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1 Research in Vestibular Science Vol. 14, No. 3, September 2015 Original Article pissn , eissn 흰쥐에서일측전정기관손상후전정보상에대한대뇌피질의역할 1 원광대학교의과대학생리학교실, 2 원광보건대학교의무부사관학과 유현광 1*, 양승범 2, 김민선 1, 박병림 1 Role of the Cerebral Cortex on Vestibular Compensation Following Unilateral Labyrinthectomy in Rats Hyun Kwang Ryoo 1*, Seung-Bum Yang 2, Min Sun Kim 1, Byung Rim Park 1 1 Department of Physiology, Wonkwang University School of Medicine, Iksan; 2 Department of Medical Noncommissioned Officer, Wonkwang Health Science University, Iksan, Korea Received Aug 7, 2015 Revised Aug 13, 2015 Accepted Aug 17, 2015 Corresponding Author: Byung Rim Park Department of Physiology, Wonkwang University School of Medicine, 460 Iksandaero, Iksan 54538, Korea Tel: Fax: byungp@wku.ac.kr *Present address: Green Cross Corp. Copyright c 2015 by The Korean Balance Society. All rights reserved. This is an open access article distributed under the terms of the Creative Commons Attribution Non-Commercial License ( which permits unrestricted non-commercial use, distribution, and reproduction in any medium, provided the original work is properly cited. Objective: The cerebral cortex can modulate vestibular functions through direct control of neuronal activities in the vestibular nuclei. The purpose of this study was to investigate the effect of unilateral cortical lesion or cortical stimulation on static vestibular symptoms and vestibular nuclear activities at the acute stage of vestibular compensation following unilateral labyrinthectomy (UL) in rats. Methods: The photothrombic ischemic injury using rose bengal was induced in the primary motor cortex or primary sensory cortex, and electrical stimulation was applied to the primary motor cortex, primary sensory cortex, or sencondary sensory cortex, respectively, in unilateral labyrinthectomized rats. Static vestibular symptoms including ocular movement and postural deficits, and expression of c-fos protein in the medial vestibular nucleus (MVN) were measured. Results: Lesion of the motor cortex produced a marked postural deficit with paralytic weakness in the hindlimb contralateral to UL. Number of spontaneous nystagmus in animals receiving cortical lesion was significantly increased 2, 6, and 12 hours after UL compared with animals being UL only. Lesion of the primary motor cortex or stimulation of the S2 sensory cortex decreased expression of c-fos protein in MVN following UL compared with UL only group. Electrical stimulation of S2 sensory areas caused significant reduction of static vestibular symptoms and decreased expression of c-fos protein in MVN 24 hours following UL. Conclusion: The present results suggest