前言: 神經回饋訓練是一種操作型制約的手法，藉由一腦機介面，使用者能察覺大腦的活性，進而透過嘗試錯誤方式學習調控所需的腦波。阿爾法波神經回饋訓練被證實，可增強健康族群者的情節式記憶與工作型記憶。至今，阿爾法波神經回饋訓練在記憶的機制了解仍被受限的。本研究目的要去開發一個大鼠的阿爾法波神經回饋系統，並藉由三個實驗去調查此系統於記憶伴隨後扣帶迴顱內操弄之影響。
方法: 老鼠被隨機指派到一組接受隨機給獎勵組 (偽對照組)或另一組接受獎勵關於被增強的阿爾法活性 (阿爾法組)，兩組皆接受每週三次神經回饋訓練，為期四週。阿爾法波振幅和總阿爾法期間的指標，會藉由腦皮層電圖所計算。工作型記憶與情節式記憶，會各自藉由空間分辨作業和視覺空間區辨予以評估。
結果: 我們開發一個阿爾法波神經回饋系統根據一被調節的標量期望理論，並驗證此理論在增強阿爾法活性有效性。偽對照組在所有阿爾法活性的指標及記憶表現經由神經回饋訓練，皆無改變；相反的，阿爾法組在所有阿爾法活性的指標及工作記憶和情節式記憶顯示顯著性增強。Bicuculline (γ-氨基丁酸拮抗劑)的微量注射至後扣帶迴，導致在兩組的阿爾法活性指標和記憶表現顯著降低，而AP5 (麩胺酸拮抗劑)或食鹽水注射至後扣帶迴顯示沒有改變。
結論: 本研究開發一套神經回饋系統關於阿爾法活性，顯示此系統在阿爾法活性和記憶增強的有效性。而後扣帶迴的阿爾法活性和記憶表現，顯著性被γ-氨基丁酸所影響。我們結果說明，後扣帶迴在阿爾法活性和記憶提升的產生，藉由γ-氨基丁酸的調節，扮演一重要的角色。

Introduction: Neurofeedback Training (NFT) is an operant conditioning technique using the feedback of user brain wave(s) through a brain computer interface, which allows users learn to adjust their brain activities on demand. NFT of alpha activity has been demonstrated to enhance episodic and working memories in healthy population. To date, mechanism of the alpha NFT on memory is still limited. The current study aimed to develop an alpha NFT system for rats and investigated its effect on memory with intracranial manipulation of the posterior cingulate cortex (PCC) through 3 experiments.
Methods: Rats were randomly assigned into a group receiving a food reward randomly (Sham) or the other group receiving food rewards regarding to increased amplitude of alpha activity (Alpha). Both groups received three NFTs per week for 4 weeks. Indexes of the alpha amplitude and total alpha duration were calculated by electrocorticography. Working memory and episodic memory were assessed by the spatial discrimination task and visuospatial association task, respectively.
Results: We developed an alpha NFT system according to a modified scalar expectancy theory and validated its effectiveness on enhancing alpha activity. The Sham group had no difference in all indexes of alpha activity and memory performance via NFT. In contrast, the Alpha group exhibited significant increase on all alpha indexes and two memory tasks. Microinjection of bicuculline (GABA antagonist) into the PCC resulted in significant decreases of alpha activity indexes and of memory performance in both groups. Injection of AP5 (glutamate antagonist) or saline into the PCC exhibited no change.
Conclusion: The present study developed an NFT system regarding to alpha activity and demonstrated its effectiveness on enhancement of both alpha activity and memory. Alpha activity of the PCC and memory performance were significantly decreased by GABA. Our results suggest that the PCC plays an important role in the generation of alpha activity and memory enhancement through GABA modulation.

Alekseeva, M. V., Balioz, N. V., Muravleva, K. B., Sapina, E. V., & Bazanova, O. M. (2012). Training for voluntarily increasing individual upper α power as a method for cognitive enhancement. Human Physiology, 38(1), 51-60. https://doi.org/10.1134/S0362119711060028.
Angelakis, E., Stathopoulou, S., Frymiare, J. L., Green, D. L., Lubar, J. F., & Kounios, J. (2007). EEG neurofeedback: a brief overview and an example of peak alpha frequency training for cognitive enhancement in the elderly. The Clinical Neuropsychologist, 21(1), 110-129. https://doi.org/10.1080/13854040600744839.
