Dopamine modulates executive function by co-jointly adjusting neurochemical transmission in the prefrontal cortex (PFC). ĭopamine neurons are located in the ventral midbrain and are involved in several cognitive functions that influence performance, motor control, reward, and cognition. Furthermore, studies found associations between dopamine polymorphisms with sustained attention, memory, and executive function phenotypes in both clinical and non-clinical populations. Cognitive neuroscience and pharmacology associate dopamine and serotonin as neuromodulators of cognition. indicated that individual differences in executive function including inhibiting dominant responses, updating working memory representations, and shifting between task sets, are almost 99 % heritable. Individuals increasingly select and modify their experiences partly based on their genetic predispositions.
Ĭognitive control processes regulating thought and action are multifaceted functions influenced by heritable genetic factors and environmental influences. HAND encompasses a wide range of cognitive impairment that includes deficient memory and attention, decreased executive function, and behavioral changes, such as apathy or lethargy.
However, the prevalence of asymptomatic and mild neurocognitive impairment have increased with increased longevity. For example, the incidence of HIV-associated dementia has declined. The manifestations of HAND have significantly changed in response to the introduction of antiretroviral therapy (ART). In addition to its deleterious effects on the cell-mediated immune system, HIV can also damage cells in the central nervous system and lead to HIV-associated neurocognitive disorders (HAND).
Human immunodeficiency virus (HIV) is a global epidemic that affects approximately 36 million people worldwide. The study shows that genetically determined differences in the SNP rs6277 DRD2 gene and DRD4 48 bp VNTR may be risk factors for deficits in executive function and cognitive flexibility. Also, DRD4 VNTR 7-allele was significantly associated with executive dysfunction. The results were further stratified by race and sex and significant results were seen in males (odds ratio = 3.5, 95 % CI 1.5–5.5 p = 0.008) and in African Americans (odds ratio = 3.1, 95 % CI 2.3–3.5 p = 0.01). Results showed significant associations with the SNP rs6277 and impaired executive function (odds ratio = 3.3, 95 % CI 1.2–2.6 p = 0.004) and cognitive flexibility (odds ratio = 1.6, 95 % CI 2.0–5.7 p = 0.001). The Short Category (SCT), Color Trail (CTT) and Rey-Osterrieth Complex Figure Tests (ROCT) were used to measure executive function and memory. A total of 267 HIV-infected adults were genotyped for polymorphisms, DRD4 48 bp-variable number tandem repeat (VNTR), DRD2 rs6277 and ANKK1 rs1800497. The present study explored the relationship between two candidate genes (DRD4 and DRD2) and neurocognitive performance in HIV-infected adults. The contribution of genetic variants affecting the metabolism and activity of dopamine may influence these individual differences. There is evidence suggesting that neurocognitive impairment is heritable and individual differences in cognition are strongly driven by genetic variations. However, several factors have been suggested including the role of genetics. The causes of neurocognitive impairment are still unclear. Experience neurocognitive deterioration despite virologically successful treatments.