Department of Anatomy and Neurobiology, Washington University School of Medicine, St Louis, Missouri 63110, USA.
Hum Brain Mapp. 2010 Nov;31(11):1686-701. doi: 10.1002/hbm.20966.
In blind, occipital cortex showed robust activation to nonvisual stimuli in many prior functional neuroimaging studies. The cognitive processes represented by these activations are not fully determined, although a verbal recognition memory role has been demonstrated. In congenitally blind and sighted (10 per group), we contrasted responses to a vibrotactile one-back frequency retention task with 5-s delays and a vibrotactile amplitude-change task; both tasks involved the same vibration parameters. The one-back paradigm required continuous updating for working memory (WM). Findings in both groups confirmed roles in WM for right hemisphere dorsolateral prefrontal (DLPFC) and dorsal/ventral attention components of posterior parietal cortex. Negative findings in bilateral ventrolateral prefrontal cortex suggested task performance without subvocalization. In bilateral occipital cortex, blind showed comparable positive responses to both tasks, whereas WM evoked large negative responses in sighted. Greater utilization of attention resources in blind were suggested as causing larger responses in dorsal and ventral attention systems, right DLPFC, and persistent responses across delays between trials in somatosensory and premotor cortex. In sighted, responses in somatosensory and premotor areas showed iterated peaks matched to stimulation trial intervals. The findings in occipital cortex of blind suggest that tactile activations do not represent cognitive operations for nonverbal WM task. However, these data suggest a role in sensory processing for tactile information in blind that parallels a similar contribution for visual stimuli in occipital cortex of sighted.
在许多先前的功能神经影像学研究中，盲人大脑枕叶对非视觉刺激表现出强烈的激活。尽管已经证明了其具有言语识别记忆的作用，但这些激活所代表的认知过程还不完全确定。在先天性盲人和视力正常的人群（每组 10 人）中，我们对比了对振动触觉 1 -back 频率保持任务和振动触觉幅度变化任务的反应；这两个任务都涉及相同的振动参数。1-back 范式需要连续更新工作记忆（WM）。这两个组的发现都证实了右半球背外侧前额叶皮层（DLPFC）和后顶叶注意成分在 WM 中的作用。双侧腹外侧前额叶皮层的阴性发现表明任务表现不需要默读。在双侧枕叶皮层中，盲人对这两个任务都表现出类似的正响应，而视力正常者的 WM 则引起较大的负响应。盲人对注意资源的更大利用被认为导致了更大的反应在背侧和腹侧注意系统、右 DLPFC 以及在感觉运动和运动前皮层之间的试验延迟之间的持续反应。在视力正常者中，感觉运动和运动前区域的反应表现出与刺激试验间隔匹配的迭代峰值。盲人枕叶皮层的这些发现表明，触觉激活并不代表非言语 WM 任务的认知操作。然而，这些数据表明，在盲人的触觉信息处理中存在一种作用，这与视力正常者枕叶皮层中视觉刺激的类似贡献相平行。
