The Effects of Methylphenidate on Different Types of Attention

A social debate concerning attention functioning and its deficits has emerge. The attention system is a neurophysiologic complex mechanism responsible for filtering sensory inputs and cognitive resource allocation. This system is subdivided into several functions of attention, though vast majority of the current diagnosis process is focused merely on sustained attention. One of the ways to measure sustained attention is the ASAT (auditory sustained attention test) paradigm, using the pre-pulse inhibition (PPI) reflex, as we recently proposed. Methylphenidate (MPH) is the Psycho-stimulating drug of choice for ADHD treatment. Despite the narrow diagnostic range as well as the fact that MPH pharmacotherapy is yet to be fully understood, MPH is commonly prescribed to treat ADHD. Thus, we aimed to examine possible differences in ASAT, selective attention and social attention in response to acute or chronic MPH administration. We found that acute administration of MPH led to impaired performance in all 3 types of attention. However, chronic administration of MPH improved both ASAT and social attention performance. Finally, we demonstrated for the first time the effect of MPH on the expression of D1 and D5 receptors in the striatum. Specifically, we found a decreased expression of D5R following acute MPH administration. Our study provides evidence for the diverge MPH effects on attention and targeting the striatum, we further suggest a possible mechanism by which MPH can disrupt attention processes when acutely administered.