Age-Related Changes in Episodic Processing of Scenes: A Functional Activation and Connectivity Study.

The posterior-to-anterior shift in aging (PASA) effect is seen as a compensatory model that enables older adults to meet increased cognitive demands to perform comparably as their young counterparts. However, empirical support for the PASA effect investigating age-related changes in the inferior frontal gyrus (IFG), hippocampus, and parahippocampus has yet to be established. 33 older adults and 48 young adults were administered tasks sensitive to novelty and relational processing of indoor/outdoor scenes in a 3-Tesla MRI scanner. Functional activation and connectivity analyses were applied to examine the age-related changes on the IFG, hippocampus, and parahippocampus among low/high-performing older adults and young adults. Significant parahippocampal activation was generally found in both older (high-performing) and young adults for novelty and relational processing of scenes. Younger adults had significantly greater IFG and parahippocampal activation than older adults, and greater parahippocampal activation compared to low-performing older adults for relational processing-providing partial support for the PASA model. Observations of significant functional connectivity within the medial temporal lobe and greater negative left IFG-right hippocampus/parahippocampus functional connectivity for young compared to low-performing older adults for relational processing also supports the PASA effect partially.

Verbal Training Induces Enhanced Functional Connectivity in Japanese Healthy Elderly Population.

This study employs fMRI to examine the neural substrates of response to cognitive training in healthy old adults. Twenty Japanese healthy elders participated in a 4-week program and practiced a verbal articulation task on a daily basis. Functional connectivity analysis revealed that in comparison to age- and education-matched controls, elders who received the cognitive training demonstrated increased connectivity in the frontotemporal regions related with language and memory functions and showed significant correlations between the behavioral change in a linguistic task and connectivity in regions for goal-oriented persistence and lexical processing. The increased hippocampal connectivity was consistent with previous research showing efficacious memory improvement and change in hippocampal functioning. Moreover, the increased intra-network connectivity following cognitive training suggested an improved neural differentiation, in contrast to the inter-network activation pattern typical in the aging brain. This research not only validates the relationship of functional change in the frontal and temporal lobes to age-associated cognitive decline but also shows promise in turning neural change toward the right direction by cognitive training.

Aging patterns of Japanese auditory semantic processing: an fMRI study.

The efficacy of listening comprehension is presumably sustained over the life span, contradicting the stereotype of universal cognitive decline. It is thus worth investigating whether and how the preserved auditory semantic function is supported by affected or unaffected neural mechanism with age. To investigate this issue, 22 younger and 21 older Japanese adults were imaged in a 3 Tesla MRI scanner while performing an auditory semantic-tone task. Results showed that (a) relative to younger adults, older participants had preserved accuracy and slowed responses, underpinned by weakened interconnectivity and largely unchanged activation and laterality; (b) older adults with superior performance developed increased regional left-lateralization and stronger interregional connectivity within the domain-general networks; (c) these age-related or performance-related cortical reorganizations were largely consistent with neurocognitive aging models that were supported by age-sensitive cognitive domains, suggesting that these models might also be accountable for relatively age-intact cognitive functions such as auditory semantic processing.

Improving Real-Time Brain State Classification of Motor Imagery Tasks During Neurofeedback Training.

In this study, we investigated the effect of the dynamic changes in brain activation during neurofeedback training in the classification of the different brain states associated with the target tasks. We hypothesized that ongoing activation patterns could change during neurofeedback session due to learning effects and, in the process, could affect the performance of brain state classifiers trained using data obtained prior to the session. Using a motor imagery paradigm, we then examined the application of an incremental training approach where classifiers were continuously updated in order to account for these activation changes. Our results confirmed our hypothesis that neurofeedback training could be associated with dynamic changes in brain activation characterized by an initially more widespread brain activation followed by a more focused and localized activation pattern. By continuously updating the trained classifiers after each feedback run, significant improvement in accurately classifying the different brain states associated with the target motor imagery tasks was achieved. These findings suggest the importance of taking into account brain activation changes during neurofeedback in order to provide more reliable and accurate feedback information to the participants, which is critical for an effective neurofeedback application.

