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Previous findings have shown essential connections between linguistic and gustatory stimuli for people with autism or lexical gustatory synesthesia. We examined the associative learning of novel linguistic forms in Japanese as a native language and tastes (candies and chocolates) for healthy people. Healthy subjects performed four phases: (a) evaluation phase of gustatory features, (b) learning phases of novel linguistic form and gustatory stimulus pairs (G) or novel word forms (W), (c) recognition memory phases linked with G and W, and (d) free recall phase for G and W. In the recognition memory phases, the performance scores of W were higher than those of G, while there was no significant difference between response times of G and W. Additionally, no difference between recall performances in G and W was also shown. A subjective evaluation of gustatory features (sweetness) negatively correlated with the recall score for linguistic forms connected to the gustatory feature, whereas the accuracy rates of the recognition memory phase in G positively correlated with those of the free recall phase in G. Although learning of novel linguistic forms is more efficient than learning of the relationships between novel linguistic forms and tastes, gustatory features influence the free recall performances of linguistic forms linked with the tastes. These results may contribute to future applications to word learning not just for patients, but also healthy people.

This study focused on the associative learning of new word forms in the first language and haptic stimuli. In this study, healthy Japanese participants performed three-step tasks. First, participants made nine subjective evaluations of haptic stimuli using five-point semantic differential scales (e.g., regarding stickiness, scored from 1 (not sticky) to 5 (sticky)). Second, the participants carried out learning and recognition tasks for associative pairs of new (meaningless) word forms in their first language (Japanese) and haptic stimulus (H condition), and performed learning and recognition tasks for new (meaningless) word forms only (W condition). The order of conditions was counterbalanced among participants. Third, participants performed free recall tasks. The results of the recognition tasks showed that the proportions and response times of the W condition were better and faster, respectively, than those of the H condition. Furthermore, preference of haptic features negatively correlated with free recall scores of the H condition, however, there was no significant difference between the free recall scores of the H and W conditions. Our results suggest that new word forms were learned better than associative pairs of new word forms and haptic stimuli in a single day of learning. Furthermore, the free recall performance of word forms associated with haptic features could also be affected by their subjective evaluation (preference).

The left prefrontal cortex is essential for verbal communication. It remains uncertain at what timing, to what extent, and what type of phrase initiates left-hemispheric dominant prefrontal activation during comprehension of spoken sentences. We clarified this issue by measuring event-related high-gamma activity during a task to respond to three-phrase questions configured in different orders. Questions beginning with a wh-interrogative deactivated the left posterior prefrontal cortex right after the 1st phrase offset and the anterior prefrontal cortex after the 2nd phrase offset. Left prefrontal high-gamma activity augmented subsequently and maximized around the 3rd phrase offset. Conversely, questions starting with a concrete phrase deactivated the right orbitofrontal region and then activated the left posterior prefrontal cortex after the 1st phrase offset. Regardless of sentence types, high-gamma activity emerged earlier, by one phrase, in the left posterior prefrontal than anterior prefrontal region. Sentences beginning with a wh-interrogative may initially deactivate the left prefrontal cortex to prioritize the bottom-up processing of upcoming auditory information. A concrete phrase may obliterate the inhibitory function of the right orbitofrontal region and facilitate top-down lexical prediction by the left prefrontal cortex. The left anterior prefrontal regions may be recruited for semantic integration of multiple concrete phrases.

Sound symbolic words consist of inevitable associations between sounds and meanings. We aimed to identify differences in familiarity, visual imageability, auditory imageability, tactile imageability, emotional valence, and arousal between Japanese sound symbolic words with voiced initial consonants (VCs; dakuon in Japanese; e.g., biribiri) and Japanese sound symbolic words with semi-voiced initial consonants (SVCs; handakuon in Japanese; e.g., piripiri), and between VCs (e.g., daradara) and Japanese sound symbolic words with voiceless initial consonants (VLCs; seion in Japanese; e.g., taratara). First, auditory imageability and arousal were significantly higher in VCs than SVCs, whereas familiarity, tactile imageability, and positive emotion (emotional valence) were significantly higher in SVCs than VCs. Second, visual imageability was higher in VCs than VLCs, while familiarity and positive emotion were higher in VLCs than VCs. Initial consonants in Japanese sound symbolic words could be associated with specific subjective evaluations such as familiarity, visual imageability, auditory imageability, tactile imageability, emotional valence, and arousal.

