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Neuropsychologia. 2018 Aug;117:551-557. doi: 10.1016/j.neuropsychologia.2018.07.021. Epub 2018 Jul 18.

Absence of associative motor learning and impaired time perception in a rare case of complete cerebellar agenesis.

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Department of Physiology, College of Basic Medical Sciences, Third Military Medical University, Chongqing 400038, China.
Department of Neurobiology and Anatomy, Drexel University College of Medicine, Philadelphia, PA 19129, USA. Electronic address:
Department of Neurosurgery, Qianfoshan Hospital, 16766 Jingshi Road, Jinan 250001, Shandong Province, China. Electronic address:
Department of Physiology, College of Basic Medical Sciences, Third Military Medical University, Chongqing 400038, China. Electronic address:


Primary cerebellar agenesis (PCA), a brain disease where the cerebellum does not develop, is an extremely rare congenital disease with only eleven living cases reported thus far. Studies of the PCA case will thus provide valuable insights into the necessity of cerebellar development for controlling and modulating cognitive functions of the brain. In this follow-up study, we further investigated the performance of associative learning and time perception of a 26-year-old female complete PCA case. We assessed whether delayed eyeblink conditioning (EBC), which represents prototypical associative motor learning function of the cerebellum, could be partially compensated by the extracerebellar brain regions in complete absence of the cerebellum. We also assessed whether the cerebellum, a critical brain region for millisecond-range interval timing, is essential for perception of the second-range time interval. Twelve neurotypical age-matched individuals were used as controls. We found that although the complete PCA patient had only mild to moderate motor deficits, she was unable to perform the delayed EBC even after 1-week of extensive training. Additionally, the PCA patient also performed poorly during time reproduction experiments in which she overproduced the millisecond-range time intervals, while underproduced the second-range time intervals. The PCA patient also failed to perform the temporal eyeblink conditioning with a 5 s fixed interval as the conditioned stimulus. These results indicate that the cerebellum is indispensable for associative motor learning and involved in timing of sub-second intervals, as well as in the perception of second-range intervals.


Associative motor learning; Cerebellar agenesis; Eyeblink conditioning; Time perception

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