Age-related differences in the activation of the mentalizing- and reward-related brain regions during the learning of others' true trustworthiness.

Behavioral studies suggest that older adults may be less adept than younger adults at remembering information contradicting their first impressions about others' trustworthiness. To identify the neural bases associated with such age-related differences, we measured the brain activity of older and younger participants using functional magnetic resonance imaging while they processed feedback on whether their initial trustworthiness impressions of stimulus persons, whose true trustworthiness had been predetermined, were right or wrong. Of special interest was the activation in mentalizing- (e.g., medial prefrontal cortex) and reward-related brain regions (e.g., striatum), which are known to be involved in impression formation and feedback learning, respectively. The reduction in the striatal responses to impression-contradicting versus impression-confirming feedback was greater in older than in younger participants. The activation of some mentalizing-related regions (medial prefrontal cortex and precuneus) was lower in older than younger participants; however, it was not modulated by impression-feedback congruency. The results suggest that age-related differences in the striatum engagement may underlie older adults' inefficiency in learning impression-incongruent information about others' trustworthiness.

Improved Volitional Recall of Motor-Imagery-Related Brain Activation Patterns Using Real-Time Functional MRI-Based Neurofeedback.

Motor imagery (MI), a covert cognitive process where an action is mentally simulated but not actually performed, could be used as an effective neurorehabilitation tool for motor function improvement or recovery. Recent approaches employing brain-computer/brain-machine interfaces to provide online feedback of the MI during rehabilitation training have promising rehabilitation outcomes. In this study, we examined whether participants could volitionally recall MI-related brain activation patterns when guided using neurofeedback (NF) during training. The participants' performance was compared to that without NF. We hypothesized that participants would be able to consistently generate the relevant activation pattern associated with the MI task during training with NF compared to that without NF. To assess activation consistency, we used the performance of classifiers trained to discriminate MI-related brain activation patterns. Our results showed significantly higher predictive values of MI-related activation patterns during training with NF. Additionally, this improvement in the classification performance tends to be associated with the activation of middle temporal gyrus/inferior occipital gyrus, a region associated with visual motion processing, suggesting the importance of performance monitoring during MI task training. Taken together, these findings suggest that the efficacy of MI training, in terms of generating consistent brain activation patterns relevant to the task, can be enhanced by using NF as a mechanism to enable participants to volitionally recall task-related brain activation patterns.

Frontal White Matter Hyperintensity Is Associated with Verbal Aggressiveness in Elderly Women with Alzheimer Disease and Amnestic Mild Cognitive Impairment.

BACKGROUND/AIMS: Behavioral and psychological symptoms of dementia (BPSD) are exhibited in most patients with Alzheimer disease (AD). Although white matter hyperintensity (WMH) is often observed with AD, the precise role of WMH in BPSD remains unclear. The current study aimed to identify the impact of regional WMH on specific features of BPSD in persons with mild to moderate AD and amnestic mild cognitive impairment (aMCI). METHODS: A sample of 256 female outpatients with AD (n = 217) and aMCI (n = 39) were recruited. We assessed BPSD using the Dementia Behavior Disturbance Scale. WMH and brain atrophy were evaluated using an automatic segmentation program. Regional WMH was evaluated as periventricular hyperintensity (PVH) and deep WMH in frontal, temporal, occipital, and parietal lobes. RESULTS: Whole-brain WMH was associated with verbal aggressiveness. In multivariate analysis, PVH in the frontal lobe was independently associated with verbal aggressiveness after adjustment for brain atrophy and clinical confounders. CONCLUSION: The current results indicated that PVH in the frontal lobe was independently associated with verbal aggressiveness.

The role of regional heterogeneity in age-related differences in functional hemispheric asymmetry: an fMRI study.