People occasionally use filler phrases or pauses, such as “uh”, “um”, or “y’know,” that interrupt the flow of a sentence and fill silent moments between ordinary (non-filler) phrases. It remains unknown which brain networks are engaged during the utterance of fillers. We addressed this question by quantifying event-related cortical high gamma activity at 70–110 Hz. During extraoperative electrocorticography recordings performed as part of the presurgical evaluation, patients with drug-resistant focal epilepsy were instructed to overtly explain, in a sentence, ‘what is in the image (subject)’, ‘doing what (verb)’, ‘where (location)’, and ‘when (time)’. Time–frequency analysis revealed that the utterance of fillers, compared to that of ordinary words, was associated with a greater magnitude of high gamma augmentation in association and visual cortex of either hemisphere. Our preliminary results raise the hypothesis that filler utterance would often occur when large-scale networks across the association and visual cortex are engaged in cognitive processing, including lexical retrieval as well as verbal working memory and visual scene scanning.

The bizarreness effect on object recognition is a strong phenomenon, but its influence has been inconsistent for bizarre object color. In this study, we manipulated three factors in separate experiments to determine whether a color bizarreness effect on object recognition memory would occur and, if not, why. Participants first saw (i.e., learned) object pictures that were either bizarrely or typically colored; they then completed a recognition memory test. In three experiments, we then manipulated (a) degree of color bizarreness (Experiment 1), (b) the orientation task (Experiment 2), and (c) additional demands for object identification (Experiment 3). In Experiment 1, we provided 49 undergraduate participants with object pictures whose colors were typical, moderately atypical, or bizarre and found no color bizarreness effect on recognition memory even for extremely bizarre colors. In Experiment 2, we manipulated the orientation task in that 28 young adult participants expressed their preferences for the pictures on a three-point scale while another 28 participants judged how natural the pictures were. Each orientation task group better recognized typically-colored rather than bizarrely-colored objects (typicality effect). In Experiment 3, we asked 27 young adults to identify the objects during the learning phase to ensure that they paid attention to the objects’ bizarre colors; recognition memory was then unaffected by either color bizarreness or typicality. Thus, despite a general bizarreness effect in recognition memory, bizarre colors are less likely to influence object recognition memory.

Objective To characterize the spatiotemporal dynamics of auditory and picture naming-related cortical activation in Japanese-speaking patients. Methods Ten patients were assigned auditory naming and picture naming tasks during extraoperative intracranial EEG recording in a tertiary epilepsy center. Time-frequency analysis determined at what electrode sites and at what time windows during each task the amplitude of high-gamma activity (65–95 Hz) was modulated. Results The superior-temporal gyrus on each hemisphere showed high-gamma augmentation during sentence listening, whereas the left middle-temporal and inferior-frontal gyri showed high-gamma augmentation peaking around stimulus offset. Auditory naming-specific high-gamma augmentation was noted in the bilateral superior-temporal gyri as well as left frontal-parietal-temporal perisylvian network regions, whereas picture naming-specific augmentation was noted in the occipital-fusiform regions, bilaterally. The inferior pre- and postcentral gyri on each hemisphere showed modality-common high-gamma augmentation time-locked to overt responses. Conclusions The spatiotemporal dynamics of auditory and picture naming-related high-gamma augmentation in Japanese-speaking patients were qualitatively similar to those previously reported in studies of English-speaking patients. Significance The cortical dynamics for auditory sentence recognition are at least partly shared by cohorts speaking two distinct languages. Multicenter studies regarding the clinical utility of high-gamma language mapping across Eastern and Western hemispheres may be feasible.

