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Flexible adaptive paradigms for fMRI using a novel software package 'Brain Analysis in Real-Time' (BART).

Hellrung L, Hollmann M, Zscheyge O, Schlumm T, Kalberlah C, Roggenhofer E, Okon-Singer H, Villringer A, Horstmann A - PLoS ONE (2015)

Bottom Line: This can have a significant impact on the results.Our fMRI findings clearly show the benefits of an adapted paradigm in terms of statistical power and higher effect sizes in emotion-related brain regions.This can be of special interest for all experiments with low statistical power due to a limited number of subjects, a limited amount of time, costs or available data to analyze, as is the case with real-time fMRI.

View Article: PubMed Central - PubMed

Affiliation: Department of Neurology, Max Planck Institute for Human Cognitive and Brain Sciences, Leipzig,Germany; Leipzig University Medical Center, Leipzig, Germany.

ABSTRACT
In this work we present a new open source software package offering a unified framework for the real-time adaptation of fMRI stimulation procedures. The software provides a straightforward setup and highly flexible approach to adapt fMRI paradigms while the experiment is running. The general framework comprises the inclusion of parameters from subject's compliance, such as directing gaze to visually presented stimuli and physiological fluctuations, like blood pressure or pulse. Additionally, this approach yields possibilities to investigate complex scientific questions, for example the influence of EEG rhythms or fMRI signals results themselves. To prove the concept of this approach, we used our software in a usability example for an fMRI experiment where the presentation of emotional pictures was dependent on the subject's gaze position. This can have a significant impact on the results. So far, if this is taken into account during fMRI data analysis, it is commonly done by the post-hoc removal of erroneous trials. Here, we propose an a priori adaptation of the paradigm during the experiment's runtime. Our fMRI findings clearly show the benefits of an adapted paradigm in terms of statistical power and higher effect sizes in emotion-related brain regions. This can be of special interest for all experiments with low statistical power due to a limited number of subjects, a limited amount of time, costs or available data to analyze, as is the case with real-time fMRI.

No MeSH data available.


Related in: MedlinePlus

Comparison of experiment timing adapted and non-adapted condition.Individual rates of the amount of trials reached as valid regarding the fixation compliance (A); Overall comparison of time that was needed to reach a certain amount of valid trials. For 95% and 100% valid trials none of the subjects reached these amounts in the non-adapted manner, therefore comparison is not shown (B); Exemplarily, the individual results for this with the threshold of 70% valid trials. 7 out of 17 subjects did not reach this amount of valid trials in the non-adapted condition. 9 out of the 10 remaining subjects need less time in the adapted condition (C). In summary, the adaption of the stimulation can help to minimize measurement time and dropout of subjects.
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pone.0118890.g005: Comparison of experiment timing adapted and non-adapted condition.Individual rates of the amount of trials reached as valid regarding the fixation compliance (A); Overall comparison of time that was needed to reach a certain amount of valid trials. For 95% and 100% valid trials none of the subjects reached these amounts in the non-adapted manner, therefore comparison is not shown (B); Exemplarily, the individual results for this with the threshold of 70% valid trials. 7 out of 17 subjects did not reach this amount of valid trials in the non-adapted condition. 9 out of the 10 remaining subjects need less time in the adapted condition (C). In summary, the adaption of the stimulation can help to minimize measurement time and dropout of subjects.

Mentions: For adapted trials, not fixating on the center of the screen resulted in an average delay of 2.3 s for each trial (± 2.9 s; High-Compliant: 0.26 s ± 0.3 s; Low-Compliant: 4.6 s ± 2.8 s). However, these delays result in 100% of valid (fixated) trials and extend the total measurement time on average for only about 1.3 min (± 1.3 min). To compare this delay with the timing of the non-adapted condition, we compared the necessary time to reach the same amount of valid trials in both conditions. This results in 54 s (± 19.2 s) less time needed in the adapted condition to reach the same amount of valid trials (up to 90%). Importantly, in the non-adapted condition none of the subjects reached more than 90% of valid trials overall (see Fig. 5).


