Medications such as modafinil have been shown to enhance cognitive processes. However, the brain-functional mechanisms underlying these effects remain poorly understood. In this study, we used behavioral and resting-state fMRI to explore how modafinil changes the right posterior insula’s intrinsic functional connectivity.
Increased Functional Connectivity in the Right Posterior Insula
Increasingly, stimulant smart pills such as Modvigil 200 Australia, and caffeine have been shown to enhance cognitive processes such as attention and memory. However, the brain-functional mechanisms underlying these effects remain poorly understood.
In this study, we used resting-state fMRI to investigate the effect of modafinil on the right posterior insula. The effects of this stimulant were quantified by measuring the increase of rsFC (relative signal to noise) in the insula in comparison with a control group.
We also investigated a variety of other functional connectivity measures including internetwork connectivity between the right SN and DMN. We found that SN-DMN rsFC was significantly increase in the modafinil condition.
Similarly, we saw an increase in rsFC between the right CEN and SN. This rsFC was also significantly larger in the modafinil group compared to the control group. In addition to the aforementioned rsFC, the rsFM (relative fractional area) measure in the right insula and right caudate was the most impressive brain-functional improvement resulting from the use of modafinil.
Increased Functional Connectivity in the Right Hippocampus
Modafinil changes the right hippocampus’ intrinsic functional connectivity, which is the connection between the hippocampus and other brain regions. This effect may explain the positive effects of modafinil on cognitive function and could help counteract some of the deficits in aging and in mild cognitive impairment (MCI) or early-stage dementia patients.
To examine the effects of modafinil on this intrinsic functional connectivity, resting state fMRI was use. ROIs were define using MNI 152 space; the resulting network maps were then combine in a graph-base approach and within-subject paired t-tests were perform to assess FC effects, controlled for the placebo condition.
After the treatment, a significant increase in rsFC was observe in the right hippocampus compare to the placebo. This coincided with lower rsFC in the left frontoparietal and somatosensory networks. This may suggest that the underlying neurotransmitter and sensory processing mechanisms play a role in the modulation of rsFC by modafinil.
Increased Functional Connectivity in the Right Frontal Cortex
Modafinil changes the right frontal cortex’s intrinsic functional connectivity (FC), which is related to memory processes. FC specifically between the frontoparietal network and default mode network does modulate by Modafinil in comparison to placebo.
The effect of modafinil on individual electroencephalogram (EEG) activity traces was observe within a 30-s sample before and after Modafinil administration, as depicted in Figure 1. A significant desynchronization was present during EEG recording and bursts of low-amplitude, high-frequency fast activity was observe in the delta and theta frequency bands.
Stimulants such as methylphenidate and modafinil have repeatedly been show to enhance cognitive processes, including attention and memory. However, brain-functional mechanisms underlying these effects are not well understand.
Increased Functional Connectivity in the Right Cerebellum
The right cerebellum is emerging as a crucial modulator of cognition as. It does know to target multiple associative areas in the parietal and frontal cortex.
To explore the modafinil effect on the cerebellum, resting-state functional magnetic resonance imaging (rs-fMRI) was perform. Using a graph-based approach that took into account topological changes occurring in functional brain networks. This voxel-wise and network-wise analysis identified a number of regions that had a major impact on rs-fMRI signals.
One such effect was a significant increase in the right cerebellar hemisphere (CEN) connectivity with the left posterior insula (SN). Another noteworthy effect was a decrease in DMN reactivation. As well as a boost in CEN connectivity with the right hippocampus.