Delphine Preissmann

Transitory glutathione deficit during brain development induces cognitive impairment in juvenile and adult rats: Relevance to schizophrenia

Glutathione (GSH) metabolism dysfunction is one risk factor in schizophrenia. A transitory brain GSH deficit was induced in Wistar (WIS) and mutant (ODS; lacking ascorbic acid synthesis) rats using BSO (l-buthionine-(S,R)-sulfoximine) from post-natal days 5-16. When GSH was re-established to physiological levels, juvenile BSO-ODS rats were impaired in the water maze task. Long after treatment cessation, adult BSO-WIS/-ODS rats showed impaired place discrimination in the homing board with distributed visual or olfactory cues. Their accuracy was restored when a single cue marked the trained position. Similarly, more working memory errors were made by adult BSO-WIS in the radial maze when several olfactory cues were present. These results reveal that BSO rats did not suffer simple sensory impairment. They were selectively impaired in spatial memory when the task required the integration of multimodal or olfactory cues. These results, in part, resemble some of the reported olfactory discrimination and cognitive impairment in schizophrenia.

The Subjective Sensation of Synchrony: An Experimental Study

People performing actions together have a natural tendency to synchronize their behavior. Consistently, people doing a task together build internal representations not only of their actions and goals, but also of the other people performing the task. However, little is known about which are the behavioral mechanisms and the psychological factors affecting the subjective sensation of synchrony, or “connecting” with someone else. In this work, we sought to find which factors induce the subjective sensation of synchrony, combining motion capture data and psychological measures. Our results show that the subjective sensation of synchrony is affected by performance quality together with task category, and time. Psychological factors such as empathy and negative subjective affects also correlate with the subjective sensation of synchrony. However, when people estimate synchrony as seen from a third person perspective, their psychological factors do not affect the accuracy of the estimation. We suggest that to feel this sensation it is necessary to, first, have a good joint performance and, second, to assume the existence of an attention monitoring mechanism that reports that the attention of both participants (self and other) is focused on the task.

Embodied memory: unconscious smiling modulates emotional evaluation of episodic memories

Since Damasio introduced the somatic markers hypothesis in Damasio (1994), it has spread through the psychological community, where it is now commonly acknowledged that somatic states are a factor in producing the qualitative dimension of our experiences. Present actions are emotionally guided by those somatic states that were previously activated in similar experiences. In this model, somatic markers serve as a kind of embodied memory. Here, we test whether the manipulation of somatic markers can modulate the emotional evaluation of negative memories. Because facial feedback has been shown to be a powerful means of modifying emotional judgements, we used it to manipulate somatic markers. Participants first read a sad story in order to induce a negative emotional memory and then were asked to rate their emotions and memory about the text. Twenty-four hours later, the same participants were asked to assume a predetermined facial feedback (smiling) while reactivating their memory of the sad story. The participants were once again asked to fill in emotional and memory questionnaires about the text. Our results showed that participants who had smiled during memory reactivation later rated the text less negatively than control participants. However, the contraction of the zygomaticus muscles during memory reactivation did not have any impact on episodic memory scores. This suggests that manipulating somatic states modified emotional memory without affecting episodic memory. Thus, modulating memories through bodily states might pave the way to studying memory as an embodied function and help shape new kinds of psychotherapeutic interventions.

Increased postsynaptic density protein-95 expression in the frontal cortex of aged cognitively impaired rats

In the present work we studied synaptic protein concentrations in relation to behavioral performance. Long-Evans rats, aged 22-23 months, were classified for individual expression of place memory in the Morris water maze, in reference to young adults. Two main subgroups of aged rats were established: the Aged cognitively Unimpaired (AU) had search accuracy within the range (percent of time in training sector within mean+2 SEM) of young rats and the Aged cognitively Impaired (AI) rats had search accuracy below this range. Samples from the hippocampus and frontal cortex of all the AI, AU and young rats were analyzed for the expression of postsynaptic protein PSD-95 by Image J analysis of immunohistochemical data and by Western blots. PSD-95 expression was unchanged in the hippocampus, but, together with synaptophysin, was significantly increased in the frontal cortex of the AI rats. A significant correlation between individual accuracy (time spent in the training zone) and PSD-95 expression was observed in the aged group. No significant effect of age or PSD-95 expression was observed in the learning of a new position. All together, these data suggest that increased expression of PSD-95 in the frontal cortex of aged rats co-occurs with cognitive impairment that might be linked to functional alterations extending over frontal networks.

