Understanding Neurodivergence: TMS Therapy for ADHD, OCD, and More

Wired Differently: Exploring Biological, Structural and Functional Differences in Neurodivergent vs Neurotypical Minds — and the Application of TMS 

If you’ve ever come across the term ‘neurodivergent’ and found yourself wondering what sets it apart, you’re not alone. For many, neurodivergence is a relatively new concept that has gained significant attention in recent years. But what does it truly mean, and how are neurodivergent brains different? 

In this blog, we’ll explore the biological, structural and functional distinctions between neurodivergent (ND) and neurotypical (NT) brains and ultimately uncover why individuals with conditions like dyslexia, attention deficit hyperactivity disorder (ADHD), or autism (ASD) process and experience the world in unique and remarkable ways. We’ll then discuss how transcranial magnetic stimulation (TMS) — a non-invasive, medication-free treatment — can be applied to improve symptoms of these conditions, such as through TMS for ADHD, TMS therapy for anxiety, and TMS for OCD. 

Definitions 

NT brains are classified as those who function and process in a way that is typical to society’s norms or standards, making up around 80% of the population. Comparatively, ND brains are defined by a difference in processing information and operating in a way that deviates from the norm and what is deemed typical — the remaining 20%. This includes, but is not limited to, dyscalculia, Tourette's, ASD, ADHD, dyslexia, dyspraxia and obsessive-compulsive disorder (OCD). 

TMS therapy is a non-invasive neuromodulation technique that aims to alter neuronal activity in the brain by delivering magnetic pulses to the cortex. This generates electrical currents in the brain and promotes neuroplasticity, helping to rebalance dysregulated brain networks in conditions such as OCD, ADHD, and anxiety disorders (Dayan et al., 2013; Fox et al., 2012; George et al., 2010; Rossini et al., 2015; Ziemann et al., 2008). 

Biological Differences 

ND brains exhibit distinct biological differences from NT brains. In ADHD, for instance, differences in dopamine transmission and receptor availability have been consistently observed, influencing attention, motivation and movement (Arnsten, 2009; Volkow et al., 2009). This dopaminergic dysregulation is one of the primary targets for TMS treatment for ADHD, which aims to modulate underactive prefrontal regions. 

Similarly, individuals with ASD often show differences in serotonin levels and receptor binding, which are linked to sensory processing and emotional regulation (Chugani, 2004; Nakamura et al., 2010). Genetic studies have further highlighted alterations in synaptic genes and neurodevelopmental pathways in both ASD and dyslexia (Paracchini et al., 2007; State & Šestan, 2012), offering insight into how structural and functional brain differences arise. 

These biological findings provide a foundation for the targeted application of TMS therapy for neurodevelopmental conditions, especially those involving neurotransmitter imbalances and dysregulated brain activity. 

Structural Differences 

Structural brain differences in ND individuals have been consistently demonstrated using MRI and other imaging modalities. For instance, ASD is associated with early brain overgrowth, particularly in the frontal and temporal lobes during infancy and early childhood (Courchesne et al., 2003). ADHD has been linked to reduced cortical thickness and volume, especially in the prefrontal cortex, which is critical for attention, impulse control and executive functioning (Shaw et al., 2007). 

In dyslexia, differences in the left temporoparietal cortex and occipitotemporal regions have been implicated in difficulties with phonological processing and word recognition (Richlan et al., 2013). These regions are often targeted in cognitive-enhancing TMS protocols. 

Moreover, individuals with dyspraxia may show abnormalities in the cerebellum and parietal lobes, affecting motor coordination and planning (Zwicker et al., 2009). Tourette’s syndrome is associated with changes in the basal ganglia and related motor circuits, which helps explain the occurrence of tics (Peterson et al., 2003). 

Functional Differences 

Functional brain differences are also evident between ND and NT individuals. Functional MRI (fMRI) studies have revealed altered connectivity patterns in networks responsible for attention, executive function and social cognition. For example, in ADHD, there is often reduced activity in the default mode network (DMN) and altered connectivity between the DMN and task-positive networks (Castellanos et al., 2008). These are now key areas of interest in TMS for ADHD interventions. 

In ASD, disruptions in the mirror neuron system and atypical activation of the fusiform face area contribute to social and communication challenges (Dapretto et al., 2006). Dyslexia is associated with underactivation in the left hemisphere language network during reading tasks (Shaywitz et al., 2002), while OCD involves hyperactivity in the cortico-striatal-thalamo-cortical (CSTC) circuit, particularly in the orbitofrontal cortex and anterior cingulate cortex (Menzies et al., 2008). TMS protocols targeting these areas have shown promising results in TMS therapy for OCD. 

The Application of Transcranial Magnetic Stimulation (TMS) 

At Smart TMS, we apply TMS therapy to target neuroplasticity through mechanisms such as long-term potentiation (LTP) or depression (LTD), cortical excitability, and changes in neurotransmitter release (Hallett, 2007; Lefaucheur et al., 2014; Ridding & Rothwell, 2007). 

TMS for OCD 

In OCD, this process aims to reduce excessive connectivity and hyperactivity in the orbitofrontal cortex (OFC), anterior cingulate cortex (ACC), and the caudate nucleus — all implicated in the pathophysiology of OCD (Fitzgerald et al., 2016). Low-frequency TMS to the right OFC and pre-supplementary motor area (preSMA) has been shown to reduce symptoms such as compulsions, intrusive thoughts, and associated anxiety. We also apply stimulation to the left dorsolateral prefrontal cortex (lDLPFC), which improves overall emotional regulation, executive functioning and anxiety-related symptoms — supporting TMS for OCD and anxiety simultaneously. 

TMS for ADHD 

In ADHD, TMS treatment focuses on stimulating the prefrontal cortex, particularly the right and left DLPFC, to enhance executive functioning — including attention, memory, planning and decision-making (Rubia, 2018). This helps alleviate symptoms of inattention, impulsivity and hyperactivity by restoring functional connectivity and promoting better communication between brain regions involved in cognitive control. 

TMS for ADHD represents a promising, drug-free intervention for both children and adults who may be resistant to medication or prefer a non-pharmaceutical approach to symptom management. 

Conclusion 

Neurodivergence encompasses a range of conditions characterised by differences in brain structure, function, and neurochemistry. These differences are not deficits but rather variations in the human experience that can pose unique challenges and strengths. 

By understanding the biological, structural and functional underpinnings of ND conditions, we can develop more effective, personalised interventions. Transcranial magnetic stimulation (TMS) offers a non-invasive, evidence-based treatment option that targets specific brain circuits involved in neurodivergent conditions — from TMS for ADHD and OCD, to broader applications in TMS therapy for anxiety and cognitive dysfunction. 

As research advances, the application of TMS in neurodivergent populations holds great promise for enhancing cognitive, emotional and behavioural outcomes, ultimately supporting individuals in leading more fulfilling and empowered lives. 

Written by Carmen, our Smart TMS Bristol practitioner

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