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1.  Caudate responses to reward anticipation associated with delay discounting behavior in healthy youth 
Choices requiring delay of gratification made during adolescence can have significant impact on life trajectory. Willingness to delay gratification can be measured using delay discounting tasks that require a choice between a smaller immediate reward and a larger delayed reward. Individual differences in the subjective value of delayed rewards are associated with risk for development of psychopathology including substance abuse. The neurobiological underpinnings related to these individual differences early in life are not fully understood. Using functional magnetic resonance imaging (fMRI), we tested the hypothesis that individual differences in delay discounting behavior in healthy youth are related to differences in responsiveness to potential reward.
Nineteen 10 to 14 year-olds performed a monetary incentive delay task to assess neural sensitivity to potential reward and a questionnaire to measure discounting of future monetary rewards.
Left ventromedial caudate activation during anticipation of potential reward was negatively correlated with delay discounting behavior. There were no regions where brain responses during notification of reward outcome were associated with discounting behavior.
Brain activation during anticipation of potential reward may serve as a marker for individual differences in ability or willingness to delay gratification in healthy youth.
PMCID: PMC3932556  PMID: 24309299
adolescent; reward; fMRI; delay discounting; intertemporal choice; delayed gratification
2.  Electrophysiological measures of attention during speech perception predict metalinguistic skills in children 
Event-related potential (ERP) evidence demonstrates that preschool-aged children selectively attend to informative moments such as word onsets during speech perception. Although this observation indicates a role for attention in language processing, it is unclear whether this type of attention is part of basic speech perception mechanisms, higher-level language skills, or general cognitive abilities. The current study examined these possibilities by measuring ERPs from 5-year-old children listening to a narrative containing attention probes presented before, during, and after word onsets as well as at random control times. Children also completed behavioral tests assessing verbal and nonverbal skills. Probes presented after word onsets elicited a more negative ERP response beginning around 100 ms after probe onset than control probes, indicating increased attention to word-initial segments. Crucially, the magnitude of this difference was correlated with performance on verbal tasks, but showed no relationship to nonverbal measures. More specifically, ERP attention effects were most strongly correlated with performance on a complex metalinguistic task involving grammaticality judgments. These results demonstrate that effective allocation of attention during speech perception supports higher-level, controlled language processing in children by allowing them to focus on relevant information at individual word and complex sentence levels.
PMCID: PMC3938020  PMID: 24316548
speech perception; selective attention; metalinguistic awareness; development; event-related potential
4.  Cognitive control network connectivity in adolescent women with and without a parental history of depression 
Adolescent women with a parental history of depression are at high risk for the onset of major depressive disorder (MDD). Cognitive theories suggest this vulnerability involves deficits in cognitive control over emotional information. Among adolescent women with and without a parental history of depression, we examined differences in connectivity using resting state functional connectivity analysis within a network associated with cognitive control over emotional information.
Twenty-four depression-naïve adolescent women underwent resting state functional magnetic resonance imaging (fMRI). They were assigned to high-risk (n = 11) and low-risk (n = 13) groups based their parents’ depression history. Seed based functional connectivity analysis was used to examine group differences in connectivity within a network associated with cognitive control.
High-risk adolescents had lower levels of connectivity between a right inferior prefrontal region and other critical nodes of the attention control network, including right middle frontal gyrus and right supramarginal gyrus. Further, greater severity of the parents’ worst episode of depression was associated with altered cognitive control network connectivity in their adolescent daughters.
Depressed parents may transmit depression vulnerability to their adolescent daughters via alterations in functional connectivity within neural circuits that underlie cognitive control of emotional information.
PMCID: PMC4209722  PMID: 24270043
depression vulnerability; adolescence; parental history of depression; cognitive control network; resting-state fMRI; functional connectivity
5.  Fractionating the neural correlates of individual working memory components underlying arithmetic problem solving skills in children 
Developmental cognitive neuroscience  2013;6:10.1016/j.dcn.2013.10.001.