Previous studies have reported that religious words and religiosity affect mental processes and behaviors. However, it is unclear what psycholinguistic features of religious words (e.g., familiarity, imageability, and emotional aspects) are associated with each dimension of personal religiosity (intellect, ideology, public practice, private practice, and experience). The purpose of this study was to examine whether and how the above-mentioned psycholinguistic features of religious words correlate with each of the core dimensions of religiosity. Japanese participants evaluated four psycholinguistic features of twelve religious words using a 5-point Semantic Differential scale for familiarity and imageability and a 9-point Self-Assessment Manikin (SAM) scale for emotional valence and emotional arousal. The participants also rated their own religiosity using the Japanese version of the Centrality of Religiosity Scale (JCRS). The results of the study revealed that (1) the scales measuring the psycholinguistic features of religious words were statistically reliable, (2) the JCRS was reliable, (3) the familiarity, emotional valence, and emotional arousal of religious words and each mean dimensional score of the JCRS score correlated positively with each other, and (4) highly religious people had higher familiarity and higher emotional arousal to religious words than non-religious people, whereas highly religious people had higher emotional valence to religious words in comparison with non-religious and religious people. In addition, religious people had higher familiarity to religious words than non-religious people. Taken together, these findings suggest that psycholinguistic features of religious words contribute to the detection of religiosity.

Auditory naming is suggested to require verbal working memory (WM) operations in addition to speech sound perception during the sentence listening period and semantic/syntactic processing during the subsequent judgement period. We attempted to dissect cortical activations attributable to verbal WM from those otherwise involved in answering auditory sentence questions. We studied 19 patients who underwent electrocorticography recordings and measured high-gamma activity during auditory naming and WM tasks. In the auditory naming task, inferior-precentral high-gamma activity was augmented during sentence listening, and the magnitude of augmentation was independently correlated to that during the WM task maintenance period as well as patient age. High-gamma augmentation during the WM task scanning period accounted for high-gamma variance during the naming task judgement period in some of the left frontal association neocortex regions (most significantly in the middle-frontal, less in the inferior-frontal, and least in the orbitofrontal gyrus). Inferior-frontal high-gamma augmentation was left-hemispheric dominant during naming task judgement but rather symmetric during WM scanning. Left orbitofrontal high-gamma augmentation was evident only during the naming task judgement period but minimal during the WM task scanning period. The inferior-precentral regions may exert WM maintenance during sentence listening, and such maintenance function may be gradually strengthened as the brain matures. The left frontal association neocortex may have a dorsal-to-ventral gradient in functional roles during naming task judgement. Namely, left middle-frontal activation may be well-attributable to WM scanning function, whereas left orbitofrontal activation may be attributable less to WM scanning but more largely to syntactic/semantic processing.

A number of investigators have reported that event-related augmentation of high-gamma activity at 70–110 Hz on electrocorticography (ECoG) can localize functionally-important brain regions in children and adults who undergo epilepsy surgery. The advantages of ECoG-based language mapping over the gold-standard stimulation include: (i) lack of stimulation-induced seizures, (ii) better sensitivity of localization of language areas in young children, and (iii) shorter patient participant time. Despite its potential utility, ECoG-based language mapping is far less commonly practiced than stimulation mapping. Here, we have provided video presentations to explain, point-by-point, our own hardware setting and time–frequency analysis procedures. We also have provided standardized auditory stimuli, in multiple languages, ready to be used for ECoG-based language mapping. Finally, we discussed the technical aspects of ECoG-based mapping, including its pitfalls, to facilitate appropriate interpretation of the data.

In this study, we examined whether vowel length affected the perceptual and emotional evaluations of Japanese sound-symbolic words. The perceptual and emotional features of Japanese sound-symbolic words, which included short and long vowels, were evaluated by 209 native Japanese speakers. The results showed that subjective evaluations of familiarity, visual imageability, auditory imageability, tactile imageability, emotional valence, arousal, and length were significantly higher for sound-symbolic words with long vowels compared to those with short vowels. Additionally, a subjective evaluation of speed was significantly higher for written Japanese sound-symbolic words with short vowels than for those with long vowels. The current findings suggest that vowel length in written Japanese sound-symbolic words increases the perceptually and emotionally subjective evaluations of Japanese sound-symbolic words.

