Products With High Purchase Frequency Require Greater Inhibitory Control: An Event-Related Potential Study.

One's past behavior influences their present behavior. The effects of such response history have often been tested using response inhibition tasks. Since previous studies have highlighted the effect of immediate action history formed directly before the subsequent response in a laboratory environment, we aimed to elucidate the longer-term effects of response history, using repetitive and habitual consumer behavior in daily life as the response history. We used event-related potentials recorded in a Go/No-go task to investigate brain activity related to inhibitory control, hypothesizing that stimuli with a high frequency of choice in everyday life would elicit stronger inhibition-related activity, that is, the No-go-N2 component. Participants were asked to evaluate the frequency of purchase and use of some products, such as food and drink or social networking services (SNS) in everyday situations. Images of each product were assigned as stimuli in the Go and No-go trials according to the frequency of choice. The results showed that frequently purchased No-go stimuli yielded a larger amplitude of the No-go-N2 component and a negative shift between 200 and 300ms after the presentation of No-go stimuli. The results suggest that frequently chosen products evoke stronger inhibition conflicts and require greater cognitive control to withhold a response. Our findings showed that repeated purchase behavior in daily life forms a response history and has a long-term influence on the inhibition of even simple approaching behaviors, such as button pressing.

ß-Lactolin Enhances Neural Activity, Indicated by Event-Related P300 Amplitude, in Healthy Adults: A Randomized Controlled Trial.

BACKGROUND: Epidemiological studies have shown that dairy product consumption is beneficial for cognitive function in elderly individuals. ß-lactolin is a Gly-Thr-Trp-Tyr lacto-tetrapeptide rich in fermented dairy products that improves memory retrieval, attention, and executive function in older adults with subjective cognitive decline and prevents the pathology of Alzheimer's disease in rodents. There has been no study on the effects of ß-lactolin on neural activity in humans. OBJECTIVE: We investigated the effects of ß-lactolin on neural activity and cognitive function in healthy adults. METHODS: In this randomized, double-blind, placebo-controlled study, 30 participants (45-64 years old) consumed ß-lactolin or placebo for 6 weeks. Neural activity during auditory and language tasks was measured through 64-channel electroencephalography. Moreover, verbal fluency tests were performed at baseline and after 6 weeks. RESULTS: The ß-lactolin group had a significantly higher P300 amplitude at the Cp2 site (a part of the parietal lobe near the center of brain, p = 0.011), and C4 site (the area between the frontal and parietal lobe, p = 0.02) during the auditory tasks after 6 weeks than the placebo group. Thus, ß-lactolin supplementation promoted neural activity in the parietal area, which increases concentration and attention during auditory cognitive tasks. Compared with the placebo group, the ß-lactolin group also showed significant changes in the scores of verbal fluency test after 6 weeks (p = 0.033). CONCLUSION: Our findings provide insight into the mechanisms underlying the effects of ß-lactolin on attention in healthy adults.

Affective and temporal orientation of thoughts: Electrophysiological evidence.

The factors that determine the content and valence of spontaneous thoughts have not yet been clarified. In this study, we focused on the effects of bodily states and depression and anxiety traits. Participants performed a past/future thinking task in which three-part sentences including temporal cues were presented in a sequential pattern, for example "in the near future/dreams/will come true". We measured heartbeat-evoked potentials (HEPs) to assess affective processing, and event-related potentials (ERPs) to assess temporal processing of thoughts that emerged when the temporal cue words were presented. The HEPs predicted thought valence irrespective of personality traits. Larger N400 ERPs were observed in response to past-oriented than to future-oriented words in participants with higher levels of depression, whereas the opposite was the case in participants with higher social anxiety. Our data suggest that afferent signals modulate affective thought-orientations as triggers, and that individuals with depression and anxiety have sensitivity toward temporal information at the neural level.

Machiavellianism and early neural responses to others' facial expressions caused by one's own decisions.

The processing of social stimuli generated by one's own voluntary behavior is an element of social adaptation. It is known that self-generated stimuli induce attenuated sensory experiences compared with externally generated stimuli. The present study aimed to examine this self-specific attenuation effect on early stimulus processing in the case of others' facial expressions during interpersonal interactions. In addition, this study explored the possibility that the self-specific attenuation effect on social cognition is modulated by antisocial personality traits such as Machiavellianism. We analyzed early components of the event-related brain potential in participants elicited by happy and sad facial expressions of others when the participant's decision was responsible for the others' emotions and when the others' facial expressions were independent of the participant's decision. Compared to the non-responsible condition, the responsible condition showed an attenuated amplitude of the N170 component in response to sad faces. Moreover, Machiavellianism explained individual differences in the self-specific attenuation effect depending on the affective valence of social signals. The present findings support the possibility that the self-specific attenuation effect extends to interpersonal interactions and imply that distorted cognition of others' emotions caused by one's own behavior is associated with personality disorders that promote antisocial behaviors.

Time course and localization of brain activity in humor comprehension: An ERP/sLORETA study.

