Distinct Neural Profiles of Frontoparietal Networks in Boys with ADHD and Boys with Persistent Depressive Disorder

Working memory deficits are common in attention-deficit/hyperactivity disorder (ADHD) and depression-two common neurodevelopmental disorders with overlapping cognitive profiles but distinct clinical presentation. Multivariate techniques have previously been utilized to understand working memory processes in functional brain networks in healthy adults but have not yet been applied to investigate how working memory processes within the same networks differ within typical and atypical developing populations. We used multivariate pattern analysis (MVPA) to identify whether brain networks discriminated between spatial versus verbal working memory processes in ADHD and Persistent Depressive Disorder (PDD). Thirty-six male clinical participants and 19 typically developing (TD) boys participated in a fMRI scan while completing a verbal and a spatial working memory task. Within a priori functional brain networks (frontoparietal, default mode, salience), the TD group demonstrated differential response patterns to verbal and spatial working memory. The PDD group showed weaker differentiation than TD, with lower classification accuracies observed in primarily the left frontoparietal network. The neural profiles of the ADHD and PDD differed specifically in the SN where the ADHD group's neural profile suggests significantly less specificity in neural representations of spatial and verbal working memory. We highlight within-group classification as an innovative tool for understanding the neural mechanisms of how cognitive processes may deviate in clinical disorders, an important intermediary step towards improving translational psychiatry.

Associations of Irritability With Functional Connectivity of Amygdala and Nucleus Accumbens in Adolescents and Young Adults With ADHD

OBJECTIVE

Irritability is a common characteristic in ADHD. We examined whether dysfunction in neural connections supporting threat and reward processing was related to irritability in adolescents and young adults with ADHD.

METHOD

We used resting-state fMRI to assess connectivity of amygdala and nucleus accumbens seeds in those with ADHD (n = 34) and an age- and gender-matched typically-developing comparison group (n = 34).

RESULTS

In those with ADHD, irritability was associated with atypical functional connectivity of both seed regions. Amygdala seeds showed greater connectivity with right inferior frontal gyrus and caudate/putamen, and less connectivity with precuneus. Nucleus accumbens seeds showed altered connectivity with middle temporal gyrus and precuneus.

CONCLUSION

The irritability-ADHD presentation is associated with atypical functional connectivity of reward and threat processing regions with cognitive control and emotion processing regions. These patterns provide novel evidence for irritability-associated neural underpinnings in adolescents and young adults with ADHD. The findings suggest cognitive and behavioral treatments that address response to reward, including omission of an expected reward and irritability, may be beneficial for ADHD.

Brain structure and parasympathetic function during rest and stress in young adult women

Heart rate variability (HRV) is an important biomarker for parasympathetic function and future health outcomes. The present study examined how the structure of regions in a neural network thought to maintain top-down control of parasympathetic function is associated with HRV during both rest and social stress. Participants were 127 young women (90 Black American), who completed a structural MRI scan and the Trier Social Stress Test (TSST), during which heart rate was recorded. Regression analyses were used to evaluate associations between cortical thickness in five regions of the Central Autonomic Network (CAN; anterior midcingulate cortex [aMCC], pregenual and subgenual anterior cingulate cortex [pgACC, sgACC], orbitofrontal cortex [OFC], and anterior insula) and high-frequency HRV during rest and stress. Results indicated that cortical thickness in CAN regions did not predict average HRV during rest or stress. Greater cortical thickness in the right pgACC was associated with greater peak HRV reactivity during the TSST, and survived correction for multiple comparisons, but not sensitivity analyses with outliers removed. The positive association between cortical thickness in the pgACC and peak HRV reactivity is consistent with the direction of previous findings from studies that examined tonic HRV in adolescents, but inconsistent with findings in adults, which suggests a possible neurodevelopmental shift in the relation between brain structure and autonomic function with age. Future research on age-related changes in brain structure and autonomic function would allow a more thorough understanding of how brain structure may contribute to parasympathetic function across neurodevelopment.

