by Dr. Fabiano de Abreu Agrela Rodrigues
Modern neuroscience reveals a perplexing paradox: there are people with exceptional intellectual capacity who fail to deliver results commensurate with their potential. The enigma lies not in intelligence itself, but in the distinction between two frequently confused brain systems: raw cognitive ability (IQ) and the executive control system that allows this ability to be used productively. The difference between these neural circuits explains why some brilliant minds fail while others, seemingly less powerful, achieve extraordinary accomplishments.
TWO CIRCUITS, TWO GENETIC ARCHITECTURES
General intelligence, measured by the g factor, represents the brain’s ability to process complex information, identify abstract patterns, and solve novel problems. Hatoum et al. (2022) identified, through genome-wide association studies (GWAS), the single nucleotide polymorphisms (SNPs) that govern this capacity. These genetic markers regulate axonal myelination, synaptic density in the posterior parietal cortex, and the efficiency of glutamatergic transmission. When we talk about high IQ, we are talking about brains with greater processing speed, more connections between distant regions, and a superior ability to form abstract mental representations.
Executive function operates on a completely different terrain. The same study isolated genes specific to executive control, concentrated in regions that encode D2 dopaminergic receptors in the dorsolateral prefrontal cortex and dopamine transporters in the striatum. This system governs three pillars: working memory (keeping information active while using it), inhibitory control (suppressing impulses and ignoring distractions), and cognitive flexibility (changing strategies quickly when necessary).
The Executive Function as a Driver of IQ
Herein lies the first cognitive profile: individuals with a high genetic predisposition for both intelligence and executive function. In these brains, the capacity for abstract reasoning is multiplied because the executive control system allows this intelligence to be used in an organized and sustained way. Robust working memory handles multiple variables simultaneously during problem-solving. Inhibitory control blocks external distractions and irrelevant thoughts. Mental flexibility reorganizes strategies when one approach fails.
Neurobiologically, we observe in these individuals high frontoparietal connectivity (favoring complex reasoning) combined with efficient dopaminergic receptors in the dorsolateral prefrontal cortex (sustaining directed attention). The result is a functionally higher IQ than raw ability would suggest. Executive function acts as a catalyst: it doesn’t create intelligence, but it allows each unit of cognitive capacity to be used with maximum efficiency. It’s the difference between having one hundred horsepower and being able to transfer all that power to the wheels, versus losing half the energy to friction and slippage.
HIGH IQ WITHOUT A CONTROL SYSTEM
The second profile reveals the cruelty of genetics: brains with a high density of NMDA receptors in the parietal cortex (favoring exceptional abstract reasoning) but low expression of dopamine transporters in the prefrontal cortex (impairing attentional control). These individuals solve impressively complex problems when they can concentrate, but they don’t maintain focus long enough to complete projects. They understand advanced concepts easily, but forget basic commitments. They plan sophisticated strategies that they never execute.
The dissociation occurs because intelligence and executive control depend on different neurotransmitter systems. Fluid intelligence correlates strongly with glutamate and BDNF-mediated synaptic plasticity (brain-derived neurotrophic factor). Executive function depends primarily on dopamine and norepinephrine in the prefrontal cortex. A brain may have excellent glutamatergic transmission (fast and complex thinking) but excessive dopaminergic reuptake (inability to sustain attention). Genetically, the SNPs that govern each system are on different chromosomes and segregate independently.
CLINICAL MANIFESTATIONS OF DISCONNECTION
In professional and academic practice, this second profile produces frustrating trajectories. Students who understand quantum physics but fail because they don’t submit assignments. Professionals who formulate innovative solutions but fail to implement them because they lose track mid-process. People who start ten projects simultaneously and finish none, not due to lack of ability, but because the prefrontal cortex cannot suppress the impulse to start something new before finishing the current one.
The psychological suffering is intense. These individuals are labeled as lazy, undisciplined, or unmotivated when faced with a specific neurobiological deficit in the executive control system. They feel their own intelligence, they know they are capable, but they cannot materialize this potential into concrete results. The frustration is compounded by the fact that people around them (often with lower IQs but intact executive function) deliver superior results simply because they are able to organize their work and see it through to the end.
Evidence-Based Interventions
The therapeutic approach is not to further train intelligence, but to compensate for the deficient executive system. External structures replace internal control: detailed lists break down large tasks into small steps, scheduled reminders compensate for limited working memory, and controlled environments reduce competing stimuli that overload the inhibitory system.
Pharmacologically, medications that increase dopamine availability in the prefrontal cortex significantly improve executive control without altering IQ. Methylphenidate, for example, inhibits the dopamine transporter DAT1, prolonging the action of dopamine in the synaptic cleft of the dorsolateral prefrontal cortex. Spencer et al. (2013) demonstrated that this intervention specifically improves working memory and inhibitory control, the two pillars most impaired in these profiles.
Targeted cognitive training can induce synaptic plasticity in executive circuits. Repeated working memory tasks (such as the N-back test) increase the density of D1 receptors in the prefrontal cortex and strengthen connections between the dorsolateral prefrontal cortex and the anterior cingulate cortex. The improvement is not dramatic, but sufficient to create a functional difference in daily tasks.
The intelligence that gets lost along the way.
The conclusion is straightforward: intelligence without executive function is wasted potential. The brain has the capacity to solve complex problems, but it cannot organize this capacity into productive action sequences. It’s like having a state-of-the-art processor with a faulty operating system. The hardware is exceptional, but the management software cannot coordinate the available resources.
Recognizing this distinction frees people from paralyzing guilt. The problem isn’t a lack of intelligence, discipline, or willpower. It’s a specific neural architecture that requires specific compensatory strategies. Some brains come with integrated executive function that multiplies base intelligence. Others need to externally construct what they lack internally. Both can achieve significant accomplishments, but the paths are fundamentally different.
REFERENCES
HATOUM, AS et al. Genome-wide association study shows that executive functioning is influenced by GABAergic processes and is a neurocognitive genetic correlate of psychiatric disorders. Biological Psychiatry, vol. 91, no. 1, p. 63-74, 2022. DOI: 10.1016/j.biopsych.2021.06.014
SPENCER, TJ et al. Effect of psychostimulants on brain structure and function in ADHD: a qualitative literature review of MRI-based neuroimaging studies. The Journal of Clinical Psychiatry, vol. 74, no. 9, p. 902-917, 2013. DOI: 10.4088/JCP.12r08287