Although a number of studies have investigated the incongruity-detection and resolution process in humor comprehension, it is difficult to functionally and anatomically dissociate these processes. We used event-related potentials (ERP) and standardized low resolution brain electromagnetic tomography analysis (sLORETA) to examine the time course and localization of brain activity during incongruity detection and resolution. We used the same materials as in our previous fMRI study. Eighteen participants read funny and unfunny scenarios and judged whether the target sentence was funny or not. Results indicated that ERPs elicited by a funny punch line showed a P2 component followed by a P600 component over the centro-parietal electrode sites. Our sLORETA analysis of the P2 ERPs revealed a stronger activation for the funny vs. unfunny condition in the superior frontal gyrus (SFG) and medial prefrontal cortex (mPFC). For the P600 ERPs, the funny punch line elicited greater activation in the temporal-parietal regions. These results indicate that incongruity-detection processes activate the SFG and mPFC in the P2 time window, while incongruity-resolution processes generate activation at the temporal-parietal regions in the P600 time window. These results provide the evidence that verbal humor comprehension is processed in steps which start with the incongruity detection in the early P2 time window and followed by a P600 component reflecting incongruity resolution.

Prospective memory mediated by interoceptive accuracy: a psychophysiological approach.

Previous studies on prospective memory (PM), defined as memory for future intentions, suggest that psychological stress enhances successful PM retrieval. However, the mechanisms underlying this notion remain poorly understood. We hypothesized that PM retrieval is achieved through interaction with autonomic nervous activity, which is mediated by the individual accuracy of interoceptive awareness, as measured by the heartbeat detection task. In this study, the relationship between cardiac reactivity and retrieval of delayed intentions was evaluated using the event-based PM task. Participants were required to detect PM target letters while engaged in an ongoing 2-back working memory task. The results demonstrated that individuals with higher PM task performance had a greater increase in heart rate on PM target presentation. Also, higher interoceptive perceivers showed better PM task performance. This pattern was not observed for working memory task performance. These findings suggest that cardiac afferent signals enhance PM retrieval, which is mediated by individual levels of interoceptive accuracy.This article is part of the themed issue 'Interoception beyond homeostasis: affect, cognition and mental health'.

Integration of cognitive and affective networks in humor comprehension.

Humor comprehension is a complex process that requires the detection and resolution of the incongruity, eliciting a positive feeling of mirth or reward. We conducted a functional magnetic resonance imaging (fMRI) study to identify the key factors involved in this complex process. To reduce the influence of other factors, we utilized a group of sentences that were nearly identical across conditions (i.e., the first two sentences and the punch line were identical, but the third sentence was different). We found that the punch line (target sentence) in the funny condition induced a perception of funniness and elicited greater activation in language and semantic neural networks, which have been implicated in comprehension processing (i.e., incongruity detection and resolution). We also found increased activation in the mesolimbic reward regions, which have been implicated in the experience of positive rewards in the funny condition. Psycho-physiological interaction analyses revealed that language and semantic regions, such as inferior frontal gyrus (IFG), middle temporal gyrus (MTG), superior temporal gyrus (STG), superior frontal gyrus (SFG), and inferior parietal lobule (IPL) are simultaneously activated during humor comprehension processing. These analyses also revealed that the right MTG, the left IPL, and IFG showed enhanced connectivity with the midbrain. Our findings suggest that these networks play a central role in incongruity detection and resolution, as well as in positive emotional response.

Anterior insular cortex mediates bodily sensibility and social anxiety.

Studies in psychiatry and cognitive neuroscience have reported an important relationship between individual interoceptive accuracy and anxiety level. This indicates that greater attention to one's bodily state may contribute to the development of intense negative emotions and anxiety disorders. We hypothesized that reactivity in the anterior insular cortex underlies the intensity of interoceptive awareness and anxiety. To elucidate this triadic mechanism, we conducted functional magnetic resonance imaging (fMRI) and mediation analyses to examine the relationship between emotional disposition and activation in the anterior insular cortex while participants evaluated their own emotional and bodily states. Our results indicated that right anterior insular activation was positively correlated with individual levels of social anxiety and neuroticism and negatively correlated with agreeableness and extraversion. The results of the mediation analyses revealed that activity in the right anterior insula mediated the activity of neural correlates of interoceptive sensibility and social fear. Our findings suggest that attention to interoceptive sensation affects personality traits through how we feel emotion subjectively in various situations.

Does simile comprehension differ from metaphor comprehension? A functional MRI study.

Since Aristotle, people have believed that metaphors and similes express the same type of figurative meaning, despite the fact that they are expressed with different sentence patterns. In contrast, recent psycholinguistic models have suggested that metaphors and similes may promote different comprehension processes. In this study, we investigated the neural substrates involved in the comprehension of metaphor and simile using functional magnetic resonance imaging (fMRI) to evaluate whether simile comprehension differs from metaphor comprehension or not. In the metaphor and simile sentence conditions, higher activation was seen in the left inferior frontal gyrus. This result suggests that the activation in both metaphor and simile conditions indicates similar patterns in the left frontal region. The results also suggest that similes elicit higher levels of activation in the medial frontal region which might be related to inference processes, whereas metaphors elicit more right-sided prefrontal activation which might be related to figurative language comprehension.