that cerebral cortex involves in recovery of static vestibular symptoms during vestibular compensation following UL. Res Vestib Sci 2015;14(3):75-82 Keywords: Cortical lesion; Cortical stimulation; Labyrinthectomy; Vestibular compensation; c-fos protein 서론전정기관은시각, 경부고유수용체및체성감각정보와함께신체의평형유지및자세조절에중요한역할을한 다. 1-3 일측전정기관의손상은정적증상과동적증상으로나누어지며, 정적증상은속상이정상측으로나타나는자발안진과손상측으로의두부편위, 자세부조화이며, 동적증상은회전자극시전정안반사및전정척수반사에서반응정 75

2 Res Vestib Sci Vol. 14, No. 3, Sep 도와양측회전자극에대한비대칭성반응등이있다. 4-7 이와같은증상이완전한회복을보이는것은아니지만, 시간이경과함에따라정적증상과동적증상에서현저한감소를보이며, 이는전정기능의보상작용이라는과정을통해일어나는것으로알려져있다. 2,3 대뇌피질에는전정수용체의구심성신호를수용하고다른감각계의감각정보들과통합하여자세변화에대한대뇌기능변화를조절하는전정피질 (vestibular cortex) 이존재한다. 원숭이에서두정엽섬전정피질영역이대부분의전정피질영역들로부터구심성신호를받고있고, 두정엽섬전정피질영역이전정피질영역들중가장중요한역할을하며, 3aNv 영역과 visual posterior sylvian (VPS) 영역도다른전정피질영역으로부터많은신호를전달받고있으며, 이러한영역사이에신경망이잘연결되어있어이들영역을내부전정피질원이라고알려져있다. 8 임상적으로최근일측전정기관이제거된환자들에서공간기억력과방향추적능력의감소와일측대뇌회백질용적이감소한보고가있어말초전정기관이대뇌피질의기능적, 구조적변화에영향을미치고있음이제시되었다. 9 이와반대로대뇌피질손상환자에서온도안진검사상자세부조화와회전자극에의한전정안반사의부조화가관찰되었다. 10,11 간질환자에서대뇌피질의전기자극에의하여자발안진이초래되는데자극강도에따라차이가있었다. 12 실험동물연구에서전정피질의자극시전정신경핵뉴론의흥분성변화가관찰되었고, 해부학적연구에서전정피질에서전정신경핵으로직접적인신경투사가관찰되었다. 13,14 따라서이러한연구결과들은대뇌피질이전정기관의흥분성에변화를주어전정기관의기능변화를야기할수있을것을강하게암시한다. 이연구에서는대뇌피질의활동성변화가말초전정기관손상후관찰되는전정보상작용에영향을미칠것으로가정하고실험적으로증명하고자한다. 전정기능의보상작용이전정신경핵을포함한중추신경내에서이루어질것이라는점을고려할때대뇌피질의손상또는전기자극역시중추신경계에작용할것으로생각되어이연구에서는흰쥐에서일측전정기관손상후대뇌피질의손상또는자극이전정보상작용에미치는영향을추구하기위하여자세부조화와자발안진의회복과정을관찰하고, 또한신경표지자로널리사용되고있는 c-fos 면역조직화학법을이용하여 15 내측전정신경핵에서 c-fos 단백발현을측정하였다. 대상및방법 1. 실험동물건강하고성숙한체중 g의 Sprague-Dawley계수컷흰쥐를사용하였으며, 실험동물을 3군으로구분하였다. 일측전정기관만을파괴한전정손상군 (sham; n=28), 일측전정기관손상후일차운동피질 (M1; n=28), 또는일차감각피질 (S1; n=28) 에뇌경색허혈손상을입힌피질손상군, 그리고일측전정기관손상후일차운동피질 (M1; n=28), 일차 (S1; n=28) 또는이차감각피질 (S2; n=28) 에전기자극을가한피질자극군으로분류하였다. 2. 뇌경색허혈손상정상동물을사용하여피질손상군의동물모델을만들기위해 isoflurane으로흡입마취를하였다. 되먹임온도조절방석 (Homeothermic blanket system, Harvard Apparatus Ltd, Holliston, MA, USA) 을이용하여체온을 37 o C±1 o C로유지하였으며, 복와위에서두부정위고정장치 (Model 900 Small animal stereotaxic instrument, David Kopf Instruments, Tujunga, CA, USA) 에두개골을고정시키고두피를절개한후두개골을노출시킨다음, 일차운동피질 (M1) 또는일차감각피질 (S1) 영역에 Rose-bengal 염료를이용한뇌경색허혈손상모델을만들었다. Rose-bengal은대퇴정맥에도뇨관을삽입하여주입하였고, 병소영역에 6 mm 직경의광원 (Illuminator-Halogen ROK-150X, Fiber Optic Korea Co., Cheonan, Korea) 을사용하여피질손상군을만들었다. 광원은 15 V, 150 W 할로겐전구를사용하였으며필터를사용하여가시광선영역만을통과시킨후광섬유가빛을전달하여열발생이없는빛 (cold light) 을사용하였다. Figure 1은일차운동피질에 rose-bengal 염료를사용하여뇌경색손상을가한후박리한뇌조직이며, 뇌경색손상정도를 manganese MRI (Bunker spine 4.7T, Mannheim, Germany) 의영상학적기법을이용하여뇌의활동성을영상화한결과영상의변화가있음을확인하였다 (Figure 1). 3. 대뇌피질전기자극피질자극군은일차운동피질 (M1), 그리고일차 (S1) 또는이차감각피질 (S2) 부위를치과용드릴을사용하여노 76

유현광외 3 인. 전정보상과대뇌피질 Figure 1. Cortical areas and photothrombotic ischemic injury. (A) Definition of cortical areas where were injured or electrically stimulated in this study.