Hypothalamic–Pituitary–Adrenal Axis Activity in Childhood Predicts Emotional Memory Effects and Related Neural Circuitry in Adolescent Girls

Negative emotional experiences can be more difficult to forget than neutral ones, a phenomenon termed the “emotional memory effect.” Individual differences in the strength of the emotional memory effect are associated with emotional health. Thus, understanding the neurobiological underpinnings of the emotional memory effect has important implications, especially for individuals at risk for emotional health problems. Although the neural basis of emotional memory effects has been relatively well defined, less is known about how hormonal factors that can modulate emotional memory, such as glucocorticoids, relate to that neural basis. Importantly, probing the role of glucocorticoids in the stress- and emotion-sensitive period of late childhood to adolescence could provide actionable points of intervention. We addressed this gap by testing whether hypothalamic–pituitary–adrenal (HPA) axis activity during a parent–child conflict task at 11 years of age predicted emotional memory and its primary neural circuitry (i.e., amygdala–hippocampus functional connectivity) at 16 years of age in a longitudinal study of 147 girls (104 with complete data). Results showed that lower HPA axis activity predicted stronger emotional memory effects, r(124) = −.236, p < .01, and higher emotional memory-related functional connectivity between the right hippocampus and the right amygdala, β = −.385, p < .001. These findings suggest that late childhood HPA axis activity may modulate the neural circuitry of emotional memory effects in adolescence, which may confer a potential risk trajectory for emotional health among girls.

Direct replication of task-dependent neural activation patterns during sadness introspection in two independent adolescent samples

Functional neuroimaging results need to replicate to inform sound models of human social cognition and its neural correlates. Introspection, the capacity to reflect on one's thoughts and feelings, is one process required for normative social cognition and emotional functioning. Engaging in introspection draws on a network of brain regions including medial prefrontal cortex (mPFC), posterior cingulate cortex (PCC), middle temporal gyri (MTG), and temporoparietal junction (TPJ). Maturation of these regions during adolescence mirrors the behavioral advances seen in adolescent social cognition, but the neural correlates of introspection in adolescence need to replicate to confirm their generalizability and role as a possible mechanism. The current study investigated whether reflecting upon one's own feelings of sadness would activate and replicate similar brain regions in two independent samples of adolescents. Participants included 156 adolescents (50% female) from the California Families Project and 119 adolescent girls from the Pittsburgh Girls Study of Emotion. All participants completed the Emotion Regulation Questionnaire (ERQ) and underwent a functional magnetic resonance imaging scan while completing the same facial emotion‐processing task at age 16–17 years. Both samples showed similar whole‐brain activation patterns when engaged in sadness introspection and when judging a nonemotional facial feature. Whole‐brain activation was unrelated to ERQ scores in both samples. Neural responsivity to task manipulations replicated in regions recruited for socio‐emotional (mPFC, PCC, MTG, TPJ) and attention (dorsolateral PFC, precentral gyri, superior occipital gyrus, superior parietal lobule) processing. These findings demonstrate robust replication of neural engagement during sadness introspection in two independent adolescent samples.

Dorsomedial Prefrontal Activity to Sadness Predicts Later Emotion Suppression and Depression Severity in Adolescent Girls

The present study used cross-lagged panel analyses to test longitudinal associations among emotion regulation, prefrontal cortex (PFC) function, and depression severity in adolescent girls. The ventromedial and dorsomedial PFC (vmPFC and dmPFC) were regions of interest given their roles in depression pathophysiology, self-referential processing, and emotion regulation. At ages 16 and 17, seventy-eight girls completed a neuroimaging scan to assess changes in vmPFC and dmPFC activation to sad faces, and measures of depressive symptom severity and emotion regulation. The 1-year cross-lagged effects of dmPFC activity at age 16 on expressive suppression at age 17 and depressive symptomatology at age 17 were significant, demonstrating a predictive relation between dmPFC activity and both suppression and depressive severity.

