Propofol Amnesia – What is Going on in the Brain?

Contemporary Clinical Neuroscience

Volumn , Issue , 2010, Pages 215-243

  Veselis, Robert A ^a   Pryor, Kane O ^a,b  

^a MEMORIAL SLOAN KETTERING CANCER CENTER   (United States)

^b WEILL CORNELL MEDICAL COLLEGE   (United States)

Author keywords

amnesia; EEG ERP; episodic; human; Memory; midazolam; propofol

Indexed keywords

EID: 85146036730     PISSN: 2627535X     EISSN: 26275341     Source Type: Book Series    
DOI: 10.1007/978-1-60761-462-3_11     Document Type: Chapter

References (130)

1. Abel, T., and K. M. Lattal. 2001. Molecular mechanisms of memory acquisition, consolidation and retrieval. Curr Opin Neurobiol 11(2):180–187.
2. Aggleton, J. P., and J. M. Pearce. 2001. Neural systems underlying episodic memory: insights from animal research. Philos Trans R Soc Lond B Biol Sci 356(1413):1467–1482.
3. Alkire, M. T., A. Vazdarjanova, H. Dickinson-Anson, N. S. White, and L. Cahill. 2001. Lesions of the basolateral amygdala complex block propofol-induced amnesia for inhibitory avoidance learning in rats. Anesthesiology 95(3):708–715.
4. Alkire, M. T., R. Gruver, J. Miller, J. R. McReynolds, E. L. Hahn, and L. Cahill. 2008. Neuroimaging analysis of an anesthetic gas that blocks human emotional memory. Proc Natl Acad Sci USA 105(5):1722–1727.
5. Allan, K., W. G. Robb, and M. D. Rugg. 2000. The effect of encoding manipulations on neural correlates of episodic retrieval. Neuropsychologia 38(8):1188–1205.
6. Anderson, M. C., K. N. Ochsner, B. Kuhl, J. Cooper, E. Robertson, S. W. Gabrieli, G. H. Glover, and J. D. Gabrieli. 2004. Neural systems underlying the suppression of unwanted memories. Science 303(5655):232–235.
7. Axmacher, N., F. Mormann, G. Fernandez, C. E. Elger, and J. Fell. 2006. Memory formation by neuronal synchronization. Brain Res Rev 52(1):170–182.
8. Blumenfeld, R. S., and C. Ranganath. 2006. Dorsolateral prefrontal cortex promotes long-term memory formation through its role in working memory organization. J Neurosci 26(3): 916–925.
9. Bowles, B., C. Crupi, S. M. Mirsattari, S. E. Pigott, A. G. Parrent, J. C. Pruessner, A. P. Yonelinas, and S. Kohler. 2007. Impaired familiarity with preserved recollection after anterior temporallobe resection that spares the hippocampus. PNAS 104(41):16382–16387.
10. Burianova, H., and C. L. Grady. 2007. Common and unique neural activations in autobiographical, episodic, and semantic retrieval. J Cogn Neurosci 19(9):1520–1534.
11. Buzsaki, G., and A. Draguhn. 2004. Neuronal oscillations in cortical networks. Science 304(5679):1926–1929.
12. Cabeza, R., and L. Nyberg. 2000. Imaging cognition II: an empirical review of 275 PET and fMRI studies. J Cogn Neurosci 12(1):1–47.
13. Cabeza, R., and P. St Jacques. 2007. Functional neuroimaging of autobiographical memory. Trends Cogn Sci 11(5):219–227.
14. Cahill, L., and J. L. McGaugh. 1998. Mechanisms of emotional arousal and lasting declarative memory. Trends Neurosci 21(7):294–299.
15. Cahill, L., R. Babinsky, H. J. Markowitsch, and J. L. McGaugh. 1995. The amygdala and emotional memory. Nature 377(6547):295–296.
16. Cahill, L., R. J. Haier, J. Fallon, M. T. Alkire, C. Tang, D. Keator, J. Wu, and J. L. McGaugh. 1996. Amygdala activity at encoding correlated with long-term, free recall of emotional information. Proc Natl Acad Sci USA 93(15):8016–8021.