(B, C) A typical photography showing photothrombotic ischemic injury (dotted circle) in the motor cortex (B) and coronal T1-weighted manganese magnetic resonance image indicating high intensity

3 유현광외 3 인. 전정보상과대뇌피질 Figure 1. Cortical areas and photothrombotic ischemic injury. (A) Definition of cortical areas where were injured or electrically stimulated in this study. M1, primary motor cortex; S1, primary somatosensory cortex; S2, secondary somatosensory cortex. (B, C) A typical photography showing photothrombotic ischemic injury (dotted circle) in the motor cortex (B) and coronal T1-weighted manganese magnetic resonance image indicating high intensity signal (arrow) on ischemic injured cortex (C). 출시킨경막상부에 teflon으로피복된직경 1.5 mm stainless steel wire 전극을각부위에삽입한후치과용시멘트로고정하여전기자극기 (Cyber Medic Co., Iksan, Korea) 를연결하였다. 피질자극군에서일측전정기관손상직후구형파 (50 Hz, 2 V, 1 ms) 의양극성전류를사용하였으며, 수술후지속적으로전기자극을실시하였다 (Figure 2). 4. 말초전정기관의손상 피질손상군또는자극군의동측전정기관에손상을가하기위하여복와위의체위에서후이개측의접근에의하여고막, 고막장근, 이소골을제거한다음난형창을노출시키고, 하방에위치한원형창을중심으로주위를파괴하여전정기관의팽대부신경을노출시켰다. 그후진공펌프를이용하여팽대부신경을모두제거하여전정기관을파괴하였고, 이때안구위치의변화로써전정기관의파괴여부를확인하였으며, 전정기관파괴후피부를원상태로봉합하고, 수술후감염을방지할목적으로항생제를근육주사하였으며, 정상동물과동일하게사육하였다. Figure 2. Set up of cortical stimulation. (A) Electrical stimulator (Cybermedic Co, Korea) that generates square pulse with 2 V, 1 ms, and 50 Hz. (B) Schematic drawing of swivel system for cortical stimulation. (C) Photograph showing fixation of electrodes on the skull. (D) Animal receiving S2 cortical stimulation 2 hours after unilateral labyrinthectomy. 6. 자발안진의기록 5. 자세변화평가수술후비디오카메라를이용하여뒷다리의위치변화를관찰하고, 이미지분석프로그램을이용하여뒷다리사이의간격을측정으로뒷다리의비대칭양상을분석하였다. 일측전정기관손상에의하여출현하는자발안진을측정하기위하여동물이두부를움직이지않을때를기다려 zoom lens가부착된비디오카메라로안구운동을기록한후비디오테이프를 TV monitor가연결된비디오작동기에서재작동시켰다. 이때실험오차를줄이기위하여한동물의안구운동을 3회이상관찰하여 10초동안의자발안진평균값을산출하였다. 77

Res Vestib Sci Vol. 14, No. 3, Sep. 2015 7. c-fos 면역조직화학법 결 과 자세변화및자발안진검사후전정신경핵에서신경세포의활성화에대한변화를관찰할목적으로양측전정신경핵에서 c-fos 단백발현을측정하였다.

