Reorganization of learning-associated prefrontal synaptic plasticity between the recall of recent and remote fear extinction memory

We have previously shown that fear extinction is accompanied by an increase of synaptic efficacy in inputs from the ventral hippocampus (vHPC) and mediodorsal thalamus (MD) to the medial prefrontal cortex (mPFC) and that disrupting these changes to mPFC synaptic transmission compromises extinction processes. The aim of this study was to examine whether these extinction-related changes undergo further plasticity as the memory of extinction becomes more remote. Changes in synaptic efficacy in both vHPC-mPFC and MD-mPFC inputs were consequently analyzed when the memory was either 1 d or 7 d old. Increases of synaptic efficacy in the vHPC-mPFC pathway were observed when the memory was 1 d old, but not 7 d after initial extinction. In contrast, potentiation of synaptic efficacy in the MD-mPFC pathway increased over time. In rats that received low-frequency vHPC stimulation immediately after extinction, both vHPC-mPFC and MD-mPFC inputs failed to develop potentiation, and the recall of extinction (both recent and remote memories) was impaired. These findings suggest that post-extinction potentiation in vHPC-mPFC inputs may be necessary for both the recall of recent memory and post-extinction potentiation in the MD-mPFC inputs. This late potentiation process may be required for the recall of remote extinction memory.     

Does a yellow filter improve visual object categorization in normal aging?

Previous studies have shown that a yellow filter (CPF450) can increase contrast, motion sensitivity, vergence, and accommodation. We investigated whether a yellow filter can reduce age-related visual deficits. We tested two groups of 60 observers (mean age 24 vs. 72) in an object categorization task. Grayscale photographs of natural objects and artifacts were displayed either centrally or peripherally (21°) at low (8%) or medium (30%) contrast. There were three filter conditions (no filter, placebo filter, and yellow filter). Both groups of observers performed similarly on central and medium-contrast pictures. The deleterious effects of reduced contrast and eccentricity were stronger in elderly individuals. Moreover, the yellow filter globally improved the speed of categorization for the elderly participants. The decrease in response time in the yellow filter condition was larger when the stimuli were displayed peripherally in both groups. A yellow filter should be considered as a potential means for visual improvement in normal aging.     

Numerical and nonnumerical estimation in children with and without mathematical learning disabilities

There are currently multiple explanations for mathematical learning disabilities (MLD). The present study focused on those assuming that MLD are due to a basic numerical deficit affecting the ability to represent and to manipulate number magnitude ( Butterworth, 1999 , 2005 ; A. J. Wilson & Dehaene, 2007 ) and/or to access that number magnitude representation from numerical symbols ( Rousselle & No?l, 2007 ). The present study provides an original contribution to this issue by testing MLD children (carefully selected on the basis of preserved abilities in other domains) on numerical estimation tasks with contrasting symbolic (Arabic numerals) and nonsymbolic (collection of dots) numbers used as input or output. MLD children performed consistently less accurately than control children on all the estimation tasks. However, MLD children were even weaker when the task involved the mapping between symbolic and nonsymbolic numbers than when the task required a mapping between two nonsymbolic numerical formats. Moreover, in the estimation of nonsymbolic numerosities, MLD children relied more than control children on perceptual cues such as the cumulative area of the dots. Finally, the task requiring a mapping from a nonsymbolic format to a symbolic format was the best predictor of MLD. In order to explain these present results, as well as those reported in the literature, we propose that the impoverished number magnitude representation of MLD children may arise from an initial mapping deficit between number symbols and that magnitude representation.     

Emotional time distortions: The fundamental role of arousal

An emotion-based lengthening effect on the perception of durations of emotional pictures has been assumed to result from an arousal-based mechanism, involving the activation of an internal clock system. The aim of this study was to systematically examine the arousal effect on time perception when different discrete emotions were considered. The participants were asked to verbally estimate the duration of emotional pictures from the International Affective Picture System (IAPS). The pictures varied either in arousal level, i.e., high/low-arousal, for the same discrete emotion (disgust or sadness) or in the depicted emotion, e.g., disgust/fear for pictures matched for arousal (high-arousal). The results systematically revealed a lengthening effect on the perception of the duration of the emotional compared to the neutral pictures and indicated that the magnitude of this effect increased with arousal level. Nevertheless, variations in time perception were observed for one and the same arousal level, with the duration of disgust-inducing pictures (e.g., body mutilation) being judged longer than that of fear-inducing pictures (e.g., snake). These results suggest that arousal is a fundamental mechanism mediating the effect of emotion on time perception. However, the effect cannot be reduced to arousal, since the impact of the content of pictures also plays a critical role.     