17. Canolty, R. T., E. Edwards, S. S. Dalal, M. Soltani, S. S. Nagarajan, H. E. Kirsch, M. S. Berger, N. M. Barbaro, and R. T. Knight. 2006. High gamma power is phase-locked to theta oscillations in human neocortex. Science 313(5793):1626–1628.
18. Caplan, J. B., and M. G. Glaholt. 2007. The roles of EEG oscillations in learning relational information. Neuroimage 38(3):604–616.
19. Cheng, V. Y., L. J. Martin, E. M. Elliott, J. H. Kim, H. T. J. Mount, F. A. Taverna, J. C. Roder, J. F. MacDonald, A. Bhambri, N. Collinson, K. A. Wafford, and B. A. Orser. 2006. {alpha}5GABAA receptors mediate the amnestic but not sedative-hypnotic effects of the general anesthetic etomidate. J Neurosci 26(14):3713–3720.
20. Cohen, N. J., and L. R. Squire. 1980. Preserved learning and retention of pattern-analyzing skill in amnesia: dissociation of knowing how and knowing that. Science 210(4466): 207–210.
21. Crochet, S., P. Fuentealba, Y. Cisse, I. Timofeev, and M. Steriade. 2006. Synaptic plasticity in local cortical network in vivo and its modulation by the level of neuronal activity. Cereb Cortex 16(5):618–631.
22. Curran, T., C. DeBuse, B. Woroch, and E. Hirshman. 2006. Combined pharmacological and electrophysiological dissociation of familiarity and recollection. J Neurosci 26(7):1979–1985.
23. Deeprose, C., J. Andrade, S. Varma, and N. Edwards. 2004. Unconscious learning during surgery with propofol anaesthesia. Br J Anaesth 92(2):171–177.
24. Deeprose, C., J. Andrade, D. Harrison, and N. Edwards. 2005. Unconscious auditory priming during surgery with propofol and nitrous oxide anaesthesia: a replication. Br J Anaesth 94(1):57–62.
25. Dickinson-Anson, H., and J. L. McGaugh. 1997. Bicuculline administered into the amygdala after training blocks benzodiazepine-induced amnesia. Brain Res 752(1–2):197–202.
26. Draganski, B., C. Gaser, G. Kempermann, H. Georg Kuhn, J. Winkler, C. Buchel, and A. May. 2006. Temporal and spatial dynamics of brain structure changes during extensive learning. J Neurosci 26(23):6314–6317.
27. Duzel, E., M. Neufang, and H.-J. Heinze. 2005. The oscillatory dynamics of recognition memory and its relationship to event-related responses. Cereb Cortex 15(12):1992–2002.
28. Duzel, E., F. Vargha-Khadem, H. J. Heinze, and M. Mishkin. 2001. Brain activity evidence for recognition without recollection after early hippocampal damage. Proc Natl Acad Sci USA 98(14):8101–8106.
29. Eichenbaum, H. 2000. A cortical-hippocampal system for declarative memory. Nat Rev Neurosci 1:41–50.
30. Eichenbaum, H. 2004. Hippocampus: cognitive processes and neural representations that underlie declarative memory. Neuron 44(1):109–120.
31. Fell, J., P. Klaver, K. Lehnertz, T. Grunwald, C. Schaller, C. E. Elger, and G. Fernandez. 2001. Human memory formation is accompanied by rhinal-hippocampal coupling and decoupling. Nat Neurosci 4(12):1259–1264.
32. Fell, J., P. Klaver, H. Elfadil, C. Schaller, C. E. Elger, and G. Fernandez. 2003. Rhinalhippocampal theta coherence during declarative memory formation: interaction with gamma synchronization? Eur J Neurosci 17(5):1082–1088.
33. Fell, J., T. Dietl, T. Grunwald, M. Kurthen, P. Klaver, P. Trautner, C. Schaller, C. E. Elger, and G. Fernandez. 2004. Neural bases of cognitive ERPs: more than phase reset. J Cogn Neurosci 16(9):1595–1604.
34. Fernandes, M. A., and M. Moscovitch. 2000. Divided attention and memory: evidence of substantial interference effects at retrieval and encoding. J Exp Psychol Gen 129(2): 155–176.