4 Res Vestib Sci Vol. 14, No. 3, Sep c-fos 면역조직화학법 결 과 자세변화및자발안진검사후전정신경핵에서신경세포의활성화에대한변화를관찰할목적으로양측전정신경핵에서 c-fos 단백발현을측정하였다. 일측전정기관손상후 2, 6, 24시간이지난시점에서 urethane을사용하여마취를시킨후 1% 와 4% paraformaldehyde로심장을관류시켜조직을고정한다음두개골을제거하여뇌조직을박리하였다. 박리된뇌조직은 4% paraformaldehyde에고정하여 4 o C에서 24시간동안보관한후 30% sucrose에서 3일이상방치하였다. 미세절단기를이용하여 35 μm 의두께로조직절편을만들어서 tris buffered saline (TBS) 로세척하고, 0.3% 과산화수소수로처리하여 endogenous peroxide의활성을차단시켰다. 조직을충분히세척한후 0.5% 의 Triton X-100 (Sigma Co., St. Louis, MO, USA) 을함유한 TBS에서 30분간방치후 TBS로조직을세척하였다. 5% milk를함유한 TBS 용액으로 1시간동안처리하였으며, c-fos에대한항체 (InnoGenex, San Ramon, CA, USA) 를 TBS 용액에희석하여 24시간동안 4 o C에보관한후실온에서 2시간동안진탕시키고 TBS로세척하였다. 그후이차항체인 Streptavidin Horseradish Peroxidase Conjugate를 20분동안진탕후 TBS로세척한후, ABC 용액 (Vectastatim from Vector Laboratory Inc., Burlingame, CA, USA) 을시간동안처리하였다. TBS로세척한후 peroxide substrate solution (DAB, Vector Laboratory Inc., Burlingame, CA, USA) 을첨가하여 3 5분간반응시켰다. 증류수로세척후 Xylene에담그고마운트용액을이용하여표본을완전고정시켰다. 광학현미경하에서진갈색의 cfos 양성세포를관찰하였고화상자동분석시스템 (Image-Pro Plus, Media Cybernetics Inc., Silver Spring, MD, USA) 을이용하여내측전정신경핵에서 c-fos 양성세포의수를측정하였다. 1. 전정보상과정에서자세부조화의회복에대한대뇌피질의영향일측전정기관을절제한전정손상군 (sham) 과일차운동피질 (M1) 또는일차감각피질 (S1) 을손상한피질손상군에서손상동측의상, 하지는굴전되고반대측상, 하지는신전되었으며, 몸통은손상동측으로굴전되는자세부조화를보였다. 전정기관이정상인동물에서뒷다리간격은 3.1±0.2 cm이었으나전정기관을절제하면뒷다리간격은증가하여자세부조화를동반하였다. 전정기관절제 4시간후뒷다리간격은전정손상군에서 5.3±0.5 cm과비교하여운동피질손상군은 8.4±0.4 cm, 감각피질손상군은 7.2±0.3 cm으로유의하게증가하였다 (p<0.01). 전정기관절제 24 시간후전정손상군과피질손상군에서뒷다리간격은점 8. 자료분석 컴퓨터통계프로그램인 STATVIEW ver. 4.0 (Abacus Concepts Inc., Piscataway, NJ, USA) 을이용하였으며통계검정은 analysis of variance 검사후사후검증으로 t-test로실시하였고 p값이 0.05 이하인경우에만통계적으로유의성이있는것으로간주하였다. Figure 3. Postural changes caused by unilateral labyrinthectomy (UL) following cortical lesion. (A) photographs showing postural changes in sham (left) and M1 lesioned animals (right) 4 hours after UL. Sham animals received just UL without cortical lesion. (B) Bar histograph illustrating changes in inter-hindlimb distance of sham, M1 lesion, and S1 lesion groups. Values are mean±standard deviation of 7 rats in each group. M1, primary motor cortex; S1, primary somatosensory cortex. *Denotes significant difference between sham and M1 or S2 lesion group (*p<0.05, **p<0.01). 78