Objective During verbal communication, humans briefly maintain mental representations of speech sounds conveying verbal information, and constantly scan these representations for comparison to incoming information. We determined the spatio-temporal dynamics of such short-term maintenance and subsequent scanning of verbal information, by intracranially measuring high-gamma activity at 70–110 Hz during a working memory task. Methods Patients listened to a stimulus set of two or four spoken letters and were instructed to remember those letters over a two-second interval, following which they were asked to determine if a subsequent target letter had been presented earlier in that trial’s stimulus set. Results Auditory presentation of letter stimuli sequentially elicited high-gamma augmentation bilaterally in the superior-temporal and pre-central gyri. During the two-second maintenance period, high-gamma activity was augmented in the left pre-central gyrus, and this effect was larger during the maintenance of stimulus sets consisting of four compared to two letters. During the scanning period following target presentation, high-gamma augmentation involved the left inferior-frontal and supra-marginal gyri. Conclusions Short-term maintenance of verbal information is, at least in part, supported by the left pre-central gyrus, whereas scanning by the left inferior-frontal and supra-marginal gyri. Significance The cortical structures involved in short-term maintenance and scanning of speech stimuli were segregated with an excellent temporal resolution.

Functional brain maps were first delineated in two dimensions 80 years ago. By analysing stimulation and intracranial EEG data from 100 patients with epilepsy, Nakai et al. generate 3D and 4D language maps incorporating space, time and causality. These whole-brain maps allow prediction of language areas for patients undergoing neurosurgery., We have provided 3-D and 4D mapping of speech and language function based upon the results of direct cortical stimulation and event-related modulation of electrocorticography signals. Patients estimated to have right-hemispheric language dominance were excluded. Thus, 100 patients who underwent two-stage epilepsy surgery with chronic electrocorticography recording were studied. An older group consisted of 84 patients at least 10 years of age (7367 artefact-free non-epileptic electrodes), whereas a younger group included 16 children younger than age 10 (1438 electrodes). The probability of symptoms transiently induced by electrical stimulation was delineated on a 3D average surface image. The electrocorticography amplitude changes of high-gamma (70–110 Hz) and beta (15–30 Hz) activities during an auditory-naming task were animated on the average surface image in a 4D manner. Thereby, high-gamma augmentation and beta attenuation were treated as summary measures of cortical activation. Stimulation data indicated the causal relationship between (i) superior-temporal gyrus of either hemisphere and auditory hallucination; (ii) left superior-/middle-temporal gyri and receptive aphasia; (iii) widespread temporal/frontal lobe regions of the left hemisphere and expressive aphasia; and (iv) bilateral precentral/left posterior superior-frontal regions and speech arrest. On electrocorticography analysis, high-gamma augmentation involved the bilateral superior-temporal and precentral gyri immediately following question onset; at the same time, high-gamma activity was attenuated in the left orbitofrontal gyrus. High-gamma activity was augmented in the left temporal/frontal lobe regions, as well as left inferior-parietal and cingulate regions, maximally around question offset, with high-gamma augmentation in the left pars orbitalis inferior-frontal, middle-frontal, and inferior-parietal regions preceded by high-gamma attenuation in the contralateral homotopic regions. Immediately before verbal response, high-gamma augmentation involved the posterior superior-frontal and pre/postcentral regions, bilaterally. Beta-attenuation was spatially and temporally correlated with high-gamma augmentation in general but with exceptions. The younger and older groups shared similar spatial-temporal profiles of high-gamma and beta modulation; except, the younger group failed to show left-dominant activation in the rostral middle-frontal and pars orbitalis inferior-frontal regions around stimulus offset. The human brain may rapidly and alternately activate and deactivate cortical areas advantageous or obtrusive to function directed toward speech and language at a given moment. Increased left-dominant activation in the anterior frontal structures in the older age group may reflect developmental consolidation of the language system. The results of our functional mapping may be useful in predicting, across not only space but also time and patient age, sites specific to language function for presurgical evaluation of focal epilepsy.

The motivation to receive rewards enhances episodic memories, and the motivation is modulated by task difficulty. In episodic retrieval, however, functional neuroimaging evidence regarding the motivation that mediates interactions between reward and task difficulty is scarce. The present fMRI study investigated this issue. During encoding performed without fMRI, participants encoded Japanese words using either deep or shallow strategies, which led to variation in difficulty level during subsequent retrieval. During retrieval with fMRI, participants recognized the target words in either high or low monetary reward conditions. In the behavioral results, a reward-related enhancement of memory was found only when the memory retrieval was difficult, and the rewarding effect on subjective motivation was greater in the retrieval of memories with high difficulty than those with low difficulty. The fMRI data showed that reward-related increases in the activation of the substantia nigra/ventral tegmental area (SN/VTA), medial temporal lobe (MTL), dorsomedial prefrontal cortex (dmPFC), and dorsolateral prefrontal cortex (dlPFC) were greater during the retrieval of memories with high difficulty than those with low difficulty. Furthermore, reward-related enhancement of functional connectivity between the SN/VTA and MTL and between the SN/VTA and dmPFC during the retrieval of memories with high difficulty was significantly correlated with reward-related increases of retrieval accuracy and subjective motivation. The reward-related enhancement of episodic retrieval and retrieval-related motivation could be most effective when the level of retrieval difficulty is optimized. Such reward-related enhancement of memory and motivation could be modulated by a network including the reward-related SN/VTA, motivation-related dmPFC, and memory-related MTL. Hum Brain Mapp 38:3428-3443, 2017. © 2017 Wiley Periodicals, Inc.