Flexible adaptive paradigms for fMRI using a novel software package 'Brain Analysis in Real-Time' (BART).

Hellrung L, Hollmann M, Zscheyge O, Schlumm T, Kalberlah C, Roggenhofer E, Okon-Singer H, Villringer A, Horstmann A - PLoS ONE (2015)

Comparison of experiment timing adapted and non-adapted condition.Individual rates of the amount of trials reached as valid regarding the fixation compliance (A); Overall comparison of time that was needed to reach a certain amount of valid trials. For 95% and 100% valid trials none of the subjects reached these amounts in the non-adapted manner, therefore comparison is not shown (B); Exemplarily, the individual results for this with the threshold of 70% valid trials. 7 out of 17 subjects did not reach this amount of valid trials in the non-adapted condition. 9 out of the 10 remaining subjects need less time in the adapted condition (C). In summary, the adaption of the stimulation can help to minimize measurement time and dropout of subjects.
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4383593&req=5

pone.0118890.g005: Comparison of experiment timing adapted and non-adapted condition.Individual rates of the amount of trials reached as valid regarding the fixation compliance (A); Overall comparison of time that was needed to reach a certain amount of valid trials. For 95% and 100% valid trials none of the subjects reached these amounts in the non-adapted manner, therefore comparison is not shown (B); Exemplarily, the individual results for this with the threshold of 70% valid trials. 7 out of 17 subjects did not reach this amount of valid trials in the non-adapted condition. 9 out of the 10 remaining subjects need less time in the adapted condition (C). In summary, the adaption of the stimulation can help to minimize measurement time and dropout of subjects.
Mentions: For adapted trials, not fixating on the center of the screen resulted in an average delay of 2.3 s for each trial (± 2.9 s; High-Compliant: 0.26 s ± 0.3 s; Low-Compliant: 4.6 s ± 2.8 s). However, these delays result in 100% of valid (fixated) trials and extend the total measurement time on average for only about 1.3 min (± 1.3 min). To compare this delay with the timing of the non-adapted condition, we compared the necessary time to reach the same amount of valid trials in both conditions. This results in 54 s (± 19.2 s) less time needed in the adapted condition to reach the same amount of valid trials (up to 90%). Importantly, in the non-adapted condition none of the subjects reached more than 90% of valid trials overall (see Fig. 5).

Bottom Line: This can have a significant impact on the results.Our fMRI findings clearly show the benefits of an adapted paradigm in terms of statistical power and higher effect sizes in emotion-related brain regions.This can be of special interest for all experiments with low statistical power due to a limited number of subjects, a limited amount of time, costs or available data to analyze, as is the case with real-time fMRI.

View Article: PubMed Central - PubMed

Affiliation: Department of Neurology, Max Planck Institute for Human Cognitive and Brain Sciences, Leipzig,Germany; Leipzig University Medical Center, Leipzig, Germany.

ABSTRACT
In this work we present a new open source software package offering a unified framework for the real-time adaptation of fMRI stimulation procedures. The software provides a straightforward setup and highly flexible approach to adapt fMRI paradigms while the experiment is running. The general framework comprises the inclusion of parameters from subject's compliance, such as directing gaze to visually presented stimuli and physiological fluctuations, like blood pressure or pulse. Additionally, this approach yields possibilities to investigate complex scientific questions, for example the influence of EEG rhythms or fMRI signals results themselves. To prove the concept of this approach, we used our software in a usability example for an fMRI experiment where the presentation of emotional pictures was dependent on the subject's gaze position. This can have a significant impact on the results. So far, if this is taken into account during fMRI data analysis, it is commonly done by the post-hoc removal of erroneous trials. Here, we propose an a priori adaptation of the paradigm during the experiment's runtime. Our fMRI findings clearly show the benefits of an adapted paradigm in terms of statistical power and higher effect sizes in emotion-related brain regions. This can be of special interest for all experiments with low statistical power due to a limited number of subjects, a limited amount of time, costs or available data to analyze, as is the case with real-time fMRI.

No MeSH data available.


Related in: MedlinePlus