35. Fernandez, G., and I. Tendolkar. 2006. The rhinal cortex: ‘gatekeeper’ of the declarative memory system. Trends Cogn Sci 10(8):358–362.
36. Fernandez, G., A. Effern, T. Grunwald, N. Pezer, K. Lehnert, M. Duempelmann, D. Van Roost, and C. E. Elger. 1999. Real-time tracking of memory formation in the human rhinal cortex and hippocampus. Science 285(3 September 1999):1582–1585.
37. Friedman, D. 1990. ERPs during continuous recognition memory for words. Biol Psychol 30: 61–87.
38. Friedman, D., and R. Johnson, Jr. 2000. Event-related potential (ERP) studies of memory encoding and retrieval: a selective review. Microsc Res Technique 51(1):6–28.
39. Galinkin, J. L., D. Janiszewski, C. J. Young, J. M. Klafta, P. A. Klock, D. W. Coalson, J. L. Apfelbaum, and J. P. Zacny. 1997. Subjective, psychomotor, cognitive, and analgesic effects of subanesthetic concentrations of sevoflurane and nitrous oxide. Anesthesiology 87(5):1082–1088.
40. Ghoneim, M. M., and R. I. Block. 1997. Learning and memory during general anesthesia. Anesthesiology 87(2):387–410.
41. Ghoneim, M. M., and J. V. Hinrichs. 1997. Drugs, memory and sedation: specificity of efects. Anesthesiology 87(Oct):734–736.
42. Ghoneim, M. M., and S. P. Mewaldt. 1990. Benzodiazepines and human memory: a review. Anesthesiology 72(5):926–938.
43. Ghoneim, M. M., R. I. Block, and V. J. Dhanaraj. 1998. Interaction of a subanaesthetic concentration of isoflurane with midazolam: effects on responsiveness, learning and memory [see comments]. Br J Anaesthesia 80(5):581–587.
44. Gonsowski, C. T., B. S. Chortkoff, E. I. Eger, II, H. L. Bennett, and R. B. Weiskopf. 1995. Subanesthetic concentrations of desflurane and isoflurane suppress explicit and implicit learning. Anesthesia Analgesia 80(3):568–572.
45. Greicius, M. D., K. Supekar, V. Menon, and R. F. Dougherty. 2008. Resting-state functional connectivity reflects structural connectivity in the default mode network. Cereb Cortex Adv Access Apr 9, bhn059.
46. Guderian, S., and E. Duzel. 2005. Induced theta oscillations mediate large-scale synchrony with mediotemporal areas during recollection in humans. Hippocampus 15(7):901–912.
47. Guillem, F., B. N’Kaoua, A. Rougier, and B. Claverie. 1995. Effects of temporal versus temporal plus extra-temporal lobe epilepsies on hippocampal ERPs: physiopathological implications for recognition memory studies in humans. Brain Res Cogn Brain Res 2(3):147–153.
48. Hebb, D. O. 1949. The organization of behavior; a neuropsychological theory. New York: Wiley.
49. Heindel, W. C., D. P. Salmon, C. W. Shults, P. A. Walicke, and N. Butters. 1989. Neuropsychological evidence for multiple implicit memory systems: a comparison of Alzheimer’s, Huntington’s, and Parkinson’s disease patients. J Neurosci 9(2):582–587.
50. Hudetz, A. G., and O. A. Imas. 2007. Burst activation of the cerebral cortex by flash stimuli during isoflurane anesthesia in rats. Anesthesiology 107(6):983–991.
51. Igaz, L. M., M. R. Vianna, J. H. Medina, and I. Izquierdo. 2002. Two time periods of hippocampal mRNA synthesis are required for memory consolidation of fear-motivated learning. J Neurosci 22(15):6781–6789.
52. Iidaka, T., A. Matsumoto, J. Nogawa, Y. Yamamoto, and N. Sadato. 2006. Frontoparietal network involved in successful retrieval from episodic memory. Spatial and temporal analyses using fMRI and ERP. Cereb Cortex 16(9):1349–1360.
53. Iijima, T., M. P. Witter, M. Ichikawa, T. Tominaga, R. Kajiwara, and G. Matsumoto. 1996. Entorhinal-hippocampal interactions revealed by real-time imaging. Science 272(5265): 1176–1179.