Older adults are more likely than young adults to show age-related increases in remembering events that never occurred. However, little is known about the neural mechanisms underlying the increased occurrence of false alarms in older adults. To investigate this issue, this fMRI study examined age-related differences in correct rejection activations during the retrieval of memory for faces. In behavioral data, older adults showed a higher rate of false alarms than young adults in subjective recollection responses. From fMRI data, an age-related decrease in brain activations during correct rejections was identified in the inferior frontal gyrus, supramarginal gyrus, and hippocampus. In addition, interaction between activations in the inferior frontal and supramarginal regions during correct rejections was significantly lower in older adults than in young adults. These findings suggest that an age-related decline in interaction between the ventral prefrontal region, which is involved in the source monitoring process during retrieval, and the inferior parietal region, which is associated with recollection by cooperating with the hippocampus, could induce impaired differentiation between old and novel stimuli in older adults.

The processing of grammatical and semantic relationships is important in sentence comprehension. Although previous studies have demonstrated brain activities during grammatical and semantic processing in declarative sentences, functional MRI (fMRI) evidence related to these processes in wh-questions is largely unavailable. In Japanese wh-questions, a wh-phrase is grammatically associated with the closest particle, and a sentential subject is semantically associated with the verb. These features in Japanese wh-questions enable us to make grammatical or semantic anomalies without adding other words or morphemes in the violation paradigm. According to this advantage of Japanese wh-questions, this fMRI study investigated the brain activities in Japanese native speakers during grammatical and semantic processing of wh-questions to judge whether or not presented sentences were natural Japanese sentences (naturalness decision task). Three types of wh-questions were presented: correct, grammatically anomalous, and semantically anomalous conditions. This study yielded three main findings. First, activity in the left inferior parietal lobule was greater during processing of grammatically anomalous than correct or semantically anomalous wh-questions. Second, activity in the left inferior frontal gyrus was greater during processing of semantically anomalous than correct or grammatically anomalous wh-questions. Finally, significant correlations were identified between activities in the left inferior parietal lobule and the left inferior frontal gyrus during grammatically anomalous and semantically anomalous wh-questions. These findings suggest that the left inferior parietal and inferior frontal regions have differential contributions to the processing of grammatical and semantic relationships in wh-question sentences, and that the interaction between these regions could be essential in the comprehension of wh-questions by combining the grammatical process with the semantic process.

This study examined behavioral changes in 15-day learning of word-picture (WP) and word-sound (WS) associations, using meaningless stimuli. Subjects performed a learning task and two recognition tasks under the WP and WS conditions every day for 15 days. Two main findings emerged from this study. First, behavioral data of recognition accuracy and response time were improved in both conditions of WP and WS by the 15-day learning of associations. Second, the performance in WP was better than that in WS for 15 days, but the correlation between accuracies in WP and WS was significant across subjects. These results suggest that even if meaningless stimuli are employed as an experimental stimulus, the long-term learning of associations between words and perceptual features could be formed in both visual and auditory modalities, between which the performance levels are highly correlated, but the learning effect could be dominant when words are associated with visual features, compared to auditory features.

