Deluca Cristina, Golzar Ashkan, Santandrea Elisa, Lo Gerfo Emanuele, Eštočinová Jana, Moretto Giuseppe, Fiaschi Antonio, Panzeri Marta, Mariotti Caterina, Tinazzi Michele, Chelazzi Leonardo
Department of Neurological and Movement Sciences, University of Verona, Verona, Italy.
Department of Neurological and Movement Sciences, University of Verona, Verona, Italy; Department of Physiology, McGill University, Montreal, Canada.
Cortex. 2014 Sep;58:52-71. doi: 10.1016/j.cortex.2014.04.017. Epub 2014 Jun 2.
Visual perceptual learning is widely assumed to reflect plastic changes occurring along the cerebro-cortical visual pathways, including at the earliest stages of processing, though increasing evidence indicates that higher-level brain areas are also involved. Here we addressed the possibility that the cerebellum plays an important role in visual perceptual learning. Within the realm of motor control, the cerebellum supports learning of new skills and recalibration of motor commands when movement execution is consistently perturbed (adaptation). Growing evidence indicates that the cerebellum is also involved in cognition and mediates forms of cognitive learning. Therefore, the obvious question arises whether the cerebellum might play a similar role in learning and adaptation within the perceptual domain. We explored a possible deficit in visual perceptual learning (and adaptation) in patients with cerebellar damage using variants of a novel motion extrapolation, psychophysical paradigm. Compared to their age- and gender-matched controls, patients with focal damage to the posterior (but not the anterior) cerebellum showed strongly diminished learning, in terms of both rate and amount of improvement over time. Consistent with a double-dissociation pattern, patients with focal damage to the anterior cerebellum instead showed more severe clinical motor deficits, indicative of a distinct role of the anterior cerebellum in the motor domain. The collected evidence demonstrates that a pure form of slow-incremental visual perceptual learning is crucially dependent on the intact cerebellum, bearing the notion that the human cerebellum acts as a learning device for motor, cognitive and perceptual functions. We interpret the deficit in terms of an inability to fine-tune predictive models of the incoming flow of visual perceptual input over time. Moreover, our results suggest a strong dissociation between the role of different portions of the cerebellum in motor versus non-motor functions, with only the posterior lobe being responsible for learning in the perceptual domain.
视觉感知学习被广泛认为反映了沿脑-皮质视觉通路发生的可塑性变化，包括在处理的最早阶段，尽管越来越多的证据表明高级脑区也参与其中。在这里，我们探讨了小脑在视觉感知学习中发挥重要作用的可能性。在运动控制领域，当运动执行持续受到干扰（适应）时，小脑支持新技能的学习和运动命令的重新校准。越来越多的证据表明，小脑也参与认知并介导认知学习形式。因此，一个明显的问题出现了，即小脑在感知领域的学习和适应中是否可能发挥类似的作用。我们使用一种新颖的运动外推心理物理学范式的变体，探究了小脑损伤患者在视觉感知学习（和适应）方面可能存在的缺陷。与年龄和性别匹配的对照组相比，小脑后部（而非前部）局灶性损伤的患者在学习速度和随时间的改善量方面均表现出明显减弱的学习能力。与双分离模式一致，小脑前部局灶性损伤的患者反而表现出更严重的临床运动缺陷，这表明小脑前部在运动领域具有独特的作用。收集到的证据表明，一种纯粹形式的缓慢渐进式视觉感知学习严重依赖于完整的小脑，并支持人类小脑作为运动、认知和感知功能的学习装置这一观点。我们将这种缺陷解释为无法随时间对视觉感知输入的信息流预测模型进行微调。此外，我们的结果表明，小脑不同部分在运动与非运动功能中的作用存在强烈分离，只有后叶负责感知领域的学习。
