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Volumn 358, Issue 1432, 2003, Pages 765-772

Long-term potentiation and the ageing brain

Author keywords

Ageing; Hippocampus; Learning; Long term potentiation; Memory

Indexed keywords

AGING; MEMORY; NEUROLOGY;

EID: 0038222582     PISSN: 09628436     EISSN: None     Source Type: Journal    
DOI: 10.1098/rstb.2002.1244     Document Type: Review
Times cited : (165)

References (55)
  • 1
    • 0033609045 scopus 로고    scopus 로고
    • Age-related defects in spatial memory are correlated with defects in the late phase of hippocampal long-term potentiation in vitro and are attenuated by drugs that enhance the cAMP signaling pathway
    • Bach, M. E., Barad, M., Son, H., Zhuo, M., Lu, Y. F., Shih, R., Mansuy, I., Hawkins, R. D. & Kandel, E. R. 1999 Age-related defects in spatial memory are correlated with defects in the late phase of hippocampal long-term potentiation in vitro and are attenuated by drugs that enhance the cAMP signaling pathway. Proc. Natl Acad. Sci. USA 96, 5280-5285.
    • (1999) Proc. Natl. Acad. Sci. USA , vol.96 , pp. 5280-5285
    • Bach, M.E.1    Barad, M.2    Son, H.3    Zhuo, M.4    Lu, Y.F.5    Shih, R.6    Mansuy, I.7    Hawkins, R.D.8    Kandel, E.R.9
  • 2
    • 0018344553 scopus 로고
    • Memory deficits associated with senescence: A neurophysiological and behavioral study in the rat
    • Barnes, C. A. 1979 Memory deficits associated with senescence: a neurophysiological and behavioral study in the rat. J. Comp. Physiol. Psychol. 93, 74-104.
    • (1979) J. Comp. Physiol. Psychol. , vol.93 , pp. 74-104
    • Barnes, C.A.1
  • 3
    • 0028107456 scopus 로고
    • Normal aging: Regionally specific changes in hippocampal synaptic transmission
    • Barnes, C. A. 1994 Normal aging: regionally specific changes in hippocampal synaptic transmission. Trends Neurosci. 17, 13-18.
    • (1994) Trends Neurosci. , vol.17 , pp. 13-18
    • Barnes, C.A.1
  • 4
    • 0002631245 scopus 로고
    • Spatial memory and hippocampal synaptic plasticity in middle-aged and senescent rats
    • ed. D. Stein. New York: Elsevier
    • Barnes, C. A. & McNaughton, B. L. 1980a Spatial memory and hippocampal synaptic plasticity in middle-aged and senescent rats. In Psychobiology of aging: problems and perspectives (ed. D. Stein), pp. 253-272. New York: Elsevier.
    • (1980) Psychobiology of Aging: Problems and Perspectives , pp. 253-272
    • Barnes, C.A.1    McNaughton, B.L.2
  • 5
    • 0019225823 scopus 로고
    • Physiological compensation for loss of afferent synapses in rat hippocampal granule cells during senescence
    • Barnes, C. A. & McNaughton, B. L. 1980b Physiological compensation for loss of afferent synapses in rat hippocampal granule cells during senescence. J. Physiol. 309, 473-485.
    • (1980) J. Physiol. , vol.309 , pp. 473-485
    • Barnes, C.A.1    McNaughton, B.L.2
  • 6
    • 0022403407 scopus 로고
    • An age comparison of the rates of acquisition and forgetting of spatial information in relation to long-term enhancement of hippocampal synapses
    • Barnes, C. A. & McNaughton, B. L. 1985 An age comparison of the rates of acquisition and forgetting of spatial information in relation to long-term enhancement of hippocampal synapses. Behav. Neurosci. 99, 1040-1048.
    • (1985) Behav. Neurosci. , vol.99 , pp. 1040-1048
    • Barnes, C.A.1    McNaughton, B.L.2
  • 7
    • 0026938051 scopus 로고
    • Region-specific age effects on AMPA sensitivity: Electrophysiological evidence for loss of synaptic contacts in hippocampal field CA1
    • Barnes, C. A., Rao, G., Foster, T. C. & McNaughton, B. L. 1992 Region-specific age effects on AMPA sensitivity: electrophysiological evidence for loss of synaptic contacts in hippocampal field CA1. Hippocampus 2, 457-468.