The motivation to receive rewards enhances episodic memories, and the motivation is modulated by task difficulty. In episodic retrieval, however, functional neuroimaging evidence regarding the motivation that mediates interactions between reward and task difficulty is scarce. The present fMRI study investigated this issue. During encoding performed without fMRI, participants encoded Japanese words using either deep or shallow strategies, which led to variation in difficulty level during subsequent retrieval. During retrieval with fMRI, participants recognized the target words in either high or low monetary reward conditions. In the behavioral results, a reward‐related enhancement of memory was found only when the memory retrieval was difficult, and the rewarding effect on subjective motivation was greater in the retrieval of memories with high difficulty than those with low difficulty. The fMRI data showed that reward‐related increases in the activation of the substantia nigra/ventral tegmental area (SN/VTA), medial temporal lobe (MTL), dorsomedial prefrontal cortex (dmPFC), and dorsolateral prefrontal cortex (dlPFC) were greater during the retrieval of memories with high difficulty than those with low difficulty. Furthermore, reward‐related enhancement of functional connectivity between the SN/VTA and MTL and between the SN/VTA and dmPFC during the retrieval of memories with high difficulty was significantly correlated with reward‐related increases of retrieval accuracy and subjective motivation. The reward‐related enhancement of episodic retrieval and retrieval‐related motivation could be most effective when the level of retrieval difficulty is optimized. Such reward‐related enhancement of memory and motivation could be modulated by a network including the reward‐related SN/VTA, motivation‐related dmPFC, and memory‐related MTL. Hum Brain Mapp 38:3428–3443, 2017. © 2017 Wiley Periodicals, Inc.

Introduction Brain-imaging techniques have begun to be popular in evaluating the effectiveness of cognitive intervention training. Although gamma activities are rarely used as an index of training effects, they have several characteristics that suggest their potential suitability for this purpose. This pilot study examined whether cognitive training in elderly people affected the high-gamma activity associated with attentional processing and whether high-gamma power changes were related to changes in behavioral performance. Methods We analyzed (MEG) magnetoencephalography data obtained from 35 healthy elderly subjects (60–75 years old) who had participated in our previous intervention study in which the subjects were randomly assigned to one of the three types of intervention groups: Group V trained in a vehicle with a newly developed onboard cognitive training program, Group P trained with a similar program but on a personal computer, and Group C was trained to solve a crossword puzzle as an active control group. High-gamma (52–100 Hz) activity during a three-stimulus visual oddball task was measured before and after training. As a result of exclusion in the MEG data analysis stage, the final sample consisted of five subjects in Group V, nine subjects in Group P, and seven subjects in Group C. Results Results showed that high-gamma activities were differently altered between groups after cognitive intervention. In particular, members of Group V, who showed significant improvements in cognitive function after training, exhibited increased high-gamma power in the left middle frontal gyrus during top-down anticipatory target processing. High-gamma power changes in this region were also associated with changes in behavioral performance. Conclusions Our preliminary results suggest the usefulness of high-gamma activities as an index of the effectiveness of cognitive training in elderly subjects.

The current study used a magnetoencephalogram to investigate the relationship between high-gamma (52–100 Hz) activity within an attention network and individual differences in behavioral performance among healthy elderly adults. We analyzed brain activity in 41 elderly subjects performing a 3-stimulus visual oddball task. In addition to the average amplitude of event-related fields in the left intraparietal sulcus (IPS), high-gamma power in the left middle frontal gyrus (MFG), the strength of high-gamma imaginary coherence between the right MFG and the left MFG, and those between the right MFG and the left thalamus predicted individual differences in reaction time. In addition, high-gamma power in the left MFG was correlated with task accuracy, whereas high-gamma power in the left thalamus and left IPS was correlated with individual processing speed. The direction of correlations indicated that higher high-gamma power or coherence in an attention network was associated with better task performance and, presumably, higher cognitive function. Thus, high-gamma activity in different regions of this attention network differentially contributed to attentional processing, and such activity could be a fundamental process associated with individual differences in cognitive aging.

Implicit or automatic detection of social signals, which discriminate animate, intentional objects in the environment, is essential for higher social cognition and its development. Using functional magnetic resonance imaging, we identified the neural substrate of detecting simple visual social signals and examined its functional link with the mechanism of inferring another’s mental state. Healthy participants were presented with the eye-gaze shift (EG) and self-propelling motion (SP) under both implicit and explicit task conditions. They also performed a social role-playing game in which mental inference (MI) was implicitly prompted during the presentation of faces (implicit MI). Implicit detection of EG and SP activated the posterior middle temporal gyrus (pMTG) bilaterally, whereas the right posterior superior temporal sulcus was activated during the explicit conditions. We revealed that the individual variation in neural response in the right pMTG during implicit eye-gaze detection explains the individual tendency to recruit the regions implicated in mental-state inference (medial prefrontal cortex, temporal pole and striatum) during the implicit MI task. Our results suggest that the implicit detection of visual social signals involves the pMTG and underlies the development of higher social cognition.

