Studying the default mode and its mindfulness-induced changes using EEG functional connectivity

Social Cognitive and Affective Neuroscience

Volumn 9, Issue 10, 2014, Pages 1616-1624

  Berkovich Ohana, Aviva ^a,b   Glicksohn, Joseph ^a   Goldstein, Abraham ^a  

^a BAR ILAN UNIVERSITY   (Israel)

^b WEIZMANN INSTITUTE OF SCIENCE   (Israel)

Author keywords

Default mode network; Electroencephalography; Functional connectivity; Mean phase coherence; Mindfulness meditation

Indexed keywords

ANALYSIS OF VARIANCE; BIOLOGICAL MODEL; BRAIN; BRAIN MAPPING; CASE CONTROL STUDY; ELECTROENCEPHALOGRAPHY; FEMALE; HUMAN; MALE; MINDFULNESS; PHYSIOLOGY;

ANALYSIS OF VARIANCE; BRAIN; BRAIN MAPPING; CASE-CONTROL STUDIES; ELECTROENCEPHALOGRAPHY; FEMALE; HUMANS; MALE; MINDFULNESS; MODELS, NEUROLOGICAL;

EID: 84899699696     PISSN: 17495016     EISSN: 17495024     Source Type: Journal    
DOI: 10.1093/scan/nst153     Document Type: Article

References (114)

