Task rules, working memory, and fluid intelligence

Many varieties of working memory have been linked to fluid intelligence. In Duncan et al. (Journal of Experimental Psychology:General 137:131–148, 2008), we described limited working memory for new task rules: When rules are complex, some may fail in their control of behavior, though they are often still available for explicit recall. Unlike other kinds of working memory, load is determined in this case not by real-time performance demands, but by the total complexity of the task instructions. Here, we show that the correlation with fluid intelligence is stronger for this aspect of working memory than for several other, more traditional varieties—including simple and complex spans and a test of visual short-term memory. Any task, we propose, requires construction of a mental control program that aids in segregating and assembling multiple task parts and their controlling rules. Fluid intelligence is linked closely to the efficiency of constructing such programs, especially when behavior is complex and novel

La régulation du comportement et des émotions pendant l’adolescence.

Les recherches en neurosciences cognitives des deux dernières décennies ont démontré qu’au-delà de la petite enfance, le cerveau continue de changer de manière significative pendant l’adolescence. La maturation des circuits neuronaux sous-tendant les émotions, la motivation et le renforcement, la cognition sociale et les fonctions exécutives sont plus ou moins sensibles aux changements hormonaux associés à la puberté et progressent différemment pendant l’adolescence. Les adolescents ressentent les émotions de manière plus forte et sont plus sensibles au contexte social que les adultes. Par conséquent, ils peuvent rencontrer des difficultés de régulation de leurs émotions et actions dans certains contextes. Ces difficultés peuvent devenir chroniques et mener à des troubles de la santé mentale, comme la dépression, l’anxiété et l’addiction. Mais l’adolescence peut aussi être considérée positivement comme une période d’exploration et de flexibilité cognitive, pendant laquelle les individus deviennent indépendants et construisent leur concept de soi. L’éducation peut jouer un rôle dans le développement des adolescents à travers des programmes ayant pour but de renforcer leur capacité de réguler leurs émotions et leur comportement

Development of the selection and manipulation of self-generated thoughts in adolescence

The ability to select and manipulate self-generated (stimulus-independent, SI), as opposed to stimulus-oriented (SO), information, in a controlled and flexible way has previously only been studied in adults. This ability is thought to rely in part on the rostrolateral prefrontal cortex (RLPFC), which continues to mature anatomically during adolescence. We investigated (1) the development of this ability behaviorally, (2) the associated functional brain development, and (3) the link between functional and structural maturation. Participants classified according to their shape letters either presented visually (SO phases) or that they generated in their head by continuing the alphabet sequence (SI phases). SI phases were performed in the presence or absence of distracting letters. A total of 179 participants (7–27 years old) took part in a behavioral study. Resistance to visual distractors exhibited small improvements with age. SI thoughts manipulation and switching between SI and SO thoughts showed steeper performance improvements extending into late adolescence. Thirty-seven participants (11–30 years old) took part in a functional MRI (fMRI) study. SI thought manipulation and switching between SO and SI thought were each associated with brain regions consistently recruited across age. A single frontal brain region in each contrast exhibited decreased activity with age: left inferior frontal gyrus/anterior insula for SI thought manipulation, and right superior RLPFC for switching between SO and SI thoughts. By integrating structural and functional data, we demonstrated that the observed functional changes with age were not purely consequences of structural maturation and thus may reflect the maturation of neurocognitive strategies

Developmental changes in effective connectivity associated with relational reasoning

Rostrolateral prefrontal cortex (RLPFC) is part of a frontoparietal network of regions involved in relational reasoning, the mental process of working with relationships between multiple mental representations. RLPFC has shown functional and structural changes with age, with increasing specificity of left RLPFC activation for relational integration during development. Here, we used dynamic causal modeling (DCM) to investigate changes in effective connectivity during a relational reasoning task through the transition from adolescence into adulthood. We examined fMRI data of 37 healthy female participants (11–30 years old) performing a relational reasoning paradigm. Comparing relational integration to the manipulation of single relations revealed activation in five regions: the RLPFC, anterior insula, dorsolateral PFC, inferior parietal lobe, and medial superior frontal gyrus. We used a new exhaustive search approach and identified a full DCM model, which included all reciprocal connections between the five clusters in the left hemisphere, as the optimal model. In line with previous resting state fMRI results, we showed distinct developmental effects on the strength of long-range frontoparietal versus frontoinsular short-range fixed connections. The modulatory connections associated with relational integration increased with age. Gray matter volume in left RLPFC, which decreased with age, partly accounted for changes in fixed PFC connectivity. Finally, improvements in relational integration performance were associated with greater modulatory and weaker fixed PFC connectivity. This pattern provides further evidence of increasing specificity of left PFC function for relational integration compared to the manipulation of single relations, and demonstrates an association between effective connectivity and performance during development. Hum Brain Mapp, 2013

