Disrupted Practice Effects and Altered Prefrontal Activation in Mild Cognitive Impairment: An fNIRS Study Using the...

Area of Science:

• Neuroscience
• Cognitive Psychology
• Medical Imaging

Background:

• Executive dysfunction, especially inhibitory control, is a key early symptom of mild cognitive impairment (MCI).
• Altered prefrontal cortical activity is linked to executive dysfunction in MCI.
• Cognitive task engagement may improve neural adaptability in prefrontal regions.

Purpose of the Study:

• To investigate how repeated Stroop task performance affects executive function and prefrontal activation in older adults with MCI versus healthy controls (HC).
• To utilize functional near-infrared spectroscopy (fNIRS) to measure these changes.

Main Methods:

• 37 older adults (17 MCI, 20 HC) performed a computerized color-word Stroop task over three sessions.
• Behavioral data (reaction time) and hemodynamic responses (oxyhemoglobin, HbO) were recorded.
• fNIRS measured activity in prefrontal regions: ventrolateral prefrontal cortex (VLPFC), dorsolateral prefrontal cortex, orbitofrontal cortex, and frontopolar cortex.

Main Results:

• Healthy controls (HC) showed improved reaction time and reduced VLPFC activation across sessions, indicating enhanced efficiency and inhibition.
• Individuals with MCI exhibited delayed and limited adaptation, with significant changes only appearing in the final session.
• fNIRS detected differential neurofunctional adaptation patterns between MCI and HC groups.

Conclusions:

• Healthy aging involves rapid neurofunctional adaptation to cognitive challenges.
• Mild cognitive impairment (MCI) is characterized by impaired plasticity in executive control circuits.
• fNIRS is a sensitive tool for detecting early executive deficits and holds potential for early diagnosis of cognitive impairment.