There are sex differences in healthy individuals in a number of neurological domains such as awareness and brain structure. In this article, impulsivity and attention are tested on whether they are sexually dimorphic or if there is a phenotypic difference between males and females of the same species. Sex might dictate such abnormalities such as attention deficit hyperactivity disorder, autism, and addiction.
In this article, attention and impulsivity are examined to see if they are sexually dimorphic in healthy individuals and also individuals with psychiatric diagnosis. The focus of the discussion is on ADHD. It is said that 75% of ADHD diagnoses are in males. Attention is the ability to select from multiple stimuli, response, memories, and thoughts. It can be broken into 3 control systems: alerting, orienting, and executive. Alerting is preparedness and maintaining an alert state. Orienting is known as scanning or selection and is the ability to select information form multiple sensory stimuli. Executive attention is one’s focused attention. Impulsivity is action without forethought. It can be classified into two entities: impulsive action and impulsive choice.
Several studies have suggested that females have an advantage when it comes to executive attention and response inhibition. In contrast, males may outperform females in visuopatial selective attention, showing increased activation in the left hemisphere. When it comes to impulsive action, sex seemed to influence the function of brain regions associated with behavioral output. In this respect, males outperformed females in decision-making. Then the sex differences in attention and impulsivity were examined in neuropsychiatric disorders. This can be seen in ADHD. ADHD is a common neurodevelopmental disorder with a strong genetic basis, characterized by deficits in attention and extreme hyperactivity. They are diagnosed under 3 types: the inattentive subtype, hyperactive impulse subtype, and combined subtype. It has been shown that inattentive ADHD is prevalent among girls and hyperactive-impulsive and combined are more common in guys. It was then concluded that sex differences when it comes to this disorder may account for sex-specific differences in diagnosis. Females with ADHD had lower rating of hyperactivity, inattention, impulsivity, and externalizing problems, but have greater intellectual impairments and more internalizing problems. The evidence for sex differences in ADHD is very limited especially since there are differences in age, study sizes, and different treatment regimes. The sex-linked genes SRY, STS, and MAOA are the clear candidates for effects on attentional and impulsive behaviors. SRY gene is a Y linked gene, which encodes a protein. This protein then acts as a transcription factor in the developing fetus to induce gene expression changes. SRY influences cognitive attributes in males. The STS is X-linked and is key to attentional and impulsive operations. MAOA is also X-linked. The treatment for ADHD often involves inhibiting monoamine oxidase activity.
The evidence is strong that the sexes differ in their disorders of attention and impulsivity. There is also evidence that healthy males and females show differences in their attentional and impulsive profiles. The research in this subject however is limited. Identifying protective and risk factors encoded by sex-linked genes should help us to treat sex-biased disorders of attention and impulsivity.
article:http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3245859/?tool=pubmed
By: Kelleigh Jio
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