    • (1992) Hippocampus , vol.2 , pp. 457-468
    • Barnes, C.A.1    Rao, G.2    Foster, T.C.3    McNaughton, B.L.4
  • 8
    • 0034282068 scopus 로고    scopus 로고
    • LTP induction threshold change in old rats at the perforant path-granule cell synapse
    • Barnes, C. A., Rao, G. & Houston, F. P. 2000a LTP induction threshold change in old rats at the perforant path-granule cell synapse. Neurobiol. Aging 21, 613-620.
    • (2000) Neurobiol. Aging , vol.21 , pp. 613-620
    • Barnes, C.A.1    Rao, G.2    Houston, F.P.3
  • 9
    • 0033757922 scopus 로고    scopus 로고
    • Age-related decrease in the Schaffer collateral-evoked EPSP in awake, freely behaving rats
    • Barnes, C. A., Rao, G. & Orr, G. 2000b Age-related decrease in the Schaffer collateral-evoked EPSP in awake, freely behaving rats. Neural Plasticity 7, 167-178.
    • (2000) Neural Plasticity , vol.7 , pp. 167-178
    • Barnes, C.A.1    Rao, G.2    Orr, G.3
  • 10
    • 0030854720 scopus 로고    scopus 로고
    • Multistability of cognitive maps in the hippocampus of old rats
    • Barnes, C. A., Suster, M. S., Shen, J. & McNaughton, B. L. 1997 Multistability of cognitive maps in the hippocampus of old rats. Nature 388, 272-275.
    • (1997) Nature , vol.388 , pp. 272-275
    • Barnes, C.A.1    Suster, M.S.2    Shen, J.3    McNaughton, B.L.4
  • 11
    • 0015850798 scopus 로고
    • Long-lasting potentiation of synaptic transmission in the dentate area of the unanaesthetised rabbit following stimulation of the perforant path
    • Bliss, T. V. P. & Gardner-Medwin, A. R. 1973 Long-lasting potentiation of synaptic transmission in the dentate area of the unanaesthetised rabbit following stimulation of the perforant path. J. Physiol. 232, 357-374.
    • (1973) J. Physiol. , vol.232 , pp. 357-374
    • Bliss, T.V.P.1    Gardner-Medwin, A.R.2
  • 12
    • 0015799240 scopus 로고
    • Long-lasting potentiation of synaptic transmission in the dentate area of the anesthetized rabbit following stimulus of perforant path
    • Bliss, T. V. P. & Lømo, T. 1973 Long-lasting potentiation of synaptic transmission in the dentate area of the anesthetized rabbit following stimulus of perforant path. J. Physiol. 232, 331-356.
    • (1973) J. Physiol. , vol.232 , pp. 331-356
    • Bliss, T.V.P.1    Lømo, T.2
  • 13
    • 0029687781 scopus 로고    scopus 로고
    • A model of spatial map formation in the hippocampus of the rat
    • Blum, K. I. & Abbott, L. F. 1996 A model of spatial map formation in the hippocampus of the rat. Neural Comp. 8, 85-93.
    • (1996) Neural Comp. , vol.8 , pp. 85-93
    • Blum, K.I.1    Abbott, L.F.2
  • 14
    • 0022273980 scopus 로고
    • Electrophysiological markers of aging and memory loss in rats
    • de Toledo-Morrell, L. & Morrell, F. 1985 Electrophysiological markers of aging and memory loss in rats. Ann. NY Acad. Sci. 444, 296-311.
    • (1985) Ann. NY Acad. Sci. , vol.444 , pp. 296-311
    • De Toledo-Morrell, L.1    Morrell, F.2
  • 15
    • 0027193830 scopus 로고
    • Age-related alterations in potentiation in the CA1 region in F344 rats
    • Deupree, D. L., Bradley, J. & Turner, D. A. 1993 Age-related alterations in potentiation in the CA1 region in F344 rats. Neurobiol. Aging 14, 249-258.
    • (1993) Neurobiol. Aging , vol.14 , pp. 249-258
    • Deupree, D.L.1    Bradley, J.2    Turner, D.A.3
  • 16
    • 0016612868 scopus 로고
    • Long-term potentiation of the perforant path-granule cell synapse in the rat hippocampus
    • Douglas, R. M. & Goddard, G. V. 1975 Long-term potentiation of the perforant path-granule cell synapse in the rat hippocampus. Brain Res. 86, 205-215.