1. Aftanas, L.I., Golocheikine, S.A. (2001). Human anterior and frontal midline theta and lower alpha reflect emotionally positive state and internalized attention: high-resolution EEG investigation of meditation. Neuroscience Letters, 310, 57-60.
2. Aftanas, L.I., Golocheikine, S.A. (2002). Non-linear dynamic complexity of the human EEG during meditation. Neuroscience Letters, 330, 143-6.
3. Baijal, S., Srinivasan, N. (2010). Theta activity and meditative states: spectral changes during concentrative meditation. Cognitive Processing, 11, 31-8.
4. Bastiaansen, M., Hagoort, P. (2006). Oscillatory neuronal dynamics during language comprehension. Progress in Brain Research, 159, 179-96.
5. Berkovich-Ohana, A., Glicksohn, J., Goldstein, A. (2011). Temporal cognition changes following mindfulness, but not transcendental meditation practice. In: Algom, D., Zakay, D., Chajut, E., Shaki, E., Mama, Y., Shakuf, V., editors. Fechner Day 2011: Proceedings of the 27th Annual Meeting of the International Society for Psychophysics. Raanana, Israel. pp. 245-50.
6. Berkovich-Ohana, A., Glicksohn, J., Goldstein, A. (2012). Mindfulness-induced changes in gamma band activity-implications for the default mode network, self-reference and attention. Clinical Neurophysiology, 123, 700-10.
7. Bhattacharya, J., Petsche, H. (2001). Enhanced phase synchrony in the electroencephalograph band for musicians while listening to music. Physical Review E, 64, 12902.
8. Bhattacharya, J., Petsche, H. (2002). Shadows of artistry: cortical synchrony during perception and imagery of visual art. Cognitive Brain Research, 13, 179-86.
9. Bhattacharya, J., Petsche, H. (2005). Drawing on mind's canvas: Differences in cortical integration patterns between artists and non-artists. Human Brain Mapping, 26, 1-14.
10. Binder, J.R., Frost, J.A., Hammeke, T.A., Bellgowan, P.S.F., Rao, S.M., Cox, R.W. (1999). Conceptual processing during the conscious resting state: a functional MRI study. Journal of Cognitive Neuroscience, 11, 80-93.
11. Bishop, S.R., Lau, M., Shapiro, S., et al. (2004). Mindfulness: A proposed operational definition. Clinical Psychology, 11, 230-41.
12. Brewer, J.A., Worhunsky, P.D., Gray, J.R., Tang, Y.Y., Weber, J., Kober, H. (2011). Meditation experience is associated with differences in default mode network activity and connectivity. Proceedings of the National Academy of Sciences of the United States of America, 108, 20254-9.
13. Brown, S.W. (1997). Attentional resources in timing: Interference effects in concurrent temporal and nontemporal working memory tasks. Perception & Psychophysics, 59, 1118-40.
14. Broyd, S.J., Demanuele, C., Debener, S., Helps, S.K., James, C.J., Sonuga-Barke, E.J.S. (2009). Default-mode brain dysfunction in mental disorders: a systematic review. Neuroscience & Biobehavioral Reviews, 33, 279-96.
15. Buckner, R.L., Andrews-Hanna, J., Schachter, D. (2008). The brain's default network: Anatomy, function, and relevance to disease. In: Kingstone, A., Miller, M.B., editors. The Year in Cognitive Neuroscience 2008. Annals of the New York Academy of Sciences. New York: New York Academy of Sciences, pp. 1-38.
16. Cacioppo, J.T., Tassinary, L.G., Fridlund, A.J. (1990). The skeletomotor system. In: Tassinary, L., editor. Principles of Psychophysiology. New York: Cambridge University Press, pp. 325-84.
17. Cahn, B.R., Polich, J. (2006). Meditation states and traits: EEG, ERP, and neuroimaging studies. Psychological Bulletin, 132, 180-211.
18. Chambers, R., Gullone, E., Allen, N.B. (2009). Mindful emotion regulation: An integrative review. Clinical Psychology Review, 23, 560-72.
19. Chan, D., Woollacott, M. (2007). Effects of level of meditation experience on attentional focus: is the efficiency of executive or orientation networks improved? The Journal of Alternative and Complementary Medicine, 13, 651-8.
20. Chen, A.C.N. (2007). EEG default modenetwork in the human brain: spectral field power, coherence, topology, and current source imaging. In: Joint meeting of the 6th international symposium on noninvasive functional source imaging of the brain and heart and the international conference on functional biomedical imaging (NFSIICFBI). Hangzhou, China: Curran Associations, pp. 215-8.
21. Chen, A.C.N., Feng, W.J., Zhao, H.X., Yin, Y.L., Wang, P.P. (2008). EEG default mode network in the human brain: spectral regional field powers. NeuroImage, 41, 561-74.