Arrubla, J., Tse, D. H. Y., Amkreutz, C., Neuner, I., & Shah, N. J. (2014). GABA concentration in posterior cingulate cortex predicts putamen response during resting state fMRI. PLOS ONE, 9(9), e106609. https://doi.org/10.1371/journal.pone.0106609.
Bauer, R. H. (1976). Short-term memory: EEG alpha correlates and the effect of increased alpha. Behavioral Biology, 17(4), 425-433. https://doi.org/10.1016/S0091-6773(76)90793-8.
Bazanova, O. M., & Vernon, D. (2014). Interpreting EEG alpha activity. Neuroscience and Biobehavioral Reviews, 44, 94-110. https://doi.org/10.1016/j.neubiorev.2013.05.007.
Besheer, J., & Bevins, R. (2000). Nicotine enhances acquisition of a T-maze visual discrimination: Assessment of individual differences. Behavioural Pharmacology, 11, 613-620. https://doi.org/10.1097/00008877-200011000-00008.
Birch, D., & Jacobs, G. H. (1975). Behavioral measurements of rat spectral sensitivity. Vision Research, 15(6), 687-691. https://doi.org/10.1016/0042-6989(75)90285-0.
Boynton, T. (2001). Applied research using alpha/theta training for enhancing creativity and well-being. Journal of Neurotherapy, 5(1-2), 5-18. http://dx.doi.org/10.1300/J184v05n01_02.
Cheng, L., Duan, B., Huang, T., Zhang, Y., Chen, Y., Britz, O., et al. (2017). Identification of spinal circuits involved in touch-evoked dynamic mechanical pain. Nature Neuroscience, 20(6), 804-814. https://doi.org/10.1038/nn.4549.
Cho, H. Y., Kim, K., Lee, B., & Jung, J. (2015). The effect of neurofeedback on a brain wave and visual perception in stroke: a randomized control trial. Journal of Physical Therapy Science, 27(3), 673-676. https://doi.org/10.1589/jpts.27.673.
Church, R. M., Meck, W. H., & Gibbon, J. (1994). Application of scalar timing theory to individual trials. Journal of Experimental Psychology: Animal Behavior Processes, 20(2), 135-155. https://doi.org/10.1037//0097-7403.20.2.135.
Coleman, T. B., & Hamilton, W. F. (1933). Color blindness in the rat. Journal of Comparative Psychology, 15(1), 177-181. https://doi.org/10.1037/h0075334.
Davelaar, E. J., Barnby, J. M., Almasi, S., & Eatough, V. (2018). Differential Subjective Experiences in Learners and Non-learners in Frontal Alpha Neurofeedback: Piloting a Mixed-Method Approach. Frontiers in Human Neuroscience, 12(402). https://doi.org/10.3389/fnhum.2018.00402.
Doppelmayr, M., Klimesch, W., Hödlmoser, K., Sauseng, P., & Gruber, W. (2005). Intelligence related upper alpha desynchronization in a semantic memory task. Brain Res Bull, 66(2), 171-177. https://doi.org/10.1016/j.brainresbull.2005.04.007.
Doppelmayr, M., Klimesch, W., Stadler, W., Pöllhuber, D., & Heine, C. (2002). EEG alpha power and intelligence. Intelligence, 30(3), 289-302. https://doi.org/10.1016/S0160-2896(01)00101-5.
Dudchenko, P. A. (2004). An overview of the tasks used to test working memory in rodents. Neuroscience & Biobehavioral Reviews, 28(7), 699-709. https://doi.org/10.1016/j.neubiorev.2004.09.002.
Escolano, C., Aguilar, M., & Minguez, J. (2011). EEG-based upper alpha neurofeedback training improves working memory performance. Annual International Conference of the IEEE Engineering in Medicine and Biology Society, 2011, 2327-2330. https://doi.org/10.1109/iembs.2011.6090651.
Farnia, S., Abedi-darzi, S., Fattahi, S., Charati, J., Motamedi, M., Bakhshian, F., et al. (2017). The effect of beta and alpha neurofeedback on memory: A randomized, double-blind, sham-controlled, clinical trial. Iranian Journal of Psychiatry and Behavioral Sciences, 11(2), e7431. https://doi.org/10.5812/ijpbs.7431.