Baddeley and Hitch’s multi-component working memory (WM) model has played an enduring and influential role in our understanding of cognitive abilities. Very little is known, however, about the neural basis of this multi-component WM model and the differential role each component plays in mediating arithmetic problem solving abilities in children. Here, we investigate the neural basis of the central executive (CE), phonological (PL) and visuo-spatial (VS) components of WM during a demanding mental arithmetic task in 7–9 year old children (N=74). The VS component was the strongest predictor of math ability in children and was associated with increased arithmetic complexity-related responses in left dorsolateral and right ventrolateral prefrontal cortices as well as bilateral intra-parietal sulcus and supramarginal gyrus in posterior parietal cortex. Critically, VS, CE and PL abilities were associated with largely distinct patterns of brain response. Overlap between VS and CE components was observed in left supramarginal gyrus and no overlap was observed between VS and PL components. Our findings point to a central role of visuo-spatial WM during arithmetic problem-solving in young grade-school children and highlight the usefulness of the multi-component Baddeley and Hitch WM model in fractionating the neural correlates of arithmetic problem solving during development.
PMCID: PMC3871177  PMID: 24212504
working memory; arithmetic cognition; development; central executive; visuo-spatial; fMRI; individual differences
6.  What changes in neural oscillations can reveal about developmental cognitive neuroscience: Language development as a case in point 
Developmental cognitive neuroscience  2013;6:10.1016/j.dcn.2013.08.002.
EEG is a primary method for studying temporally precise neuronal processes across the lifespan. Most of this work focuses on Event Related Potentials (ERPs); however, using time-locked time frequency analysis to decompose the EEG signal can identify and distinguish multiple changes in brain oscillations underlying cognition (Bastiaansen et al., 2010). Further this measure is thought to reflect changes in inter-neuronal communication more directly than ERPs (Nunez & Srinivasan, 2006). Although time frequency has elucidated cognitive processes in adults, applying it to cognitive development is still rare. Here, we review the basics of neuronal oscillations, some of what they reveal about adult cognitive function, and what little is known relating to children. We focus on language because it develops early and engages complex cortical networks. Additionally, because time frequency analysis of the EEG related to adult language comprehension has been incredibly informative, using similar methods with children will shed new light on current theories of language development and increase our understanding of how neural processes change over the lifespan. Our goal is to emphasize the power of this methodology and encourage its use throughout developmental cognitive neuroscience.
PMCID: PMC3875138  PMID: 24060670
7.  Cortical gray-matter thinning is associated with age-related improvements on executive function tasks 
Developmental cognitive neuroscience  2013;6:10.1016/j.dcn.2013.07.002.
Across development children show marked improvement in their executive functions (EFs), including the ability to hold information in working memory and to deploy cognitive control, allowing them to ignore prepotent responses in favor of newly learned behaviors. How does the brain support these age-related improvements? Age-related cortical gray-matter thinning, thought to result from selective pruning of inefficient synaptic connections and increases in myelination, may support age-related improvements in EFs. Here we used structural MRI to measure cortical thickness. We investigate the association between cortical thickness in three cortical regions of interest (ROIs), and age-related changes in cognitive control and working memory in 5–10 year old children. We found significant associations between reductions in cortical thickness and age-related improvements in performance on both working memory and cognitive control tasks. Moreover, we observed a dissociation between ROIs typically thought to underlie changes in cognitive control (right Inferior Frontal gyrus and Anterior Cingulate cortex) and age-related improvements in cognitive control, and ROIs for working memory (superior parietal cortex), and age-related changes in a working memory task. These data add to our growing understanding of how structural maturation of the brain supports vast behavioral changes in executive functions observed across childhood.
PMCID: PMC3876892  PMID: 23896579
Brain development; Executive functions; Cognitive control; Structural MRI
8.  Biological impact of preschool music classes on processing speech in noise 
Developmental cognitive neuroscience  2013;0:10.1016/j.dcn.2013.06.003.
