[讨论]感觉皮质重塑(reorganizations of cortical repres

老板让我开一个盲人视觉皮质的课题,今年2月已经做了两例实验,有了初步分析结果.明年2月份再接着做6-10例,博士研究就结束有望了.

借这个帖子,我将我掌握的reorganizations of cortical representation maps的知识介绍给大家,开个话题,大家一起讨论,互相学习,如同另一个关于听觉处理的帖子一样.在这个帖子里我要尽可能地在引用他人观点的时候注明出处,这样一来大家想看原文的时候也方便查找.

侵入研究(A V S)

在猴的体感皮质处曾观察到了大规模的cortical representation maps重塑[1]; 人截肢后也能观测的同样的效果[2].这些发现证明中枢神经系统在输入和输出条件发生改变的时候可以改变自身的功能组织以适应这种变化[review,3].猫[4]和猴[5]的单细胞研究显示视觉剥夺后,处理听觉和体感的神经元数量(在各自所属的皮质区内)分别增加,反之视觉神经元所占百分比下降.同样的效果也可以在superior colliculus上观察到[6].

人为阻断体感(脊髓处)和听觉(听神经出)的传入及视觉皮质后,可以观察到,somatosensory and auditory thalamus可以处理视觉信息.[review,7,8],进而,听皮质和体感皮质也相应处理视觉信号.反之,visual thalamus and cortex的神经元开始处理非视觉信号[9] . 视觉剥夺的灵长类,执行触觉检测任务时,可以在其视皮质处观测到fire [10]

1/ Pons, T.P., Garraghty, P.E., Ommaya, A.K., Kaas, J.H., Taub, E. and Mishkin, M., Massive cortical reorganization after sensory deafferentation in adult macaques, Science, 252 (1991) 1857-1860.

2/ Pascual-Leone, A., Cohen, L.G. and Hallett, M., Cortical map plasticity in humans, Trends Neurosci., 15 (1992) 13-14.

3/ Merzenich, M.M. and Jenkins, W.M., Reorganization of cortical representations of the hand following alternations of skin input induced by nerve injury, skin island transfer, and experience, J. Hand. Ther., 6 (1993) 89-104.

4/Trends Neurosci., 18(1995) 36-43

5/Exp. Brain Res., 42(1981) 1-8

6/Exp. Brain Res., 50(1983) 63-83

7/Frost, D.O., Visual processing by novel, surgically created neural circuits. In D.M.-K. Lam and G.M. Bray (Eds.), Regeneration and Plasticity in the Mammalian Visual System, Bradford, London, UK,1992, pp. 197-219.

8/Sur, M., Pallas, S.L. and Roe, A.W., Cross-modal plasticity in cortical development: differentiation and specification of sensory neocortex, Trends Neurosci., 13 (1990) 227-233.

9/Asanuma, C. and Stanfield, B.B., Induction of somatic sensory inputs to the lateral geniculate nucleus in congenitally blind mice and in phenotypically normal mice, Neuroscience, 39 (1990) 533-545.

10/ Hyv~irinen, J., Carlson, S. and Hyr'dvinen, L., Early visual deprivation alters modality of neuronal responses in area 19 of monkey cortex, Neurosci. Lett., 26 (1981) 239-243.

 

［此帖子已被 zhixl 在 2005-11-9 18:24:10 编辑过］

前几年好象看到过，就是肓人的视觉皮质区神经元仍在起作用，但起着其它感觉的作用。

引用：

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原文由 zhixl 发表于 2005-11-4 18:43:08 :

在猴的体感皮质处曾观察到了大规模的cortical representation maps重塑[1]; 人截肢后也能观测的同样的效果[2].这些发现证明中枢神经系统在输入和输出条件发生改变的时候可以改变自身的功能组织以适应这种变化[review,3].猫[4]和猴[5]的单细胞研究显示视觉剥夺后,处理听觉和体感的神经元数量(在各自所属的皮质区内)分别增加,反之视觉神经元所占百分比下降.同样的效果也可以在superior colliculus上观察到[6].

 

1/ Pons, T.P., Garraghty, P.E., Ommaya, A.K., Kaas, J.H., Taub, E. and Mishkin, M., Massive cortical reorganization after sensory deafferentation in adult macaques, Science, 252 (1991) 1857-1860.

2/ Pascual-Leone, A., Cohen, L.G. and Hallett, M., Cortical map plasticity in humans, Trends Neurosci., 15 (1992) 13-14.

3/ Merzenich, M.M. and Jenkins, W.M., Reorganization of cortical representations of the hand following alternations of skin input induced by nerve injury, skin island transfer, and experience, J. Hand. Ther., 6 (1993) 89-104.

4/Trends Neurosci., 18(1995) 36-43

5/Exp. Brain Res., 42(1981) 1-8

6/Exp. Brain Res., 50(1983) 63-83

［此帖子已被 zhixl 在 2005-11-4 22:49:08 编辑过］

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Please continue into more details if not cost you too much time.

好象越是早期，可塑性越强。

相关的现象和实验很多，不知道有没有比较详细又有威望的理论。

引用：

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原文由 remind_me 发表于 2005-11-5 12:12:19 :

好象越是早期，可塑性越强。

相关的现象和实验很多，不知道有没有比较详细又有威望的理论。

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现在还没有理论,但有些现象可以引起注意:早盲(5岁前失明)与晚盲的reorganization of visual cortical representational maps是不同的.