The motivation of getting rewards or avoiding punishments reinforces learning behaviors. Although the neural mechanisms underlying the effect of rewards on episodic memory have been demonstrated, there is little evidence of the effect of punishments on this memory. Our functional magnetic resonance imaging (fMRI) study investigated the effects of monetary rewards and punishments on activation during the encoding of source memories. During encoding, participants memorized words (item) and locations of presented words (source) under 3 conditions (Reward, Punishment, and Control). During retrieval, participants retrieved item and source memories of the words and were rewarded or penalized according to their performance. Source memories encoded with rewards or punishments were remembered better than those without such encoding. fMRI data demonstrated that the ventral tegmental area and substantia nigra and nucleus accumbens activations reflected both the processes of reward and punishment, whereas insular activation increased as a linear function of punishment. Activation in the hippocampus and parahippocampal cortex predicted subsequent retrieval success of source memories. Additionally, correlations between these reward/punishment-related regions and the hippocampus were significant. The successful encoding of source memories could be enhanced by punishments and rewards, and interactions between reward/punishment-related regions and memory-related regions could contribute to memory enhancement by reward and/or punishment.

BackgroundDo brain training games work? The beneficial effects of brain training games are expected to transfer to other cognitive functions. Yet in all honesty, beneficial transfer effects of the commercial brain training games in young adults have little scientific basis. Here we investigated the impact of the brain training game (Brain Age) on a wide range of cognitive functions in young adults.MethodsWe conducted a double-blind (de facto masking) randomized controlled trial using a popular brain training game (Brain Age) and a popular puzzle game (Tetris). Thirty-two volunteers were recruited through an advertisement in the local newspaper and randomly assigned to either of two game groups (Brain Age, Tetris). Participants in both the Brain Age and the Tetris groups played their game for about 15 minutes per day, at least 5 days per week, for 4 weeks. Measures of the cognitive functions were conducted before and after training. Measures of the cognitive functions fell into eight categories (fluid intelligence, executive function, working memory, short-term memory, attention, processing speed, visual ability, and reading ability).Results and discussionOur results showed that commercial brain training game improves executive functions, working memory, and processing speed in young adults. Moreover, the popular puzzle game can engender improvement attention and visuo-spatial ability compared to playing the brain training game. The present study showed the scientific evidence which the brain training game had the beneficial effects on cognitive functions (executive functions, working memory and processing speed) in the healthy young adults.ConclusionsOur results do not indicate that everyone should play brain training games. However, the commercial brain training game might be a simple and convenient means to improve some cognitive functions. We believe that our findings are highly relevant to applications in educational and clinical fields.Trial registrationUMIN Clinical Trial Registry 000005618.

Our impressions of other people are formed mainly from the two possible factors of facial attractiveness and trustworthiness. Previous studies have shown the importance of orbitofrontal–hippocampal interactions in the better remembering of attractive faces, and psychological data have indicated that faces giving an impression of untrustworthiness are remembered more accurately than those giving an impression of trustworthiness. However, the neural mechanisms of the latter effect are largely unknown. To investigate this issue, we investigated neural activities with event-related fMRI while the female participants rated their impressions of the personalities of men in terms of trustworthiness. After the rating, memory for faces was tested to identify successful encoding activity. As expected, faces that gave bad impressions were remembered better than those that gave neutral or good impressions. In fMRI data, right insular activity reflected an increasing function of bad impressions, and bilateral hippocampal activities predicted subsequent memory success. Additionally, correlation between these insular and hippocampal regions was significant only in the encoding of faces associated with a bad impression. Better memory for faces associated with an impression of bad personality could reflect greater interaction between the avoidance-related insular region and the encoding-related hippocampal region.

