Takahashi T, Kinsman S, Makris N, Grant E, Haselgrove C, McInerney S, Kennedy D N, Takahashi Ta, Fredrickson K, Mori S, Caviness V S
Department of Neurology, Massachusetts General Hospital, Harvard Medical School, Boston, MA 02114, USA.
Cereb Cortex. 2003 Dec;13(12):1299-312. doi: 10.1093/cercor/bhg077.
We present an MRI-based anatomic analysis of a series of seven human brains with the semilobar form of holoprosencephaly. The analysis defines a set of common descriptors for a pattern of topological anomaly which is uniform for the set of seven brains. The core of the anomaly is a rostro-caudally aligned midline gray matter 'seam' that extends from the telencephalic-suprachiasmatic junctional region to abut the posterior aspect of the callosal commissure. The seam forms the ventricular roof throughout its extent. Rostrally it is formed by the conjoined heads of caudate/accumbens nuclei. It continues caudally as a gray matter bridge in the fundus of the interhemispheric fissure, where it bridges right and left neocortex. Fornix, septal nuclei and septal limb of the choroid plexus are absent, and the telencephalic ventricles communicate with the diencephalic via open septal limbs of the choroid fissures. By contrast, the temporal limb of hippocampal formation and the choroid plexus are normal and the temporal limb of the choroid fissure is closed. This topological anomaly of conjoined left and right cortical and nuclear gray matter into a midline seam and absent septal structures is thus confined to the region of the midline telencephalic hemisphere evagination. Total telencephalic growth is strongly correlated with the length of this topologically abnormal midline telencephalic segment. The set of findings is consistent with graded failure of induction of rostral to caudal specification in the midline rostral telencephalic zone.
我们展示了对一系列七例半脑叶型前脑无裂畸形人类大脑的基于磁共振成像（MRI）的解剖学分析。该分析定义了一组针对拓扑异常模式的通用描述符，这一模式在这七例大脑中是一致的。异常的核心是一条从端脑 - 视交叉交界区域延伸至胼胝体连合后部的前后向排列的中线灰质“缝”。这条缝在其整个范围内构成脑室顶。在前端，它由尾状核/伏隔核的联合头部形成。在后端，它作为半球间裂底部的灰质桥继续延伸，在那里连接左右新皮质。穹窿、隔核和脉络丛的隔叶缺失，端脑室通过脉络膜裂的开放隔叶与间脑相通。相比之下，海马结构的颞叶和脉络丛是正常的，脉络膜裂的颞叶是闭合的。这种左右皮质和核灰质联合形成中线缝且隔结构缺失的拓扑异常因此局限于中线端脑半球外翻区域。端脑的总体生长与这条拓扑异常的中线端脑段的长度密切相关。这些发现与中线前端脑区从前向后规格诱导的分级失败一致。