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我在2楼里加入了如下内容:

人为阻断体感(脊髓处)和听觉(听神经出)的传入及视觉皮质后,可以观察到,somatosensory and auditory thalamus可以处理视觉信息.[review,7,8],进而,听皮质和体感皮质也相应处理视觉信号.反之,visual thalamus and cortex的神经元开始处理非视觉信号[9] . 视觉剥夺的灵长类,执行触觉检测任务时,可以在其视皮质处观测到fire [10]

葡萄糖代谢 (V 皮质)

葡萄糖代谢依然存在于盲人的visual cortex,代谢的量等于甚至超过正常人[1,2,3,4].这个发现说明视觉剥夺后,视觉皮质还在工作,但还不能说它一定在为听觉出体感觉工作.

1/ Phelps, M.E., Mazziotta, J.C., Kuhl, D., Nuwer, M., Packwood, J., Metter, J. and Engel, J.J., Tomographic mapping of human cerebral metabolism: visual stimulation and deprivation, Neurology, 31 (1981) 517-529.

2/ Uhl, F., Franzen, P., Podreka, I., Steiner, M. and Deecke, L., Increased regional cerebral blood flow in inferior occipital cortex and cerebellum of early blind humans, Neurosci. Lett., 150 (1993) 162-164.

3/ Veraart, C., De Voider, A.G., Wanet-Defalque, M.C., Bol, A., Michel, C. and Goffinet, A.M., Glucose utilization in human visual cortex is abnormally elevated in blindness of early onset but decreases in blindness of late onset, Brain Res., 510 (1990) 115-121.

4/ Wanet-Defalque, M.C., Veraart, C., De Volder, A., Metz, R., Michel, C., Dooms, G. and Goffinet, A., High metabolic activity in the  visual cortex of early blind human subjects, Brain Res., 446 (1988) 369-373.

 

［此帖子已被 zhixl 在 2005-11-9 18:34:51 编辑过］

PET/fMRI (V 皮质)

否认存在reorganization的研究结果

一些早期的PET研究指出:无论是葡萄糖代谢还是脑血流,subjects在静止时比在处理听觉/体感觉辨别任务时更高些,无论这个任务的数量和难易程度有何变化[review 1]. So, the occipital activity in blind subjects was not found to be related to specifc information processing functions.

1/ B. Roder et al., Cogn.Brain Res. 4 (1996) 77-93

［此帖子已被 zhixl 在 2005-11-9 18:55:25 编辑过］

EEG/MEG

肯定reorganization的研究

早期的EEG研究发现盲人的听觉[1,2]和体感觉[3]ERP中晚成分的振幅[2]被增强,潜伏期缩短. 这些学者推测这是联合皮质(不是V皮质)发生reorganization而引起的.对deaf subjects的研究发现了类似的效果[4,5,6,7]

有些研究报告指出:盲人的N2b[8]和PN[9](由attended acousitc stimuli引出)比普通人的分布更靠近枕部.

有研究指出当(早期)盲人阅读盲文的时候可以在枕部记录到一些负的晚电位[10]

1/  Niemeyer, W. and Starlinger, I., Do blind hear better? Investigations on auditory processing in congential early acquired blindness. II. Central functions, Audiology, 20 (1981) 510-515.

2/  Woods, D.L., Clayworth, C.C. and Bach-y-Rita, P., Early blindness reorganizes auditory processing in humans. 15th Annual Meeting of the Society for Neuroscience, Dallas, TX, p. 449.

3/  Feinsod, M., Bach-y-Rita, P. and Madey, J.M., Somatosensory evoked responses: differences in blind and sighted persons, Brain Res., 60 (1973) 219-223.

4/ Neville, H.J. and Lawson, D., Attention to central and peripheral visual space in a movement detection task: an event-related potential and behavioral study. I. Normal hearing adults, Brain Res., 405 (1987) 253-267.

5/  Neville, H.J. and Lawson, D., Attention to central and peripheral visual space in a movement detection task: an event-related potential and behavioral study. II. Congenitally deaf adults, Brain Res., 405 (1987) 268-283.

6/  Neville, H.J. and Lawson, D., Attention to central and peripheral visual space in a movement detection task. III. Separate effects of auditory deprivation and acquisition of a visual language, Brain Res., 405 (1987) 284-294.

7/  Neville, H.J., Schmidt, A. and Kutas, M., Alternated visual-evoked potentials in congenitally deaf adults, Brain Res., 266 (1983) 127- 132.

8/  Kujala, T., Alho, K., Paavilainen, P., Summala, H. and N~i~it~inen, R., Neuronal plasticity in processing of sound location by the early blind: an event-related potential study, Electroencephalogr. Clin. NeurophysioL, 84 (1992) 469-472.

9/Alho, K., Kujala, T., Paavilainen, P., Summala, H. and N~i~it~nen, R., Auditory processing in visual brain areas of the early blind: evidence from event-related potentials, Electroencephalogr. Clin. Neurophysiol., 86 (1993) 418-427.

10/ Uhl, F., Franzen, P., Lindinger, G., Lang, W. and Deecke, L., On the functionality of the visually deprived occipital cortex in early blind persons, Neurosci. Lett., 124 (1991) 256-259.