Gómora-Arrati, P., Dominguez, G., & Ågmo, A. (2016). GABA receptors in the medial preoptic area modulate the onset of oestradiol-induced maternal behaviour in hysterectomised-ovariectomised, pregnant rats. Journal of Neuroendocrinology, 28(11). https://doi.org/10.1111/jne.12434.
Gibbon, J. (1977). Scalar expectancy theory and Weber's law in animal timing. Psychological Review, 84(3), 279-325. https://doi.org/10.1037/0033-295X.84.3.279.
Gordon, S., Todder, D., Deutsch, I., Garbi, D., Alkobi, O., Shriki, O., et al. (2019). Effects of neurofeedback and working memory-combined training on executive functions in healthy young adults. Psychological Research, 1-24. https://doi.org/10.1007/s00426-019-01170-w.
Griffin, A., & Hallock, H. (2013). Hippocampal signatures of episodic memory: Evidence from single-unit recording studies. Frontiers in Behavioral Neuroscience, 7(54). https://doi.org/10.3389/fnbeh.2013.00054.
Grundman, M., Petersen, R. C., Ferris, S. H., Thomas, R. G., Aisen, P. S., Bennett, D. A., et al. (2004). Mild cognitive impairment can be distinguished from Alzheimer disease and normal aging for clinical trials. Archives of Neurology, 61(1), 59-66. https://doi.org/10.1001/archneur.61.1.59.
Gruzelier, J. H. (2014a). EEG-neurofeedback for optimising performance. I: A review of cognitive and affective outcome in healthy participants. Neuroscience and Biobehavioral Reviews, 44, 124-141. https://doi.org/10.1016/j.neubiorev.2013.09.015.
Guez, J., Rogel, A., Getter, N., Keha, E., Cohen, T., Amor, T., et al. (2014). Influence of electroencephalography neurofeedback training on episodic memory: A randomized, sham-controlled, double-blind study. Memory, 23(5), 683-694. https://doi.org/10.1080/09658211.2014.921713.
Hahn, B., Ross, T. J., & Stein, E. A. (2007). Cingulate activation increases dynamically with response speed under stimulus unpredictability. Cerebral Cortex, 17(7), 1664-1671. https://doi.org/10.1093/cercor/bhl075.
Hampson, M., Driesen, N. R., Skudlarski, P., Gore, J. C., & Constable, R. T. (2006). Brain connectivity related to working memory performance. The Journal of Neuroscience, 26(51), 13338. https://doi.org/10.1523/JNEUROSCI.3408-06.2006.
Hanslmayr, S., Sauseng, P., Doppelmayr, M., Schabus, M., & Klimesch, W. (2005). Increasing individual upper alpha power by neurofeedback improves cognitive performance in human subjects. Applied Psychophysiology and Biofeedback, 30(1), 1-10. https://doi.org/10.1007/s10484-005-2169-8.
Heinrich, H., Gevensleben, H., & Strehl, U. (2007). Annotation: neurofeedback - train your brain to train behaviour. Journal of Child Psychology and Psychiatry, 48(1), 3-16. https://doi.org/10.1111/j.1469-7610.2006.01665.x.
Hsueh, J. J., Chen, T. S., Chen, J. J., & Shaw, F. Z. (2016). Neurofeedback training of EEG alpha rhythm enhances episodic and working memory. Human Brain Mapping, 37(7), 2662-2675. https://doi.org/10.1002/hbm.23201.
Huijbers, W., Vannini, P., Sperling, R. A., Pennartz, C., Cabeza, R., & Daselaar, S. (2012). Explaining the encoding/retrieval flip: Memory-related deactivations and activations in the posteromedial cortex. Neuropsychologia, 50. https://doi.org/10.1016/j.neuropsychologia.2012.08.021.
Jacobs, G. H., Fenwick, J. A., & Williams, G. A. (2001). Cone-based vision of rats for ultraviolet and visible lights. The Journal of Experimental Biology, 204(Pt 14), 2439-2446. https://jeb.biologists.org/content/204/14/2439.long.
Jensen, O., Gelfand, J., Kounios, J., & Lisman, J. E. (2002). Oscillations in the alpha band (9–12 Hz) increase with memory load during retention in a short-term memory task. Cerebral Cortex, 12(8), 877-882. https://doi.org/10.1093/cercor/12.8.877.
