Title: Alpha neurofeedback training and its implications for studies of cognitive creativity

Transcription

1 Title: Alpha neurofeedback training and its implications for studies of cognitive creativity Authors: Henk J. Haarmann, Timothy G. George, Alexei Smaliy, Kristin Grunewald, & Jared M. Novick Affiliation: University of Maryland Center for Advanced Study of Language (CASL) Abstract: We report a method for increasing alpha brain waves through Electroencephalography neurofeedback training (NT), intended for subsequent research on cognitive creativity. Increased alpha power over right posterior cortex is associated with greater originality in divergent thinking (Grabner et al., 2007) and overcoming impasses during insight problem solving (Jung-Beeman et al., 2004; sensor location PO8). NT aimed at increasing alpha power has successfully demonstrated a causal connection between alpha activity and cognitive function, particularly mental rotation (Hanslmayr et al., 2005). This finding creates the prospect of using alpha NT to also test a hypothetical causal connection between alpha activity and cognitive creativity. To identify an alpha NT protocol appropriate for such a study, thirteen college students participated in three sessions of alpha NT. The neurofeedback information was derived from a sensor placed over right lateral parietal-occipital scalp (PO8) and displayed as a moving bar whose height corresponded to degree of alpha activity. Participants task involved increasing the height of this bar by adopting a calm and alert state during nine 2.5-minute NT segments interleaved with four 1-minute baseline segments. The alpha NT resulted in a statistically reliable within-session increase in alpha and theta (but not beta) activity and a between-session increase in alpha activity. There was also a within-session reduction in state anxiety. Thus, alpha NT is a reliable method for increasing alpha activity in regions associated with cognitive creativity. Implications for the use of this method to understand and improve performance on cognitive creativity tests will be discussed. Introduction Goal: To identify a reliable EEG neurofeedback training (NT) method that increases alpha power over the right posterior parietal-occipital cortex (PO8) in one to three brief sessions, to allow future studies to use this method to test the causal role of alpha brain waves in cognition, in particular, creative cognition. Previous findings: Increased alpha power over right posterior cortex is associated with better creative cognition, including: o originality in divergent thinking (Grabner et al., 2007); and o insight solutions (Jung-Beeman et al., 2004; sensor location PO8) Separately, alpha NT has been used to demonstrate a causal connection between alpha activity and cognitive function during a mental rotation task (Hanslmayr et al., 2005), but not yet during tasks of creative cognition. 1

2 Increased alpha power has been demonstrated in a single session of alpha neurofeedback (sensor location: Cz, eyes: closed, feedback signal: tone) in a within-subject design with repeated baseline (feedback absent) and training segments (feedback present) (Fell et al., 2002). o We tried but failed to replicate these results and therefore adapted this method (see below). Methods Subjects: Thirteen members of the University of Maryland community (6 female, mean age /- 7.3, years old) participated in the EEG NT protocol. An additional six subjects from the same population participated in a control condition without any feedback. Procedure: Adapted NT method from Fell et al. (2002) Fell et al. (2002) This study Figure Sensor placement Cz PO8 Eyes Closed Open Feedback signal Auditory (varying pitch, above individual threshold) Visual (moving bar, above individual threshold) Figure 1 Verbal instructions Relax as much as possible and breathe regularly Let all thoughts, feelings, and everything else pass Let yourself sink deeper and deeper into the chair Session structure Alternating baseline & training segments Same Same Figure 2 No. of sessions 1 3 EEG recording Single sensor, Left ear reference, 100 samples/sec., Theta (4-8 Hz), alpha (8-12HZ), beta (12-20Hz) Same, except 256 samples/sec, added EEG EMG inhibit band (

3 Hz) Results [Insert Figure 1 here] [Insert Figure 2 here] [Insert Figure 3 here] [Insert Figure 4 here] [Insert Figure 5 here] [Insert Figure 6 here] Text for figure legends: Figure 1: Feedback information As alpha power increased, the bar increased in height Subjects aimed to increase the height of the bar as much as possible above the horizontal line (threshold) The bar color changed to red if activity in the EEG EMG band exceeded a preset threshold A still, static image of the bar was presented during baseline segments Figure 2: Neurofeedback training protocol Events within and across trials. T = training segment (2½ min), B = baseline segment (90 s), R = rest (20 s), C = cluster of three training segments Participants in a single-session, no-neurofeedback control group watched a moving bar that was not connected to their alpha power (not shown) Figure 3: Alpha power increased within and across sessions Within-session increases were larger (η 2 =.54) than across-session increases (η 2 =.30) 3

4 At the individual level, 10 of 13 subjects in the NT group showed a significant increase in alpha power within the first session (not shown) Participants in the no-neurofeedback control group did not show a within-session increase in alpha power (not shown) Figure 4: Theta power increased within the first session only during training Figure5: Beta power did not change reliably Figure 6: State anxiety decreased Participants were administered the Spielberger State-Trait Anxiety Inventory (Spielberger, 1983) to assess both state and trait anxiety prior to NT After sessions 2 and 3, participants state anxiety levels were lowered Discussion & Conclusions The EEG NT method increased alpha power over PO8 within a single session o A second session of EEG NT was necessary to obtain a frequency-specific increase in alpha power First session: increase in alpha and theta power Second and third session: increase in alpha power only o There was a larger within- than across-session increase in alpha power Follow-up studies could use this EEG NT method to test the hypothesis that increased alpha power results in more original divergent thinking and/or more insight solutions in creative cognition (Grabner et al., 2007; Jung-Beeman et al., 2004). o Two sessions of alpha NT would suffice References Fell, J., Elfadil, H., Klaver, P., Roschke, J., Elger, C. E., & Fernandez, G. (2002). Covariation of spectral and nonlinear EEG measures with alpha biofeedback. International Journal of Neuroscience, 112(9),

5 Grabner, R. H., Fink, A., & Neubauer, A. C. (2007). Brain Correlates of Self-Rated Originality of Ideas: Evidence From Event-Related Power and Phase-Locking Changes in the EEG. Behavioral Neuroscience, 121(1), Hanslmayr, S., Sauseng, P., Doppelmayr, M., Schabus, M., & Klimesch, W. (2005). Increasing individual upper alpha power by neurofeedback improves cognitive performance in human subjects. Appl. Psychophysiol. Biofeedback, 30(1), Jung-Beeman, M., Bowden, E. M., Haberman, J., Frymiare, J. L., Arambel-Liu, S., Greenblatt, R., et al. (2004). Neural activity when people solve verbal problems with insight. PLoS Biol, 2(4), Spielberger, C. D. (1983). Manual for the State-Trait Anxiety Inventory (STAI). Palo Alto, CA: Consulting Psychologists Press. Acknowledgements: This material is based upon work supported, in whole or in part, with funding from the United States Government. Any opinions, findings and conclusions or recommendations expressed in this material are those of the author(s) and do not necessarily reflect the views of the University of Maryland, College Park and/or any agency or entity of the United States Government. Appendix: Figure 1: Feedback information Comment [LL1]: Henk for Alex: we will show a total of three such panels showing the bar at three different heights as in the executive report of the TR. Please insert the other two bar figures from the TR to achieve this. 5

6 Figure 2: Neurofeedback training protocol Figure 3: Alpha power increased within and across sessions Figure 4 - Theta power increased within the first session only during training 6

7 Figure 5 Beta power did not change reliably Figure 6 State anxiety decreased 7