Rewards enhance proactive and reactive control in adolescence and adulthood

Cognitive control allows the coordination of cognitive processes to achieve goals. Control may be sustained in anticipation of goal-relevant cues (proactive control) or transient in response to the cues themselves (reactive control). Adolescents typically exhibit a more reactive pattern than adults in the absence of incentives. We investigated how reward modulates cognitive control engagement in a letter array working memory (WM) task in 30 adolescents (12-17 years) and 20 adults (23-30 years) using a mixed block- and event-related functional magnetic resonance imaging design. After a Baseline run without rewards, participants performed a Reward run where 50% trials were monetarily rewarded. Accuracy and reaction time (RT) differences between Reward and Baseline runs indicated engagement of proactive control, which was associated with increased sustained activity in the bilateral anterior insula (AI), right dorsolateral prefrontal cortex (PFC) and right posterior parietal cortex (PPC). RT differences between Reward and No reward trials of the Reward run suggested additional reactive engagement of cognitive control, accompanied with transient activation in bilateral AI, lateral PFC, PPC, supplementary motor area, anterior cingulate cortex, putamen and caudate. Despite behavioural and neural differences during Baseline WM task performance, adolescents and adults showed similar modulations of proactive and reactive control by reward

Developmental differences in the control of action selection by social information

Our everyday actions are often performed in the context of a social interaction. We previously showed that, in adults, selecting an action on the basis of either social or symbolic cues was associated with activations in the fronto-parietal cognitive control network, whereas the presence and use of social versus symbolic cues was in addition associated with activations in the temporal and medial prefrontal cortex (MPFC) social brain network. Here we investigated developmental changes in these two networks. Fourteen adults (21–30 years of age) and 14 adolescents (11–16 years) followed instructions to move objects in a set of shelves. Interpretation of the instructions was conditional on the point of view of a visible “director” or the meaning of a symbolic cue (Director Present vs. Director Absent) and the number of potential referent objects in the shelves (3-object vs. 1-object). 3-object trials elicited increased fronto-parietal and temporal activations, with greater left lateral prefrontal cortex and parietal activations in adults than adolescents. Social versus symbolic information led to activations in superior dorsal MPFC, precuneus, and along the superior/middle temporal sulci. Both dorsal MPFC and left temporal clusters exhibited a Director × Object interaction, with greater activation when participants needed to consider the directors' viewpoints. This effect differed with age in dorsal MPFC. Adolescents showed greater activation whenever social information was present, whereas adults showed greater activation only when the directors' viewpoints were relevant to task performance. This study thus shows developmental differences in domain-general and domain-specific PFC activations associated with action selection in a social interaction context

Social and non-social relational reasoning in adolescence and adulthood

Reasoning during social interactions requires the individual manipulation of mental representations of one’s own traits and those of other people, as well as their joint consideration (relational integration). Research using non-social paradigms has linked relational integration to activity in the rostrolateral prefrontal cortex (RLPFC). Here, we investigated whether social reasoning is supported by the same general system or whether it additionally relies on regions of the social brain network, such as the medial prefrontal cortex (MPFC). We further assessed the development of social reasoning. In the social task, participants evaluated themselves or a friend, or compared themselves with their friend, on a series of traits. In the non-social task, participants evaluated their hometown or another town, or compared the two. In a behavioural study involving 325 participants (11-39 years), we found that integrating relations compared to performing single relational judgements improves during adolescence, both for social and non-social information. Thirty-nine female participants (10-31 years) took part in a neuroimaging study using a similar task. Activation of the relational integration network, including the RLPFC, was observed in the comparison condition of both the social and non-social tasks, while MPFC showed greater activation when participants processed social as opposed to non-social information across conditions. Developmentally, the right anterior insula showed greater activity in adolescents compared with adults during the comparison of non-social vs. social information. This study shows parallel recruitment of the social brain and the relational reasoning network during the relational integration of social information in adolescence and adulthood

The relationship between pubertal status and neural activity during risky decision-making in male adolescents

