Ghilardi M F, Silvestri G, Feigin A, Mattis P, Zgaljardic D, Moisello C, Crupi D, Marinelli L, Dirocco A, Eidelberg D
Department of Physiology & Pharmacology, CUNY Medical School, New York, NY 10031, USA.
Parkinsonism Relat Disord. 2008 Aug;14(6):457-64. doi: 10.1016/j.parkreldis.2007.11.009. Epub 2008 Mar 3.
Learning deficits may be part of the early symptoms of Huntington's disease (HD). Here we characterized implicit and explicit aspects of sequence learning in 11 pre-symptomatic HD gene carriers (pHD) and 11 normal controls. Subjects moved a cursor on a digitizing tablet and performed the following tasks: SEQ: learning to anticipate the appearance of a target sequence in two blocks; VSEQ: learning a sequence by attending to the display without moving for one block, and by moving to the sequence in a successive block (VSEQ test). Explicit learning was measured with declarative scores and number of anticipatory movements. Implicit learning was measured as a strategy change reflected in movement time. By the end of SEQ, pHD had a significantly lower number of correct anticipatory movements and lower declarative scores than controls, while in VSEQ and VSEQ test these indices improved. During all three tasks, movement time changed in controls, but not in pHD. These results suggest that both explicit and implicit aspects of sequence learning may be impaired before the onset of motor symptoms. However, when attentional demands decrease, explicit, but not implicit, learning may improve.
学习缺陷可能是亨廷顿舞蹈症（HD）早期症状的一部分。在此，我们对11名症状前HD基因携带者（pHD）和11名正常对照者的序列学习的内隐和外显方面进行了特征描述。受试者在数位板上移动光标并执行以下任务：SEQ：在两个阶段学习预测目标序列的出现；VSEQ：在一个阶段通过注视显示屏而不移动来学习一个序列，并在随后的阶段移动到该序列（VSEQ测试）。通过陈述性得分和预期动作的数量来衡量外显学习。以内隐学习作为运动时间所反映的策略变化来衡量。在SEQ结束时，pHD的正确预期动作数量和陈述性得分显著低于对照组，而在VSEQ和VSEQ测试中，这些指标有所改善。在所有三项任务中，对照组的运动时间发生了变化，而pHD组则没有。这些结果表明，序列学习的外显和内隐方面在运动症状出现之前可能都会受到损害。然而，当注意力需求降低时，外显学习（而非内隐学习）可能会得到改善。
