The cerebellum acts as the analog to the medial temporal lobe for sensorimotor memory

• 成果类型: Article
• 署名作者: Hadjiosif, Alkis M.; Gibo, Tricia L.; Smith, Maurice A.
• 署名单位: Harvard University; Harvard University Medical Affiliates; Massachusetts General Hospital; Philips; Philips Healthcare; Johns Hopkins University; Harvard University
• 刊物名称: PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA
• ISSN/ISSBN: 0027-14139
• DOI: 10.1073/pnas.2411459121
• 发表日期: 2024-10-15
• 关键词: sensory prediction errors; long-term retention; internal-models; adaptive-control; motor memory; prefrontal cortex; working-memory; adaptation; involvement; degeneration

摘要

The cerebellum is critical for sensorimotor learning. The specific contribution that it makes, however, remains unclear. Inspired by the classic finding that for declarative memories, medial temporal lobe (MTL) structures provide a gateway to the formation of long- term memory but are not required for short- term memory, we hypothesized that for sensorimotor memories, the cerebellum may play an analogous role. Here, we studied the sensorimotor learning of individuals with severe ataxia from cerebellar degeneration. We dissected the memories they formed during sensorimotor learning into a short- term temporally- volatile component, that decays rapidly with a time constant of just 15 to 20 s and thus cannot lead to long- term retention, and a longer- term temporally- persistent component that is stable for 60 s or more and leads to long- term retention. Remarkably, we find that these individuals display dramatically reduced levels of temporally- persistent sensorimotor memory, despite spared and even elevated levels of temporally- volatile sensorimotor memory. In particular, we find both impairment that systematically worsens with memory window duration over shorter memory windows (<12 s) and near- complete impairment of memory maintenance over longer memory windows (>25 s). This dissociation uncovers a unique role for the cerebellum as a gateway for the formation of long- term but not short- term sensorimotor memories, mirroring the role of the MTL for declarative memories. It thus reveals the existence of distinct neural substrates for short- term and long- term sensorimotor memory, and it explains both the trial- to- trial differences identified in this study and long- standing study- to- study differences in the effects of cerebellar damage on sensorimotor learning ability.