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Brain Disorders and Therapeutics
Mental Heal th and Psychology
5th International Conference on
Joint Event
&
Journal of Brain and Neurology| Volume: 2
November 05-06, 2018 | Edinburgh, Scotland
A model for Attention-Deficit/Hyperactivity Disorder: Linking brain asymmetry patterns and temporal
integration deficits
PK Douglas, Z Koch, C N Dutta, A Anderson and L Christov-Moore
University of Central Florida, USA
ADHD is a highly heritable (60-75%), 1 child-onset
neurodevelopmental disorder that effects ~ 5% of school
aged children. It is characterized by problems with sustained
attention and task prioritization, which often diminish an
individual’s productivity and social relationships. Both structural
and functional neuroimaging studies have demonstrated
that individuals with ADHD have alterations in fronto-striatal
circuitry2, and a recent mega-analyses by the ENIGMA working
group demonstrated consistent diminutions in subcortical
volumes (e.g., amygdala) across the lifespan. Nonetheless,
results from quantitative structural and functional MRI
studies have varied with respect to the laterality of findings3.
Recently, our group has shown that alterations in inter-
hemispheric asymmetries across volumetric andmorphometric
measurements may be a more sensitive measure for detecting
baseline differences in the ADHD brain4 as well as response
to therapeutic intervention via pharmaceuticals that alter
dopamine signaling. In particular, these patterns of asymmetry
differences were most prominent in white matter tracts, as
evidenced by metrics derived from diffusion imaging. Here,
we suggest that these asymmetries may either result from or
be a compensatory mechanism related to temporal integration
deficits in the ADHD brain. For example, changes in fiber
myelination, and axonal diameter that are reflected in DTI
measurements, are correlated with conduction velocities in the
brain. Increased asymmetriesmay therefore lead to unbalanced
conduction speeds, and improper integration of sensorial
information at higher levels of processing. This temporal
integration model may also help explain some of the hallmark
behavioral traits of ADHD including increased reaction time (RT)
variability. Additionally, studies documenting the genetic basis
for ADHD suggest either hyper-active reuptake of dopamine or
diminished postsynaptic receptor sensitivity due to alterations
in the dopamine transporter allele5. Our model is therefore
also consistent with recent findings indicating the importance
of precise dopamine regulation in the perception of time.6
Speaker Biography
PK Douglas completed a PhD in neuroengineering at UCLA, postdoctoral work at the
University College London, and is currently an assistant professor in the Modeling and
Simulation Department at UCF, and in the department of Psychiatry and Biobehavioral
Medicine at UCLA. Dr. Douglas has a long history of publishing work in utilizing decoding
approaches to study functional representations in fMRI and EEG. Recent work in Dr.
Douglas’s lab includes applying both supervised and unsupervised learning approaches
to study structural-functional integration in youths with Attention-Deficit/Hyperactivity
disorder, with a focus on modeling excessive novelty seeking behavior observed in
certain phenotypic presentations within this childhood neurodevelopmental disorder.
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