Neuroimaging literature has documented age-related hemispheric asymmetry reduction in frontal regions during task performances. As most studies employed working memory paradigms, it is therefore less clear if this pattern of neural reorganization is constrained by working memory processes or it would also emerge in other cognitive domains which are predominantly lateralized. Using blocked functional magnetic resonance imaging (fMRI), the present study used a homophone judgment task and a line judgment task to investigate age-related differences in functional hemispheric asymmetry in language and visuospatial processing respectively. Young and older adults achieved similar task accuracy although older adults required a significantly longer time. Age-related functional hemispheric asymmetry reduction was found only in dorsal inferior frontal gyrus and was associated with better performance when the homophone condition was contrasted against fixation, and not line condition. Our data thus highlights the importance of considering regional heterogeneity of aging effects together with general age-related cognitive processes.

Impact of frontal white matter hyperintensity on instrumental activities of daily living in elderly women with Alzheimer disease and amnestic mild cognitive impairment.

BACKGROUND: Instrumental activities of daily living (IADL) start to decline during the progression of amnestic mild cognitive impairment (aMCI) to Alzheimer disease (AD). Cognitive and physical decline are involved in the loss of functional independence. However, little is known about AD-related neural change that leads to IADL impairment. The purpose of this study was to clarify the effects of regional white matter hyperintensity (WMH) on IADL impairment in persons with AD and aMCI. METHODS: The participants were 347 female subjects aged 65-85 years diagnosed with AD (n = 227), aMCI (n = 44) or normal cognition (n = 76). IADL was assessed by the Lawton Index. Cognition, mood and mobility function were evaluated by comprehensive geriatric assessment batteries. WMH and brain atrophy were analyzed with brain magnetic resonance imaging, using an automatic segmentation program. Regional WMH was measured in the frontal, temporal, occipital and parietal lobes. RESULTS: Ability to carry out IADL of shopping, food preparation, mode of transportation, responsibility for own medication, and ability to handle finances was obviously impaired in the early stage of AD. Frontal WMH was specifically associated with disability to do shopping and food preparation even after adjusting for several confounders including brain atrophy. CONCLUSIONS: IADL subcategories were differentially impaired along with cognitive status in persons with AD and aMCI. Frontal WMH was an important predictor of impaired ability to do shopping and food preparation. A preventive strategy for WMH might lead to suppression of IADL disability and slow the progression of AD.

Use of the sit-to-stand task to evaluate motor function of older adults using telemetry.

BACKGROUND: Physical exercises are widely used in community programs, but not all older adults are willing to participate. Information and communication technology may solve this problem by allowing older people to participate in fitness programs at home. Use of remote instruction will facilitate physical exercise classes without requiring that participants gather at one place. The aim of this study was to examine use of a sit-to-stand task in evaluating motor function using conventional video communication in a telemetry system to enable real-time monitoring, and evaluation in physical performance of older adults at home. METHODS: The participants were 59 older individuals and 81 university students. Three physical exercise batteries were used: arm curl, figure-of-eight walk test, and functional reach. The knee extension maximum angular velocity (KEMAV) and the iliac elevation maximum velocity (IEMV) during standing up from a chair and the heel rise frequency were used in the motion-capture measurements. The results were assessed using multi-group structural equation modeling (SEM) for the young and older groups. RESULTS: Young participants consistently performed better than their older counterparts on all items. Analyses with multi-group SEM based on correlations between items yielded a good model-fit for the data. Among all path diagrams for IEMV and KEMAV in the older and young groups, paths from muscular strength to skillfulness showed significant effects. The path from the IEMV to muscular strength was also significant in the older group. CONCLUSIONS: Multi-group SEM suggested that video-based measurements of IEMV during sit-to-stand motion can estimate muscular strength, which suggests that remote monitoring of physical performance can support wellness of community-dwelling older adults.

Involvement of the Ventrolateral Prefrontal Cortex in Learning Others' Bad Reputations and Indelible Distrust.