    • (1975) Brain Res. , vol.86 , pp. 205-215
    • Douglas, R.M.1    Goddard, G.V.2
  • 17
    • 0035974793 scopus 로고    scopus 로고
    • NMDA receptor antagonism blocks experience-dependent expansion of hippocampal 'place fields'
    • Ekstrom, A. D., Meltzer, J., McNaughton, B. L. & Barnes, C. A. 2001 NMDA receptor antagonism blocks experience-dependent expansion of hippocampal 'place fields'. Neuron 31, 631-638.
    • (2001) Neuron , vol.31 , pp. 631-638
    • Ekstrom, A.D.1    Meltzer, J.2    McNaughton, B.L.3    Barnes, C.A.4
  • 18
    • 0025942963 scopus 로고
    • Increase in perforant path quantal size in aged F-344 rats
    • Foster, T. C., Barnes, C. A., Rao, G. & McNaughton, B. L. 1991 Increase in perforant path quantal size in aged F-344 rats. Neurobiol. Aging 12, 441-448.
    • (1991) Neurobiol. Aging , vol.12 , pp. 441-448
    • Foster, T.C.1    Barnes, C.A.2    Rao, G.3    McNaughton, B.L.4
  • 19
    • 0026938047 scopus 로고
    • Age-related loss of axospinous synapses formed by two afferent systems in the rat dentate gyrus as revealed by the unbiased stereological dissector technique
    • Geinisman, Y., de Toledo-Morrell, L., Morrell, F., Persina, I. S. & Rossi, M. 1992 Age-related loss of axospinous synapses formed by two afferent systems in the rat dentate gyrus as revealed by the unbiased stereological dissector technique. Hippocampus 2, 437-444.
    • (1992) Hippocampus , vol.2 , pp. 437-444
    • Geinisman, Y.1    De Toledo-Morrell, L.2    Morrell, F.3    Persina, I.S.4    Rossi, M.5
  • 21
    • 0029805375 scopus 로고    scopus 로고
    • Dynamics of mismatch correction in the hippocampal ensemble code for space: Interaction between path integration and environmental cues
    • Gothard, K. M., Skaggs, W. E. & McNaughton, B. L. 1996 Dynamics of mismatch correction in the hippocampal ensemble code for space: interaction between path integration and environmental cues. J. Neurosci. 16, 8027-8040.
    • (1996) J. Neurosci. , vol.16 , pp. 8027-8040
    • Gothard, K.M.1    Skaggs, W.E.2    McNaughton, B.L.3
  • 22
    • 0025089008 scopus 로고
    • Two components of long-term potentiation induced by different patterns of afferent activation
    • Graver, L. M. & Teyler, T. J. 1990 Two components of long-term potentiation induced by different patterns of afferent activation. Nature 347, 477-479.
    • (1990) Nature , vol.347 , pp. 477-479
    • Graver, L.M.1    Teyler, T.J.2
  • 23
    • 0032568888 scopus 로고    scopus 로고
    • Abolition of long-term stability of new hippocampal place cell maps by NMDA receptor blockade
    • Kentros, C., Hargreaves, E., Hawkins, R. D., Kandel, E. R., Shapiro, M. & Muller, R. V. 1998 Abolition of long-term stability of new hippocampal place cell maps by NMDA receptor blockade. Science 280, 2121-2126.
    • (1998) Science , vol.280 , pp. 2121-2126
    • Kentros, C.1    Hargreaves, E.2    Hawkins, R.D.3    Kandel, E.R.4    Shapiro, M.5    Muller, R.V.6
  • 24
    • 0025935624 scopus 로고
    • Chronic stress-induced acceleration of electrophysiologic and morphometric biomarkers of hippocampal aging
    • Kerr, D. S., Campbell, L. W., Applegate, M. D., Brodish, A. & Landfield, P. W. 1991 Chronic stress-induced acceleration of electrophysiologic and morphometric biomarkers of hippocampal aging. J. Neurosci. 11, 1316-1326.
