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Biomedical subjects

Roland Jouvent

Publications and source records attributed to Roland Jouvent.

9 recordsLinked to original sources
PubMed2006

High sensitivity to multisensory conflicts in agoraphobia exhibited by virtual reality.

The primary aim of this study was to evaluate the effect of auditory feedback in a VR system planned for clinical use and to address the different factors that should be taken into account in building a bimodal virtual environment (VE). We conducted an experiment in which we assessed spatial performances in agoraphobic patients and normal subjects comparing two kinds of VEs, visual alone (Vis) and auditory-visual (AVis), during separate sessions. Subjects were equipped with a head-mounted display coupled with an electromagnetic sensor system and immersed in a virtual town. Their task was to locate different landmarks and become familiar with the town. In the AVis condition subjects were equipped with the head-mounted display and headphones, which delivered a soundscape updated in real-time according to their movement in the virtual town. While general performances remained comparable across the conditions, the reported feeling of immersion was more compelling in the AVis environment. However, patients exhibited more cybersickness symptoms in this condition. The result of this study points to the multisensory integration deficit of agoraphobic patients and underline the need for further research on multimodal VR systems for clinical use.

Adult↗
PubMed2006

Spontaneous appetence for wheel-running: a model of dependency on physical activity in rat.

According to human observations of a syndrome of physical activity dependence and its consequences, we tried to examine if running activity in a free activity paradigm, where rats had a free access to activity wheel, may present a valuable animal model for physical activity dependence and most generally to behavioral dependence. The pertinence of reactivity to novelty, a well-known pharmacological dependence predictor was also tested. Given the close linkage observed in human between physical activity and drugs use and abuse, the influence of free activity in activity wheels on reactivity to amphetamine injection and reactivity to novelty were also assessed. It appeared that (1) free access to wheel may be used as a valuable model for physical activity addiction, (2) two populations differing in activity amount also differed in dependence to wheel-running. (3) Reactivity to novelty did not appeared as a predictive factor for physical activity dependence (4) activity modified novelty reactivity and (5) subjects who exhibited a high appetence to wheel-running, presented a strong reactivity to amphetamine. These results propose a model of dependency on physical activity without any pharmacological intervention, and demonstrate the existence of individual differences in the development of this addiction. In addition, these data highlight the development of a likely vulnerability to pharmacological addiction after intense and sustained physical activity, as also described in man. This model could therefore prove pertinent for studying behavioral dependencies and the underlying neurobiological mechanisms. These results may influence the way psychiatrists view behavioral dependencies and phenomena such as doping in sport or addiction to sport itself.

Amphetamine↗
PubMed2006

Negative priming in a numerical Piaget-like task as evidenced by ERP.

Inhibition is a key executive function in adults and children for the acquisition and expression of cognitive abilities. Using event-related potentials in a priming adaptation of a Piaget-like numerical task taken from developmental psychology, we report a negative priming effect in adults measured just after the cognitive inhibition of a misleading strategy, the visuospatial length-equals-number bias. This effect was determined in the N200 information processing stage through increased N200 amplitude. We show here that for accuracy in numerical quantification, the adult brain still had to control the child-like cognition biases that are stored in a kind of "developmental memory."

Adult↗
PubMed2005

Episodic autobiographical memory in depression: Specificity, autonoetic consciousness, and self-perspective.

Autobiographical memory (AM) and the self are closely linked. AM retrieval in depression is characterized by a lack of specificity, suggesting an impairment of episodic AM. Autonoetic consciousness and self-perspective, which are critical to episodic AM, have never been addressed in depression. Twenty-one depressed inpatients and 21 matched controls were given an episodic AM task designed to assess positive and negative memories regarding specificity, autonoetic consciousness (remember/know procedure), and self-perspective (field/observer procedure). For specificity, "remember", and "field" responses, ANOVAs revealed a main group effect and a group x valence interaction. Between groups, patients showed lower scores than controls for positive memories. Within groups, patients showed greater scores for negative memories, and controls showed greater scores for positive memories. There is a global episodic AM impairment of positive memories in depression regarding specificity, autonoetic consciousness, and self-perspective. Our results suggest new cognitive interventions to improve the self-relevance of positive memories in depression.