A bad reputation can persistently affect judgments of an individual even when it turns out to be invalid and ought to be disregarded. Such indelible distrust may reflect that the negative evaluation elicited by a bad reputation transfers to a person. Consequently, the person him/herself may come to activate this negative evaluation irrespective of the accuracy of the reputation. If this theoretical model is correct, an evaluation-related brain region will be activated when witnessing a person whose bad reputation one has learned about, regardless of whether the reputation is deemed valid or not. Here, we tested this neural hypothesis with functional magnetic resonance imaging (fMRI). Participants memorized faces paired with either a good or a bad reputation. Next, they viewed the faces alone and inferred whether each person was likely to cooperate, first while retrieving the reputations, and then while trying to disregard them as false. A region of the left ventrolateral prefrontal cortex (vlPFC), which may be involved in negative evaluation, was activated by faces previously paired with bad reputations, irrespective of whether participants attempted to retrieve or disregard these reputations. Furthermore, participants showing greater activity of the left ventrolateral prefrontal region in response to the faces with bad reputations were more likely to infer that these individuals would not cooperate. Thus, once associated with a bad reputation, a person may elicit evaluation-related brain responses on their own, thereby evoking distrust independently of their reputation.

How the Non-attending Brain Hears Its Owner's Name.

We used functional magnetic resonance imaging to investigate how attended and non-attended hearing of a subject's own name (SON) captures his or her attention. It has been reported that SON presentation activates the medial prefrontal cortex (mPFC), which is considered to be the key region for self-recognition. However, it remains unclear whether non-attended SON presentation also activates the mPFC. We hypothesized that an attended SON should activate mPFC more than a non-attended SON. To test this hypothesis, we designed an experiment in which we manipulated the task-relevance of SON; in a name-detection task, SON was a target stimulus, whereas in a tone-judgment task, SON was unrelated to the task. In each condition, identical sets of sound stimuli were presented. SON activated mPFC in the name-detection task but not in the tone-judgment task, supporting our hypothesis. In contrast, non-attended SON activated midbrain reticular formation, thalamus, insula, auditory cortex, and precuneus. We interpreted these to be related to low-level, automatic SON detection. Thus, hearing one's own name in a non-attended condition does not primarily engage the mPFC, but recruits a cortico-subcortical auditory attention network; this may account for the oft-observed salience of SON.

Effectiveness of Disaster-prevention Technologies against Quake-induced Damage of MR Scanners during the Great East Japan Earthquake.

In the present study, we have performed a statistical analysis to investigate damages in magnetic resonance (MR) scanners caused by the Great East Japan Earthquake (GEJE, magnitude 9.0) and evaluated whether these disaster-prevention technologies contributed to the reduction of damages in the GEJE or not. It was confirmed that the extent of damage was significantly different between seismic scale (SS) 5 and SS over 6. Our survey study demonstrated that anchoring of MR facilities reduced damages due to quakes and demonstrated that anchoring is an efficient method for quake-induced damage prevention. The odds ratio revealed that base isolation was very useful to prevent damages in MR scanners.

Investigation of age-related changes in brain activity during the divalent task-switching paradigm using functional MRI.

This study compared the brain activation of young and older subjects during the use of the task-switching paradigm (TSP) at various task speeds to examine the relationship between task load and brain activation. Specifically, it attempted to examine whether the task load-dependent BOLD response gradient is a useful tool for functional magnetic resonance imaging-based assessments of age-related changes in cognitive function. We predicted that the extent of the activation of the brain regions responsible for task-set reconfiguration and the inhibition of task switching functions induced during the performance of a TSP-based task would vary according to age. Task difficulty was controlled by altering the inter-stimulus interval. Although similar brain regions were activated in both age groups, significant differences in the extent of the activation were detected between the young and older groups. In particular, some regions were activated in the older group, but not the young group. This study indicated that TSP-based task performance-induced activation of the brain regions linked to executive function increases with age and that the degree and pattern of such activation depend on the content and difficulty of the task being performed. This indicates that the age- and task difficulty-dependent augmentation of brain activation varies between brain regions.

Frontal white matter hyperintensity predicts lower urinary tract dysfunction in older adults with amnestic mild cognitive impairment and Alzheimer's disease.