    • (1991) J. Neurosci. , vol.11 , pp. 1316-1326
    • Kerr, D.S.1    Campbell, L.W.2    Applegate, M.D.3    Brodish, A.4    Landfield, P.W.5
  • 25
    • 0017669091 scopus 로고
    • Impaired monosynaptic potentiation in in vitro hippocampal slices from aged, memory-deficient rats
    • Landfield, P. W. & Lynch, G. 1977 Impaired monosynaptic potentiation in in vitro hippocampal slices from aged, memory-deficient rats. J. Gerontol. 32, 523-533.
    • (1977) J. Gerontol. , vol.32 , pp. 523-533
    • Landfield, P.W.1    Lynch, G.2
  • 26
    • 0021645626 scopus 로고
    • 2+-dependent after hyperpolarizations in hippocampal neurons of aged rats
    • 2+-dependent after hyperpolarizations in hippocampal neurons of aged rats. Science 226, 1089-1092.
    • (1984) Science , vol.226 , pp. 1089-1092
    • Landfield, P.W.1    Pitler, T.A.2
  • 27
    • 0018146937 scopus 로고
    • Impaired synaptic potentiation process in the hippocampus of aged, memory deficient rats
    • Landfield, P. W., McGaugh, J. L. & Lynch, G. 1978 Impaired synaptic potentiation process in the hippocampus of aged, memory deficient rats. Brain Res. 150, 85-101.
    • (1978) Brain Res. , vol.150 , pp. 85-101
    • Landfield, P.W.1    McGaugh, J.L.2    Lynch, G.3
  • 28
    • 77957090033 scopus 로고
    • A computation approach to hippocampal function
    • ed. R. D. Hawkins & G. H. Bower. New York: Academic Press
    • Levy, W. B. 1989 A computation approach to hippocampal function. In Computational models of learning in simple neural systems (ed. R. D. Hawkins & G. H. Bower), pp. 243-305. New York: Academic Press.
    • (1989) Computational Models of Learning in Simple Neural Systems , pp. 243-305
    • Levy, W.B.1
  • 29
    • 0020522951 scopus 로고
    • Temporal contiguity requirements for long-term associative potentiation/depression in the hippocampus
    • Lew, W. B. & Steward, O. 1983 Temporal contiguity requirements for long-term associative potentiation/depression in the hippocampus. Neuroscience 8, 791-797.
    • (1983) Neuroscience , vol.8 , pp. 791-797
    • Lew, W.B.1    Steward, O.2
  • 30
    • 0023620017 scopus 로고
    • Hippocampal synaptic enhancement and information storage within a distributed memory system
    • McNaughton, B. L. & Morris, R. G. M. 1987 Hippocampal synaptic enhancement and information storage within a distributed memory system. Trends Neurosci. 10, 408-415.
    • (1987) Trends Neurosci. , vol.10 , pp. 408-415
    • McNaughton, B.L.1    Morris, R.G.M.2
  • 32
    • 0014931688 scopus 로고
    • A theory of cerebral neocortex
    • Marr, D. 1970 A theory of cerebral neocortex. Proc. R. Soc. Lond. B 176, 161-234.
    • (1970) Proc. R. Soc. Lond. B , vol.176 , pp. 161-234
    • Marr, D.1
  • 33
    • 0015083717 scopus 로고
    • Simple memory: A theory for archicortex
    • Marr, D. 1971 Simple memory: a theory for archicortex. Phil. Trans. R. Soc. Lond. B 262, 23-81.
    • (1971) Phil. Trans. R. Soc. Lond. B , vol.262 , pp. 23-81
    • Marr, D.1
  • 34
    • 0030744211 scopus 로고    scopus 로고
    • Experience-dependent, asymmetric expansion of hippocampal place fields
    • Mehta, M. R., Barnes, C. A. & McNaughton, B. L. 1997 Experience-dependent, asymmetric expansion of hippocampal place fields. Proc. Natl Acad. Sci. USA 94, 8918-8921.
    • (1997) Proc. Natl. Acad. Sci. USA , vol.94 , pp. 8918-8921
    • Mehta, M.R.1    Barnes, C.A.2    McNaughton, B.L.3
  • 35
    • 0027298841 scopus 로고
    • Hippocampal plasticity induced by primed burst, but not long-term potentiation, stimulation is impaired in area CA1 of aged Fischer 344 rats
    • Moore, C. I., Browning, M. D. & Rose, G. M. 1993 Hippocampal plasticity induced by primed burst, but not long-term potentiation, stimulation is impaired in area CA1 of aged Fischer 344 rats. Hippocampus 3, 57-66.