54. Izquierdo, I., L. R. Bevilaqua, J. I. Rossato, J. S. Bonini, J. H. Medina, and M. Cammarota. 2006. Different molecular cascades in different sites of the brain control memory consolidation. Trends Neurosci 29(9):496–505.
55. John, E. R. 2001. A field theory of consciousness. Conscious Cogn 10(2):184–213.
56. John, E. R., P. Easton, and R. Isenhart. 1997. Consciousness and cognition may be mediated by multiple independent coherent ensembles [published erratum appears in Conscious Cogn 1997 Dec; 6(4):598–599]. Consci Cogn 6(1):3–39; discussion 40-1, 50-5, 65-6.
57. John, E. R., L. S. Prichep, W. Kox, P. Valdes-Sosa, J. Bosch-Bayard, E. Aubert, M. Tom, F. diMichele, and L. D. Gugino. 2001. Invariant reversible qEEG effects of anesthetics. Consci Cogn 10(2):165–183.
58. Johnson, R., Jr. 1995. Event-related potential insights into the neurobiology of memory systems. In Handbook of Neuropsychology, vol. 10, edited by R. J. Johnson and J. C. Baron. Amsterdam and New York: Elsevier Science B.V.
59. Kahana, M. J. 2006. The cognitive correlates of human brain oscillations. J Neurosci 26(6): 1669–1672.
60. Kahn, I., L. Davachi, and A. D. Wagner. 2004. Functional-neuroanatomic correlates of recollection: implications for models of recognition memory. J Neurosci 24(17):4172–4180.
61. Kim, J. J., H. J. Lee, J. S. Han, and M. G. Packard. 2001. Amygdala is critical for stressinduced modulation of hippocampal long-term potentiation and learning. J Neurosci 21(14): 5222–5228.
62. Kirk, I. J., and J. C. Mackay. 2003. The role of theta-range oscillations in synchronising and integrating activity in distributed mnemonic networks. Cortex 39(4–5):993–1008.
63. Klimesch, W., M. Doppelmayr, J. Schwaiger, T. Winkler, and W. Gruber. 2000. Theta oscillations and the ERP old/new effect: independent phenomena? Clin Neurophysiol 111(5):781–793.
64. Klimesch, W., S. Hanslmayr, P. Sauseng, W. Gruber, C. J. Brozinsky, N. E. Kroll, A. P. Yonelinas, and M. Doppelmayr. 2006. Oscillatory EEG correlates of episodic trace decay. Cereb Cortex 16(2):280–290.
65. Koene, R. A., and M. E. Hasselmo. 2006. First-in-first-out item replacement in a model of shortterm memory based on persistent spiking. Cereb Cortex eAP:Oct 9 bhl088.
66. Konorski, J. 1948. Conditioned reflexes and neuron organization. Cambridge [Eng.]: Cambridge University Press.
67. Kozinn, J., L. Mao, A. Arora, L. Yang, E. E. Fibuch, and J. Q. Wang. 2006. Inhibition of glutamatergic activation of extracellular signal-regulated protein kinases in hippocampal neurons by the intravenous anesthetic propofol. Anesthesiology 105(6):1182–1191.
68. Lachaux, J. P., E. Rodriguez, J. Martinerie, and F. J. Varela. 1999. Measuring phase synchrony in brain signals. Hum Brain Mapp 8(4):194–208.
69. Lamprecht, R., and J. LeDoux. 2004. Structural plasticity and memory. Nat Rev Neurosci 5(1): 45–54.
70. Leuner, B., J. Falduto, and T. J. Shors. 2003. Associative memory formation increases the observation of dendritic spines in the hippocampus. J Neurosci 23(2):659–665.
71. Levy, D. A., P. J. Bayley, and L. R. Squire. 2004. The anatomy of semantic knowledge: medial vs. lateral temporal lobe. PNAS 101(17):6710–6715.
72. Lisman, J. E. 2005. Hippocampus, II: memory connections. Am J Psychiatry 162(2):239.
73. Lisman, J. E., and M. A. Idiart. 1995. Storage of 7 +/− 2 short-term memories in oscillatory subcycles. Science 267(5203):1512–1515.