Khan, A., Wang, X., Chun Hang Eden, T., Chun-Yu, T., & Kai-Yu, T. (2020). Anodal transcranial direct current stimulation of anterior cingulate cortex modulates subcortical brain regions resulting in cognitive enhancement. Frontiers in Human Neuroscience, 14, 584136-584136. https://doi.org/10.3389/fnhum.2020.584136.
Klimesch, W. (1999). EEG alpha and theta oscillations reflect cognitive and memory performance: a review and analysis. Brain Research Reviews, 29(2-3), 169-195. https://doi.org/10.1016/S0165-0173(98)00056-3.
Klimesch, W., Doppelmayr, M., & Hanslmayr, S. (2006). Upper alpha ERD and absolute power: Their meaning for memory performance. Progress in Brain Research, 159, 151-165. https://doi.org/10.1016/s0079-6123(06)59010-7.
Klimesch, W., Sauseng, P., & Hanslmayr, S. (2007). EEG alpha oscillations: the inhibition-timing hypothesis. Brain Research Reviews, 53(1), 63-88. https://doi.org/10.1016/j.brainresrev.2006.06.003.
Koralek, A. C., Costa, R. M., & Carmena, J. M. (2013). Temporally precise cell-specific coherence develops in corticostriatal networks during learning. Neuron, 79(5), 865-872. https://doi.org/10.1016/j.neuron.2013.06.047.
Koralek, A. C., Jin, X., Long, J. D., 2nd, Costa, R. M., & Carmena, J. M. (2012). Corticostriatal plasticity is necessary for learning intentional neuroprosthetic skills. Nature, 483(7389), 331-335. https://doi.org/10.1038/nature10845.
Kuang, S. Y., Yang, X., Wang, Z., Huang, T., Kindy, M., Xi, T., et al. (2016). How microelectrode array-based chick forebrain neuron biosensors respond to glutamate NMDA receptor antagonist AP5 and GABAA receptor antagonist musimol. Sensing and Bio-Sensing Research, 10, 9-14. https://doi.org/10.1016/j.sbsr.2016.06.003.
Lecomte, G., & Juhel, J. (2011). The effects of neurofeedback training on memory performance in elderly subjects. Psychology, 02, 846-852. https://doi.org/10.4236/psych.2011.28129.
Leech, R., & Sharp, D. J. (2014). The role of the posterior cingulate cortex in cognition and disease. Brain : A Journal of Neurology, 137(Pt 1), 12-32. https://doi.org/10.1093/brain/awt162.
Lim, C., & Alexander, M. P. (2009). Stroke and episodic memory disorders. Neuropsychologia, 47(14), 3045-3058. https://doi.org/10.1016/j.neuropsychologia.2009.08.002.
Luijmes, R. E., Pouwels, S., & Boonman, J. (2016). The effectiveness of neurofeedback on cognitive functioning in patients with Alzheimer's disease: Preliminary results. Neurophysiologie Clinique, 46(3), 179-187. https://doi.org/10.1016/j.neucli.2016.05.069.
Medina, J. J. (2008). The biology of recognition memory. Psychiatric Times, 25(7), 13-15. https://www.psychiatrictimes.com.
Miyake, A., & Shah, P. (1999): Models of working memory: Mechanisms of active maintenance and executive control. In. New York, NY, US. https://doi.org/10.1017/CBO9781139174909.
Murray, C. L., Obiang, P., Bannerman, D., & Cunningham, C. (2013). Endogenous IL-1 in cognitive function and anxiety: a study in IL-1RI-/- mice. PLOS ONE, 8(10), e78385. https://doi.org/10.1371/journal.pone.0078385.
Naas, A., Rodrigues, J., Knirsch, J. P., & Sonderegger, A. (2019). Neurofeedback training with a low-priced EEG device leads to faster alpha enhancement but shows no effect on cognitive performance: A single-blind, sham-feedback study. PLOS ONE, 14(9), e0211668. https://doi.org/10.1371/journal.pone.0211668.
Nan, W., Rodrigues, J. P., Ma, J., Qu, X., Wan, F., Mak, P. I., et al. (2012). Individual alpha neurofeedback training effect on short term memory. International Journal of Psychophysiology, 86(1), 83-87. https://doi.org/10.1016/j.ijpsycho.2012.07.182.