    • (1993) Hippocampus , vol.3 , pp. 57-66
    • Moore, C.I.1    Browning, M.D.2    Rose, G.M.3
  • 36
    • 0029795945 scopus 로고    scopus 로고
    • Increased susceptibility to induction of long-term depression and long-term potentiation reversal during aging
    • Norris, C. M., Korol, D. L. & Foster, T. C. 1996 Increased susceptibility to induction of long-term depression and long-term potentiation reversal during aging. J. Neurosci. 16, 5382-5392.
    • (1996) J. Neurosci. , vol.16 , pp. 5382-5392
    • Norris, C.M.1    Korol, D.L.2    Foster, T.C.3
  • 37
    • 0015145985 scopus 로고
    • The hippocampus as a spatial map. Preliminary evidence from unit activity in the freely-moving rat
    • O'Keefe, J. & Dostrovsky, J. 1971 The hippocampus as a spatial map. Preliminary evidence from unit activity in the freely-moving rat. Brain Res. 34, 171-175.
    • (1971) Brain Res. , vol.34 , pp. 171-175
    • O'Keefe, J.1    Dostrovsky, J.2
  • 39
    • 0033920579 scopus 로고    scopus 로고
    • Age-related deficits in the ability to encode contextual change: A place cell analysis
    • Oler, J. A. & Markus, E. J. 2000 Age-related deficits in the ability to encode contextual change: a place cell analysis. Hippocampus 10, 338-350.
    • (2000) Hippocampus , vol.10 , pp. 338-350
    • Oler, J.A.1    Markus, E.J.2
  • 41
    • 0029821150 scopus 로고    scopus 로고
    • Preserved neuron number in the hippocampus of aged rats with spatial learning deficits
    • Rapp, P. R. & Gallagher, M. 1996 Preserved neuron number in the hippocampus of aged rats with spatial learning deficits. Proc. Natl Acad. Sci. USA 93, 9926-9930.
    • (1996) Proc. Natl. Acad. Sci. USA , vol.93 , pp. 9926-9930
    • Rapp, P.R.1    Gallagher, M.2
  • 42
    • 0030053883 scopus 로고    scopus 로고
    • Memory impaired aged rats: No loss of principal hippocampal and subicular neurons
    • Rasmussen, T., Schliemann, T., Sorensen, J. C., Zimmer, J. & West, M. J. 1996 Memory impaired aged rats: no loss of principal hippocampal and subicular neurons. Neurobiol. Aging 17, 143-147.
    • (1996) Neurobiol. Aging , vol.17 , pp. 143-147
    • Rasmussen, T.1    Schliemann, T.2    Sorensen, J.C.3    Zimmer, J.4    West, M.J.5
  • 44
    • 0031730368 scopus 로고    scopus 로고
    • Reconciling Barnes et al. (1997) and Tanila et al. (1997a,b)
    • Redish, A. D., McNaughton, B. L. & Barnes, C. A. 1998 Reconciling Barnes et al. (1997) and Tanila et al. (1997a,b). Hippocampus 8, 438-443.
    • (1998) Hippocampus , vol.8 , pp. 438-443
    • Redish, A.D.1    McNaughton, B.L.2    Barnes, C.A.3
  • 46
    • 0038212382 scopus 로고    scopus 로고
    • Age-related changes in hippocampal map realignment. Program no. 678.6
    • Washington, DC: Society for Neuroscience, Online
    • Rosenzweig, E. S., Redish, A. D., McNaughton, B. L. & Barnes, C. A. 2002 Age-related changes in hippocampal map realignment. Program no. 678.6. Abstract Viewer/Itinerary Planner. Washington, DC: Society for Neuroscience, Online.
    • (2002) Abstract Viewer/Itinerary Planner
    • Rosenzweig, E.S.1    Redish, A.D.2    McNaughton, B.L.3    Barnes, C.A.4
  • 47
    • 0030877821 scopus 로고    scopus 로고
    • Path integration and cognitive mapping in a continuous attractor neural network model
    • Samsonovich, A. & McNaughton, B. L. 1997 Path integration and cognitive mapping in a continuous attractor neural network model. J. Neurosci. 17, 5900-5920.