74. Logothetis, N. K. 2003. The underpinnings of the BOLD functional magnetic resonance imaging signal. J Neurosci 23(10):3963–3971.
75. Logothetis, N. K. 2008. What we can do and what we cannot do with fMRI. Nature 453(7197): 869–878.
76. Ludowig, E., P. Trautner, M. Kurthen, C. Schaller, C. G. Bien, C. E. Elger, and T. Rosburg. 2008. Intracranially recorded memory-related potentials reveal higher posterior than anterior hippocampal involvement in verbal encoding and retrieval. J Cogn Neurosci 20(5):841–851.
77. Lynch, M. A. 2004. Long-term potentiation and memory. Physiol Rev 84(1):87–136.
78. Maccotta, L., R. L. Buckner, F. G. Gilliam, and J. G. Ojemann. 2006. Changing frontal contributions to memory before and after medial temporal lobectomy. Cereb Cortex eAP: March 17 bhj161.
79. Mainy, N., J. Jung, M. Baciu, P. Kahane, B. Schoendorff, L. Minotti, D. Hoffmann, O. Bertrand, and J. P. Lachaux. 2008. Cortical dynamics of word recognition. Hum Brain Mapp 29(11):1215–1230.
80. Malenka, R. C., and R. A. Nicoll. 1999. Long-term potentiation – a decade of progress? Science 285(5435):1870–1874.
81. Mashour, G. A. 2006. Integrating the science of consciousness and anesthesia. Anesth Analg 103(4):975–982.
82. May, A., G. Hajak, S. Ganssbauer, T. Steffens, B. Langguth, T. Kleinjung, and P. Eichhammer. 2006. Structural brain alterations following 5 days of intervention: dynamic aspects of neuroplasticity. Cereb Cortex eAP:Feb 15.
83. McGaugh, J. L. 2000. Memory – a century of consolidation. Science 287(5451):248–251.
84. McGaugh, J. L., C. K. McIntyre, and A. E. Power. 2002. Amygdala modulation of memory consolidation: interaction with other brain systems. Neurobiol Learn Mem 78(3):539–552.
85. Meltzer, J. A., H. P. Zaveri, Goncharova, II, M. M. Distasio, X. Papademetris, S. S. Spencer, D. D. Spencer, and R. T. Constable. 2008. Effects of working memory load on oscillatory power in human intracranial EEG. Cereb Cortex 18(8):1843–1855.
86. Miller, G. A. 1956. The magical number seven, plus or minus two: some limits on our capacity for processing information. Psychol Rev 63:81–97.
87. Miller, G. 2004. Forgetting and remembering. Learning to forget. Science 304(5667):34–36.
88. Montgomery, S. M., and G. Buzsaki. 2007. Gamma oscillations dynamically couple hippocampal CA3 and CA1 regions during memory task performance. Proc Natl Acad Sci 104(36): 14495–14500.
89. Montgomery, S. M., M. I. Betancur, and G. Buzsaki. 2009. Behavior-dependent coordination of multiple theta dipoles in the hippocampus. J Neurosci 29(5):1381–1394.
90. Mormann, F., J. Fell, N. Axmacher, B. Weber, K. Lehnertz, C. E. Elger, and G. Fernandez. 2005. Phase/amplitude reset and theta-gamma interaction in the human medial temporal lobe during a continuous word recognition memory task. Hippocampus 15(7):890–900.
91. Mormann, F., H. Osterhage, R. G. Andrzejak, B. Weber, G. Fernandez, J. Fell, C. E. Elger, and K. Lehnertz. 2008. Independent delta/theta rhythms in the human hippocampus and entorhinal cortex. Front Hum Neurosci 2:3.
92. Morris, J. S., A. Ohman, and R. J. Dolan. 1998. Conscious and unconscious emotional learning in the human amygdala [see comments]. Nature 393(6684):467–470.
93. Morris, J. S., C. D. Frith, D. I. Perrett, D. Rowland, A. W. Young, A. J. Calder, and R. J. Dolan. 1996. A differential neural response in the human amygdala to fearful and happy facial expressions. Nature 383(6603):812–815.
