Akua Nimarko is a PhD candidate in Neurosciences at Stanford. Her research focuses on understanding how brain differences influence whether high-risk youth will develop mood disorders and identifying brain factors that contribute to resilience to adolescent mood disorders.
Honors & Awards
DARE (Diversifying Academia, Recruiting Excellence) Doctoral Fellowship Program, Office of the Vice Provost for Graduate Education
Graduate Research Fellowship Program, National Science Foundation
Ford Foundational Fellowship Progrsm, National Academics of Sciences
Education & Certifications
B.S., University of Maryland, Baltimore County, Biological Sciences (2015)
B.S., University of Maryland, Baltimore County, Psychology (2015)
Changes in Intrinsic Brain Connectivity in Family-Focused Therapy Versus Standard Psychoeducation Among Youth at High Risk for Bipolar Disorder.
Journal of the American Academy of Child and Adolescent Psychiatry
OBJECTIVE: We compared intrinsic network connectivity in symptomatic youth at high risk (HR) for bipolar disorder (BD) and healthy comparison (HC) youth, and, in HR youth, investigated treatment-related changes in intrinsic connectivity following family focused therapy for high-risk youth (FFT-HR) versus standardized family psychoeducation.METHOD: HR youth (N=34; age 9-17 years; mean 14 years, 56% girls) with depressive and/or hypomanic symptoms and at least one first- or second-degree relative with BD I or II were randomly assigned to 4 months of FFT-HR (12 sessions of psychoeducation, communication, and problem-solving skills training) or Enhanced Care (EC; 3 family and 3 individual psychoeducation sessions). Before and after 4-months of treatment, participants underwent resting state functional magnetic resonance imaging (rs-fMRI). A whole brain independent component analysis compared rs-fMRI networks in HR youth and 30 age-matched HC youth at a pretreatment baseline. Then, we identified pretreatment to post-treatment (4-month) changes in network connectivity in HR youth receiving FFT-HR (n=16) or EC (n=18) and correlated these changes with depression improvement.RESULTS: At baseline, HR youth had greater connectivity between the ventrolateral prefrontal cortex (VLPFC) and the anterior default mode network (aDMN) than did HCs (p=.004). Over 4 months of treatment, FFT-HR-assigned HR youth had increased VLPFC-aDMN connectivity from pre- to post-treatment (p=.003), whereas HR youth in EC showed no significant change over time (p=.11) (treatment by time interaction, [t(31)=3.33, CI 95% [0.27, 1.14], p=.002]. Reduction in depression severity over 4 months inversely correlated with enhanced anterior DMN (r= -.71) connectivity in the FFT-HR but not in the EC (r=-.07) group (z=-2.17, p=.015).CONCLUSION: Compared to standard psychoeducation, FFT-HR is associated with stronger connectivity between the VLPFC and aDMN, suggesting possible enhancements of self- and illness awareness and emotion regulation.
View details for DOI 10.1016/j.jaac.2020.07.892
View details for PubMedID 32745598
Neural Correlates of Positive Emotion Processing That Distinguish Healthy Youth at Familial Risk for Bipolar Versus Major Depressive Disorder.
Journal of the American Academy of Child and Adolescent Psychiatry
OBJECTIVE: Familial risk for bipolar (BD) or major depressive (MDD) disorder may lead to differential emotion processing signatures, resulting in unique neural vulnerability.METHOD: Healthy offspring of a parent with BD (n=29, "BD-risk") or MDD (n=44, "MDD-risk") and youth without any personal or family psychopathology (n=28, "HC") ages 8-17 (13.64 ± 2.59) completed an implicit emotion perception functional magnetic resonance imaging task. Whole-brain voxel-wise and psychophysiological interaction analyses examined neural differences in activation and connectivity during emotion processing. Regression modeling tested for neural associations with behavioral strengths and difficulties and conversion to psychopathology at follow-up (3.71 ± 1.91 years).RESULTS: BD-risk youth showed significantly reduced bilateral putamen activation, and decreased connectivity between the left putamen and the left ventral anterior cingulate cortex (vACC) and the right posterior cingulate cortex (PCC) during positive-valence emotion processing compared to MDD-risk and HC (Z >2.3; p <.001). Decreased left putamen- right PCC connectivity correlated with subsequent peer problems in BD-risk (beta = -2.90; p <.05) and MDD-risk (beta = -3.64; p <.05). Decreased left (beta = -.09; p < .05) and right putamen activation (beta = -.07; p = .04) were associated with conversion to a mood or anxiety disorder in BD-risk. Decreased left putamen-right PCC connectivity was associated with a higher risk of conversion in BD-risk (HR = 8.28 , p < .01) and MDD-risk (HR = 2.31, p = .02).CONCLUSION: Reduced putamen activation and connectivity during positive emotion processing appear to distinguish BD-risk youth from MDD-risk and HC youth, and may represent a marker of vulnerability.
