Modafinil has shown a number of cognitive-enhancing effects in studies on animals and is currently being used in clinical trials. These include improvements in episodic memory, working memory, and attentional processes that require cognitive control.
The cognitive effects of modafinil are mediated by the action of its dopamine (DA) agonist. DA is a neurotransmitter associate with vigilance, and a recent study found that a dose-dependent enhancement of DA-induced wakefulness was related to improved performance on spatial discrimination tasks in rats.
Episodic Memory
Several studies have shown that modafinil improves memory performance on cognitive tests in patients with narcolepsy. The effects are associate with increased activity in the frontal and cingulate cortex. You can Buy Modalert online to improve working memory.
These researchers found that the drug significantly improved performance on a number of episodic memory and working memory tasks. They also found that it did not improve planning or sustained attention.
They note that the study was only a short-term trial and that longer-term studies are needed to determine whether modafinil has any long-term effects on cognition. “Although the findings suggest that modafinil might be an effective treatment for cognitive symptoms of depression, more studies are need to confirm these findings and to explore safety,” wrote Sahakian and Burdick.
The researchers found that the drug significantly improved digit span, visual pattern recognition memory, spatial planning, and stop-signal reaction time. They also found that the drug decreased the time taken to complete a delayed matching to sample task. These results suggest that the drug may be a useful treatment for those with depressed memory problems, said Sahakian and Burdick.
Working Memory
Modafinil has shown efficacy in a number of medical and psychiatric illnesses, including fatigue syndromes, treatment-resistant depression, and attention deficit/hyperactivity disorder (ADHD). There is no evidence from animal models and neuroimaging that these effects are related to the remediation of cognitive dysfunction, involving frontal cortex activity.
For instance, pre-treatment with modafinil is associate with a dose-dependent improvement in working memory performance on a sequential alternation task in mice, without affecting exploratory or anxiety-related activities. This effect is most pronounced for subjects with longer visual P300 latencies (Sangal et al., 1999b).
In eight medication-free men aged 21 to 35 following overnight sleep deprivation, a single 200 mg dose of modafinil significantly improved working memory performance with associated increased cortical activation. The effect was strongest with the N-Back test, which measures spatial memory span and rapid visual information processing. It also increased performance on digit span, visual pattern recognition memory, and spatial planning and reduced stop-signal reaction time.
Attention
Modafinil improves attention and alertness by increasing dopamine levels in the nucleus accumbens. It also increases the number of neurons in the preoptic area and the medial prefrontal cortex.
In addition to its ability to increase wakefulness, modafinil is thought to improve memory and learning. It is use to treat sleep disorders such as narcolepsy and has been find to improve cognitive performance in patients with remitted depression.
Researchers at Beth Israel Deaconess Medical Center in Boston, Massachusetts, measured the effects of a single 200-dose of modafinil on the working memory of eight medication-free men between the ages of 21 and 35. The study found that modafinil significantly improved the participants’ working memory, although only at an intermediate level of task difficulty.
Learning
Modafinil improves memory performance by activating the dopamine D1 receptor in rhesus monkeys performing an oculomotor delayed-response task. It also reduces learning impairments caused by a 10-hr sleep deprivation period in mice.
To evaluate the effects of modafinil on learning, sixty healthy young adult volunteers received a single oral dose of placebo or 100 mg or 200 mg of modafinil before performing cognitive tests designe to assess working memory and attention. The results showed that the performance of the modafinil group was significantly better than that of the placebo group at all test versions after controlling for preexisting cognitive performance.
The results suggest that modafinil is able to improve cognition in remit patients suffering from depression with persistent cognitive dysfunction. But further studies are need before this effect can be confirmed.