AIM: Lower urinary tract symptoms often limit activities of daily life and impair quality of life in the elderly. The purpose of the present study was to determine whether regional white matter hyperintensity (WMH) can predict lower urinary tract symptoms in elderly with amnestic mild cognitive impairment or Alzheimer's disease. METHODS: The participants were 461 patients aged 65-85 years diagnosed with amnestic mild cognitive impairment or Alzheimer's disease. Patients and their caregivers were asked about symptoms of lower urinary tract symptoms (urinary difficulty, frequency and incontinence). Cognition, behavior and psychological symptoms of dementia and medication were evaluated. WMH and brain atrophy were analyzed using an automatic segmentation program. Regional WMH was evaluated in the frontal, parietal, temporal and occipital lobes. RESULTS: Patients with urinary incontinence showed significantly greater volume of WMH. WMH increased with age, especially in the frontal lobe. WMH in the frontal lobe was closely associated with urinary incontinence after adjustment for brain atrophy and classical confounding factors. CONCLUSIONS: Frontal WMH was a predictive factor for urinary incontinence in older adults with amnestic mild cognitive impairment or Alzheimer's disease. Urinary incontinence in demented older adults is not an incidental event, and careful insight into regional WMH on brain magnetic resonance imaging might greatly help in diagnosing individuals with a higher risk of urinary incontinence.

Evaluation of the magnetic properties of cosmetic contact lenses with a superconducting quantum interference device.

We evaluated the magnetization of 21 cosmetic contact lens samples that included various coloring materials with a superconducting quantum interference device with regard to magnetic resonance (MR) safety. We found 7 samples were ferromagnetic; two had both ferromagnetic and diamagnetic properties; and the rest were diamagnetic. The saturated magnetization of the most ferromagnetic sample was 15.0 µJ/T, which yielded a magnetically induced displacement force of 90.0 µN when the spatial gradient of the static magnetic field was 6.0 T/m. The force was less than one-third of the gravitational force.

Age-related differences in effective connectivity of brain regions involved in Japanese kanji processing with homophone judgment task.

Reading is a complex process involving neural networks in which connections may be influenced by task demands and other factors. We employed functional magnetic resonance imaging and dynamic causal modeling to examine age-related influences on left-hemispheric kanji reading networks. During a homophone judgment task, activation in the middle frontal gyrus, and dorsal and ventral inferior frontal gyri were identified, representing areas involved in orthographic, phonological, and semantic processing, respectively. The young adults showed a preference for a semantically-mediated pathway from orthographic inputs to the retrieval of phonological representations, whereas the elderly preferred a direct connection from orthographic inputs to phonological lexicons prior to the activation of semantic representations. These sequential pathways are in line with the lexical semantic and non-semantic routes in the dual-route cascaded model. The shift in reading pathways accompanied by slowed reaction time for the elderly might suggest age-related declines in the efficiency of network connectivity.

Distant functional connectivity for bimanual finger coordination declines with aging: an fMRI and SEM exploration.

Although bimanual finger coordination is known to decline with aging, it still remains unclear how exactly the neural substrates underlying the coordination differ between young and elderly adults. The present study focused on: (1) characterization of the functional connectivity within the motor association cortex which is required for successful bimanual finger coordination, and (2) to elucidate upon its age-related decline. To address these objectives, we utilized functional magnetic resonance imaging (fMRI) in combination with structural equation modeling (SEM). This allowed us to compare functional connectivity models between young and elderly age groups during a visually guided bimanual finger movement task using both stable in-phase and complex anti-phase modes. Our SEM exploration of functional connectivity revealed significant age-related differences in connections surrounding the PMd in the dominant hemisphere. In the young group who generally displayed accurate behavior, the SEM model for the anti-phase mode exhibited significant connections from the dominant PMd to the non-dominant SPL, and from the dominant PMd to the dominant S1. However, the model for the elderly group's anti-phase mode in which task performance dropped, did not exhibit significant connections within the aforementioned regions. These results suggest that: (1) the dominant PMd acts as an intermediary to invoke intense intra- and inter-hemispheric connectivity with distant regions among the higher motor areas including the dominant S1 and the non-dominant SPL in order to achieve successful bimanual finger coordination, and (2) the distant connectivity among the higher motor areas declines with aging, whereas the local connectivity within the bilateral M1 is enhanced for the complex anti-phase mode. The latter may underlie the elderly's decreased performance in the complex anti-phase mode of the bimanual finger movement task.