Musicians have increased resilience to the effects of noise on speech perception and its neural underpinnings. We do not know, however, how early in life these enhancements arise. We compared auditory brainstem responses to speech in noise in 32 preschool children, half of whom were engaged in music training. Thirteen children returned for testing one year later, permitting the first longitudinal assessment of subcortical auditory function with music training. Results indicate emerging neural enhancements in musically trained preschoolers for processing speech in noise. Longitudinal outcomes reveal that children enrolled in music classes experience further increased neural resilience to background noise following one year of continued training compared to nonmusician peers. Together, these data reveal enhanced development of neural mechanisms undergirding speech-in-noise perception in preschoolers undergoing music training and may indicate a biological impact of music training on auditory function during early childhood.
PMCID: PMC3844086  PMID: 23872199
Auditory; ABR; brainstem; language; musicians; music training; subcortical; development
9.  Topographic Analysis of the Development of Individual Activation Patterns During Performance Monitoring in Medial Frontal Cortex 
Developmental cognitive neuroscience  2013;6:10.1016/j.dcn.2013.09.001.
Age-related improvements in human performance monitoring have been linked to maturation of medial frontal cortex (MFC) in healthy youth, however, imaging studies conflict regarding age-related changes in MFC activation patterns. Topographical analysis of single-subject activation enables measurement of variation in location of MFC activation by age, as well as other potentially influential factors (e.g., performance on task). In this study, 22 youth (ages 8 - 17 years) and 21 adults (ages 23 - 51 years) underwent functional magnetic resonance imaging during a performance monitoring task examining interference and errors. Single-subject factors (extent of MFC activation, age and accuracy) were entered into a three-level hierarchical linear model to test the influence of these characteristics on location of MFC activation. Activation shifted from a rostral/anterior to a more dorsal/posterior location with increasing age and accuracy during interference. Inclusion of age and accuracy accounted for almost all of the unexplained variance in location of interference-related activation within MFC. This pattern links improvement of performance-monitoring capacity to age-related increases in posterior MFC and decreases in anterior MFC activation. Taken together, these results show the maturation of performance monitoring capacity to depend on more focal engagement of posterior MFC substrate for cognitive control.
PMCID: PMC3857610  PMID: 24095989
single subject activation; fMRI; human development; cognitive control; hierarchical linear modeling
10.  Harsh Parenting and Fearfulness in Toddlerhood Interact to Predict Amplitudes of Preschool Error-Related Negativity 
Temperamentally fearful children are at increased risk for the development of anxiety problems relative to less-fearful children. This risk is even greater when early environments include high levels of harsh parenting behaviors. However, the mechanisms by which harsh parenting may impact fearful children’s risk for anxiety problems are largely unknown. Recent neuroscience work has suggested that punishment is associated with exaggerated error-related negativity (ERN), an event-related potential linked to performance monitoring, even after the threat of punishment is removed. In the current study, we examined the possibility that harsh parenting interacts with fearfulness, impacting anxiety risk via neural processes of performance monitoring. We found that greater fearfulness and harsher parenting at 2 years of age predicted greater fearfulness and greater ERN amplitudes at age 4. Supporting the role of cognitive processes in this association, greater fearfulness and harsher parenting also predicted less efficient neural processing during preschool. This study provides initial evidence that performance monitoring may be a candidate process by which early parenting interacts with fearfulness to predict risk for anxiety problems.
PMCID: PMC4061243  PMID: 24721466
Fearful temperament; ERN; Harsh Parenting; Anxiety Risk
11.  Motor fMRI and cortical grey matter volume in adults born very preterm 
•Adults born very preterm (VPT) and controls performed a motor fMRI task.•VPT adults activated the cerebellum and adjacent temporal lobe more than controls.•Grey matter volume in the premotor cortex was smaller in the VPT group.•Grey matter volume in premotor cortex explained 33% of activation in the cerebellum.•Preterm birth is associated with functional neuroanatomical alterations in adulthood.