Natu, V. S., Lin, J. J., Burks, A., Arora, A., Rugg, M. D., & Lega, B. (2019). Stimulation of the posterior cingulate cortex impairs episodic memory encoding. The Journal of Neuroscience 39(36), 7173-7182. https://doi.org/10.1523/JNEUROSCI.0698-19.2019.
Neitz, J., & Jacobs, G. H. (1986). Reexamination of spectral mechanisms in the rat (Rattus norvegicus). Journal of Comparative Psychology 100(1), 21-29. https://doi.org/10.1037/0735-7036.100.1.21.
Palva, S., & Palva, J. M. (2007). New vistas for alpha-frequency band oscillations. Trends in Neurosciences, 30(4), 150-158. https://doi.org/10.1016/j.tins.2007.02.001.
Pei, G., Wu, J., Chen, D., Guo, G., Liu, S., Hong, M., et al. (2018). Effects of an integrated neurofeedback system with dry electrodes: EEG acquisition and cognition assessment. Sensors, 18(10). https://doi.org/10.3390/s18103396.
Phye, G. D., & Andre, T. (1989). Delayed retention effect: Attention, perseveration, or both? Contemporary Educational Psychology, 14(2), 173-185. https://doi.org/10.1016/0361-476X(89)90035-0.
Read, M. L., & Lissaman, R. (2020). Commentary: Stimulation of the posterior cingulate cortex impairs episodic memory encoding. Frontiers in Human Neuroscience, 14(334). https://doi.org/10.3389/fnhum.2020.00334.
Reis, J., Portugal, A. M., Fernandes, L., Afonso, N., Pereira, M., Sousa, N., et al. (2016). An alpha and theta intensive and short neurofeedback protocol for healthy aging working-memory training. Frontiers in Aging Neuroscience, 8, 157. https://doi.org/10.3389/fnagi.2016.00157.
Renton, T., Tibbles, A., & Jane, T. V. (2017). Neurofeedback as a form of cognitive rehabilitation therapy following stroke: A systematic review. PLOS ONE, 12(5), e0177290. https://doi.org/10.1371/journal.pone.0177290.
Reyes-Trejo, B., Morales-Hernández, M., Anduaga, G., Balderas López, J., Carvalho, J. C., & Navarrete, A. (2019). Evidence for involvement of TRPV1 receptors and potassium channels in the seizures induced by α-sanshool. Planta Medica International Open, 6, e23-e27. https://doi.org/10.1055/a-0871-2496.
Ros, T., Munneke, M. A., Parkinson, L. A., & Gruzelier, J. H. (2014). Neurofeedback facilitation of implicit motor learning. Biological Psychology, 95, 54-58. https://doi.org/10.1016/j.biopsycho.2013.04.013.
Ros, T., Théberge, J., Frewen, P. A., Kluetsch, R., Densmore, M., Calhoun, V. D., et al. (2013). Mind over chatter: Plastic up-regulation of the fMRI salience network directly after EEG neurofeedback. NeuroImage, 65, 324-335. https://doi.org/10.1016/j.neuroimage.2012.09.046.
Sestieri, C., Capotosto, P., Tosoni, A., Luca Romani, G., & Corbetta, M. (2013). Interference with episodic memory retrieval following transcranial stimulation of the inferior but not the superior parietal lobule. Neuropsychologia, 51(5), 900-906. https://doi.org/10.1016/j.neuropsychologia.2013.01.023.
Spowart-Manning, L., & van der Staay, F. J. (2004). The T-maze continuous alternation task for assessing the effects of putative cognition enhancers in the mouse. Behavioural Brain Research, 151(1-2), 37-46. https://doi.org/10.1016/j.bbr.2003.08.004.
Steingrimsson, S., Bilonic, G., Ekelund, A.-C., Larson, T., Stadig, I., Svensson, M., et al. (2020). Electroencephalography-based neurofeedback as treatment for post-traumatic stress disorder: A systematic review and meta-analysis. European Psychiatry, 63(1), e7. https://doi.org/10.1192/j.eurpsy.2019.7.
Sterman, M. B., Goodman, S. J., & Kovalesky, R. A. (1978). Effects of sensorimotor EEG feedback training on seizure susceptibility in the rhesus monkey. Experimental Neurology, 62(3), 735-747. https://doi.org/10.1016/0014-4886(78)90281-9.
