Abstract
Background: Episodic memory (EM) is particularly sensitive to pathological conditions and aging. In a neurocognitive context, the paired-associate learning (PAL) paradigm, which requires participants to learn and recall associations between stimuli, has been used to measure EM. The present study aimed to explore whether functional near-infrared spectroscopy (fNIRS) can be employed to determine cortical activity underlying encoding and retrieval. Moreover, we examined whether and how different aspects of task (i.e., novelty, difficulty) affects those cortical activities. Methods: Twenty-two male college students (age: M = 20.55, SD = 1.62) underwent a face-name PAL paradigm under 40-channel fNIRS covering fronto-parietal and middle occipital regions. Results: A decreased activity during encoding in a broad network encompassing the bilateral frontal cortex (Brodmann areas 9, 11, 45, and 46) was observed during the encoding, while an increased activity in the left orbitofrontal cortex (Brodmann area 11) was observed during the retrieval. Increased HbO concentration in the superior parietal cortices and decreased HbO concentration in the inferior parietal cortices were observed during encoding while dominant activation of left PFC was found during retrieval only. Higher task difficulty was associated with greater neural activity in the bilateral prefrontal cortex and higher task novelty was associated with greater activation in occipital regions. Conclusion: Combining the PAL paradigm with fNIRS provided the means to differentiate neural activity characterising encoding and retrieval. Therefore, the fNIRS may have the potential to complete EM assessments in clinical settings.
Highlights
Episodic memory (EM) refers to the process of currently retrieving events from the past [1,2]
These outcomes were partially consistent with previous functional magnetic resonance imaging (f MRI) [16,17,18] and functional near-infrared spectroscopy (f NIRS) [22] studies
Our findings indicate the f NIRS
Summary
Episodic memory (EM) refers to the process of currently retrieving events from the past [1,2]. EM incorporates two main phases: (a) an encoding stage, which contributes to the formation of a new memory trace, and (b) a retrieval stage, which refers to the conscious remembering of past events. EM is an essential process for various higher cortical functions such as judgment and decision making [1,2]. EM performance has been reported to be sensitive to aging and pathological conditions such as amnesia, mild cognitive impairment (MCI), and Alzheimer’s disease (AD) [3,4]. Episodic memory (EM) is sensitive to pathological conditions and aging. The present study aimed to explore whether functional near-infrared spectroscopy (f NIRS) can be employed to determine cortical activity underlying encoding and retrieval. We examined whether and how different aspects of task (i.e., novelty, difficulty) affects those cortical activities
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