5 유현광외 3 인. 전정보상과대뇌피질 차감소되었으나피질손상군은전정손상군과비교하여유의한증가를보였으며 (p<0.05), 이러한자제부조화는시간의경과에따라점차감소하여전정기관절제 48시간후에는전정손상군과피질손상군에서유의한차이를보이지않았다. 그러나피질자극군은피질손상군에서출현하는자세부조화가동반되지않았기때문에실험군에서제외하였다 (Figure 3). 2. 전정보상과정에서자발안진의회복에대한대뇌피질의영향정상동물은안정된상태에서자발안진이출현하지않지만일측전정기관을절제하면그직후부터지속적인자발안진이출현하였다. 전정기관절제 2시간후전정손상군은자발안진이 25±3 beats/10 sec의출현빈도를보였으며, 운동피질손상군은 28±5 beats/10 sec, 감각피질손상군은 30±3 beats/10 sec의출현빈도를갖는자발안진이출현하여피질손상군은전정손상군과비교하여유의한증가를보였다 (p<0.05). 이러한자발안진은시간의경과에따라점차감소되어전정기관절제 48시간후전정손상군은 8±4 beats/10 sec의출현빈도를보였다. 그러나피질손상군은전정손상군과비교하여자발안진의출현빈도가증가하였으며, 특히감각피질손상군의자발안진은 14±4 beats/10 sec 으로유의한증가를보였다 (p<0.01; Figure 4A). 일차운동피질과일차또는이차감각피질을전기자극한피질자극군은자발안진의출현빈도가전정손상군과 비교하여유의한감소를보였다. 즉, 전정기관절제 2시간후자발안진의출현빈도는일차운동피질자극군에서 24±3 beats/10 sec (p<0.05), 일차감각피질자극군에서 21±3 beats /10 sec (p<0.05), 이차감각피질자극군에서 17±2 beats/10 sec (p<0.01) 으로전정손상군과비교하여유의한감소를보였다 (Figure 4B). 3. 전정보상과정에서내측전정신경핵의 c-fos 단백발현에대한대뇌피질의영향전정손상군, 일차운동피질손상군, 그리고이차감각피질자극군에서내측전정신경핵으로부터 c-fos 면역반응세포의발현을측정하였다. 전정기능이정상인동물의내측전정신경핵은 c-fos 단백발현을보이지않으나, 일측전정기관을절제하면초기에 c-fos 단백발현이손상측과반대측전정신경핵에서심한비대칭성을이루며, 그후시간이경과함에따라 c-fos 단백발현은점차감소함과동시에양측전정신경핵에서대칭성에접근함을보였다. 전정손상군에서전정기관절제 2시간후손상측내측전정신경핵은 165±13개, 정상측에서 230±12개의 c-fos 변역반응세포를보였으며, 일차운동피질손상군은손상측 89±14개, 정상측 139±11개, 이차감각피질자극군은손상측 25±4개, 정상측 45±5개의 c-fos 면역반응세포의발현을보여일차운동피질손상군과이차감각피질자극군이전정기관손상군과비교했을때 c-fos 단백발현이유의하게감소하였다 (p< 0.01). 그리고시간이경과함에따라대뇌피질손상군과대 Figure 4. Effect of cortical lesion (A) or cortical stimulation (B) on time-dependent changes in spontaneous nystagmus 2, 4, 6, 12, 24, and 48 hours following unilateral labyrinthectomy (UL). Continuous electrical stimulation to each cortical area was performed for 48 hours after UL. Values are mean±standard deviation of 7 rats in each group. M1, primary motor cortex; S1, primary somatosensory cortex. *Denotes significant difference between sham and M1 or S2 lesion groups (*p<0.05, **p<0.01). 79

Res Vestib Sci Vol. 14, No. 3, Sep. 2015 Figure 5.

