Rhodiola rosea, commonly known as Arctic Root or Golden Root, is a medicinal plant traditionally used to combat stress, fatigue, and cognitive decline. The adaptogenic properties of Rhodiola rosea, which help the body resist physical, chemical, and biological stressors, make it a popular supplement for enhancing mental and physical performance. The primary active compounds in Rhodiola rosea include rosavin, salidroside, and tyrosol, which are believed to contribute to its cognitive-enhancing effects.
This study explores the impact of Rhodiola rosea extract on mental resource allocation and attention using an event-related potential (ERP) dual task paradigm. By analyzing brain activity and cognitive performance, the study aims to determine whether Rhodiola rosea can improve cognitive function in healthy adults, particularly in demanding tasks that require multitasking and sustained attention.
Contents
Methods
Participants
Fifty healthy adults aged 30 to 50 years participated in the study. All participants were free of chronic illnesses, neurological, and psychiatric disorders. They were recruited through advertisements and underwent physical and neurological examinations at the screening visit to ensure eligibility.
Study Design
The study followed an open-label single-arm design. Participants received 200 mg of Rhodiola rosea extract twice daily for 12 weeks. Assessments were conducted at baseline, 6 weeks, and 12 weeks. These included neuropsychological tests and ERP measurements during a dual task paradigm to evaluate changes in cognitive function and mental resource allocation.
Neuropsychological Measurements
- Attention Network Task (ANT): Assesses different aspects of attention, including alerting, orienting, and executive control.
- Go/Nogo Test: Measures the ability to react to target stimuli while withholding reactions to non-target stimuli.
- Divided Attention Test: Evaluates the ability to divide attention between concurrent visual and auditory tasks.
- Number Connection Test: A timed test to assess cognitive processing speed.
- Beck Depression Inventory II (BDI-II): Assesses symptoms of depression.
- Recent Perceived Stress Questionnaire (PSQ-R): Measures subjectively experienced stress.
Event-Related Potential Task
ERPs were recorded during a dual task paradigm combining a visual search task and an auditory target detection task. Participants were required to respond to visual and auditory targets while their brain activity was monitored through EEG. The P3 component of the ERP, associated with mental resource allocation, was of particular interest.
Statistical Analysis
Data were analyzed using General Linear Model statistics with repeated measures on time and treatment. Significant differences were identified using Wilks’ Lambda and Greenhouse–Geisser alpha levels, with a significance level set at p < 0.05.
Results
Neuropsychological Measures
Significant improvements were observed in several neuropsychological measures. The Attention Network Task (ANT) showed reductions in reaction time and improvements in the orienting and executive effects. The Go/Nogo test demonstrated decreased reaction times, and the Divided Attention Test showed improvements in reaction times and error rates.
- Attention Network Task (ANT):
- Reduction in total reaction time
- Improvement in orienting and executive effects
- Stable alerting effect and error rate
- Go/Nogo Test:
- Reduction in reaction time
- Stable error rate
- Divided Attention Test:
- Improvement in reaction times for both visual and auditory stimuli
- Reduction in error rates
- Number Connection Test:
- Decreased time to complete the task
- BDI-II:
- Decreased total scores indicating reduced depression symptoms
- PSQ-R:
- Decreased perceived stress scores
Dual Task Paradigm
The dual task paradigm results showed significant reductions in reaction times and error rates across all conditions. The P3 component of the ERP, associated with mental resource allocation, showed increased amplitude in visual tasks, indicating improved mental resources. This suggests that Rhodiola rosea enhances the brain’s ability to allocate resources efficiently, leading to better performance in multitasking situations.
- Reaction Times: Significant reductions in both auditory and visual tasks.
- Dual Task Costs: Reduced dual task costs indicating improved multitasking ability.
- Error Rates: Decreased error rates across all conditions.
- P3 Amplitude: Increased amplitude in visual tasks, suggesting enhanced mental resource allocation.
Discussion
The study’s findings suggest that Rhodiola rosea extract has beneficial effects on mental resource allocation and attention. The improvements in reaction times, error rates, and P3 amplitude indicate enhanced cognitive performance and mental resources. These results align with previous research showing that Rhodiola rosea can improve cognitive function, reduce mental fatigue, and enhance physical performance.
The adaptogenic properties of Rhodiola rosea, which help the body resist stress, may play a crucial role in its cognitive-enhancing effects. By reducing stress and improving mental resilience, Rhodiola rosea can help individuals maintain focus and performance under demanding conditions.
Potential Mechanisms
The cognitive enhancements observed with Rhodiola rosea may be due to several mechanisms, including:
- Increasing the availability of neurotransmitters such as dopamine, serotonin, and norepinephrine.
- Reducing the release of stress hormones like cortisol.
- Enhancing neuronal energy metabolism and mitochondrial function.
- Providing antioxidative effects, which protect neurons from oxidative stress and support overall brain health.
Comparison with Previous Research
Previous studies have demonstrated the cognitive benefits of Rhodiola rosea in various populations, including individuals with stress-related fatigue and cognitive impairments. This study extends these findings by showing that Rhodiola rosea can also enhance cognitive function in healthy adults, particularly in tasks requiring multitasking and sustained attention.
Limitations
The study’s limitations include the open-label design and lack of a placebo control group. These factors may introduce bias and limit the generalizability of the findings. Future research should include double-blind, placebo-controlled studies with larger sample sizes to confirm the cognitive benefits of Rhodiola rosea and elucidate its mechanisms of action.
References
For further details, you can access the full study here.