Previous neuroimaging studies have reported that learning multisensory associations involves the superior temporal regions (Tanabe et al, 2005). However, the neural mechanisms underlying the retrieval of multi-sensory associations were unclear. This functional MRI (fMRI) study investigated brain activations during the retrieval of multi-sensory associations. Eighteen right-handed college-aged Japanese participants learned associations between meaningless pictures and words (Vw), meaningless sounds and words (Aw), and meaningless sounds and visual words (W). During fMRI scanning, participants were presented with old and new words and were required to judge whether the words were included in the conditions of Vw, Aw, W or New. We found that the left superior temporal region showed greater activity during the retrieval of words learned in Aw than in Vw, whereas no region showed greater activity for the Vw condition versus the Aw condition (k > 10, p < .001, uncorrected). Taken together, the left superior temporal region could play an essential role in the retrieval process of auditory-word associations.

Memory for face–name associations is an important type of memory in our daily lives, and often deteriorates in older adults. Although difficulty retrieving face–name associations is often apparent in the elderly, there is little neuroscientific evidence of age-related decline in this memory. The current fMRI study investigated differences in brain activations between healthy young and older adults during the successful retrieval of people's names (N) and job titles (J) associated with faces. During encoding, participants viewed unfamiliar faces, each paired with a job title and name. During retrieval, each learned face was presented with two job titles or two names, and participants were required to choose the correct job title or name. Retrieval success activity (RSA) was identified by comparing retrieval-phase activity for hits versus misses in N and J, and the RSAs in each task were compared between young and older adults. The study yielded three main findings. First, the hippocampus showed significant RSA in both tasks of N and J, and the activity was greater for young compared to older subjects. Second, the left anterior temporal lobe (ATL) showed greater RSA in N than in J, but there was no age difference in the activity in this region. Third, functional connectivity between hippocampal and ATL activities in both retrieval tasks was higher for young than for older adults. Taken together, age-related differences in hippocampal activities and hippocampus–ATL connectivity could contribute to age-related decline in relational memory and to complaints of poor retrieval of people's names by older adults.

Memory for person identity information consists of three main components: face-related information, name-related information, and person-related semantic information, such as the person's job title. Although previous studies have demonstrated the importance of the anterior temporal lobe (ATL) in the retrieval of associations between these kinds of information, there is no evidence concerning whether the ATL region contributes to the encoding of this memory, and whether ATL roles are dissociable between different levels of association in this memory. Using fMRI, we investigated dissociable roles within the ATL during successful encoding of this memory. During encoding, participants viewed unfamiliar faces, each paired with a job title and name. During retrieval, each learned face was presented with two job titles or two names, and participants were required to choose the correct job title or name. Successful encoding conditions were categorized by subsequent retrieval conditions: successful encoding of names and job titles (HNJ), names (HN), and job titles (HJ). The study yielded three main findings. First, the dorsal ATL showed greater activations in HNJ than in HN or HJ. Second, ventral ATL activity was greater in HNJ and HJ than in HN. Third, functional connectivity between these regions was significant during successful encoding. The results are the first to demonstrate that the dorsal and ventral ATL roles are dissociable between two steps of association, associations of person-related semantics with name and with face, and a dorsal–ventral ATL interaction predicts subsequent retrieval success of memory for person identity information.

Although many studies have investigated the neural basis of top-down and bottom-up attention, it still requires refinement in both temporal and spatial terms. We used magnetoencephalography to investigate the spatiotemporal dynamics of high-gamma (52-100 Hz) activities during top-down and bottom-up visual attentional processes, aiming to extend the findings from functional magnetic resonance imaging and event-related potential studies. Fourteen participants performed a 3-stimulus visual oddball task, in which both infrequent non-target and target stimuli were presented. We identified high-gamma event-related synchronization in the left middle frontal gyrus, the left intraparietal sulcus, the left thalamus, and the visual areas in different time windows for the target and non-target conditions. We also found elevated imaginary coherence between the left intraparietal sulcus and the right middle frontal gyrus in the high-gamma band from 300 to 400 ms in the target condition, and between the left thalamus and the left middle frontal gyrus in theta band from 150 to 450 ms. In addition, the strength of high-gamma imaginary coherence between the left middle frontal gyrus and left intraparietal sulcus, between the left middle frontal gyrus and the right middle frontal gyrus, and the high-gamma power in the left thalamus predicted inter-subject variation in target detection response time. This source-level electrophysiological evidence enriches our understanding of bi-directional attention processes: stimulus-driven bottom-up attention orientation to a salient, but irrelevant stimulus; and top-down allocation of attentional resources to stimulus evaluation.