Sterman, M. B., & Wyrwicka, W. (1967). EEG correlates of sleep: evidence for separate forebrain substrates. Brain Research, 6(1), 143-163. https://doi.org/10.1016/0006-8993(67)90186-2.
Sterman, M. B., Wyrwicka, W., & Roth, S. (1969). Electrophysiological correlates and neural substrates of alimentary behavior in the cat. Annals New York Academy of Sciences 157(2), 723-739. https://doi.org/10.1111/j.1749-6632.1969.tb12916.x.
Su, K. H., Hsueh, J. J., Chen, T. S., & Shaw, F. Z. (2018). Current dipoles analysis for alpha activity of EEG neurofeedback training. The 3rd Global Conference on Biomedical Enginerring https://twbiogroup.org/activity_apply_en.aspx.
Tanaka, N., Sano, K., Rahman, M. A., Miyata, R., Capi, G., & Kawahara, S. (2018). Change in hippocampal theta oscillation associated with multiple lever presses in a bimanual two-lever choice task for robot control in rats. PLOS ONE, 13(2), e0192593. https://doi.org/10.1371/journal.pone.0192593.
Tomasi, D., & Volkow, N. D. (2010). Functional connectivity density mapping. Proceedings of the National Academy of Sciences, 107(21), 9885-9890. https://doi.org/10.1073/pnas.1001414107.
van Lutterveld, R., Houlihan, S. D., Pal, P., Sacchet, M. D., McFarlane-Blake, C., Patel, P. R., et al. (2017). Source-space EEG neurofeedback links subjective experience with brain activity during effortless awareness meditation. NeuroImage, 151, 117-127. https://doi.org/10.1016/j.neuroimage.2016.02.047.
Wan, F., Nan, W., Vai, M. I., & Rosa, A. (2014). Resting alpha activity predicts learning ability in alpha neurofeedback. Frontiers in Human Neuroscience, 8, 500. https://doi.org/10.3389/fnhum.2014.00500.
Wang, J. R., & Hsieh, S. (2013). Neurofeedback training improves attention and working memory performance. Clinical Neurophysiology, 124(12), 2406-2420. https://doi.org/10.1016/j.clinph.2013.05.020.
Wei, T. Y., Chang, D. W., Liu, Y. D., Liu, C. W., Young, C. P., Liang, S. F., et al. (2017). Portable wireless neurofeedback system of EEG alpha rhythm enhances memory. Biomedical Engineering Online, 16(1), 128. https://doi.org/10.1186/s12938-017-0418-8.
Wyrwicka, W., & Sterman, M. B. (1968). Instrumental conditioning of sensorimotor cortex EEG spindles in the waking cat. Physiology & Behavior, 3(5), 703-707. https://doi.org/10.1016/0031-9384(68)90139-X.
Xiong, S., Cheng, C., Wu, X., Guo, X., Yao, L., & Zhang, J. (2014). Working memory training using EEG neurofeedback in normal young adults. Biomedical Materials and Engineering, 24(6), 3637-3644. https://doi.org/10.3233/bme-141191.
Yeh, W. H., Hsueh, J. J., & Shaw, F. Z. (2021). Neurofeedback of alpha activity on memory in healthy participants: A systematic review and meta-analysis. Frontiers in Human Neuroscience, 14, 562360. https://doi.org/10.3389/fnhum.2020.562360.
Zentall, T. R., Clement, T. S., Bhatt, R. S., & Allen, J. (2001). Episodic-like memory in pigeons. Psychonomic Bulletin and Review, 8(4), 685-690. https://doi.org/10.3758/bf03196204.
Zoccolan, D. (2015). Invariant visual object recognition and shape processing in rats. Behavioural Brain Research, 285, 10-33. https://doi.org/10.1016/j.bbr.2014.12.053.
Zoefel, B., Huster, R. J., & Herrmann, C. S. (2011). Neurofeedback training of the upper alpha frequency band in EEG improves cognitive performance. Neuroimage, 54(2), 1427-1431. https://doi.org/10.1016/j.neuroimage.2010.08.078.
Zou, Q., Wu, C. W., Stein, E. A., Zang, Y., & Yang, Y. (2009). Static and dynamic characteristics of cerebral blood flow during the resting state. Neuroimage, 48(3), 515-524. https://doi.org/10.1016/j.neuroimage.2009.07.006.