The Neurobiology of ADHD

Attention Deficit Hyperactivity Disorder (ADHD) is the most common neurodevelopmental disorder of childhood.  One of the core underlying impairments in ADHD is in executive control, which manifests behaviorally as symptoms of inattention, hyperactivity and impulsivity.  These symptoms can be improved with medication and behavioral interventions in some cases, but not all.  Given the heterogeneity in symptom presentation and treatment response, we need to investigate factors that relate to these individual differences.  Our lab studies how genes related to ADHD and brain function interact with the environment and aims to elucidate the neurobiological factors contributing to this heterogeneity.

Our lab is perfectly situated to investigate important questions in the field of ADHD given our affiliation with the Center for Children and Families (CCF), which runs an internationally recognized intensive behavioral intervention program for children with behavioral problems, particularly those with ADHD.   In collaboration with others in the Psychology Department at Florida International University, we are able to study hundreds of children and adolescents with ADHD, putting us in a unique position to conduct cutting edge research in the field.

Broadly speaking, our overall goal is to understand the cognitive neurobiology of ADHD to create more objective measures which can aid clinicians in the diagnosis and treatment of the disorder, and get children on a better developmental trajectory as early as possible.

Mel3Emotion-Cognition Interaction

How do we regulate our emotions? Emotional material can increase our attention. This has evolutionary advantage (we want to notice predators or hostile facial expressions); however, in other circumstances, emotions can get in the way of our goals. Regions of the prefrontal cortex, such as the ventromedial aspect of the PFC, can help us suppress distracting emotional information. We study individual differences in this ability.

For an example, our lab has conducted research which demonstrates how cognitive control neural circuitry responds to positive and negative emotional context in an opposite way depending on one’s serotonin transporter genotype: PDF.

The Reasoning Brain

Our lab also investigates the neuroscience of deduction.  We test theories of logical reasoning using methods from cognitive neuroscience, such as fMRI, genetics, and pharmacological techniques.  Our focus is on the role of cognitive control in the suppression of reasoning biases.  How can our genes interact with a situation to enable us to make rational decisions?  Are certain individuals at risk for allowing their personal  beliefs to bias their judgement, whether it be in everyday situations or in formal settings such as legal decision-making in a court of law?  Read more: PDF


The Gut Microbiome

As the field of scientific research continues to shift focus from investigating individual body system pathologies to an integrated view of the whole being, there has been an increased interest in the role bacteria play in mental health. Humans are host to a plethora of bacteria, fungi, and other microorganisms which comprise the microbiome and are said to outnumber human cells within the body tenfold. Often called the “neglected” organ, the gut microbiome, found in a person’s digestive tract, communicates bidirectionally with the central nervous system through the production and release of metabolites such as neurotransmitters and hormones. Prior studies in this field have shown correlations between gut microbiome composition and conditions such as Depression and Autism. We are now working to elucidate how differences within the gut microbiome may contribute to neuropsychiatric disorder in adults, namely ADHD.