Một MRI coronal của . có hình giống mỏ chim (A) đuôi (C) cho thấy mức độ cắt bỏ vùng đồi thị hai bên (trái) so với một chủ đề 66 năm bình thường (phải), lưu ý sự phá hủy của hạch hạnh nhân (A), vùng đồi thị (H), và entorhinal vỏ não trước (EC) với mức của các cơ quan hình giống núm vú | Michael S. Mega 48 Figure A coronal MRI of . from rostral A to caudal C showing the extent of bilateral hippocampal ablation left compared with a normal 66-year-old subject right note the destruction of the amygdala A hippocampus H and entorhi-nal cortex EC anterior to the level of the mamillary bodies MMN with relative sparing of the posterior perirhinal cortex PR in the banks of the collateral sulcus cs . V temporal horn of lateral ventricle. Adapted from Corkin et al. 1997. 1989c Zola-Morgan Squire Ramus 1994 . The greatest recognition memory defect occurs when the perirhinal cortex is ablated along with the H lesion hippocampus dentate gyrus and subicular complex Zola-Morgan et al. 1993 followed by the combined caudal entorhinal and perirhinal cortices and the H lesion Mahut Zola-Morgan Moss 1982 Zola-Morgan et al. 1989c this defect is greater than that resulting from the H lesion alone Alvarez et al. 1995 . Restricted lesions of the perirhinal and parahippocampal Suzuki et al. 1993 Zola-Morgan et al. 1989c or entorhinal and perirhinal cortices Meunier et al. 1993 produce chronic multimodal memory deficits similar to those of a bilateral medial temporal lobectomy Suzuki et al. 1993 . Thus each of these medial temporal regions makes a contribution to the mnemonic process with the resultant recognition memory defect becoming more severe with the removal of each additional processing region Zola-Morgan et al. 1994 . What the unique functions are if any within each region is not known Eichenbaum Otto Cohen 1994 Gaffan 1994a . Amnesia 49 Diencephalic Lesions Hippocampal output from the subiculum via the fornix enters the mamillary body primarily the medial mamillary nucleus and projects to the anterior thalamic nuclei Aggleton Desimone Mishkin 1986 . The anterior thalamic region also receives direct hippocampal input via the fornix Aggleton et al. 1986 and has reciprocal connections with the cingulate gyrus and anterior reticu-larus thalami Gonzalo-Ruiz Morte
