparison with the control conditions approaching the male actors' values, which were different from those of the female participants and actors. The variation in lip kinematics induced changes also in voice formants but only in the visual presentation. The data suggest that both features of the lip kinematics and of the voice spectra tend to be automatically imitated when repeating a string-of-phonemes presented by a visible and/or audible speaking interlocutor. The use of imitation, in place of the usual lip kinematics and vocal features, suggests an automatic and unconscious tendency of the perceiver to interact closely with the interlocutor. This is in accordance with the idea that resonant circuits are activated by the activity of the mirror system, which relates observation to execution of arm and mouth gestures.

Adult↗

PubMed2006

Repetitive transcranial magnetic stimulation of Broca's area affects verbal responses to gesture observation.

The aim of the present study was to determine whether Broca's area is involved in translating some aspects of arm gesture representations into mouth articulation gestures. In Experiment 1, we applied low-frequency repetitive transcranial magnetic stimulation over Broca's area and over the symmetrical loci of the right hemisphere of participants responding verbally to communicative spoken words, to gestures, or to the simultaneous presentation of the two signals. We performed also sham stimulation over the left stimulation loci. In Experiment 2, we performed the same stimulations as in Experiment 1 to participants responding with words congruent and incongruent with gestures. After sham stimulation voicing parameters were enhanced when responding to communicative spoken words or to gestures as compared to a control condition of word reading. This effect increased when participants responded to the simultaneous presentation of both communicative signals. In contrast, voicing was interfered when the verbal responses were incongruent with gestures. The left stimulation neither induced enhancement on voicing parameters of words congruent with gestures nor interference on words incongruent with gestures. We interpreted the enhancement of the verbal response to gesturing in terms of intention to interact directly. Consequently, we proposed that Broca's area is involved in the process of translating into speech aspects concerning the social intention coded by the gesture. Moreover, we discussed the results in terms of evolution to support the theory [Corballis, M. C. (2002). From hand to mouth: The origins of language. Princeton, NJ: Princeton University Press] proposing spoken language as evolved from an ancient communication system using arm gestures.

Adult↗

PubMed2005

Speech and gesture share the same communication system.

Humans speak and produce symbolic gestures. Do these two forms of communication interact, and how? First, we tested whether the two communication signals influenced each other when emitted simultaneously. Participants either pronounced words, or executed symbolic gestures, or emitted the two communication signals simultaneously. Relative to the unimodal conditions, multimodal voice spectra were enhanced by gestures, whereas multimodal gesture parameters were reduced by words. In other words, gesture reinforced word, whereas word inhibited gesture. In contrast, aimless arm movements and pseudo-words had no comparable effects. Next, we tested whether observing word pronunciation during gesture execution affected verbal responses in the same way as emitting the two signals. Participants responded verbally to either spoken words, or to gestures, or to the simultaneous presentation of the two signals. We observed the same reinforcement in the voice spectra as during simultaneous emission. These results suggest that spoken word and symbolic gesture are coded as single signal by a unique communication system. This signal represents the intention to engage a closer interaction with a hypothetical interlocutor and it may have a meaning different from when word and gesture are encoded singly.

Adult↗

PubMed2004

How does action resist visual illusion? Uncorrected oculomotor information does not account for accurate pointing in peripersonal space.

Using spatially identical displays (variants of the Müller-Lyer illusion), we compared the accuracy of spatial verbal judgments with that of saccadic (eye) and pointing (hand) movements. Verbal judgments showed a clear effect of the illusion. The amplitude of the primary saccade from one endpoint of the pattern (at fixation) to the other also showed an effect of the illusion. Conversely, movement amplitudes when pointing from one endpoint (initial finger position) to the other were significantly more accurate than both saccades and verbal responses. In a control experiment in which the viewing conditions between the saccade and pointing experiments were equalized, saccade amplitude was again affected by the illusion. In several studies, systematic biases in conscious spatial judgments have been contrasted with accurate open-loop pointing in peripersonal space. It has been proposed that such seeming dissociations between vision-for-action and vision-for-consciousness might in fact be because of a simple oculomotor strategy: saccade to the target before it disappears, then use the efference copy of the (accurate) saccadic movement to drive pointing. The present data do not support the hypothesis in this simple form.

Eye Movements↗

PubMed2003

When does action resist visual illusions? Effector position modulates illusory influences on motor responses.

Actors viewed horizontal segments either in isolation or embedded in patterns that produce spatial illusory effects (Kanizsa's compression illusion and the "dumbbell" version of the Müller-Lyer compression-expansion illusion). They were asked to reproduce the apparent horizontal extent of these segments by the amplitude of open- or closed-loop motor responses (after having positioned a finger on position A, choose a position B on the right of A such that apparent width = B-A). A touchmonitor was used to present the displays and to record movement amplitudes and times. In open-loop motor responses, displays were turned off as soon as actors raised their finger from position A. In closed-loop responses, displays could be viewed continuously during the actions. Four conditions were investigated: (1). open-loop responses starting from A at the right endpoint of the segment; (2). closed-loop responses from A at the right endpoint of the segment; (3). open-loop responses from A at the left endpoint of the segment; and (4). open-loop responses from A aligned horizontally with the left endpoint of the segment but displaced vertically below that segment. With both kinds of display, results in conditions (1). and (2). demonstrated illusory effects comparable to those measured in standard visual matching experiments, whereas results in conditions (3). and (4). showed essentially no illusory effects. Implications for models of visuomotor transformations in peripersonal space are discussed.

Adult↗

PubMed2002

Dissociating perception and action in Kanizsa's compression illusion.

When a horizontally elongated surface is occluded in the middle by a larger surface, it appears narrower than its true width (Kanizsa's compression illusion). We report that a similar compression effect occurs for closed-loop visuomotor matches of size, but not for otherwise comparable open-loop "mimed" reaching or size-matching visuomotor responses. Our study is the first in which a comparison of size perception in personal space with bilateral actions performed with both hands (instead of precision grips employing the thumb and the index finger) is used to investigate motor responses to Kanizsa's compression illusion. Implications for the current debate on the existence of dissociations between spatial perception and visually controlled actions in personal space are discussed.

Adult↗