A case of visuo-auditory sensory substitution in rats.

Sensory substitution refers to a process whereby an agent, by means of a removable specialized instrumentation, becomes capable of exploiting an available sensory modality in order to perceive properties of the environment which are normally accessible by means of a different modality. We describe a situation of visual-auditory sensory substitution in the rat. Rats were placed in complete darkness, and trained to follow a virtual path whose position was signalled by a sound activated by a video-tracking device. Our hypothesis was that the rats would be able to succeed in this task of spatial navigation, following the sound contour by means of sensory-motor coupling based on seeking the sound (all-or-none) and mastering the relation between their own actions and the expected sensory feedback. Our results confirm this hypothesis and show the progressive structuring of meaningful exploratory activity, leading from the appearance of stopping behaviour when the sound is lost or acceleration when the sound is discovered, up to a veritable sensory-motor strategy which maximizes the possibilities for discovering and following the sound path. Thus, the animals seem to have developed a new form of perception which translates in particular into motor behaviour adapted to the search for sound.

Joint Perception of a Shared Object: A Minimalist Perceptual Crossing Experiment.

The minimalist perceptual crossing paradigm has emphasized the essential role of interpersonal dynamics on social understanding. Within the particular case of minimalist interaction, it has been argued that interpersonal processes can constitute social cognition, at least partially, which calls for a paradigm shift in social cognition studies. In this paper, we review several perceptual crossing experiments and their theoretical implications, and propose an original experiment to go beyond strictly dyadic interactions. Whereas past experiments have used objects as distracters of dyadic interaction, our experiment aims at integrating objects themselves as the goal of interpersonal coordination. We asked 24 subjects to participate in a minimalist perceptual crossing experiment where they had to decide, based on their on-line interaction in a one-dimensional digital space, which of the objects they perceived was also perceptible by their partner. The main results suggest that the mutual awareness of a shared object (SO) arises from the quality of sensorimotor coordination between the partners. Indeed, the presence of a SO acts as a simultaneous affordance that attracts and structures individual perceptive activities, giving both partners the opportunity to co-construct a shared world where their respective actions make sense. We discuss our results by way of an enactive account of social cognition, taking the joint perception of a SO as a first step to account for joint attention.

[Impact of cancer treatments on cognitive functions: the patients' view, their expectation and their interest in participating to cognitive rehabilitation workshops]. / Impact des traitements en cancérologie sur les fonctions cognitives : le point de vue des patients, leur attente et leur souhait de participer à des ateliers de rééducation cognitive.

INTRODUCTION: Cancer and chemotherapy can have adverse effects on cognitive functions and quality of life of patients. We wanted to know the patients' view on these disorders, but also their expectations in terms of assessment and support. METHODS AND RESULTS: A survey was conducted in day care hospital among 551 patients from three cancer centers. Most of the patients were between 40 and 74 years and suffered from breast cancer. Eighty-four percent were treated with chemotherapy. Forty-one percent of patients report memory problems, 26% were affected by specific concentration disorders, and 19% of the attention. On the whole, 52% of patients report at least one of the previous cognitive impairment. Among these patients, 80% evoked that the support of these problems was essential and 70% were willing to participate in "workshops" to deal with these disorders. CONCLUSION: The cognitive impairment occurrence is a real problem for patients receiving chemotherapy and becomes a priority in the global management of their disease. Studies assessing a specific support of theses symptoms should be encouraged to help patients.

Questioning implicit motor learning as instantiated by the pursuit-tracking task.

The effect of concurrent visual feedback on the implicit learning of repeated segments in a task of pursuit tracking has been tested. Although this feedback makes it possible to regulate the positional error during the movement, it could also induce negative guidance effects. To test this hypothesis, a first set of participants (N=42) were assigned to two groups, which performed either the standard pursuit-tracking task based on the experimental paradigm of Pew ( 1974 ; group F-ST), or a task called "movement reproduction" in which the feedback was suppressed (group noF-ST). A second set of participants (N=26) performed in the same feedback condition groups but in a dual-task situation (F-DT and noF-DT; Experiment 2). The results appear to confirm our predictions since the participants in groups without feedback, contrary to those in groups with feedback, succeeded with practice in differentiating their performances as a function of the nature of the segments (repeated or nonrepeated) both in simple (Experiment 1) and in dual-task (Experiment 2) situations. These experiments indicate that the feedback in the pursuit-tracking task induces a guidance function potentially resulting in an easiness tracking that prevents the participants from learning the repetition.

Joint visual attention and social triangular engagement at 3 and 6 months.

Two experiments document infants' ability to detect breaks of contact in an ongoing dyadic interaction and to use the joint attention mechanism for social triangular communication purposes. In Experiment 1, the ability of 3- and 6-month-olds to show joint attention when an adult turned to face another person in sight, and to react when both adults conversed in a reciprocal manner, was measured. In Experiment 2, 3-month-olds were tested in two joint attention conditions: a Person-Person-Object condition (PPO) and a Person-Person-Person condition (PPP). Results showed that both 3- and 6-month-olds' gazed backwards and forwards between the two adults and produced socially directed behaviors towards the adults, thus initiating a social triangular coordinated interaction. Three-month-olds replicated this pattern in the PPP condition but not in the PPO condition. The social context with three persons may be particularly facilitative for infant early communication and sharing within the family.