    • (1997) J. Neurosci. , vol.17 , pp. 5900-5920
    • Samsonovich, A.1    McNaughton, B.L.2
  • 48
    • 0031893277 scopus 로고    scopus 로고
    • Aging differentially alters forms of long-term potentiation in rat hippocampal area CA1
    • Shankar, S., Teyler, T. J. & Robbins, N. 1998 Aging differentially alters forms of long-term potentiation in rat hippocampal area CA1. J. Neurophysiol. 79, 334-341.
    • (1998) J. Neurophysiol. , vol.79 , pp. 334-341
    • Shankar, S.1    Teyler, T.J.2    Robbins, N.3
  • 49
    • 16944363524 scopus 로고    scopus 로고
    • The effect of aging on experience-dependent plasticity of hippocampal place cells
    • Shen, J., Barnes, C. A., McNaughton, B. L., Skaggs, W. E. & Weaver, K. L. 1997 The effect of aging on experience-dependent plasticity of hippocampal place cells. J. Neurosci. 17, 6769-6782.
    • (1997) J. Neurosci. , vol.17 , pp. 6769-6782
    • Shen, J.1    Barnes, C.A.2    McNaughton, B.L.3    Skaggs, W.E.4    Weaver, K.L.5
  • 50
    • 0030012117 scopus 로고    scopus 로고
    • Replay of neuronal firing sequences in rat hippocampus during sleep following spatial experience
    • Skaggs, W. E. & McNaughton, B. L. 1996 Replay of neuronal firing sequences in rat hippocampus during sleep following spatial experience. Science 271, 1870-1873.
    • (1996) Science , vol.271 , pp. 1870-1873
    • Skaggs, W.E.1    McNaughton, B.L.2
  • 51
    • 0028100048 scopus 로고
    • Centrally active modulators of glutamate receptors facilitate the induction of long-term potentiation in viva
    • Staubli, U., Perez, Y., Xu, F., Rogers, G., Ingvar, M., Stone-Elander, S. & Lynch, G. 1994 Centrally active modulators of glutamate receptors facilitate the induction of long-term potentiation in viva. Proc. Natl Acad. Sci USA 91, 11 158-11 162.
    • (1994) Proc. Natl. Acad. Sci USA , vol.91 , pp. 11158-11162
    • Staubli, U.1    Perez, Y.2    Xu, F.3    Rogers, G.4    Ingvar, M.5    Stone-Elander, S.6    Lynch, G.7
  • 52
    • 0030915192 scopus 로고    scopus 로고
    • Brain aging: Changes in the nature of information coding by the hippocampus
    • Tanila, H., Shapiro, M., Gallagher, M. & Eichenbaum, H. 1997 Brain aging: changes in the nature of information coding by the hippocampus. J. Neurosci. 17, 5155-5166.
    • (1997) J. Neurosci. , vol.17 , pp. 5155-5166
    • Tanila, H.1    Shapiro, M.2    Gallagher, M.3    Eichenbaum, H.4
  • 53
    • 0029782113 scopus 로고    scopus 로고
    • Increase in single L-type calcium channels in hippocampal neurons during aging
    • Thibault, O. & Landfield, P. W. 1996 Increase in single L-type calcium channels in hippocampal neurons during aging. Science 272, 1017-1020.
    • (1996) Science , vol.272 , pp. 1017-1020
    • Thibault, O.1    Landfield, P.W.2
  • 54
    • 0027440875 scopus 로고
    • Dynamics of the hippocampal ensemble code for space
    • Wilson, M. A. & McNaughton, B. L. 1993 Dynamics of the hippocampal ensemble code for space. Science 261, 1055-1058.
    • (1993) Science , vol.261 , pp. 1055-1058
    • Wilson, M.A.1    McNaughton, B.L.2
  • 55
    • 0028095260 scopus 로고
    • Reactivation of hippocampal ensemble memories during sleep
    • Wilson, M. A. & McNaughton, B. L. 1994 Reactivation of hippocampal ensemble memories during sleep. Science 265, 676-679.
    • (1994) Science , vol.265 , pp. 676-679
    • Wilson, M.A.1    McNaughton, B.L.2


* 이 정보는 Elsevier사의 SCOPUS DB에서 KISTI가 분석하여 추출한 것입니다.