94. Nelson, L. E., T. Z. Guo, J. Lu, C. B. Saper, N. P. Franks, and M. Maze. 2002. The sedative component of anesthesia is mediated by GABA(A) receptors in an endogenous sleep pathway. Nat Neurosci 5(10):979–984.
95. Nordstrom, O., and R. Sandin. 1996. Recall during intermittent propofol anaesthesia. Br J Anaesthesia 76(5):699–701.
96. O’Gorman, D. A., A. W. O’Connell, K. J. Murphy, D. C. Moriarty, T. Shiotani, and C. M. Regan. 1998. Nefiracetam prevents propofol-induced anterograde and retrograde amnesia in the rodent without compromising quality of anesthesia. Anesthesiology 89(3):699–706.
97. Osipova, D., A. Takashima, R. Oostenveld, G. Fernandez, E. Maris, and O. Jensen. 2006. Theta and gamma oscillations predict encoding and retrieval of declarative memory. J Neurosci 26(28):7523–7531.
98. Parker, E. S., L. Cahill, and J. L. McGaugh. 2006. A case of unusual autobiographical remembering. Neurocase 12(1):35–49.
99. Perouansky, M., H. Hentschke, M. Perkins, and R. A. Pearce. 2007. Amnesic concentrations of the nonimmobilizer 1,2-dichlorohexafluorocyclobutane (F6, 2 N) and isoflurane alter hippocampal theta oscillations in vivo. Anesthesiology 106(6):1168–1176.
100. Plourde, G., P. Belin, D. Chartrand, P. Fiset, S. B. Backman, G. Xie, and R. J. Zatorre. 2006. Cortical processing of complex auditory stimuli during alterations of consciousness with the general anesthetic propofol. Anesthesiology 104(3):448–457.
101. Pryor, K. O., R. A. Veselis, R. A. Reinsel, and V. A. Feshchenko. 2004. Enhanced visual memory effect for negative versus positive emotional content is potentiated at sub-anaesthetic concentrations of thiopental. Br J Anaesth 93(3):348–355.
102. Pulvermuller, F. 2001. Brain reflections of words and their meaning. Trends Cogn Sci 5(12): 517–524.
103. Qiu, M., R. Ramani, M. Swetye, and R. T. Constable. 2008. Spatial nonuniformity of the resting CBF and BOLD responses to sevoflurane: in vivo study of normal human subjects with magnetic resonance imaging. Hum Brain Mapp 29(12):1390–1399.
104. Qiu, M., R. Ramani, M. Swetye, N. Rajeevan, and R. T. Constable. 2008. Anesthetic effects on regional CBF, BOLD, and the coupling between task-induced changes in CBF and BOLD: an fMRI study in normal human subjects. Magn Reson Med 60(4):987–996.
105. Ramani, R., M. Qiu, and R. T. Constable. 2007. Sevoflurane 0.25 MAC preferentially affects higher order association areas: a functional magnetic resonance imaging study in volunteers. Anesth Analg 105(3):648–655.
106. Ranganath, C., M. X. Cohen, and C. J. Brozinsky. 2005. Working memory maintenance contributes to long-term memory formation: neural and behavioral evidence. J Cogn Neurosci 17(7): 994–1010.
107. Rizzuto, D. S., J. R. Madsen, E. B. Bromfield, A. Schulze-Bonhage, D. Seelig, R. AschenbrennerScheibe, and M. J. Kahana. 2003. Reset of human neocortical oscillations during a working memory task. Proc Natl Acad Sci USA 100(13):7931–7936.
108. Rugg, M. D., and T. Curran. 2007. Event-related potentials and recognition memory. Trends Cogn Sci 11(6):251–257.
109. Rugg, M. D., R. C. Roberts, D. D. Potter, C. D. Pickles, and M. E. Nagy. 1991. Event-related potentials related to recognition memory. Effects of unilateral temporal lobectomy and temporal lobe epilepsy. Brain 114(Pt 5):2313–2332.
110. Schacter, D. L., and E. Tulving. 1994. Memory systems 1994. Cambridge, MA: MIT Press.
111. Scoville, W.B., and B Milner. 1957. Loss of recent memory after bilateral hippocampal lesions. J Neurol Neurosurg Psychiatry 20:11–21.