The primary aim of this study was to investigate the functional neuroanatomy of motor planning, initiation and execution in a cohort of young adults (mean age 20 years) who were born very preterm (VPT; <33 weeks of gestation), as these individuals are at increased risk of experiencing neuromotor difficulties compared to controls. A cued motor task was presented to 20 right-handed VPT individuals and 20 controls within a functional magnetic resonance imaging (fMRI) paradigm. Whole-brain grey matter volume was also quantified and associations with functional data were examined. Despite comparable task performance, fMRI results showed that the VPT group displayed greater brain activation compared to controls in a region comprising the right cerebellum and the lingual, parahippocampal and middle temporal gyri. The VPT group also displayed decreased grey matter volume in the right superior frontal/premotor cortex and left middle temporal gyri. Grey matter volume in the premotor and middle temporal clusters was significantly negatively correlated with BOLD activation in the cerebellum. Overall, these data suggest that preterm birth is associated with functional neuronal differences that persist into adulthood, which are likely to reflect neural reorganisation following early brain injury.
PMCID: PMC4256062  PMID: 25016248
Preterm; Adult; fMRI; Motor; Cognitive; Neurodevelopment
12.  Averaging, not internal noise, limits the development of coherent motion processing 
•Motion processing abilities develop gradually through childhood.•This lengthy development could be due to local noise and/or poor averaging.•5–11-year-olds and adults performed equivalent noise and motion coherence tasks.•Through childhood, internal noise reduces and averaging increases.•Yet, only improved averaging explains developments in motion coherence sensitivity.
The development of motion processing is a critical part of visual development, allowing children to interact with moving objects and navigate within a dynamic environment. However, global motion processing, which requires pooling motion information across space, develops late, reaching adult-like levels only by mid-to-late childhood. The reasons underlying this protracted development are not yet fully understood. In this study, we sought to determine whether the development of motion coherence sensitivity is limited by internal noise (i.e., imprecision in estimating the directions of individual elements) and/or global pooling across local estimates. To this end, we presented equivalent noise direction discrimination tasks and motion coherence tasks at both slow (1.5°/s) and fast (6°/s) speeds to children aged 5, 7, 9 and 11 years, and adults. We show that, as children get older, their levels of internal noise reduce, and they are able to average across more local motion estimates. Regression analyses indicated, however, that age-related improvements in coherent motion perception are driven solely by improvements in averaging and not by reductions in internal noise. Our results suggest that the development of coherent motion sensitivity is primarily limited by developmental changes within brain regions involved in integrating motion signals (e.g., MT/V5).
PMCID: PMC4256063  PMID: 25160679
Visual development; Motion processing; Direction discrimination
13.  Cognitive, Affective, and Conative Theory of Mind (ToM) in Children with Traumatic Brain Injury 
We studied three forms of dyadic communication involving theory of mind (ToM) in 82 children with traumatic brain injury (TBI) and 61 children with orthopedic injury (OI): Cognitive (concerned with false belief), Affective (concerned with expressing socially deceptive facial expressions), and Conative (concerned with influencing another’s thoughts or feelings). We analyzed the pattern of brain lesions in the TBI group and conducted voxel-based morphometry for all participants in five large-scale functional brain networks, and related lesion and volumetric data to ToM outcomes. Children with TBI exhibited difficulty with Cognitive, Affective, and Conative ToM. The perturbation threshold for Cognitive ToM is higher than that for Affective and Conative ToM, in that Severe TBI disturbs Cognitive ToM but even Mild-Moderate TBI disrupt Affective and Conative ToM. Childhood TBI was associated with damage to all five large-scale brain networks. Lesions in the Mirror Neuron Empathy network predicted lower Conative ToM involving ironic criticism and empathic praise. Conative ToM was significantly and positively related to the package of Default Mode, Central Executive, and Mirror Neuron Empathy networks and, more specifically, to two hubs of the Default Mode network, the posterior cingulate/retrosplenial cortex and the hippocampal formation, including entorhinal cortex and parahippocampal cortex.
