Cognitive reserve involves decision making and is associated with left parietal and hippocampal hypertrophy in neurodegeneration.

Cognitive reserve is the ability to actively cope with brain deterioration and delay cognitive decline in neurodegenerative diseases. It operates by optimizing performance through differential recruitment of brain networks or alternative cognitive strategies. We investigated cognitive reserve using Huntington's disease (HD) as a genetic model of neurodegeneration to compare premanifest HD, manifest HD, and controls. Contrary to manifest HD, premanifest HD behave as controls despite neurodegeneration. By decomposing the cognitive processes underlying decision making, drift diffusion models revealed a response profile that differs progressively from controls to premanifest and manifest HD. Here, we show that cognitive reserve in premanifest HD is supported by an increased rate of evidence accumulation compensating for the abnormal increase in the amount of evidence needed to make a decision. This higher rate is associated with left superior parietal and hippocampal hypertrophy, and exhibits a bell shape over the course of disease progression, characteristic of compensation.

Differential effects of mindfulness meditation and cognitive training on cool and hot inhibitory control in children and adolescents.

Inhibitory control (IC) can occur either in a neutral context (cool) or in social contexts involving emotions (hot). Cool and hot IC have specific developmental trajectories; cool IC develops linearly from childhood to adulthood, whereas hot IC follows a quadratic trajectory. Some activities can improve the IC, such as cognitive training (CT) and mindfulness meditation (MM). The aim of our study was to compare the effects of 5 weeks of computerized MM versus CT on IC performance in 66 children (9-10 years old) and 63 adolescents (16-17 years old) by specifically analyzing cool and hot dimensions in the same participants and from a developmental perspective. We fit a linear mixed-effect model on the Stroop interference score with time (pretest vs. posttest) and type of conflict (cool vs. hot) as within-participant factors and intervention group (CT vs. MM) and age group (child vs. adolescent) as between-participant factors. The findings revealed that children but not adolescents benefitted from interventions. More specifically, CT improved cool IC but not hot IC, whereas MM practice improved hot IC but not cool IC. This study supports the benefits of MM at a young age. Theoretical issues linking MM programs to emotional competence grounded in hot IC skills are considered in academic settings.

Language disorders in patients with striatal lesions: Deciphering the role of the striatum in language performance.

The classical neural model of language refers to a cortical network involving frontal, parietal and temporal regions. However, patients with subcortical lesions of the striatum have language difficulties. We investigated whether the striatum is directly involved in language or whether its role in decision-making has an indirect effect on language performance, by testing carriers of Huntington's disease (HD) mutations and controls. HD is a genetic neurodegenerative disease primarily affecting the striatum and causing language disorders. We asked carriers of the HD mutation in the premanifest (before clinical diagnosis) and early disease stages, and controls to perform two discrimination tasks, one involving linguistic and the other non-linguistic stimuli. We used the hierarchical drift diffusion model (HDDM) to analyze the participants' responses and to assess the decision and non-decision parameters separately. We hypothesized that any language deficits related to decision-making impairments would be reflected in the decision parameters of linguistic and non-linguistic tasks. We also assessed the relative contributions of both HDDM decision and non-decision parameters to the participants' behavioral data (response time and discriminability). Finally, we investigated whether the decision and non-decision parameters of the HDDM were correlated with brain atrophy. The HDDM analysis showed that patients with early HD have impaired decision parameters relative to controls, regardless of the task. In both tasks, decision parameters better explained the variance of response time and discriminability performance than non-decision parameters. In the linguistic task, decision parameters were positively correlated with gray matter volume in the ventral striatum and putamen, whereas non-decision parameters were not. Language impairment in patients with striatal atrophy is better explained by a deficit of decision-making than by a deficit of core linguistic processing. These results suggest that the striatum is involved in language through the modulation of decision-making, presumably by regulating the process of choice between linguistic alternatives.

A network analysis of executive functions before and after computerized cognitive training in children and adolescents.

