Here is the design of a clinical trial:

Official Title: Targeting Hippocampal Hyperactivity With Real-time Functional MRI Based Neurofeedback in Elderly Individuals With and Without Memory Problems

Included conditions:
- Mild Cognitive Impairment

Study Armgroups:
- {'label': 'healthy elderly participants receiving feedback from the hippocampus', 'type': 'ACTIVE_COMPARATOR', 'description': 'This group will consist of healthy elderly volunteers, who will receive feedback from their hippocampal activity.', 'interventionNames': ['Other: real-time fMRI based neurofeedback from the hippocampus']}
- {'label': 'healthy elderly participants receiving feedback from another area', 'type': 'SHAM_COMPARATOR', 'description': 'This group will consist of healthy elderly volunteers, who will receive feedback from another brain area.', 'interventionNames': ['Other: real-time fMRI based neurofeedback from another brain area']}
- {'label': 'patients with MCI receiving feedback from the hippocampus', 'type': 'EXPERIMENTAL', 'description': 'This group will consist of patients with mild cognitive impairment, who will receive feedback from their hippocampal activity.', 'interventionNames': ['Other: real-time fMRI based neurofeedback from the hippocampus']}
- {'label': 'patients with MCI receiving feedback from another brain area', 'type': 'SHAM_COMPARATOR', 'description': 'This group will consist of patients with mild cognitive impairment, who will receive feedback from another brain area.', 'interventionNames': ['Other: real-time fMRI based neurofeedback from another brain area']}

Interventions:
- {'type': 'OTHER', 'name': 'real-time fMRI based neurofeedback from the hippocampus', 'description': "During real-time fMRI neurofeedback, participants are trained to 'control' hippocampal activity. The training is accomplished by continuously measuring brain activity, analysing it in real-time, and then providing feedback about the current (and the targeted) brain activity to the participant.", 'armGroupLabels': ['healthy elderly participants receiving feedback from the hippocampus', 'patients with MCI receiving feedback from the hippocampus']}
- {'type': 'OTHER', 'name': 'real-time fMRI based neurofeedback from another brain area', 'description': "During real-time fMRI neurofeedback, participants are trained to 'control' hippocampal activity. The training is accomplished by continuously measuring brain activity, analysing it in real-time, and then providing feedback about the current (and the targeted) brain activity to the participant.", 'armGroupLabels': ['healthy elderly participants receiving feedback from another area', 'patients with MCI receiving feedback from another brain area']}

Primary Outcomes:
- {'measure': 'Rate of change in hippocampal activity during a memory task', 'description': 'Measured by fMRI (rate of change in activity from baseline to after the intervention)', 'timeFrame': 'Directly after the intervention'}

Please estimate the sample size based on the assumption: 
ANOVA with repeated measurements and between-within interactions, significance level (α) = 0.01, power (1-β) = 0.99, number of groups = 4, number of measurements = 4
Sample size calculation
        For the determination of sample size, we used G*power [32]. Since no study so far tried to downregulate hippocampal activity, we opted for the detection of at least a small effect (i.e., cohenâs fâ=â0.25). This would require an inclusion of nâ=â84 in total (that is, nâ=â21 in each group) for a repeated measures design with 4 groups and 4 measurements (i.e., baseline, post-intervention, follow-up 1, follow-up 2). We used the following criteria to calculate sample size: ANOVA with repeated measurements and between-within interactions, Î± errâ=â0.01, 1-Î²â=â0.99, number of groupsâ=â4, number of measurementsâ=â4.