PMCID: PMC3620837  PMID: 23291312
14.  Fronto-limbic Function in Unaffected Offspring at Familial Risk for Bipolar Disorder during an Emotional Working Memory Paradigm 
Evidence from neuroimaging studies indicate that individuals with bipolar disorder (BD) exhibit altered functioning of fronto-limbic systems implicated in voluntary emotion regulation. Few studies, however, have examined the extent to which unaffected youth at familial risk for BD exhibit such alterations. Using an fMRI emotional working memory paradigm, we investigated the functioning of fronto-limbic systems in fifteen healthy bipolar offspring (8–17 years old) with at least one parent diagnosed with BD (HBO), and 16 age-matched healthy control (HC) participants. Neural activity and functional connectivity analyses focused on a priori neural regions supporting emotion processing (amygdala, ventral striatum) and voluntary emotion regulation (ventrolateral prefrontal cortex (VLPFC), dorsolateral prefrontal cortex (DLPFC), anterior cingulate cortex (ACC)). Relative to HC, HBO exhibited greater right VLPFC (BA47) activation in response to positive emotional distracters and reduced VLPFC modulation of the amygdala to both the positive and negative emotional distracters; there were no group differences in connectivity for the neutral distracters. These findings suggest that alterations in the functioning of fronto-limbic systems implicated in voluntary emotion regulation are present in unaffected bipolar offspring. Future longitudinal studies are needed to determine the extent to which such alterations represent neurodevelopmental markers of risk for future onset of BD.
PMCID: PMC3676715  PMID: 23590840
bipolar disorder; risk; functional magnetic resonance imaging (fMRI); functional connectivity; emotion; attentional control
15.  Specific aspects of cognitive and language proficiency account for variability in neural indices of semantic and syntactic processing in children 
The neural activity mediating language processing in young children is characterized by large individual variability that is likely related in part to individual strengths and weakness across various cognitive abilities. The current study addresses the following question: How does proficiency in specific cognitive and language functions impact neural indices mediating language processing in children? Thirty typically developing seven- and eight-year-olds were divided into high-normal and low-normal proficiency groups based on performance on nonverbal IQ, auditory word recall, and grammatical morphology tests. Event-related brain potentials (ERPs) were elicited by semantic anomalies and phrase structure violations in naturally spoken sentences. The proficiency for each of the specific cognitive and language tasks uniquely contributed to specific aspects (e.g., timing and/or resource allocation) of neural indices underlying semantic (N400) and syntactic (P600) processing. These results suggest that distinct aptitudes within broader domains of cognition and language, even within the normal range, influence the neural signatures of semantic and syntactic processing. Furthermore, the current findings have important implications for the design and interpretation of developmental studies of ERPs indexing language processing, and they highlight the need to take into account cognitive abilities both within and outside the classic language domain.
PMCID: PMC3676731  PMID: 23557881
ERPs; Semantics (N400); Syntax (P600); Language; Proficiency; Children
16.  Atypical Lateralization of ERP Response to Native and Non-Native Speech in Infants at Risk for Autism Spectrum Disorder 
Language impairment is common in autism spectrum disorders (ASD) and is often accompanied by atypical neural lateralization. However, it is unclear when in development language impairment or atypical lateralization first emerges. To address these questions, we recorded event-related-potentials (ERPs) to native and non-native speech contrasts longitudinally in infants at risk for ASD (HRA) over the first year of life to determine whether atypical lateralization is present as an endophenotype early in development and whether these infants show delay in a very basic precursor of language acquisition: phonemic perceptual narrowing. ERP response for the HRA group to a non-native speech contrast revealed a trajectory of perceptual narrowing similar to a group of low-risk controls (LRC), suggesting that phonemic perceptual narrowing does not appear to be delayed in these high-risk infants. In contrast there were significant group differences in the development of lateralized ERP response to speech: between 6 and 12 months the LRC group displayed a lateralized response to the speech sounds, while the HRA group failed to display this pattern. We suggest the possibility that atypical lateralization to speech may be an ASD endophenotype over the first year of life.
PMCID: PMC3676696  PMID: 23287023
Event-related potential; infancy; autism spectrum disorder; endophenotype; speech perception
17.  Learning to remember: The early ontogeny of episodic memory☆ 
•We review literature on the ontogeny of episodic memory in the first postnatal year.•We discuss several extant points of contention.•One of which involves the status of hippocampal function.•We highlight the potential usefulness of MRI in progressing points of debate.