22. Christoff, K., Gordon, A.M., Smallwood, J., Smith, R., Schooler, J.W. (2009). Experience sampling during fMRI reveals default network and executive system contributions to mind wandering. Proceedings of the National Academy of Sciences of the United States of America, 106, 8719-24.
23. Corbetta, M., Patel, G., Shulman, G.L. (2008). The reorienting system of the human brain: from environment to theory of mind. Neuron, 58, 306-24.
24. Coull, J.T. (2004). fMRI studies of temporal attention: allocating attention within, or towards, time. Cognitive Brain Research, 21, 216-26.
25. Coull, J.T., Nobre, A.C. (1998). Where and when to pay attention: the neural systems for directing attention to spatial locations and to time intervals as revealed by both PET and fMRI. Journal of Neuroscience, 18, 7426-35.
26. Craig, A.D. (2002). How do you feel? Interoception: the sense of the physiological condition of the body. Nature Reviews Neuroscience, 3, 655-66.
27. Craig, A.D. (2009). How do you feel-now? The anterior insula and human awareness. Nature Reviews Neuroscience, 10, 59-70.
28. Davidson, R.J., Chapman, J.P., Chapman, L.J., Henriques, J.B. (1990). Asymmetrical brain electrical activity discriminates between psychometrically-matched verbal and spatial cognitive tasks. Psychophysiology, 27, 528-43.
29. Dillbeck, M.C., Bronson, E.C. (1981). Short-term longitudinal effects of the Transcendental Meditation technique on EEG power and coherence. International Journal of Neuroscience, 14, 147-51.
30. Dillbeck, M.C., Vesely, S.A. (1986). Participation in the Transcendental Meditation program and frontal EEG coherence during concept learning. International Journal of Neuroscience, 29, 45-55.
31. Dumermuth, G., Lehmann, D. (1981). EEG power and coherence during non-REM and REM phases in humans in all-night sleep analyses. European Neurology, 20, 429-34.
32. Dunn, B.R., Hartigan, J.A., Mikulas, W.L. (1999). Concentration and mindfulness meditations: Unique forms of consciousness? Applied Psychophysiology and Biofeedback, 24, 147-65.
33. Earle, J.B. (1984). Cerebral laterality and meditation: A review of the literature. In: Shapiro, D.H., Walsh, R., editors. Meditation: Classic and Contemporary Perspectives. New York, USA: Aldine Publishing, pp. 396-414.
34. Faber, P.L., Lehmann, D., Gianotti, L.R.R., Kaelin, M., Pascual-Marqui, R.D. (2004). Scalp and intracerebral (LORETA) theta and gamma EEG coherence in meditation. In: Meeting of the International Society for Neuronal Regulation. Winterthur, Switzerland.
35. Farb, N.A.S., Segal, Z.V., Mayberg, H., Bean, J., McKeon, D., Fatima, Z., et al. (2007). Attending to the present: mindfulness meditation reveals distinct neural modes of selfreference. Social Cognitive and Affective Neuroscience, 2, 313-22.
36. Farrow, J.T., Hebert, J.R. (1982). Breath suspension during the Transcendental Meditation technique. Psychosomatic Medicine, 44, 133-53.
37. Ferrandez, A.-M., Hugueville, L., Lehéricy, S., Poline, J.-B., Marsault, C., Pouthas, V. (2003). Basal ganglia and supplementary motor area subtend duration perception: an fMRI study. NeuroImage, 19, 1532-44.
38. Ferree, T.C., Luu, P., Russell, G.S., Tucker, D.M. (2001). Scalp electrode impedance, infection risk, and EEG data quality. Clinical Neurophysiology, 112, 536-44.
39. Fine, E.M., Delis, D.C., Dean, D., et al. (2009). Left frontal lobe contributions to concept formation: A quantitative MRI study of performance on the Delis-Kaplan Executive Function System Sorting Test. Journal of Clinical and Experimental Neuropsychology, 31, 624-31.
40. Fingelkurts, A.A., Fingelkurts, A.A., Ermolaev, V.A., Kaplan, A.Y. (2006). Stability, reliability and consistency of the compositions of brain oscillations. International Journal of Psychophysiology, 59, 116-26.
41. Fox, M.D., Snyder, A.Z., Vincent, J.L., Corbetta, M., Van Essen, D.C., Raichle, M.E. (2005). The human brain is intrinsically organized into dynamic, anticorrelated functional networks. Proceedings of the National Academy of Sciences of the United States of America, 102, 9673-8.
42. Gaylord, C., Orme-Johnson, D., Travis, F. (1989). The effects of the Transcendental Mediation technique and progressive muscle relaxation on EEG coherence, stress reactivity, and mental health in black adults. International Journal of Neuroscience, 46, 77-86.
43. Gazzaniga, M.S. (1989). Organization of the human brain. Science, 245, 947-52.
44. Gazzaniga, M.S. (2000). Cerebral specialization and interhemispheric communication: Does the corpus callosum enable the human condition? Brain, 123, 1293-326.