Functional magnetic resonance imaging study of Piaget's conservation-of-number task in preschool and school-age children: a neo-Piagetian approach

Jean Piaget’s theory is a central reference point in the study of logico-mathematical development in children. One of the most famous Piagetian tasks is number conservation. Failures and successes in this task reveal two fundamental stages in children’s thinking and judgment, shifting at approximately 7 years of age from visuospatial intuition to number conservation. In the current study, preschool children (nonconservers, 5-6 years of age) and school-age children (conservers, 9-10 years of age) were presented with Piaget’s conservation-of-number task and monitored by functional magnetic resonance imaging (fMRI). The cognitive change allowing children to access conservation was shown to be related to the neural contribution of a bilateral parietofrontal network involved in numerical and executive functions. These fMRI results highlight how the behavioral and cognitive stages Piaget formulated during the 20th century manifest in the brain with age.     

Career exploration in adolescents: The role of anxiety, attachment, and parenting style

The aim of the study was to examine the role of parent-adolescent attachment, adolescent anxiety and parenting style in the career exploration process and in career satisfaction. Three kinds of anxiety were considered: general trait anxiety, fear of failing in one’s career and fear of disappointing one’s parents. The participants were 283 French high school students on the threshold of one of the most important school transitions. The results varied by gender. For girls, general anxiety and neglectful style were negatively related to career exploration; secure attachment and fear of failing were positively related to it. For boys, fear of disappointing parents was positively related to career exploration. Attachment to parents, authoritative style, general anxiety, and fear of failing were related to some career exploration satisfaction scores, though differently for boys and girls. The differences between boys and girls in the roles played by anxiety, attachment and parenting style are discussed.     

Spontaneous response to and expressive regulation of mirth elicited by humorous cartoons in younger and older adults

Many studies have examined the effect of aging on the ability to regulate negative emotions but less is known about the way the elderly people control their positive affects. Thirty-eight younger and 38 older adults were compared on their affective, expressive, physiological, and behavioral spontaneous responses to and in expressive regulation of mirth elicited by humorous cartoons. Compared to younger adults, older adults were equally amused and aroused but showed lower expressivity in their spontaneous reaction. They were similarly successful in implementing expressive regulation but they had lower physiological activation under amplification condition and more gaze avoidance from the key areas of the cartoons under suppression condition. This indicates that in older, amplification skills are disjointed from the physiological responses and suppression skills seem supplanted by a less costly strategy of attention redeployment. This also suggests that older adults’ behavior is not driven by a greater preference for positive information.     

Inferential language processes across adolescence: A test with novel idioms

Idiom comprehension relies on the ability to draw inferences from different cues in a communication situation. Adopting a developmental perspective, we investigated how this ability changes across adolescence. To this end, we designed a computerized system that allowed us to simulate a communication situation through short videos placing participants at the center of the interaction. Four groups of participants (11, 13, 15, and adult students) performed an idiomatic expression comprehension task, in which idiom familiarity was controlled. We manipulated the idioms’ transparency (vs. opacity) and presentation (supportive narrative context inducing an idiomatic interpretation of the expression vs. nonsupportive narrative context). Analyses revealed an improvement in idiom comprehension in terms of contextual inferences but they failed to reveal any significant difference in terms of semantic inferences. This study yields fresh arguments in support of the notion that inferential ability based on context continues to develop beyond childhood.     

Contribution of the priming paradigm to the understanding of the conceptual developmental shift from 5 to 9 years of age

We conducted three experiments to study the role of instrumental (e.g. knife–bread) and categorical (e.g. cake–bread) relations in the development of conceptual organization with a priming paradigm, by varying the nature of the task (naming – Experiment 1 – or categorical decision – Experiments 2 and 3). The participants were 5‐, 7‐ and 9‐year‐old children and adults. The results showed that on both types of task, adults and 9‐year‐old children presented instrumental and categorical priming effects, whereas 5‐year‐old children presented mainly instrumental priming effects, with categorical effects remaining marginal. Moreover, the magnitude of the instrumental priming effects decreased with age. Finally, the priming effects observed for 7‐year‐old children depended on the task, especially for the categorical effects. The theoretical implications of these results for our understanding of conceptual reorganization from 5 to 9 years of age are discussed.