Tactile Adaptation in Tourette Syndrome: Probing GABA-Mediated Neuroplasticity

Tourette Syndrome (TS) is a common developmental disorder characterized by repetitive, involuntary movements and vocalizations called tics. Long seen as involving only the motor system, research has begun to highlight the involvement of sensory system dysfunction in TS as well. This notion is supported by both research and anecdotal evidence; people with TS often report a sensory urge (e.g., itchy throat) that contributes to the need to complete the tic (e.g., throat clearing), which provides temporary relief. It is thought that the persistent nature of these sensory urges may represent the brain’s difficulty with adapting to tactile (touch) sensory experiences. This means that the brain may have difficulty ignoring stimuli in the environment that most people acclimate to or don’t even notice. This ability to adapt has been found to be associated with inhibitory (GABA) neurotransmission in the brain. Preliminary data from our laboratory suggest that children with TS have abnormalities in tactile adaptation that is consistent with inhibitory (GABAergic) dysfunction.

TS has a significant impact on quality of life, yet the treatments remain moderately effective, at best, for many with this syndrome.  A more thorough understanding of the pathophysiology of TS, from premonitory urge to the tic itself, would lead to more targeted and effective treatments. Addressing this, we are examining tactile sensitivity and adaption, brain GABA concentration, and GABA inhibitory function in the sensorimotor systems in children with and without TS. The comparison between these groups will contribute to improved understanding of sensorimotor dysregulation, and resulting tics as well as other symptoms (e.g., ADHD and obsessive-compulsive behavior), seen in TS.

Frustration Tolerance in Children with ADHD

Emotion dysregulation is a key impairment for children with Attention-Deficit/Hyperactivity Disorder (ADHD), one of the most common psychiatric disorders of childhood. In fact, the prevalence of emotion dysregulation in individuals with ADHD is between 24%-50% in children and 34%-70% in adults suggesting it is problem for many individuals with ADHD. Emotion regulation refers to, “an individual’s ability to modify an emotional state so as to promote adaptive, goal-oriented behaviors”, and is essential to interpersonal, academic, and adaptive functioning. Longitudinally, emotion dysregulation in children with ADHD is associated with increased psychiatric comorbidity, particularly with mood and anxiety disorders, greater social impairments, poorer quality of life and greater academic and occupational difficulties. Therefore, it is of great clinical significance to better understand the behavioral and biological mechanisms underlying emotion dysregulation in children with ADHD.

One of the most common forms of emotion dysregulation in children with ADHD is irritability which is defined as a “mood state characterized by a low threshold for frustration” in which frustration refers to “an affective response to blocked goal attainment”.  Research shows that compared to their peers, children with ADHD exhibit greater levels (i.e., intensity) of frustration, are more likely to quit a frustrating task, exhibit greater focus on the negative aspects of the task and display less constructive patterns of emotional coping when frustrated.

Therefore, the goal of this research project is to identify the clinical features and brain regions involved in low frustration tolerance in children ages 8-12 years-old with ADHD. We will use behavioral frustration tasks and structural and functional neuroimaging methods to examine the behavioral and neural correlates of poor frustration tolerance in children with ADHD.  Findings from this research will inform what is known about emotion dysregulation, especially poor frustration tolerance, in children with ADHD. Additionally, our results have the potential to inform early identification, prevention, and targeted intervention efforts for those children with ADHD at greatest risk of poor outcomes.

Movement-Based Tai Chi Training for Children with ADHD

Attention-Deficit/Hyperactivity Disorder (ADHD) is the most common behavioral diagnosis in childhood.  It can contribute to difficulties in school and can lead to mental illness. Standard treatments with stimulant medications primarily target the symptoms themselves and do not address the core features. There are tremendous potential benefits of movement-based mindfulness training, such as Tai Chi, for remediating the core features of ADHD. Addressing this, we are investigating the impact of an 8-week Tai Chi training program for children with ADHD.  More >

Motor Skill Learning in Autism

Autism is a disorder that presents in early childhood and is characterized by deviance and delays in development of reciprocal social interaction, communication, and the child’s range of interests and activities. Investigations of brain-behavior mechanisms contributing to autism have thus far principally relied on approaches adapted from adult lesion-based models in which existing cognitive and behavioral domains (e.g., attention, perception, executive function) are examined.  Despite the clear developmental nature of autism, relatively few studies have focused on detailed examination of neural mechanisms central to learning. Such an approach would be critical to understanding the developmental basis of autism and might also lead to improvements in therapeutic intervention. More >

Neurology of Deficient Response Control in ADHD

ADHD is the most common neuropsychiatric disorder in childhood, affecting an estimated 3-8% of children. The core behavioral symptoms of this disorder (inattention, impulsivity and hyperactivity) cause impairment in family and social relationships and in school performance.  The impact of ADHD is amplified further through its comorbidity with a number of psychiatric and neurodevelopmental disorders, including learning disabilities and Tourette syndrome.  Although the causes of ADHD are unknown, recent research clearly identifies ADHD as a neurobiological disorder. More >

Anomalous Motor Physiology in ADHD

Attention Deficit Hyperactivity Disorder (ADHD) is the most common behavioral diagnosis in childhood. It incurs high medical costs and can contribute to poor academic achievement, adult mental illness, substance abuse, and criminal behavior. Standard treatments, such as stimulant medications, primarily target symptoms and long-term follow-up studies of children treated for ADHD reveal that their outcomes remain significantly worse as compared to typically developing peers. A critical obstacle to improving long term ADHD treatment outcomes is the lack of quantitative markers which correlate with symptoms and reveal neurobiological mechanisms in ways that could point toward more accurate prognosis and more effective future treatments.
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Delay Discounting in ADHD

ADHD is the most commonly diagnosed mental health disorder in childhood and is associated with functional impairments across multiple academic and social domains throughout the life span. It has become increasingly clear that there are multiple causes of ADHD and functional outcomes for individuals with ADHD are dependent on a number of factors. Intensive, evidence-based treatments for ADHD (i.e., behavior modification and stimulant medication) are generally effective in reducing symptoms of ADHD, although many individuals with ADHD continue to show both symptoms and functional impairment, despite receiving treatment. Understanding the factors related to which individuals will respond to treatment and how treatments work are crucial to improving the outcomes for individuals with ADHD. More >

Traumatic Brain Injury Studies:

Neural Correlates of Response Control in Children with Traumatic Brain Injury (TBI)

Children with traumatic brain injury often have difficulty with regulating their responses to the environment.  For example, many children will have slowed response times as well as difficulty inhibiting unwanted responses or behaviors.  We have two studies evaluating response control in children with mild complicated to severe TBI in association with parent report on the child’s “real-world” function and imaging studies. More >

Somatosensory Information Processing in Children with Concussion

Currently the “gold standard” for evaluating recovery from concussion is to ensure that a child is symptom-free and performing at his/her typical level of pre-injury function prior to return to activities which put the child at risk for another injury to the head.  Research suggests, however, that the brain may be functioning differently to support return to typical function after a concussion. More >

Body Fluid Markers of Pediatric Traumatic Brain Injury (TBI)

The ability to identify early after a TBI what kind of assistance a child will need in the months after injury would be very helpful for planning for the child’s care and identifying which children may most benefit from early treatments to optimize outcome after injury.  Research suggests that measuring the amounts of certain proteins in the blood, urine, and/or cerebrospinal fluid after a TBI may be useful for this purpose. More >