Executive functions (EFs) play a key role in cognitive and socioemotional development. Factor analyses have revealed an age dependent structure of EFs spanning from a single common factor in early childhood to three factors in adults corresponding to inhibitory control (IC), switching and updating. IC performances change not only with age but also with cognitive training. Surprisingly, few studies have investigated training-related changes in EFs structure. We used the regularized partial correlation network model to analyze EFs structure in 137 typically developing children (9-10 years) and adolescents (15-17 years) before and after computerized cognitive training. Network models (NMs) -a graph theory-based approach allowing us to describe the structure of complex systems- can provide a priori free insight into EFs structures. We tested the hypothesis that training-related changes may mimic developmental-related changes. Quantitative and qualitative changes were detected in the EFs network structure with age and also with cognitive training. Of note, the EFs network structure in children after training was more similar to adolescents' networks than before training. This study provided the first evidence of structural changes in EFs that are age and training-dependent and supports the hypothesis that training could accelerate the development of some structural aspects of EFs. Due to the sample size, these findings should be considered preliminary before replication in independent larger samples.

Development of cool and hot theory of mind and cool and hot inhibitory control abilities from 3.5 to 6.5 years of age.

Attributing affectively neutral mental states such as thoughts (i.e., cool theory of mind, cool ToM) to others appears to be rooted in different processes than the ones involved in attributing affectively charged mental states such as emotions (i.e., hot ToM) to others. However, no study has investigated the developmental pattern of hot and cool ToM abilities using a similar task and the relative contribution of cool and hot inhibitory control (IC) to cool and hot ToM development. To do so, we tested 112 children aged 3.5 to 6.5 years on a cool and a hot version of a ToM task and on a cool and hot version of an IC task. We found that hot ToM abilities developed more rapidly than cool ToM. Importantly, we found that hot IC abilities mediated the relation between age and hot ToM abilities. Taken together, our results suggest that the ability to attribute emotions to others develops more rapidly than the ability to attribute thoughts and that the growing efficiency of hot ToM with age is specifically rooted in the growing efficiency of hot IC abilities.

Structural priming in sentence comprehension: A single prime is enough.

Experiencing a syntactic structure affects how we process subsequent instances of that structure. This phenomenon, called structural priming, is observed both in language production and in language comprehension. However, while abstract syntactic structures can be primed independent of lexical overlap in sentence production, evidence for structural priming in comprehension is more elusive. In addition, when structural priming in comprehension is found, it can often be accounted for in terms of participants' explicit expectations. Participants may use the structural repetition over several sentences and build expectations, which create a priming effect. Here, we use a new experimental paradigm to investigate structural priming in sentence comprehension independent of lexical overlap and of participants' expectations. We use an outcome dependent variable instead of commonly used online measures, which allows us to more directly compare these effects with those found in sentence production studies. We test priming effects in syntactically homogeneous and heterogeneous conditions on a sentence-picture matching task that forces participants to fully parse the sentences. We observe that, while participants learn the structural regularity in the homogeneous condition, structural priming is also found in the heterogeneous condition, in which participants do not expect any particular structure. In fact, we find that a single prime is enough to trigger priming. Our results indicate that-like in sentence production-structural priming can be observed in sentence comprehension without lexical repetition and independent of participants' expectation.

Neural dynamics of prediction and surprise in infants.

Prior expectations shape neural responses in sensory regions of the brain, consistent with a Bayesian predictive coding account of perception. Yet, it remains unclear whether such a mechanism is already functional during early stages of development. To address this issue, we study how the infant brain responds to prediction violations using a cross-modal cueing paradigm. We record electroencephalographic responses to expected and unexpected visual events preceded by auditory cues in 12-month-old infants. We find an increased response for unexpected events. However, this effect of prediction error is only observed during late processing stages associated with conscious access mechanisms. In contrast, early perceptual components reveal an amplification of neural responses for predicted relative to surprising events, suggesting that selective attention enhances perceptual processing for expected events. Taken together, these results demonstrate that cross-modal statistical regularities are used to generate predictions that differentially influence early and late neural responses in infants.