Kotz Sonja A, Schwartze Michael, Schmidt-Kassow Maren
Max Planck Institute for Human Cognitive and Brain Sciences, Research Group "Neurocognition of Rhythm in Communication", Leipzig, Germany.
Cortex. 2009 Sep;45(8):982-90. doi: 10.1016/j.cortex.2009.02.010. Epub 2009 Mar 9.
While the primary function of the basal ganglia (BG) is linked to motor behaviour, several investigations of non-motor behaviour allocate cognitive and language-specific functions to the BG. What may such seemingly discrepant functions have in common? Some neurophysiologic theories of motor behaviour assign temporal sequencing, others the sequencing of general cognitive patterns to the BG. Turning to auditory language perception and syntax in particular, one may consider syntactic processing as a hierarchical sequencing phenomenon. Furthermore, previous data have shown that if events are predictable, the processing of successively following events in a sequence is facilitated. We propose that sequencing is closely linked to the perception of predictable cues (regular beats, meter, temporal chunks etc.). If this is the case, syntactic processing should rely on the extraction of predictable cues in auditory language perception. Consequently, dysfunctional extraction of such cues in BG patients should then lead to secondary deficits in syntactic processing as evidenced in recent behavioural and electrophysiological evidence (ERP). The fact that such "secondary syntactic deficits" can be compensated by external and speech inherent predictable cues permits two conclusions: (i) syntactic deficits in BG patients are epiphenomenal, and (ii) sequencing dysfunctions of the pre-supplementary motor area (SMA)-BG circuit may be compensated by increased influence of the cerebellar-thalamic-pre-SMA pathway. In the current review we elaborate on this possibility drawing comparisons to similar proposals in motor and language production.
虽然基底神经节(BG)的主要功能与运动行为相关,但一些关于非运动行为的研究将认知和特定语言功能归因于BG。这些看似矛盾的功能可能有什么共同之处呢?一些关于运动行为的神经生理学理论将时间序列分配给BG,另一些则将一般认知模式的序列分配给BG。特别是在听觉语言感知和句法方面,人们可能会将句法处理视为一种层次序列现象。此外,先前的数据表明,如果事件是可预测的,那么序列中相继出现的事件的处理就会得到促进。我们提出,序列与可预测线索(规则节拍、韵律、时间块等)的感知密切相关。如果是这样,句法处理应该依赖于听觉语言感知中可预测线索的提取。因此,BG患者中此类线索的功能失调提取应该会导致句法处理的继发性缺陷,正如最近行为和电生理证据(ERP)所证明的那样。这种“继发性句法缺陷”可以通过外部和言语固有的可预测线索得到补偿,这一事实可以得出两个结论:(i)BG患者的句法缺陷是附带现象,(ii)补充运动前区(SMA)-BG回路的序列功能障碍可能通过小脑-丘脑-运动前区通路增加的影响得到补偿。在当前的综述中,我们详细阐述了这种可能性,并与运动和语言产生方面的类似提议进行了比较。