Assessing Neural Compensation With Visuospatial Working Memory Load Using Near-Infrared Imaging.
Summary
Neural compensation is intact in mild cognitive impairment (MCI) but not in mild Alzheimer's disease (mAD). A novel visual working memory task revealed compensatory hyperactivation in MCI, but not in mAD, suggesting neurodegeneration impacts this ability.
Area of Science:
- Neuroscience
- Cognitive Psychology
- Medical Imaging
Background:
- Alzheimer's disease (AD) involves cognitive decline, particularly in working memory.
- Mild cognitive impairment (MCI) precedes AD, with intact neural compensation.
- Neural compensation is believed to be impaired in AD.
Purpose of the Study:
- To investigate neural compensation differences in healthy controls (HC), MCI, and mild AD (mAD) using a visual working memory (VSWM) task.
- To explore the effects of increasing task load on neural activity in the prefrontal cortex (PFC).
- To assess the feasibility of a novel VSWM task for inducing and measuring neural compensation.
Main Methods:
- Functional near-infrared spectroscopy (fNIRS) was used to measure bilateral PFC activation.
- Participants included 31 HC, 12 MCI patients, and 18 mAD patients.
- A VSWM task with three increasing load levels (1-3) was administered.
Main Results:
- All groups showed behavioral performance decline with increased task load.
- MCI patients exhibited significant load-dependent cortical response (fNIRS).
- MCI showed neural compensation (hyperactivation) at moderate task load, absent in mAD, which had poorer performance.
Conclusions:
- Neural compensation mechanisms differ between MCI and mAD, with MCI showing compensatory hyperactivation.
- The novel VSWM task effectively induces neural compensation at appropriate cognitive loads.
- Findings offer insights into cognitive load theory and neural compensation, potentially aiding dementia rehabilitation strategies.