Over the past 60 years the neural correlates of human episodic memory have been the focus of intense neuroscientific scrutiny. By contrast, neuroscience has paid substantially less attention to understanding the emergence of this neurocognitive system. In this review we consider how the study of memory development has evolved. In doing so, we concentrate primarily on the first postnatal year because it is within this time window that the most dramatic shifts in scientific opinion have occurred. Moreover, this time frame includes the critical age (∼9 months) at which human infants purportedly first begin to demonstrate rudimentary hippocampal-dependent memory. We review the evidence for and against this assertion, note the lack of direct neurocognitive data speaking to this issue, and question how demonstrations of exuberant relational learning and memory in infants as young as 3-months old can be accommodated within extant models. Finally, we discuss whether current impasses in the infant memory literature could be leveraged by making greater use of neuroimaging techniques, such as magnetic resonance imaging (MRI), which have been deployed so successfully in adults.
PMCID: PMC4071442  PMID: 24480487
Memory development; Infantile amnesia; Hippocampus; fMRI; Episodic memory; Navigation
18.  Comment on “The physiology of developmental changes in BOLD functional imaging signals” by Harris, Reynell, and Attwell 
PMCID: PMC4034377  PMID: 22483071
fMRI; Development; Group comparisons; Vasculature
19.  Training-associated changes and stability of attention bias in youth: Implications for Attention Bias Modification Treatment for pediatric anxiety 
Attention Bias Modification Treatment (ABMT), an emerging treatment for anxiety disorders, is thought to modify underlying, stable patterns of attention. Therefore, ABMT research should take into account the impact of attention bias stability on attention training response, especially in pediatric populations. ABMT research typically relies on the dot-probe task, where individuals detect a probe following an emotional-neutral stimulus pair. The current research presents two dot-probe experiments relevant to ABMT and attention-bias stability. In Experiment 1, anxious youth receiving 8-weeks of cognitive-behavioral therapy (CBT) were randomly assigned to ABMT that trains attention towards happy faces (n=18) or placebo (n=18). Two additional comparison groups, anxious youth receiving only CBT (n=17) and healthy comparison youth (n=16), were studied. Active attention training towards happy faces did not augment clinician-rated response to CBT; however, individuals receiving training exhibited reductions on self-report measures of anxiety earlier than individuals receiving CBT only. In Experiment 2, healthy youth (n=12) completed a dot-probe task twice while undergoing functional magnetic resonance imaging. Intra class-correlation demonstrated stability of neural activation in response to attention bias in the ventrolateral prefrontal cortex and amygdala. Together, these two studies investigate the ways in which attention-bias stability may impact future work on ABMT.
PMCID: PMC3606014  PMID: 23200784
dot-probe; attention training; test-retest reliability; fMRI
20.  Preliminary data suggesting the efficacy of attention training for school-aged children with ADHD 
A pilot randomized clinical trial was conducted to examine the initial efficacy of Pay Attention!, an intervention training sustained, selective, alternating, and divided attention, in children diagnosed with Attention-Deficit/Hyperactivity Disorder (ADHD). After a diagnostic and baseline evaluation, school-aged children with ADHD were randomized to receive 16 bi-weekly sessions of Pay Attention! (n = 54) or to a waitlist control group (n = 51). Participants completed an outcome evaluation approximately 12 weeks after their baseline evaluation. Results showed significant treatment effects for parent and clinician ratings of ADHD symptoms, child self-report of ability to focus, and parent ratings of executive functioning. Child performance on neuropsychological tests showed significant treatment-related improvement on strategic planning efficiency, but no treatment effects were observed on other neuropsychological outcomes. Treatment effects were also not observed for teacher ratings of ADHD. These data add to a growing body of literature supporting effects of cognitive training on attention and behavior, however, additional research is warranted.
PMCID: PMC3617931  PMID: 23219490
ADHD; Attention training; Cognitive training; Executive functioning; Intervention
22.  Attention training towards positive stimuli in clinically anxious children 
Attention bias modification training (ABMT) is a promising treatment. Nevertheless, few studies examine its effectiveness in anxious children. This study examined the efficacy of such an ABMT protocol in pediatric anxiety.
