Layer-specific Contribution to Consolidation of Skill Learning in the Primary Motor Cortex

Study Description:

Training on a novel motor skill often involves periods of active practice interspersed with periods of rest. During early motor skill learning, performance improvements develop primarily during short offline rest periods that occur between practice blocks. These performance gains during rest have been referred to as 'micro-offline consolidation'. Primary motor cortex (M1) is a crucial contributor to skill consolidation, however, due to the poor spatial specificity and vascular biases of available imaging methods, the specific neural mechanisms of consolidation in M1 are not known. Recent innovations in functional magnetic resonance imaging (fMRI) have made it possible to measure functional changes across cortical layers. This study will use these techniques to investigate the contributions of specific cortical layers in M1 to motor skill learning and consolidation.

Objectives:

The primary aim is to determine the correlation between activity in superficial M1 cortical layers and behavioral gains during microoffline rest periods. Additionally, we will evaluate the role of superficial and deep cortical layers of M1 in the consolidation of motor skill learning. To address this question, we will measure neural activations across cortical laminae in M1 while participants consolidate a newly acquired motor skill.

Endpoints:

The primary endpoint measures will be: 1) activity in superficial M1 cortical layers during micro-offline rest periods, which will be measured using vascular space occupancy (VASO) MR imaging and 2) behavioral gains during micro-offline rest periods measured as correct sequence typing speed (sequences per second). The secondary endpoint measure will be the ratio of activity between superficial and deep M1 layers during practice and during rest periods compared to pre-learning and to post-learning rest and the localizing random sequence.

Exploratory endpoints will include other fMRI measures that may relate learning with layer activity. For example, we will use multivoxel pattern analysis (MVPA) of activation data to: (a) gain insight into the presence of layer-specific reactivation of sequence task performance during rest periods; and (b) investigate whether this reactivation predicts learning.

Study Population:

45 Healthy participants (18-50 years of age)

Phase:

N/A

Description of Sites/Facilities Enrolling Participants:

This protocol utilizes the NIH Clinical Center Outpatient Clinic, and NMRF core facilities.

Intervention Study Duration:

24 months

Participant Duration:

Approximately 2-5 hours per session, for up to 4 sessions over a 1-4-day time period.

Study Description:

Training on a novel motor skill often involves periods of active practice interspersed with periods of rest. During early motor skill learning, performance improvements develop primarily during short offline rest periods that occur between practice blocks. These performance gains during rest have been referred to as "micro-offline consolidation". Primary motor cortex (M1) is a crucial contributor to skill consolidation; however, due to the poor spatial specificity and vascular biases of available imaging methods, the specific neural mechanisms of consolidation in M1 are not known. Recent innovations in functional magnetic resonance imaging (fMRI) have made it possible to measure functional changes across cortical layers. This study will use these techniques to investigate the contributions of specific cortical layers in M1 to motor skill learning and consolidation.