Spatial Representations in the Rat: Case Study or Perspective on Episodic Memory?

Spatial orientation in animals or in men requires memory as an essential feature and may be considered as a complex manifestation emerging from multiple brain structures with the hippocampus at “the crossroad”. In this chapter, we present the underlying biological mechanisms of spatial behavior along a contextual and historical dimension, in an ethological perspective. We propose that study of spatial memory in mammals, and more precisely in laboratory rats, sheds some light on the development and evolution of episodic memory.

A Motion Capture Study to Measure the Feeling of Synchrony in Romantic Couples and in Professional Musicians

The feeling of synchrony is fundamental for most social activities and prosocial behaviors. However, little is known about the behavioral correlates of this feeling and its modulation by intergroup differences. We previously showed that the subjective feeling of synchrony in subjects involved in a mirror imitation task was modulated by objective behavioral measures, as well as contextual factors such as task difficulty and duration of the task performance. In the present study, we extended our methodology to investigate possible interindividual differences. We hypothesized that being in a romantic relationship or being a professional musician can modulate both implicit and explicit synchronization and the feeling of synchrony as well as the ability to detect synchrony from a third person perspective. Contrary to our hypothesis, we did not find significant differences between people in a romantic relationship and control subjects. However, we observed differences between musicians and control subjects. For the implicit synchrony (spontaneous synchronization during walking), the results revealed that musicians that had never met before spontaneously synchronized their movements earlier among themselves than control subjects, but not better than people sharing a romantic relationship. Moreover, in explicit behavioral synchronization tasks (mirror game), musicians reported earlier feeling of synchrony and had less speed errors than control subjects. This was in interaction with tasks difficulty as these differences appeared only in tasks with intermediate difficulty. Finally, when subjects had to judge synchrony from a third person perspective, musicians had a better performance to identify if they were present or not in the videos. Taken together, our results suggest that being a professional musician can play a role in the feeling of synchrony and its underlying mechanisms.

Self-Deception as Affective Coping. An Empirical Perspective on Philosophical Issues

In the philosophical literature, self-deception is mainly approached through the analysis of paradoxes. Yet, it is agreed that self-deception is motivated by protection from distress. In this paper, we argue, with the help of findings from cognitive neuroscience and psychology, that self-deception is a type of affective coping. First, we criticize the main solutions to the paradoxes of self-deception. We then present a new approach to self-deception. Self-deception, we argue, involves three appraisals of the distressing evidence: (a) appraisal of the strength of evidence as uncertain, (b) low coping potential and (c) negative anticipation along the lines of Damasios somatic marker hypothesis. At the same time, desire impacts the treatment of flattering evidence via dopamine. Our main proposal is that self-deception involves emotional mechanisms provoking a preference for immediate reward despite possible long-term negative repercussions. In the last part, we use this emotional model to revisit the philosophical paradoxes.

ArthroPlanner: a surgical planning solution for acromioplasty

PurposeWe present a computer-assisted planning solution “ArthroPlanner” for acromioplasty based on 3D anatomical models, computed tomography and joint kinematic simulations.MethodsIn addition to a standard static clinical evaluation (anamnesis, radiological examination), the software provides a dynamic assessment of the shoulder joint by computing in real time the joint kinematics from a database of activities of daily living. During motion, the precise bone resection (location and amount) is computed based on detected subacromial impingements, providing surgeons with precise information about the surgical procedure. Moreover, to improve the subjective reading of medical images, the software provides 3D measurement tools based on anatomical models assisting in the analysis of shoulder morphological features.ResultsWe performed an in vivo assessment of the software in a prospective randomized clinical study conducted with 27 patients beneficiating from the planning solution and a control group of 31 patients without planning. Postoperatively, patient’s pain decreased, and the shoulder range of motion and the functional outcomes improved significantly and the rotator cuff healing rate was good for both groups without intergroup differences. The amount of bone resected at surgery was comparable between the groups. The percentage of remaining impingement after surgery was in average reduced to 51% without groups difference.ConclusionsArthroPlanner software includes all required materials (images data, 3D models, motion, morphological measurements, etc.) to improve orthopedists’ performance in the surgical planning of acromioplasty. The solution offers a perfect analysis of the patient’s anatomy and the ability to precisely analyze a dynamic mechanism to fully apprehend the patient’s condition and to fulfill his/her expectations. The study however failed to detect any statistically significant difference in clinical outcomes and bone resection between the groups. Short-term clinical and radiological results were excellent in both groups.