Biology subjects

MacMaster, F. P.

Publications and source records attributed to MacMaster, F. P..

2 recordsLinked to original sources

bioRxiv2024

Right Caudate Volume and Executive Functions in Children with Attention-Deficit/Hyperactivity Disorder (ADHD)

BackgroundThe caudate and putamen have previously been implicated in Attention-Deficit/Hyperactivity Disorder (ADHD). However, previous studies have not investigated the relationship between the caudate and putamen with executive function (EF). The current study investigated the clinical relevance of the caudate and putamen with respect to EF. MethodWe studied 49 children (24 ADHD/25 typically developing children (TDC)). All participants in the ADHD group had to undergo a 48-hour stimulant medication washout period. Participants completed cognitive tasks related to working memory/inhibition and underwent a T1-weighted MRI sequence. All parents completed behaviour rating scales using the Behavior Rating Inventory of Executive Function, Second Edition (BRIEF-2). Data were analyzed using multivariate analysis of covariance, Pearson correlations, and linear regressions. ResultsChildren with ADHD demonstrated a higher frequency of perseverative errors compared to TDC (p <.05), and their parents reported significantly more EF challenges (p <.001). No difference was observed in the working memory tasks. No significant volumetric differences were seen in the caudate or the putamen. A linear regression model suggested that the right caudate volume accounted for 10.3% of the variance in emotion regulation as reported by parents on the BRIEF-2 in the overall sample. DiscussionWe observed significant EF challenges without volumetric differences. However, the right caudate was correlated to parent ratings of emotional regulation, highlighting the need to consider emotional regulation difficulties in ADHD.

neuroscience↗

bioRxiv2019

Effects of Transcranial Direct Current Stimulation on GABA and Glutamate in Children: A Pilot Study

Transcranial direct current stimulation (tDCS) is a form of non-invasive brain stimulation that safely modulates brain excitability and has therapeutic potential for many conditions. Several studies have shown that anodal tDCS of the primary motor cortex (M1) facilitates motor learning and plasticity, but there is little information about the underlying mechanisms. Using magnetic resonance spectroscopy (MRS) it has been shown that tDCS can affect local levels of {gamma}-aminobutyric acid (GABA) and Glx (a measure of glutamate and glutamine combined) in adults, both of which are known to be associated with skill acquisition and plasticity; however this has yet to be studied in children and adolescents. This study examined GABA and Glx in response to conventional anodal tDCS (a-tDCS) and high definition tDCS (HD-tDCS) targeting the M1 in a pediatric population. Twenty-four typically developing, right handed children ages 12-18 years participated in five consecutive days of tDCS intervention (sham, a-tDCS or HD-tDCS) targeting the right M1 while training in a fine motor task (Purdue Pegboard Task) with their left hand. Glutamate and GABA were measured before and after the protocol (at day 5 and 6 weeks) using conventional MRS and GABA-edited MRS in the sensorimotor cortices. Glutamate measured in the left sensorimotor cortex was higher in the HD-tDCS group compared to a-tDCS and sham at 6 weeks (p = 0.001). No changes in GABA were observed in either sensorimotor cortex at any time. These results suggest that neither a-tDCS or HD-tDCS locally affect GABA and glutamate in the developing brain and therefore it may demonstrate different responses in adults.

neuroscience↗