Long K D, Lomber S G, Payne B R
Department of Anatomy and Neurobiology, Boston University School of Medicine, MA 02118, USA.
Exp Brain Res. 1996 Aug;110(3):335-46. doi: 10.1007/BF00229134.
We measured changes in metabolic activity in middle suprasylvian (MS) cortex of cats subjected to early or late removal of areas 17 and 18 to localize shifts in activity possibly indicative of regions within MS cortex that may receive expanded inputs and be involved in the sparing of some visual behaviors following early primary visual cortex damage. Cytochrome oxidase (CO) activity was measured in MS cortex of mature, intact cats and of others with areas 17 and 18 removed in adulthood (P180), or on postnatal day 28 (P28) or postnatal day 1 (P1). Not less than 9 months after the ablation, brain sections were prepared and reacted for the presence of CO. The density of CO reactivity in each of the six cortical layers in MS cortex was measured and standardized against densities from ventral periaqueductal gray or hypothalamus on the same section. Following lesions on P1, significant increases in CO activity occurred in deep layer III and in layer IV of the medial bank of the MS sulcus, including all of area PMLS and the posterior portion of AMLS. In contrast, there were no significant differences in the level of CO activity among P28, P180, or intact cats for any of the cortical layers, and all had lower levels than the P1 cats. This metabolic change provides an anatomical marker for localizing adjustments in MS cortex and can be linked to amplified projections into MS cortex from the thalamus (LPm and A and C laminae of the dorsal lateral geniculate nucleus) and ventral posterior suprasylvian cortex following P1 ablations. Furthermore, this neurochemical analysis implicates a distinct region of MS cortex as the cortical locus of some spared visual functions following early primary visual cortex damage.
我们测量了猫中颞上回（MS）皮质的代谢活动变化，这些猫在早期或晚期被切除17区和18区，以定位活动的变化，这些变化可能表明MS皮质内的区域，这些区域可能接受扩大的输入，并参与早期初级视觉皮质损伤后某些视觉行为的保留。在成年、完整的猫以及成年期（P180）、出生后第28天（P28）或出生后第1天（P1）切除17区和18区的其他猫的MS皮质中测量了细胞色素氧化酶（CO）活性。在切除后不少于9个月，制备脑切片并对CO的存在进行反应。测量了MS皮质六个皮质层中每层的CO反应密度，并以同一切片上腹侧导水管周围灰质或下丘脑的密度为标准进行标准化。在P1损伤后，MS沟内侧壁的深层III和IV层，包括整个PMLS区和AMLS的后部，CO活性显著增加。相比之下，P28、P180或完整猫的任何皮质层之间的CO活性水平没有显著差异，并且所有这些猫的CO活性水平都低于P1猫。这种代谢变化为定位MS皮质的调整提供了解剖学标记，并且可以与P1切除后从丘脑（背外侧膝状体核的LPm和A及C层）和腹侧后颞上回皮质向MS皮质的放大投射联系起来。此外，这种神经化学分析表明，MS皮质的一个独特区域是早期初级视觉皮质损伤后某些保留视觉功能的皮质位点。
