Activation of the prefrontal cortex during memory learning: Near‐infrared spectroscopy study

Abstract

Near-infrared spectroscopy (NIRS) is an optical method to determine oxygenated and deoxygenated hemoglobin concentration changes in the human cerebral cortex. The purpose of this study was to examine the hemodynamic response of the prefrontal area during words memory learning using NIRS. A total of 23 healthy subjects participated in the present study. Hemodynamic response in the prefrontal cortex was measured using a NIRS system. The number of words recalled and stimulus category repetition (SCR) were analyzed by the words memory learning task. During the words memory learning task, oxygenated hemoglobin concentrations increased and deoxygenated hemoglobin concentrations decreased. This typical pattern was maintained during each memory stage, but the degree of change of [oxyHb] during encoding from the first condition to the second condition was significantly larger than that during retrieval. This suggests that memory organization is facilitated during encoding of the first condition, and that the retrieval period through two conditions still involves more activation in the prefrontal area than the encoding period. An increase of [oxyHb] was not recognized and activation was inhibited when the strategy was applied. Subjects produced more SCR in the second condition than in the first condition in spite of strategy instruction. This result suggests healthy people can find out implicit category by themselves following learning even without instruction. There were no significant relationships between the behavior indices and the changes in hemoglobin. Further studies are needed to clarify usefulness of NIRS in patients with psychiatric disorder.

Less Effort, Better Results: How Does Music Act on Prefrontal Cortex in Older Adults during Verbal Encoding? An fNIRS Study

“…Furthermore, considering also HHb values, the repeated-measures ANOVA on THb values (Figure 3A) confirmed a main effect of condition [ F (1, 15) = 14.329, p  = 0.009, strong Eta-squared effect size = 0.22] in almost all channels, as shown by post hoc Bonferroni-corrected paired t -tests (Figure 3A). In line with several other fNIRS studies (e.g., Matsui et al, 2007; Okamoto et al, 2011), only HHb values did not show a significant effect.…”

“…Although recent studies suggest that caution should be exercised when applying fNIRS to infer PFC activation because of the task-evoked changes occurring in forehead skin perfusion (Kohno et al, 2007; Gagnon et al, 2011, 2012; Takahashi et al, 2011; Kirilina et al, 2012), these results confirm both the involvement of DLPFC during episodic memory encoding (Blumenfeld and Ranganath, 2007; Murray and Ranganath, 2007; Innocenti et al, 2010), and the suitability of fNIRS to investigate long-term memory processes (Kubota et al, 2006; Matsui et al, 2007; Okamoto et al, 2011; see also Cutini et al, 2012 for a review). The fNIRS results also showed a weak but significant interaction between memory encoding condition and hemispheric laterality, with greater left and right DLPFC activity (represented by O 2 Hb increases) in the silence and music conditions, respectively.…”

“…We hypothesized that music would enhance the encoding of verbal material in older adults by enriching the context and supplying organizational, associative, and semantic processes. Considering previous fNIRS studies showing better behavioral performance and PFC deactivation in response to facilitatory cues (Matsuda and Hiraki, 2004, 2006; Matsui et al, 2007; Ramasubbu et al, 2012), we therefore expected to find improved episodic memory performance at a behavioral level together with minimal demand on PFC activity during music encoding condition as compared to silence encoding condition. In particular, a classical activation pattern should be observed for the silence encoding condition, namely an increase of O 2 Hb and a decrease of HHb concentrations changes.…”

“…Moreover, fNIRS makes it possible to conduct more ecological cognitive experimental setups (subject sitting in a chair in a quiet room), which are not feasible in more traditional fMRI protocols, and it is thus suitable for investigating cortical activation in special populations such as older adults and neurological patients (Ferreri et al, in press). Recent fNIRS studies on verbal memory and learning have shown that facilitatory cues such as strategies (Matsuda and Hiraki, 2004, 2006; Matsui et al, 2007), pharmacological stimulants (Ramasubbu et al, 2012), or background music (Ferreri et al, 2013) during verbal encoding could result in deactivation, rather than greater activation, of PFC regions, suggesting less involvement/greater efficiency of high-cognitive functions mediated by PFC regions (such as the DLPFC) known to be crucial during memory encoding processes. In our previous experiment (Ferreri et al, 2013), we monitored bilateral DLPFC activation during verbal encoding with fNIRS and showed, for the first time, that background music during the encoding of verbal material can modulate DLPFC activity (i.e., decreased responses compared to a silent background) and, at the same time, facilitate the retrieval of the encoded material.…”

Effects of Essence of Chicken on Cognitive Brain Function: A Near-Infrared Spectroscopy Study

“…[13][14][15][16] Also, NIRS studies indicate that hemoglobin oxygenation in response to brain activation is influenced by physiological aging. [17][18][19] Elderly subjects showed significantly lower increases in oxy-Hb and total-Hb concentrations in the frontal cortex than young subjects during a calculation task.…”