Task-specific modulation of corticospinal neuron activity during motor learning in mice.

Motor skill learning relies on the plasticity of the primary motor cortex as task acquisition drives cortical motor network remodeling. Large-scale cortical remodeling of evoked motor outputs occurs during the learning of corticospinal-dependent prehension behavior, but not simple, non-dexterous tasks. Here we determine the response of corticospinal neurons to two distinct motor training paradigms and assess the role of corticospinal neurons in the execution of a task requiring precise modulation of forelimb movement and one that does not. In vivo calcium imaging in mice revealed temporal coding of corticospinal activity coincident with the development of precise prehension movements, but not more simplistic movement patterns. Transection of the corticospinal tract and optogenetic regulation of corticospinal activity show the necessity for patterned corticospinal network activity in the execution of precise movements but not simplistic ones. Our findings reveal a critical role for corticospinal network modulation in the learning and execution of precise motor movements.

Geriatric Elements and Oral Anticoagulant Prescribing in Older Atrial Fibrillation Patients: SAGE-AF.

OBJECTIVES: Oral anticoagulants are the cornerstone of stroke prevention in high-risk patients with atrial fibrillation (AF). Geriatric elements, such as cognitive impairment and frailty, commonly occur in these patients and are often cited as reasons for not prescribing oral anticoagulants. We sought to systematically assess geriatric impairments in patients with AF and determine whether they were associated with oral anticoagulant prescribing. DESIGN: Cross-sectional analysis of baseline data from the ongoing Systematic Assessment of Geriatric Elements in Atrial Fibrillation (SAGE-AF) prospective cohort study. SETTING: Multicenter study with site locations in Massachusetts and Georgia that recruited participants from cardiology, electrophysiology, and primary care clinics from 2016 to 2018. PARTICIPANTS: Participants with AF age 65 years or older, CHA2 DS2 -VASc (congestive heart failure; hypertension; aged ≥75 y [doubled]; diabetes mellitus; prior stroke, transient ischemic attack, or thromboembolism [doubled]; vascular disease; age 65-74; female sex) score of 2 or higher, and no oral anticoagulant contraindications (n = 1244). MEASUREMENTS: A six-component geriatric assessment included validated measures of frailty, cognitive function, social support, depressive symptoms, vision, and hearing. Oral anticoagulant use was abstracted from the medical record. RESULTS: A total of 1244 participants (mean age = 76 y; 49% female; 85% white) were enrolled; 42% were cognitively impaired, 14% frail, 53% pre-frail, 12% socially isolated, and 29% had depressive symptoms. Oral anticoagulants were prescribed to 86% of the cohort. Oral anticoagulant prescribing did not vary according to any of the geriatric elements (adjusted odds ratios [ORs] for oral anticoagulant prescribing and cognitive impairment: OR = .75; 95% confidence interval [CI] = .51-1.09; frail OR = .69; 95% CI = .35-1.36; social isolation OR = .90; 95% CI = .52-1.54; depression OR = .79; 95% CI = .49-1.27; visual impairment OR = .98; 95% CI = .65-1.48; and hearing impairment OR = 1.05; 95% CI = .71-1.54). CONCLUSION: Geriatric impairments, particularly cognitive impairment and frailty, were common in our cohort, but treatment with oral anticoagulants did not differ by impairment status. These geriatric impairments are commonly cited as reasons for not prescribing oral anticoagulants, suggesting that prescribers may either be unaware or deliberately ignoring the presence of these factors in clinical settings. J Am Geriatr Soc 68:147-154, 2019.