6 Res Vestib Sci Vol. 14, No. 3, Sep Figure 5. Effect of cortical lesion or cortical stimulation on c-fos protein expression in the medial vestibular nuclei following unilateral labyrinthectomy (UL). In upper panel, photographs showing expression of c-fos protein in the vestibular nuclei of sham (A), M1 lesion (B), and S2 stimulation animals (C). In lower panel, time-dependent changes in c-fos protein expression in the MVN of sham, M1 lesion, and S2 stimulation groups 2, 6, and 24 hours after UL. CONT, contralateral side to UL; IPSI, ipsilateral side to UL; MVN, medial vestibular nucleus; PrH, prepositus hypoglossi. Values are mean±standard deviation of 7 rats in each group. M1, primary motor cortex; S1, primary somatosensory cortex. *Denotes significant difference between sham and M1 or S2 lesion groups (*p<0.05, **p<0.01). 뇌피질자극군모두전정기관손상군과비교하여양측내측전정신경핵에서 c-fos 단백발현의비대칭성이소실되는현상을보였다 (Figure 5). 고찰말초전정기관의구심성신호는시상을경유하여전정피질에도달하며, 전정신경핵은시상아핵으로직접투사하는신경섬유들이존재한다. 고양이에서전정신경핵으로부터신경세포의축삭들이반대측시상으로투사되는것이관찰되었으며, 16 또한원숭이에서는전정신경핵뉴런이양측시상으로투사하며, 특히동측시상으로더많은신경섬유가투사됨이관찰되었다. 17 흰쥐의양측시상은전정신경핵뉴론으로부터구심성섬유를받으며, 이중전정신경핵과동측시상에서더많은섬유를받는다. 최근연구에서전정신경핵에서동측내측섬유띠옆쪽을경유하여시상으로직접투사하는동측전정시상투사로의존재가보고되었고, 또한전정신경핵에내측종속을경유하여반대측시상으로투사하는신경로가제시되었다. 17 사람을대상으로양전자방사단층촬영등의영상기법을이용한연구에서일측 전정기관을흥분시켰을때양측시상에서흥분되며, 18 일측시상의허혈성괴사환자에서일측전정기관자극시반대측대뇌의흥분성이현저히감소함을밝힘으로써일측전정신경핵에서양측시상으로전정신호가투사됨을확인하였다. 19 하지만일측말초전정기관을자극하면동측전정피질에서반대측보다흥분이더욱많이발생하는점을고려할때, 전정신경핵에서동측시상을경유하여동측전정피질로구심성신호가전달되는신경로가우세한것으로보인다. 20 원숭이에서다수의전정피질은전정신경핵으로축삭을직접투사하며, 13 전정신경핵에축삭을투사하는전정피질중 PIVC, T3 영역에서는양측전정신경핵으로투사하며, 3aV 영역에서는반대측전정신경핵으로보다많은축삭이투사된다. 흰쥐는대뇌피질에서전정신경핵으로신경섬유가직접투사되는데, 두정-측두부위, 전앞다리, 전뒷다리, 복측측두부위영역에서신경세포의축삭이양측전정신경핵으로투사되지만특히반대측으로더많이투사된다. 21 다양한실험동물에서피질-전정신경로에대한많은전기생리학적연구들이진행되었지만동물간에결과의차이가있어기능적특성이충분히규명되지않았다. 22 고양이의 area 6을전기자극하면대부분의전정신경핵뉴런에서자 80