Adult↗
PubMed2005

Generalization of frequency discrimination learning across frequencies and ears: implications for underlying neural mechanisms in humans.

Frequency discrimination thresholds (FDTs) at 750, 1500, 3000, and 6000 Hz were measured in 32 normal-hearing listeners before and after each listener practiced the task for 12 h at one of the above frequencies using a single ear. Marked improvements in thresholds taking place over several hours were observed during the frequency- and ear-specific training period. Comparisons between pre- and posttraining thresholds showed large improvements at the trained frequency, but also at other frequencies. The improvements were initially slightly-but significantly-larger at the trained frequency than at untrained frequencies. However, this trained-frequency advantage disappeared rapidly during the course of the two-hour multifrequency posttraining session, suggesting rapid relearning or learning generalization across frequencies. In contrast, no significant ear specificity was found, not even at early stages of the posttraining session. These findings add to earlier results suggesting that, in humans, frequency discrimination learning is only weakly frequency-specific, and they reveal that a complete generalization across frequencies can occur rapidly with little retraining at the initially untrained frequencies. Implications regarding underlying mechanisms are discussed.

Adult↗
PubMed2004

A new method for the assessment of spatial orientation and spatial anxiety in mice.

The implication of integrated functional sensory relations of the body to space in anxiety disorders is a very important issue which encourages the development of animal models, in particular, for pharmacological perspectives and for the functional assessment of the deficits induced by genetic manipulation in the mouse or the rat. A new experimental device is presented here: It is comprised of a rotating tunnel and a rotating-beam controlled by computer which can be used for multiple visuo-idiothetic and kinesthetic sensory conflict situations during active locomotor behaviour by mice. The system is linked to a digital video system, Video-Track trade mark, designed to track and record the movements of the animals. Anxious BALB/cByJ mice were compared to non-anxious C57BL/6J mice and were seen to display highly disturbed locomotor behaviour in a sensory conflict situation. The model highlights the advantages of video-digital analysis for animal behavioural sciences.

Animals↗
PubMed2004

Time-on-task effect in trait anhedonia.

The capacity to sustain attention was explored in a sample of anhedonic subjects according to the Chapman physical anhedonia scale. Sustained attention was determined by studying task-induced changes over the duration of the Eriksen response competition task [Percept. Psychophys. 16 (1974) 143]. Anhedonic subjects had longer reaction times (RTs), but missed no more targets than control subjects. Anhedonic subject RTs got longer with time-on-task (TOT) and displayed greater intra-subject variability. These results confirm those of a previous study indicating that anhedonic subjects may have developed a more conservative response strategy [Psychophysiology 37 (2000) 711] and suggest that this strategy may result in a more rapid decrease in energetical resources. Moreover, the greater intra-subject variability demonstrates the importance of assessing performance over time and its relationship to the variability of responses in the cognitive performance of anhedonic subjects.

Adolescent↗
PubMedDate not supplied

Verbal memory performance of patients with a first depressive episode and patients with unipolar and bipolar recurrent depression.

Depression is usually associated with episodic memory impairment. The main clinical features of depression associated with that memory impairment are not clearly defined. The main goal of that study was to assess the role of the diagnostic subtypes and the number of depressive episodes on the memory performance of acute unipolar (UP) and bipolar (BP) depressed patients.Twenty-three patients with a first major depressive episode (FE), 28 patients meeting DSM-IV criteria for UP recurrent depression (UR) and 18 BP patients with recurrent depression were compared with 88 healthy subjects on a verbal episodic memory task. Patients suffering from a first depressive episode did not show verbal memory impairment as compared to normal controls. Unlike FE patients, UR and BP patients exhibited verbal memory deficits with impaired free recall and normal cued recall and recognition. The memory deficits of the UR and BP patients was present in the first free recall trial. Depressed patients improved their memory performance across the three trials of the task at the same rate than normal controls. Our results suggest that the number of depressive episodes has a negative influence on verbal memory performance of acute depressed patients. The effects of the repetition of the depressive episodes are not modulated by the subtypes of depression and may reflect sensitization to the cognitive impact of depression associated with increasing prefrontal dysfunction.

Adult↗