37 anxious children were randomly assigned to one of two ABMT conditions. In the attention-towards-positive (ATP) condition, children searched 3 × 3 matrices for a happy face amongst angry faces. In the attention-training-control (ATC) condition, they searched for a bird amongst flowers. Children completed 160 trials in each of four training sessions per week for three weeks at home (1920 total trials). Clinical and attention bias measures were assessed before and after ABMT.
Children randomized to ATP showed greater post-training attention bias towards happy faces than children randomized to ATC. ATP also produced significantly greater reductions in clinician-rated diagnostic severity and number of diagnoses, compared to ATC. In the ATP group, 50% of children who completed training did not meet criteria for their principal diagnosis, compared to 8% in the ATC group.
Training anxious children to focus attention on positive features of their environment may be a promising treatment.
PMCID: PMC3947762  PMID: 23063461
Attention bias; Anxiety; Attention bias modification training; Cognitive behavioural therapy
23.  Neural mechanisms of impulse control in sexually risky adolescents 
The consequences of risky sexual behavior are of public concern. Adolescents contribute disproportionately to negative consequences of risky sexual behavior. However, no research has examined the neural correlates of impulse control and real-world engagement in risky sexual behavior in this population. The aim of the present study was to examine this question. Twenty sexually active adolescents performed an impulse control task during a functional magnetic resonance imaging (fMRI) scan and risky sexual behaviors were assessed through self-report. Sexual riskiness ratings were negatively associated with activation in the prefrontal cortex during response inhibition. These results suggest that diminished engagement of impulse control circuitry may contribute to sexual riskiness in adolescents.
PMCID: PMC3924962  PMID: 23835204
Adolescence; Brain development; Impulse control; Risky sexual behavior
24.  Habituation of visual evoked responses in neonates and fetuses: A MEG study 
Developmental cognitive neuroscience  2012;2(3):10.1016/j.dcn.2012.03.001.
In this study we aimed to develop a habituation paradigm that allows the investigation of response decrement and response recovery and examine its applicability for measuring the habituation of the visually evoked responses (VERs) in neonatal and fetal magnetoencephalographic recordings.
Two paradigms, one with a long and one with a short inter-train interval (ITI), were developed and tested in separate studies. Both paradigms consisted of a train of four light flashes; each train being followed by a 500 Hz burst tone. Healthy pregnant women underwent two prenatal measurements and returned with their babies for a neonatal investigation.
The amplitudes of the neonatal VERs in the long-ITI condition showed within-train response decrement. An increased response to the auditory dishabituator was found confirming response recovery. In the short-ITI condition, neonatal amplitude decrement could not be demonstrated while response recovery was present. In both ITI conditions, the response rate of the cortical responses was much lower in the fetuses than in the neonates. Fetal VERs in the long-ITI condition indicate amplitude decline from the first to the second flash with no further decrease. The long-ITI paradigm might be useful to investigate habituation of the VERs in neonates and fetuses, although the latter requires precaution.
PMCID: PMC3881959  PMID: 22483416
Habituation; Response recovery; Fetal and neonatal evoked responses; Magnetoencephalography
25.  Developmental differences in the neural correlates of relational encoding and recall in children: An event-related fMRI study 
Despite vast knowledge on the behavioral processes mediating the development of episodic memory, little is known about the neural mechanisms underlying these changes. We used event-related fMRI to examine the neural correlates of both encoding and recall processes during an episodic memory task in two different groups of school age children (8–9 & 12–13 years). The memory task was composed of an encoding phase in which children were presented with a series of unrelated pictorial pairs, and a retrieval phase during which one of these items acted as a cue to prompt recall of the paired item. Age-related differences in activations were observed for both encoding and recall. Younger children recruited additional regions in the right dorsolateral prefrontal and right temporal cortex compared to older children during successful encoding of the pairs. During successful recall, older children recruited additional regions in the left ventrolateral prefrontal and left inferior parietal cortex compared to younger children. The results suggest that the prefrontal cortex contributes to not only the formation of memories but also access to them, and this contribution changes with development. The protracted development of the prefrontal cortex has implications for our understanding of the development of episodic memory.
PMCID: PMC3514559  PMID: 22884992
neurodevelopment; episodic memory development; relational memory; children; event-related fMRI

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