7 유현광외 3 인. 전정보상과대뇌피질 발활동성이증가, 억제, 증가후억제등여러형태의반응을보이며, 또한 area 2, 3을전기자극하면동측전정신경핵뉴런들의자발활동성이변화하며이때도다양한반응이관찰되었다. 23 이러한연구결과를토대로대뇌피질이전정기관의흥분성에변화를주어전정기관의기능변화를일으켜전정기관손상후보상작용에영향을미칠것이라생각된다. 정상인을대상으로대뇌피질에전기자극하여전정기능의변화를관찰한연구는거의없으며, 뇌전증환자들을대상으로주로이루어졌다. 뇌전증환자에서측두엽, 두정엽, 전두엽, 후두엽및뇌섬을선택적으로전기자극하면회전하는환상을경험하였으며, 특히두정엽섬전정피질영역을전기자극하였을때증상이가장쉽게유발되었다. 24 뇌전증환자에서상측두이랑을전기자극하면시야흐림과수평자발안진이유발되었으며이때자발안진의서상은자극동측으로출현하였다. 그러나전기자극강도를증가하면 3차원안진이유발되면서안진의방향이자극반대측으로변화하였다. 12 이것은일측전정손상후출현하는안운동반사의행동학적평가로볼수있으며, 자극의강도에따라흥분성이변화하여전정신경핵에미치는영향이바뀔수있다는것을제시할수있다. c-fos 단백은다양한자극 30분후부터뉴런에서발현되는조기유전자로알려져있으며신경표지자로널리이용되고있다. 15 따라서일측전정기관손상후전정보상과정을추구할목적으로양측전정신경핵에서 c-fos 단백발현의시간적변화를관찰한연구가수행되어왔다 일측전정기관의손상직후양측내측전정신경핵은 c-fos 단백발현의양적비대칭이발생하고, 시간이경과함에따라비대칭이소실되며, 이러한변화는전정증상의행동학적변화와일치함이보고되었다. 즉일측전정기관손상 2시간후정상측내측전정신경핵은손상측과비교하여유의한증가를보이지만 6시간후부터는손상측이정상측보다증가하는비대칭을보이고 72시간후에는 c-fos 단백발현이소실된다. 따라서이연구에서대뇌피질이전정보상에미치는영향을평가할목적으로 c-fos 단백발현을지표로사용할수있다. 이연구에서전정손상군보다대뇌피질영역에전기자극을가한피질자극군에서자발안진의출현빈도가현저하게감소하는것을볼수있었다. 이것은대뇌피질에서전기자극의흥분성이동측전정신경핵에흥분을야기하여안구운동에대한보상이일어난것으로예측되며, c-fos 면역반응세포에서전정기관손상후양측전정신경핵에서 비대칭성을보이다가시간이경과함에따라대칭성을이룬것은자발안진이소실되고피질전기자극에의한안구반응이회복되는시점과일치하는것으로보아전기자극에의한흥분성의변화가전정보상작용에영향을미칠수있음을시사한다. 뇌졸중에의한두정-측두엽과후두엽손상환자들에서회전자극에의한전정안반사의변화를관찰한결과일측손상환자에서동측으로회전자극시안진의서상속도가유의하게감소하고위상차이가발생하였다. 또한회전자극중단직후자발안진의발생빈도도일측손상환자는동측으로회전자극후멈추었을때더욱많이관찰되었다. 11 이러한결과는일측말초전정기관을자극하면동측전정피질에서반대측보다흥분이더욱많이발생한것으로일측전정신경핵에서동측전정피질로구심성신호전달이우세함을시사한다. 이연구에서대뇌피질의손상에따른피질손상군은전정손상군과비교하여자발안진의출현이많음은대뇌피질손상이손상측전정기관에억제반응을일으켜자발안진의출현이증가한것으로보인다. 또한일측전정기관손상후나타나는자세부조화는피질손상군에서전정손상군보다증가함은대뇌피질손상이행동학적보상에대해지연시키는것임을관찰할수있었다. 이상의실험결과는흰쥐에서대뇌피질이전정기관손상후전정안반사및전정척수반사의가소성형성과정에영향을미칠수있다는실험적증거로대뇌피질의전기자극이전정보상작용을촉진시킬수있을것으로생각된다. 결론일측전정기관손상후전정보상에서대뇌피질의전기자극이전정안반사및전정척수반사의회복을촉진시킴으로대뇌피질이전정기관의가소성형성과정에영향을미칠수있을것으로생각된다. 중심단어 : 대뇌피질손상, 대뇌피질전기자극, 일측전정기관절제, 전정보상, c-fos 면역단백 CONFLICT OF INTEREST No potential conflict of interest relevant to this article was reported. 81

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