- Purpose: Adolescence is a time of dramatic changes in a range of behaviours, which occur in tandem with changes in brain structure and function. These coincide with the physiological changes of puberty, but little research has focussed on the possible contributing role of puberty. One important behaviour emerging in adolescence is the increased propensity to make risky decisions. A prominent theory to explain this increased propensity for risk is the ‘dual systems’ model (Casey et al., 2008), where risky decisions result from a dissociation in the timing of the maturation of the limbic system and the prefrontal cortex, both regions involved in risky decision-making. The limbic system (incorporating the ventral striatum) is hypothesised to mature relatively early in adolescence, and is thought to be related to pubertal maturation. In contrast, the prefrontal cortex is thought to undergo more protracted development throughout adolescence. This study explores how developmental changes in brain function when performing a risk-taking fMRI (functional Magnetic Resonance Imaging) task are related to puberty, independently of chronological age. - Methods: Forty-five male participants aged 13-14 years underwent fMRI scanning whilst performing a risk-taking task (BART task, adapted from Lejuez et al., 2002). In this age range, there is normal variability in pubertal development, with individuals being at all stages of puberty from pre-puberty to having completed puberty. In the BART task, participants had to decide whether to inflate a virtual balloon on a screen. Successful inflation of the balloon resulted in the opportunity to earn more money, but risked the balloon popping and the money being lost. Stopping allowed the participants to save the money towards their final earnings. Participants completed four six-minute runs of the task. Pubertal stage was assessed using self-report measures including a pictorial Tanner stage and the Pubertal Developmental Scale (Petersen et al., 1988). Salivary hormone levels were collected to measure levels of Testosterone, Oestradiol and DHEA. Participants also completed validated self-report questionnaires of risk-taking, impulsivity and sensation-seeking. - Results: The analysis focused on a main effect, across the entire group, of active decision-making compared to the control condition in regions including the prefrontal cortex and limbic system, which are known to be involved in risky decision-making. We also investigated whether this activation was differentially related to puberty across regions, using both group-wise and regression analyses. - Conclusions; This study investigated a role for puberty in the functional development of brain regions involved in risky decision-making in males, and further informs the usefulness of the dual systems model of risk taking during adolescence

Internalising and externalising in early adolescence predict later executive function, not the other way around: a cross-lagged panel analysis

Developmental changes in the brain networks involved in emotion regulation are thought to contribute to vulnerability to mental health problems during adolescence. Executive control is often viewed as allowing top-down regulation of emotional responses. However, while associations between executive control and mental health are commonly observed in both clinical and non-clinical populations, the direction of these associations remains unclear. Low, or immature, cognitive control could limit emotion regulation. Reversely, high emotionality could impede cognitive functioning. The scarcity of longitudinal studies testing for bi-directional effects, particularly in adolescence, has made it difficult to draw conclusions. This study utilised data from 1,445 participants of a longitudinal cohort in a cross-lagged panel design to understand bi-directional longitudinal associations between executive function and emotional behaviours across adolescence. Executive function was assessed using experimental working memory and inhibitory control tasks, emotional behaviours through parental report of internalising and externalising behaviours. Cross-sectional associations were replicated. Controlling for cross-sectional associations, early executive functions were not found to predict later emotional behaviours. Instead, early emotional behaviours predicted later executive function, with the strongest link observed between early externalising and later working memory. These results suggest that emotional well-being may affect the maturation of executive function during adolescence

Association between action kinematics and emotion perception across adolescence

Research with adults suggests that we interpret others’ internal states from kinematic cues, using models calibrated to our own action experiences. Changes in action production that occur during adolescence may therefore have implications for adolescents’ understanding of others. Here we examined whether, like adults, adolescents use velocity cues to determine others’ emotions, and whether any emotion perception differences would be those predicted based on differences in action production. We measured preferred walking velocity in groups of Early (11-12 years old), Middle (13-14 years old) and Late (16-18 years old) adolescents, and adults, and recorded their perception of happy, angry and sad ‘point-light walkers’. Preferred walking velocity decreased across age and ratings of emotional stimuli with manipulated velocity demonstrated that all groups used velocity cues to determine emotion. Importantly, the relative intensity ratings of different emotions also differed across development in a manner that was predicted based on the group differences in walking velocity. Further regression analyses demonstrated that emotion perception was predicted by own movement velocity, rather than age or pubertal stage per se. These results suggest that changes in action production across adolescence are indeed accompanied by corresponding changes in how emotions are perceived from velocity. These findings indicate the importance of examining differences in action production across development when interpreting differences in understanding of others