This study used signal detection theory to examine how neuroscientists identify the default mode network compared to other prominent resting-state networks. Twenty participants were asked to distinguish the default mode network from three other networks in a rapid forced-choice task, where the networks were presented at different signal thresholds. Results showed that participants more accurately identified the default mode network when it was presented at the most stringent threshold, and made the most conservative decisions when networks were not thresholded. These findings suggest that thresholding fMRI data improves accuracy in identifying brain networks.

1. Rest Self-Examination
V. Adam, B. Baird, P. Bazin, P. Bellec, B. Bernhardt, J. Berson, C. Bonhage, J. Böttger, T. Buschmann, X. Castellanos, B. Cheung, C. Cioli, V. Conde, C. Craddock, E. Dickie, P. Dickinson, M. Doherty, E. Duff, H. Engen, K. Franke, T. Fritz, G.
Gauthier, S. Ghosh, C. Gorgolewski, M. Hanke, P. Haueis, T. Hoffmann, R.M. Hutchison, A. Kanaan, S. Kharabian, K. Kipping, S. Kotz, S. Lerique, G. Lohmann, S. Löhne, X. Long, D. Margulies, D. McLaren, T. Melicher, M. Mennes, S. Mesmoudi,
P. Mikolas, M. Milham, K. Mills, K. Müller, D. Pahwa, F. Ruby, A. Sadvakas, A. Schäfer, R. Schurade, M. Seal, J. Smallwood, J. Soch, C. Steele, J. Stelzer, R. Toro, R. Turner, L. Uddin, S. Urchs, S. Valk, T. Vanderwal, A. Villringer, C. Yan, T.
Yarkoni
Overview Stimuli Discussion
One important evolutionary feature of the human mind is its z = -∞ z=0 z = 2.3 Our data demonstrate that the accuracy with which
capacity to understand itself. Recent advances in functional neuroscientist make can be captured by signal detection theory.
neuroimaging have revealed a core network, commonly Participants’ accuracy at detecting the default mode network
referred to as the default mode network (DMN) that are used by Default-mode increased when it was thresholded conservatively and when
humans to understand their own mental states, as well as presented with functional maps with no thresholds made the
simulating the mental states of others. The current study used most conservative decisions. Given that at present at least,
signal detection theory to explored how neuroscientists identify neuroimaging relies on the subjective decisions made by the
this constellation of brain regions relative to several other investigator, these data provide important evidence that
prominent brain networks. Participants were asked to thresholding improves the accuracy of diagnoses of brain data.
distinguish between the default mode network and three other Motor In the future we hope to explore which networks participants are
commonly found resting-state networks in a speeded force most able to confuse with the default mode network, extend this
choice paradigm. To vary the strength of the signal each investigation to incorporate other brain networks and understand
network was presented at three different z-scored thresholds. the neural substrates that support this process. Further
Results indicated that (i) participants were better able to identify investigations should also consider how the experience of the
the default mode network when it was presented at the most investigator impacts upon their ability to rapidly identify brain
stringent threshold and (ii) made the most conservative Salience data at thresholds at thresholds to explore the possibility that
decisions when the data was not thresholded at all. These data investigators with greater experience are better able to correctly
underline the value of thresholding fMRI data in order to make identify brain data under conditions which are more ambiguous
informed choices regarding functional brain activity. with regards to the underlying brain dynamics than their less
experienced colleagues.
Methods Fronto-parietal
The Story
Participants
Behind the shenanigans
- N = 20
- Recruited during the Brainhack unconference 2012 in Leipzig Results
- Age (M = 31.9, SD = 8.9)
- 15 males, 5 females Criterion d’
Stimuli
-Spatial maps of resting state networks overlaid on 3D
renderings: default, motor, salience, and frontal parietal
-Thresholded at 3 z-score levels: -∞, 0, 2.3.
Paradigm
- task: To recognize DMN, answer 'yes', 'no’ with button press
- 2 runs per 7.5 minutes
- 26 DMN, 104 other networks, 3 thresholds/network
- stimulus duration: 1500 ms -∞ 0 2.3 -∞ 0 2.3
- Response time: 1500 ms Threshold Threshold
Conclusions on Collaboration
- Interval period (blank screen): 500 ms
Questionnaire
- Demographics and questions concerning level of expertise z =-∞ z=0 z = 2.3
with DMN and other resting-state networks.
Mean Hit 0.5 0.34 0.34
Mean False Alarm 0.94 1.27 1.74