Dissociation between two aspects of procedural learning in Tourette syndrome: Enhanced statistical and impaired sequence learning

ABSTRACT

Tourette syndrome (TS) is a childhood-onset neurodevelopmental disorder that primarily affects the cortico-basal ganglia-thalamo-cortical (CBGTC) circuitry and is characterized by motor and vocal tics. Previous studies have found enhancement in procedural memory, which depends on the CBGTC circuitry and plays an important role in the learning and processing of numerous motor, social, and cognitive skills and habits. Based on these studies, procedural hyperfunctioning in TS has been proposed. However, the neurocognitive mechanism underlying such hyperfunctioning is poorly understood. Here, we investigated how two aspects of procedural learning, namely 1) frequency-based statistical learning and 2) order-based sequence learning, are affected in TS. Twenty-one children with TS between the ages of ten and fifteen as well as 21 typically developing controls were tested on a probabilistic sequence learning task that enables the parallel assessment of these two aspects. We found that children with TS showed enhanced sensitivity to statistical information but impaired sequence learning compared to typically developing children. The deconstruction of procedural memory suggests that procedural hyperfunctioning in TS may be supported by enhanced sensitivity to statistical information. These results can provide a potential path for improving therapy methods and skill-oriented educational programs for TS.

KEYWORDS:

• Tourette syndrome
• sub-cortical structures
• procedural memory
• skill learning
• basal ganglia
• statistical learning

Acknowledgments

We thank Réka Vidomusz and the Cognitive-Behavioral Therapy Team (Méhkas) of Vadaskert Child Psychiatry Hospital for their help in data acquisition and Megan MacDonald and Aleysia Whitmore for their comments and suggestions on the manuscript. D. N. is thankful for the support of IMÉRA.

Disclosure statement

The authors report no competing interest.

Supplementary material

Supplemental data for this article can be accessed at https://doi.org/10.1080/09297049.2021.1894110.

Additional information

Funding

E.T-F. was supported by the ÚNKP-17-2 New National Excellence Program of the Ministry of Human Capacities, Hungary. This research was supported by the National Brain Research Program (project 2017-1.2.1-NKP-2017-00002); Hungarian Scientific Research Fund (OTKA PD 121151 to Á.T., NKFIH-OTKA K 128016 to D.N., NKFIH-OTKA PD 124148 to K.J., NKFIH-OTKA FK 124412 to A.K.); János Bolyai Research Scholarship of the Hungarian Academy of Sciences (to K.J. and A.K.); IDEXLYON Fellowship of the University of Lyon as part of the Programme Investissements d’Avenir (ANR-16-IDEX-0005) (to D.N.); and by a grant from the Deutsche Forschungsgemeinschaft (DFG) FOR 2698 and DFG TA 1616/2-1 (to Á.T.).