45. Glicksohn, J. (1998). States of consciousness and symbolic cognition. Journal of Mind and Behavior, 19, 105-18.
46. Glicksohn, J., Hadad, Y. (2012). Sex differences in time production revisited. Journal of Individual Differences, 33, 35-42.
47. Golland, Y., Bentin, S., Gelbard, H., et al. (2007). Extrinsic and intrinsic systems in the posterior cortex of the human brain revealed during natural sensory stimulation. Cerebral Cortex, 17, 766-77.
48. Gusnard, D.A., Akbudak, E., Shulman, G.L., Raichle, M.E. (2001). Medial prefrontal cortex and self-referential mental activity: relation to a default mode of brain function. Proceedings of the National Academy of Sciences of the United States of America, 98, 4259-64.
49. Hasenkamp, W., Barsalou, L.W. (2012). Effects of meditation experience on functional connectivity of distributed brain networks. Frontiers in Human Neuroscience, 6, 1-14.
50. Hebert, R., Lehmann, D., Tan, G., Travis, F., Arenander, A. (2005). Enhanced EEG alpha time-domain phase synchrony during Transcendental Meditation: implications for cortical integration theory. Signal Processing, 85, 2213-32.
51. Hölzel, B.K., Carmody, J., Vangel, M., et al. (2011a). Mindfulness practice leads to increases in regional brain gray matter density. Psychiatry Research: Neuroimaging, 191, 36-43.
52. Hölzel, B.K., Lazar, S.W., Gard, T., Schuman-Olivier, Z., Vago, D.R., Ott, U. (2011b). How does Mindfulness meditation work? Proposing mechanisms of action from a conceptual and neural perspective. Perspectives on Psychological Science, 6, 537-59.
53. Hölzel, B.K., Ott, U., Hempel, H., et al. (2007). Differential engagement of anterior cingulate and adjacent medial frontal cortex in adept meditators and non-meditators. Neuroscience Letters, 421, 16-21.
54. Horan, R. (2009). The neuropsychological connection between creativity and meditation. Creativity Research Journal, 21, 199-222.
55. Ivanovski, B., Malhi, G.S. (2007). The psychological and neurophysiological concomitants of mindfulness forms of meditation. Acta Neuropsychiatrica, 19, 76-91.
56. Ives-Deliperi, V.L., Solms, M., Meintjes, E.M. (2011). The neural substrates of mindfulness: An fMRI investigation. Social Neuroscience, 6, 231-42.
57. Jang, J., Jung, W.H., Kang, D.H., et al. (2011). Increased default mode network connectivity associated with meditation. Neuroscience Letters, 487, 358-62.
58. Jerbi, K., Vidal, J.R., Ossandon, T., et al. (2010). Exploring the electrophysiological correlates of the default-mode network with intracerebral EEG. Frontiers in Systems Neuroscience, 4, 1-9.
59. Kabat-Zinn, J. (2003). Mindfulness-based interventions in context: past, present, and future. Clinical Psychology: Science & Practice, 10, 144-56.
60. Kilpatrick, L.A., Suyenobu, B.Y., Smith, S.R., et al. (2011). Impact of mindfulness-based stress reduction training on intrinsic brain connectivity. NeuroImage, 56, 290-298.
61. Kim, H. (2012). A dual-subsystem model of the brain's default network: Self-referential processing, memory retrieval processes and autobiographical memory retrieval. NeuroImage, 61, 966-77.
62. Knyazev, G.G., Slobodskoj-Plusnin, J.Y., Bocharov, A.V., Pylkova, L.V. (2011). The default mode network and EEG alpha oscillations: An independent component analysis. Brain Research, 1402, 67-79.
63. Lachaux, J.P., Rodriguez, E., Martinerie, J., Varela, F.J. (1999). Measuring phase synchrony in brain signals. Human Brain Mapping, 8, 194-208.
64. Laufs, H., Krakow, K., Sterzer, P., et al. (2003). Electroencephalographic signatures of attentional and cognitive default modes in spontaneous brain activity fluctuations at rest. Proceedings of the National Academy of Sciences of the United States of America, 100, 11053-8.
65. Lehmann, D., Faber, P.L., Tei, S., Pascual-Marqui, R.D., Milz, P., Kochi, K. (2012). Reduced functional connectivity between cortical sources in five meditation traditions detected with lagged coherence using EEG tomography. NeuroImage, 60, 1574-86.
66. Luders, E., Kurth, F., Mayer, E.A., Toga, A.W., Narr, K.L., Gaser, C. (2012). The unique brain anatomy of meditation practitioners: alterations in cortical gyrification. Frontiers in Human Neuroscience, 6, 1-9.
67. Lutz, A., Greischar, L.L., Rawlings, N.B., Ricard, M., Davidson, R.J. (2004). Long-term meditators self-induce high-amplitude gamma synchrony during mental practice. Proceedings of the National Academy of Sciences of the United States of America, 101, 16369-73.
