Aerobic Exercise Improves Cortical Inhibitory Function After Stroke: A Preliminary Investigation

Abstract

Background and Purpose: Aerobic exercise can elicit positive effects on neuroplasticity and cognitive executive function but is poorly understood after stroke. We tested the effect of 4 weeks of aerobic exercise training on inhibitory and facilitatory elements of cognitive executive function and electroencephalography markers of cortical inhibition and facilitation. We investigated relationships between stimulus-evoked cortical responses, blood lactate levels during training, and aerobic fitness postintervention. Methods: Twelve individuals with chronic (>6 months) stroke completed an aerobic exercise intervention (40 minutes, 3×/wk). Electroencephalography and motor response times were assessed during congruent (response facilitation) and incongruent (response inhibition) stimuli of a Flanker task. Aerobic fitness capacity was assessed as during a treadmill test pre- and postintervention. Blood lactate was assessed acutely (<1 minute) after exercise each week. Cortical inhibition (N2) and facilitation (frontal P3) were quantified as peak amplitudes and latencies of stimulus-evoked electroencephalographic activity over the frontal cortical region. Results: Following exercise training, the response inhibition speed increased while response facilitation remained unchanged. A relationship between earlier cortical N2 response and faster response inhibition emerged postintervention. Individuals who produced higher lactate during exercise training achieved faster response inhibition and tended to show earlier cortical N2 responses postintervention. There were no associations between and metrics of behavioral or neurophysiologic function. Discussion and Conclusions: These preliminary findings provide novel evidence for selective benefits of aerobic exercise on inhibitory control during the initial 4-week period after initiation of exercise training and implicate a potential therapeutic effect of lactate on poststroke inhibitory control. Video Abstract available for more insights from the authors (see the video, Supplemental Digital Content 1 available at: http://links.lww.com/JNPT/A450).

Measuring Neuroplasticity in Response to Cardiovascular Exercise in People With Stroke: A Critical Perspective

“…The chronic changes in brain activity were examined in a similar study using the same stimulus-evoked paradigm to study cortical inhibition (N200) and facilitation (P300) over the frontal cortical region following 4 weeks of treadmill and overground walking. 23 While no significant changes in cortical activity were evoked with CE, a positive association between cortical (N200 latency) and behavioral (response inhibition in Flanker task) inhibitory indices was found after the intervention, suggesting a link between cortical processing and cognitive inhibitory responses.…”

“…Brain activity and connectivity recorded with electroencephalography (EEG) can capture brain oscillations reflecting postsynaptic excitation and inhibition, both of which have been used in the diagnosis of cerebral ischemia, outcome prediction, and treatment response after stroke ( Figure 1 ; Box 1 ). Three studies used EEG to examine the effects of CE on brain activity and connectivity poststroke 21 - 23 ( Table 1 ). In 1 study, acute changes in brain activity were examined while performing a modified Eriksen Flanker executive function task following a single bout of stepping exercise performed at moderate intensity.…”