View details for DOI 10.1016/j.jaac.2020.07.890
View details for PubMedID 32738282
- Neural correlates of emotion processing predict resilience in youth at familial risk for mood disorders DEVELOPMENT AND PSYCHOPATHOLOGY 2019; 31 (3): 1037–52
Insulin Resistance and Structural Change in the Anterior Cingulate Cortex in Youth With Depression and Obesity
NATURE PUBLISHING GROUP. 2019: 143–44
View details for Web of Science ID 000509665600281
Functional Connectivity Biomarkers of Emotion Regulation That Distinguish Risk for Bipolar Versus Unipolar Depression in Clinically Asymptomatic High-Risk Youth
NATURE PUBLISHING GROUP. 2019: 434–35
View details for Web of Science ID 000509665600788
- REWARD PROCESSING IN DEPRESSED AND OBESE CHILDREN ELSEVIER SCIENCE INC. 2019: S274
- MECHANISMS AND RISK FACTORS UNDERLYING ADVERSE EVENTS FROM TREATING YOUTH WITH OR AT RISK FOR BIPOLAR DISORDER ELSEVIER SCIENCE INC. 2019: S335–S336
- DISSOCIABLE NEURAL NETWORK MARKERS OF RISK AND RESILIENCE IN PEDIATRIC BIPOLAR DISORDER ELSEVIER SCIENCE INC. 2019: S362
- The Relation Between Tanner Stage and Age is Moderated by Trauma in Youth With Depression and Obesity ELSEVIER SCIENCE INC. 2019: S315–S316
- The Relation Between Hippocampal Volume and Allostatic Load is Moderated by Tanner Stage, Sex, and Adversity in Youth With Depression and Obesity ELSEVIER SCIENCE INC. 2019: S318
- Neural Correlates of Emotion Processing in Youth at Familial Risk for Mood Disorders ELSEVIER SCIENCE INC. 2019: S262–S263
- Emotion Network Predictors of Clinical Outcome in Youth at High Risk for Bipolar Disorder ELSEVIER SCIENCE INC. 2019: S2
- Nucleus Accumbens Volume Predicts Allostatic Load and is Moderated by Sex and Treatment Modality in Youth With Depression and Obesity ELSEVIER SCIENCE INC. 2019: S262
Neural correlates of emotion processing predict resilience in youth at familial risk for mood disorders.
Development and psychopathology
Aberrant face emotion processing has been demonstrated in youth with and at a familial risk for bipolar and major depressive disorders. However, the neurobiological factors related to emotion processing that underlie resilience from youth-onset mood disorders are not well understood. Functional magnetic resonance imaging data during an implicit emotion processing task were collected at baseline from a sample of 50 youth, ages 8-17, who were healthy but also familially at high risk for either bipolar disorder or major depressive disorder, and 24 healthy controls with no family history of psychopathology (HCL). Participants were reevaluated 3 years later and classified into three groups for analysis: high-risk youth who converted to a psychiatric diagnosis (CVT; N = 23), high-risk youth who were resilient from developing any psychopathology (RES; N = 27), and HCL youth (N = 24) who remained healthy at follow-up. For happy > calm faces, the CVT and RES groups had significantly lower activation in the left inferior parietal lobe (IPL), while the RES group had lower activation in the right supramarginal gyrus. For fear > calm faces, the RES group had lower activation in the right precuneus and inferior frontal gyrus (IFG) compared to the CVT group. Connectivity analyses revealed the RES group exhibited higher left IPL connectivity with visual cortical regions for happy > calm faces, and higher IFG connectivity with frontal, temporal, and limbic regions for fear > calm faces. These connectivities were correlated with improvements in prosocial behaviors and global functioning. Our findings suggest that differential activation and connectivity in the IPL, IFG, and precuneus in response to emotional stimuli may represent distinct resilience and risk markers for youth-onset mood disorders.
View details for PubMedID 31064610
Fractional Anisotropy in the Frontal Segment of the Uncinate Fasciculus in Adolescents at Risk for Depression
NATURE PUBLISHING GROUP. 2017: S496–S497
View details for Web of Science ID 000416846303033
Dissecting the Role of P/Q-Type Calcium Channels in Corticothalamic Circuit Dysfunction and Absence Epilepsy.
The Journal of neuroscience : the official journal of the Society for Neuroscience
2016; 36 (21): 5677–79
View details for PubMedID 27225758