Self-paced and externally triggered rhythmical lower limb movements: a functional MRI study.

Self-paced rhythmical lower limb movement is an important component of locomotive motion in humans. External stimuli are known to facilitate the generation of rhythmical motion. The importance of such self-paced and externally triggered movements is widely recognized, and these movements of the upper limbs have been studied in detail. However, the difference in neural mechanisms between the self-paced and externally triggered movements of the lower limbs is not clear even in healthy subjects. The present study investigated the neural regions involved in the lower limb movements by using functional magnetic resonance imaging (fMRI). The subjects were fixed face-up to an MRI bed and performed lower limb movements that mimicked walking under self-paced and externally triggered conditions. The results showed that the supplementary motor area, sensorimotor cortex and cerebellum were involved in both types of movement, but the basal ganglia and the thalamus were selectively recruited for the self-paced lower limb movement. These results are compatible with those of previous studies on the control of the lower limbs, and on upper limb movement under self-paced and externally triggered conditions.

Neural processing associated with comprehension of an indirect reply during a scenario reading task.

In daily communication, we often use indirect speech to convey our intention. However, little is known about the brain mechanisms that underlie the comprehension of indirect speech. In this study, we conducted a functional MRI experiment using a scenario reading task to compare the neural activity induced by an indirect reply (a type of indirect speech) and a literal sentence. Participants read a short scenario consisting of three sentences. The first two sentences explained the situation of the protagonists, whereas the third sentence had an indirect, literal, or unconnected meaning. The indirect reply condition primarily activated the bilateral fronto-temporal networks (Brodmann's Areas (BA) 47 and 21) and the dorso-medial prefrontal cortex (dmPFC). In the literal sentence condition, only the left fronto-temporal network (BA 45 and 21) and the dmPFC (posterior region) were activated. In addition, we found greater activation resulting from comprehension of an indirect reply than from literal sentence comprehension in the dmPFC, the left middle frontal area (BA 9), the bilateral inferior frontal area (BA 9/47), and the right middle temporal area (BA 21). Our findings indicate that the right and left fronto-temporal networks play a crucial role in detecting contextual violations, whereas the medial frontal cortex is important for generating inferences to make sense of remarks within a context.

Neural substrates of irony comprehension: A functional MRI study.

In daily communication, we sometimes use ironic expressions to convey the opposite meaning. To understand these contradictory statements, we have to infer contextual implications and the speaker's mental state. However, little is known about how our brains carry out these complex processes. In this study, we investigated the neural substrates involved in irony comprehension using echoic utterance (Sperber and Wilson, 1986, 1995). Participants read a short scenario that consisted of five sentences. The first four sentences explained the situation of the protagonists. The fifth connoted either an ironic, literal, or unconnected meaning. The participants had to press a button to indicate whether or not the final sentence expressed irony. In the ironic sentence condition, the bilateral superior frontal gyrus, middle frontal gyrus, inferior frontal gyrus, medial prefrontal cortex, superior temporal gyrus, inferior parietal lobule, caudate, thalamus, the left insula, and amygdala were activated. In the literal sentence condition, the right superior frontal gyrus, the bilateral middle frontal gyrus, inferior frontal gyrus, medial prefrontal cortex, superior temporal gyrus, inferior parietal lobule, caudate, the left insula, the right thalamus, and the left amygdala were activated. However, in the ironic sentence condition minus the literal sentence condition, we observed higher activation in the right medial prefrontal cortex (BA 10), the right precentral (BA 6), and the left superior temporal sulcus (BA 21). Our results suggest that irony comprehension is strongly related to mentalizing processes and that activation in these regions might be affected by higher-order cognitive operations.

Neural mechanisms involved in the comprehension of metaphoric and literal sentences: an fMRI study.

In this study, we investigated the neural substrate involved in the comprehension of novel metaphoric sentences by comparing the findings to those obtained with literal and anomalous sentences using event-related functional magnetic resonance imaging (fMRI). Stimuli consisted of 63 copula sentences ("An A is a B") in Japanese with metaphorical, literal, or anomalous meanings. Thirteen normal participants read these sentences silently and responded as to whether or not they could understand the meaning of each sentence. When participants read metaphoric sentences in contrast to literal sentences, higher activation was seen in the left medial frontal cortex (MeFC: Brodmann's area (BA) 9/10), the left superior frontal cortex (SFC: BA 9), and the left inferior frontal cortex (IFC: BA 45). The opposite contrast (literal sentences in contrast to metaphoric sentences) gave higher activation in the precuneus (BA 7) and the right middle and SFC (BA 8/9). These findings suggest that metaphor comprehension is involved in specific neural mechanisms of semantic and pragmatic processing which differ from those in literal comprehension. Especially, our results suggest that activation in the left IFC reflects the semantic processing and that activation in the MeFC reflects the process of inference for metaphorical interpretation to establish semantic coherence.