Niimi K, Imataki T, Ono K, Matsuoka H, Miyata Y
Third Department of Anatomy, Okayama University Medical School, Japan.
J Hirnforsch. 1987;28(3):271-80.
The topical organization of thalamic projections to the second and fourth somesthetic areas in the anterior ectosylvian gyrus of the cat has been studied using the technique of retrograde axonal transport of horseradish peroxidase. The projections of the posterolateral and posteromedial ventral nuclei (VPL, VPM) to the second somesthetic area (SII) are organized somatotopically. The posterior portion of SII (hindlimb area) receives fibers mainly from the dorsolateral part of VPL, the middle portion of SII (forelimb area) from the ventromedial part of VPL, and the anterior portion of SII (face area) from VPM. These topical projections are more loosely organized and less densely arranged than those to the first somesthetic area. The SII receives a few fibers from the medial geniculate nucleus, particularly its magnocellular and dorsal principal parts, and from the suprageniculate nucleus. The posterior part of SII lying near the secondary auditory area receives many fibers from the medial geniculate and suprageniculate nuclei, and only a few fibers from the lateral central and paracentral nuclei. The fourth somesthetic area (SIV), located in the dorsal bank of the anterior ectosylvian sulcus, receives fibers mainly from the dorsal principal and magnocellular parts of the medial geniculate nucleus, and from the suprageniculate nucleus. The SIV receives a fair number of fibers from VPL and VPM roughly in a somatotopical manner. The posterior portion of SIV receives fibers chiefly from the dorsolateral part of VPL, the middle portion of SIV from the ventromedial part of VPL, and the anterior portion from VPM. In addition, SIV receives a few fibers from the lateral central, paracentral, ventral lateral and ventral medial nuclei. The SIV, together with the most posterior part of SII, forms an auditory area, receiving many fibers from the medial geniculate and suprageniculate nuclei, and a few fibers from the intralaminar nuclei.
运用辣根过氧化物酶逆行轴突运输技术，对猫前外侧沟回中丘脑向第二和第四躯体感觉区的局部投射进行了研究。后外侧腹核和后内侧腹核（VPL、VPM）向第二躯体感觉区（SII）的投射呈躯体定位组织。SII的后部（后肢区）主要接收来自VPL背外侧部分的纤维，SII的中部（前肢区）接收来自VPL腹内侧部分的纤维，SII的前部（面部区）接收来自VPM的纤维。这些局部投射比向第一躯体感觉区的投射组织更松散、排列更稀疏。SII从内侧膝状体核，特别是其大细胞部和背侧主部，以及上膝状体核接收少量纤维。位于第二听觉区附近的SII后部接收来自内侧膝状体和上膝状体核的许多纤维，以及来自外侧中央核和中央旁核的少量纤维。位于前外侧沟背侧缘的第四躯体感觉区（SIV）主要接收来自内侧膝状体核的背侧主部和大细胞部以及上膝状体核的纤维。SIV大致以躯体定位方式从VPL和VPM接收相当数量的纤维。SIV的后部主要接收来自VPL背外侧部分的纤维，SIV的中部接收来自VPL腹内侧部分的纤维，前部接收来自VPM的纤维。此外，SIV从外侧中央核、中央旁核、腹外侧核和腹内侧核接收少量纤维。SIV与SII的最后部一起形成一个听觉区，接收来自内侧膝状体和上膝状体核的许多纤维，以及来自板内核的少量纤维。