Global and local grey matter reductions in boys with ADHD combined type and ADHD inattentive type

Attention-deficit/hyperactivity disorder (ADHD) has reliably been associated with global grey matter reductions but local alterations are largely inconsistent with perhaps the exception of the caudate nucleus. The aim of this study was to examine local and global brain volume differences between typically developing children (TD) and children with a diagnosis of ADHD. We also addressed whether these parameters would differ between children with the ADHD-combined type (ADHD-C) and those with the ADHD-inattentive type (ADHD-I). Using an ROI approach caudate volume differences were also examined. 79 boys between the ages of 8 and 17 participated in the study. Of those 33 met diagnostic criteria for the ADHD-C and 15 for the ADHD-I subtype. 31 boys were included in the TD group. Structural magnetic resonance imaging data were analysed using voxel-based morphometry. The ADHD group had significantly lower global and local grey matter volumes within clusters in the bilateral frontal, right parietal and right temporal regions compared to TD. A significant group by age interaction was found for right caudate nucleus volume. No differences between the ADHD-C and ADHD-I groups were found. Right caudate nucleus volume and age are more strongly related in ADHD than in TD consistent with previous research.

Executive function and attention in children and adolescents with depressive disorders: a systematic review

Numerous studies have shown that Major Depressive Disorder (MDD) in adults is associated with deficits in cognitive control. Particularly, impairment on executive function (EF) tasks has been observed. Research into EF deficits in children and adolescents with MDD has reported mixed results and it is currently unclear whether paediatric MDD is characterised by impairments in EF and attention. PsycInfo, Scopus and Medline were systematically searched to identify all studies that have investigated EF and attention in paediatric depressive disorders between 1994 and 2014. 33 studies meeting inclusion/exclusion criteria were identified. While across different domains of EF some studies identified a deficit in the clinical group, the majority of studies failed to find deficits in response inhibition, attentional set shifting, selective attention, verbal working memory, and verbal fluency. More research is needed to clarify the relationship between depressive disorders in children and adolescents and spatial working memory processing, sustaining attention, planning, negative attentional bias and measures of 'hot' EF. There is little support for EF deficits in paediatric depression. However, there are numerous methodological problems that may account for null findings. Alternatively, chronicity and/or severity of symptoms may explain discrepancies between cognitive deficits in adult and paediatric MDD. Recommendations for future studies are discussed.

Frontoparietal function in young people with dysthymic disorder (DSM-5: Persistent depressive disorder) during spatial working memory

BACKGROUND

Dysthymic disorder (DD) is a depressive disorder characterised by persistent low and/or irritable mood and has been identified as a major risk factor for developing major depressive disorder (MDD). MDD and DD have been associated with executive function difficulties of working memory and attention. Little is known about how executive function networks in the brain are affected in children and adolescents with MDD and even less in DD. This study used fMRI and two spatial working memory paradigms to investigate associated brain function in young people with DD and an age-, gender- and IQ- matched typically developing group.

METHODS

Nineteen male patients with DD (mean age 11.2±1.5 years) diagnosed according to DSM-IV criteria and 16 typically developing boys (mean age 10.5±1.1 years) performed a mental rotation and a delay-match to sample (DMTS) task while undergoing fMRI. All participants were medication-naïve at the time of testing.

RESULTS

Compared to typically developing young people, the DD group showed less activation in left frontal regions including left ventro- and dorsolateral prefrontal cortices (PFC) during mental rotation. Medial frontal regions including dorsomedial PFC, anterior cingulate cortex and frontal pole also showed relatively reduced activation. During the DMTS task patients showed significantly more activation in the right precuneus and posterior cingulate cortex.

LIMITATIONS

This was a cross-sectional study with a small sample limiting the generalizability of the results.

CONCLUSIONS

The results complement previous findings in adults with MDD that have shown differential activation of left PFC regions during working memory tasks. Additionally, altered function of cortical midline structures in young patients with DD was identified. This supports findings in children, adolescents and adults with MDD suggesting that the pathophysiology of depressive disorders extends to DD as a risk factor for MDD and exhibits continuity over the lifespan.