112. Sederberg, P. B., A. Schulze-Bonhage, J. R. Madsen, E. B. Bromfield, D. C. McCarthy, A. Brandt, M. S. Tully, and M. J. Kahana. 2006. Hippocampal and neocortical gamma oscillations predict memory formation in humans. Cereb Cortex eAP:jul10 bhl030.
113. Shimizu, E., Y. P. Tang, C. Rampon, and J. Z. Tsien. 2000. NMDA receptor-dependent synaptic reinforcement as a crucial process for memory consolidation. Science 290(5494): 1170–1174.
114. Smith, M. E., and E. Halgren. 1989. Dissociation of recognition memory components following temporal lobe lesions. J Exp Psychol Learn Mem Cogn 15(1):50–60.
115. Smith, C. N., and L. R. Squire. 2009. Medial temporal lobe activity during retrieval of semantic memory is related to the age of the memory. J Neurosci 29(4):930–938.
116. Sonner, J. M., D. F. Werner, F. P. Elsen, Y. Xing, M. Liao, R. A. Harris, N. L. Harrison, M. S. Fanselow, E. I. Eger, II, and G. E. Homanics. 2007. Effect of isoflurane and other potent inhaled anesthetics on MAC, learning, and the righting reflex in mice engineered to express alpha1 GABA-A receptors unresponsive to isoflurane. Anesthesiology 106(1):107–113.
117. Squire, L. R., and S. Zola-Morgan. 1991. The medial temporal lobe memory system. Science 253(5026):1380–1386.
118. Tulving, E. 2001. Episodic memory and common sense: how far apart? Philos Trans R Soc Lond BBiolSci356(1413):1505–1515.
119. Tulving, E., and D. L. Schacter. 1990. Priming and human memory systems. Science 247(4940):301–306.
120. Ungerleider, L. G. 1995. Functional brain imaging studies of cortical mechanisms for memory. Science 270(5237):769–775.
121. Varela, F., J. P. Lachaux, E. Rodriguez, and J. Martinerie. 2001. The brainweb: phase synchronization and large-scale integration. Nat Rev Neurosci 2(4):229–239.
122. Vertes, R. P. 2005. Hippocampal theta rhythm: a tag for short-term memory. Hippocampus 15(7):923–935.
123. Veselis, R. A., R. A. Reinsel, and V. A. Feshchenko. 2001. Drug-induced amnesia is a separate phenomenon from sedation: electrophysiologic evidence. Anesthesiology 95(4):896–907.
124. Veselis, R. A., R. A. Reinsel, V. A. Feshchenko, and M. Wronski. 1997. The comparative amnestic effects of midazolam, propofol, thiopental, and fentanyl at equisedative concentrations. Anesthesiology 87(4):749–764.
125. Veselis, R. A., R. A. Reinsel, V. A. Feshchenko, and R. Johnson, Jr. 2004. Information loss over time defines the memory defect of propofol: A comparative response with thiopental and dexmedetomidine. Anesthesiology 101(4):831–841.
126. Veselis, R. A., K. O. Pryor, R. A. Reinsel, M. Mehta, H. Pan, and R. Johnson, Jr. 2008. Low-dose propofol-induced amnesia is not due to a failure of encoding: left inferior prefrontal cortex is still active. Anesthesiology 109(2):213–224.
127. Veselis, R. A., K. O. Pryor, R. A. Reinsel, Y. Li, M. Mehta, and R. Johnson, Jr. 2009. Propofol and midazolam inhibit conscious memory processes very soon after encoding: an eventrelated potential study of familiarity and recollection in volunteers. Anesthesiology 110(2): 295–312.
128. Vincent, J. L., A. Z. Snyder, M. D. Fox, B. J. Shannon, J. R. Andrews, M. E. Raichle, and R. L. Buckner. 2006. Coherent spontaneous activity identifies a hippocampal-parietal memory network. J Neurophysiol 96(6):3517–3531.
129. Ward, L. M. 2003. Synchronous neural oscillations and cognitive processes. Trends Cogn Sci 7(12):553–559.
130. Wixted, J. T. 2005. A theory about why we forget what we once knew. Curr Directions Psychol Sci 14(1):6–9.