68. Lutz, A., Slagter, H.A., Dunne, J.D., Davidson, R.J. (2008). Attention regulation and monitoring in meditation. Trends in Cognitive Sciences, 12, 163-9.
69. Macar, F., Anton, J.L., Bonnet, M., Vidal, F. (2004). Timing functions of the supplementary motor area: an event-related fMRI study. Cognitive Brain Research, 21, 206-15.
70. Mantini, D., Perrucci, M.G., Del Gratta, C., Romani, G.L., Corbetta, M. (2007). Electrophysiological signatures of resting state networks in the human brain. Proceedings of the National Academy of Sciences of the United States of America, 104, 13170-5.
71. Martinez-Conde, S., Macknik, S.L., Hubel, D.H. (2004). The role of fixational eye movements in visual perception. Nature Reviews Neuroscience, 5, 229-40.
72. Mason, M.F., Norton, M.I., Van Horn, J.D., Wegner, D.M., Grafton, S.T., Macrae, C.N. (2007). Wandering minds: the default network and stimulus-independent thought. Science, 315, 393-5.
73. Meltzer, J.A., Negishi, M., Mayes, L.C., Constable, R.T. (2007). Individual differences in EEG theta and alpha dynamics during working memory correlate with fMRI responses across subjects. Clinical Neurophysiology, 118, 2419-36.
74. Mormann, F., Lehnertz, K., David, P., Elger, C. (2000). Mean phase coherence as a measure for phase synchronization and its application to the EEG of epilepsy patients. Physica D, 144, 358-69.
75. Murata, T., Takahashi, T., Hamada, T., et al. (2004). Individual trait anxiety levels characterizing the properties of Zen meditation. Neuropsychobiology, 50, 189-94.
76. Nolfe, G. (2011). EEG and meditation. Clinical Neurophysiology, 123, 631-2.
77. Northoff, G., Heinzel, A., De Greck, M., Bermpohl, F., Dobrowolny, H., Panksepp, J. (2006). Self-referential processing in our brain-a meta-analysis of imaging studies on the self. NeuroImage, 31, 440-57.
78. Oliveri, M., Koch, G., Caltagirone, C. (2009). Spatial-temporal interactions in the human brain. Experimental Brain Research, 195, 489-97.
79. Orme-Johnson, D.W., Haynes, C.T. (1981). EEG phase coherence, pure consciousness, creativity, and TM-Sidhi experiences. International Journal of Neuroscience, 13, 211-7.
80. Ossandón, T., Jerbi, K., Vidal, J.R., et al. (2011). Transient suppression of broadband gamma power in the default-mode network is correlated with task complexity and subject performance. Journal of Neuroscience, 31, 14521-30.
81. Pagnoni, G., Cekic, M., Guo, Y. (2008). "Thinking about Not-Thinking": Neural correlates of conceptual processing during Zen meditation. PLoS One, 3, 3083.
82. Pereda, E., Quiroga, R.Q., Bhattacharya, J. (2005). Nonlinear multivariate analysis of neurophysiological signals. Progress in Neurobiology, 77, 1-37.
83. Perrin, F., Pernier, J., Bertrand, O., Echallier, J.F. (1989). Spherical splines for scalp potential and current density mapping. Electroencephalography and Clinical Neurophysiology, 72, 184-7.
84. Preminger, S., Harmelech, T., Malach, R. (2010). Stimulus-free thoughts induce differential activation in the human default network. NeuroImage, 54, 1692-702.
85. Raichle, M.E., MacLeod, A.M., Snyder, A.Z., Powers, W.J., Gusnard, D.A., Shulman, G.L. (2001). A default mode of brain function. Proceedings of the National Academy of Sciences of the United States of America, 98, 676-82.
86. Reiterer, S., Pereda, E., Bhattacharya, J. (2009). Measuring second language proficiency with EEG synchronization: how functional cortical networks and hemispheric involvement differ as a function of proficiency level in second language speakers. Second Language Research, 25, 77-106.
87. Rubia, K. (2009). The neurobiology of meditation and its clinical effectiveness in psychiatric disorders. Biological Psychology, 82, 1-11.
88. Sajonz, B., Kahnt, T., Margulies, D.S., et al. (2010). Delineating self-referential processing from episodic memory retrieval: Common and dissociable networks. NeuroImage, 50, 1606-17.
89. Sauseng, P., Klimesch, W., Schabus, M., Doppelmayr, M. (2005). Fronto-parietal EEG coherence in theta and upper alpha reflect central executive functions of working memory. International Journal of Psychophysiology, 57, 97-103.
90. Scheeringa, R., Bastiaansen, M., Petersson, K.M., Oostenveld, R., Norris, D.G., Hagoort, P. (2008). Frontal theta EEG activity correlates negatively with the default mode network in resting state. International Journal of Psychophysiology, 67, 242-51.
91. Scola, M.D., David, A. (2011). The hemispheric specialization of the human brain and its application to psychoanalytic principles. Jefferson Journal of Psychiatry, 2, 2-11.
92. Smallwood, J., Brown, K., Baird, B., Schooler, J.W. (2012). Cooperation between the default mode network and the frontal-parietal network in the production of an internal train of thought. Brain Research, 1428, 60-70.
93. Smallwood, J., McSpadden, M., Schooler, J.W. (2007). The lights are on but no one's home: Meta-awareness and the decoupling of attention when the mind wanders. Psychonomic Bulletin & Review, 14, 527-33.
94. Smallwood, J., Schooler, J.W. (2006). The restless mind. Psychological Bulletin, 132, 946-58.
95. Soddu, A., Boly, M., Nir, Y., et al. (2009). Reaching across the abyss: recent advances in functional magnetic resonance imaging and their potential relevance to disorders of consciousness. Progress in Brain Research, 177, 261-74.
96. Spreng, R.N., Stevens, W.D., Chamberlain, J.P., Gilmore, A.W., Schacter, D.L. (2010). Default network activity, coupled with the frontoparietal control network, supports goal-directed cognition. NeuroImage, 53, 303-317.
97. Swenson, R.A., Tucker, D.M. (1983). Multivariate analysis of EEG coherence: Stability of the metric, individual differences in patterning and response to arousal. Biological Psychology, 17, 59-75.
98. Tang, Y.Y., Posner, M.I. (2013). Special issue on mindfulness neuroscience. Social Cognitive and. Affective Neuroscience, 8, 1-3.
99. Tang, Y.Y., Ma, Y., Fan, Y., et al. (2009). Central and autonomic nervous system interaction is altered by short-term meditation. Proceedings of the National Academy of Sciences of the United States of America, 106, 8865-71.
100. Taylor, V.A., Daneault, V., Grant, J., et al. (2013). Impact of meditation training on the default mode network during a restful state. Social Cognitive and Affective Neuroscience, 8, 4-14.
101. Tian, L., Jiang, T., Liu, Y., et al. (2007). The relationship within and between the extrinsic and intrinsic systems indicated by resting state correlational patterns of sensory cortices. NeuroImage, 36, 684-90.
102. Travis, F. (2001). Autonomic and EEG patterns distinguish transcending from other experiences during Transcendental Meditation practice. International Journal of Psychophysiology, 42, 1-9.
103. Travis, F.T. (1991). Eyes open and TM EEG patterns after one and after eight years of TM practice. Psychophysiology, 28, S58.
104. Travis, F., Shear, J. (2010). Focused attention, open monitoring and automatic selftranscending: Categories to organize meditations from Vedic, Buddhist and Chinese traditions. Consciousness and Cognition, 19, 1110-8.
105. Travis, F., Tecce, J., Arenander, A., Wallace, R.K. (2002). Patterns of EEG coherence, power, and contingent negative variation characterize the integration of transcendental and waking states. Biological Psychology, 61, 293-319.
106. Travis, F., Wallace, R.K. (1999). Autonomic and EEG patterns during eyes-closed rest and Transcendental Meditation (TM) practice: the basis for a neural model of TM practice. Consciousness and Cognition, 8, 302-18.
107. Tucker, D.M., Roth, D.L., Bair, T.B. (1986). Functional connections among cortical regions: topography of EEG coherence. Electroencephalography and Clinical Neurophysiology, 63, 242-50.
108. Vincent, J.L., Kahn, I., Snyder, A.Z., Raichle, M.E., Buckner, R.L. (2008). Evidence for a frontoparietal control system revealed by intrinsic functional connectivity. Journal of Neurophysiology, 100, 3328-42.
109. Walsh, V. (2003). A theory of magnitude: common cortical metrics of time, space and quantity. Trends in Cognitive Sciences, 7, 483-8.
110. Whitham, E.M., Pope, K.J., Fitzgibbon, S.P., et al. (2007). Scalp electrical recording during paralysis: quantitative evidence that EEG frequencies above 20Hz are contaminated by EMG. Clinical Neurophysiology, 118, 1877-88.
111. Wittmann, M. (2009). The inner experience of time. Philosophical Transactions of the Royal Society B: Biological Sciences, 364, 1955-67.
112. Wittmann, M., Simmons, A.N., Aron, J.L., Paulus, M.P. (2010). Accumulation of neural activity in the posterior insula encodes the passage of time. Neuropsychologia, 48, 3110-20.
113. Yuval-Greenberg, S., Deouell, L.Y. (2009). The broadband-transient induced gamma-band response in scalp EEG reflects the execution of saccades. Brain Topography, 22, 3-6.
114. Zeidan, F., Johnson, S.K., Diamond, B.J., David, Z., Goolkasian, P. (2010). Mindfulness meditation improves cognition: Evidence of brief mental training. Consciousness and Cognition, 19, 597-605.