Bilateral Frontotemporal Areas Research Articles

Divergent patterns of cognitive deficits and structural brain alterations between older adults in mixed-sex and same-sex relationships.

BackgroundSexual minority (SM) older adults experience mental health disparities. Psychiatric disorders and neuropsychiatric symptoms (NPS) are risk factors for cognitive decline. Although older people in same-sex (SSR) compared to mixed-sex relationships (MSR) perform more poorly on cognitive screening tests, prior studies found no differences in rates of dementia diagnosis or neuropsychological profiles. We sought to explore the role of NPS on neurocognitive outcomes for SM populations. We compared cognitive performance and structural brain parameters of older adults in SSR and MSR.MethodsData were originally collected at Alzheimer's Disease Research Centers (ADRCs). Inclusion criteria were: age of 55+ years, a study partner identified as a spouse/partner, and availability of T1-MRI brain volumes/thickness. Participants were labeled as either SSR or MSR based on their/their co-participant's reported sex. We identified 1,073 participants (1,037 MSR−555 cognitively unimpaired [CU]; 36 SSR−23 CU) with structural MRI data, Mini-Mental State Exam (MMSE), and Neuropsychiatric Inventory Questionnaire (NPI-Q) scores. A subset of the overall sample completed comprehensive neuropsychological assessment (n = 939; 908 MSR−494 CU; 31 SSR−22 CU). Covariates included in statistical models were age, sex, education, total intracranial volume, and apolipoprotein E genotype.ResultsMultivariate general linear models showed significant diagnosis-by-relationship interaction effects on the left parahippocampal gyrus volume. After stratification by relationship group, only cognitively impaired (CI) MSR had significantly smaller left parahippocampal volumes than MSR-CU. The SSR group showed better episodic memory performance. Severity of neuropsychiatric symptoms was negatively associated with volume/thickness of bilateral fronto-temporal areas and with MMSE scores, predominantly in the MSR group.ConclusionIn our study, MSR participants presented with a more compromised cognitive profile than SSR participants. MSR-CI participants showed significantly smaller left medio-temporal volumes, a neural signature of AD. Neuropsychiatric symptoms predicted smaller fronto-temporal volumes in the MSR more consistently than in the SSR group. These findings may be due to unexplored protective factors against cognitive decline in SM elders. Indeed, social support has been proposed as a protective factor warranting future investigation.

The recognition of human voice in deaf and hearing infants

Purpose: Deafness in infancy has longlasting consequences on brain organization. To achieve the best developmental outcomes in case of profound deafness, cochlear implantation (CI) needs to take place in a critical period during the first year of life, before the cross-modal reorganization of the brain due to auditory deprivation stabilises, preventing the typical development of the auditory cortices. Despite its importance for implantation outcomes, the nature of this critical period and the underlying neural reorganization have not been fully explored. Materials and methods: To fill this knowledge gap, we investigated the cortical responses of 12-month-old profoundly deaf infants and their age-matched controls to sounds produced by a human voice as compared to non-human sounds using functional near-infrared spectroscopy (fNIRS). The deaf infants were tested before undergoing CI surgery and wore hearing aids, allowing them to perceive low frequencies. Human voice stimuli have been shown to trigger brain responses early in development, possibly due to its evolutionary relevance for survival. Results: We found increased brain responses to the human voice in the deaf infants in the bilateral fronto-temporal areas, and their responses correlated with their residual hearing thresholds. These results suggest that even the limited sound stimulation that these deaf infants receive due to their residual hearing allowed the temporal cortices to develop sensitivity to the human voice prior to implantation. The hearing control group showed an inverted hemodynamic response to both voice and non-voice stimuli in the left parietal and right temporal areas, suggesting that by 12 months of age, they habituate rapidly to these very familiar stimuli. While both groups showed an inverted response to the non-voice stimuli, they differed in their responses to voice stimuli. Conclusions: We hypothesize that the responses found in deaf infants to human voice can be consider a good cochlear implant prognosis.

Behavioral Reserve in Behavioral Variant Frontotemporal Dementia.

“Reserve” refers to the individual clinical differences in response to a neuropathological burden. We explored the behavioral reserve (BR) and associated neural substrates in 40 participants with behavioral variant frontotemporal dementia (bvFTD) who were assessed with the frontal behavioral inventory (FBI) and magnetic resonance imaging. Because neuroimaging abnormality showed a high negative correlation with the FBI negative (but not positive) symptom scores, we developed a linear model only to calculate the nBR (BR for negative symptoms) marker using neuroimaging abnormalities and the FBI score. Participants were divided into high nBR and low nBR groups based on the nBR marker. The FBI negative symptom score was lower in the high nBR group than in the low nBR group having the same neuroimaging abnormalities. However, the high nBR group noted a steeper decline in cortical atrophy and showed less atrophy in the left frontotemporal cortices than the low nBR group. In addition, the fractional anisotropy (FA) values were greater in the high nBR than in the low nBR group, except in the sensory-motor and occipital areas. We identified an nBR-related functional network composed of bilateral frontotemporal areas and the left occipital pole. We propose the concept of BR in bvFTD, and these findings can help predict the disease progression.

Data-driven prognostic features of cognitive trajectories in patients with amnestic mild cognitive impairments

BackgroundAlthough amnestic mild cognitive impairment (aMCI) is generally considered to be a prodromal stage of Alzheimer’s disease, patients with aMCI show heterogeneous patterns of progression. Moreover, there are few studies investigating data-driven cognitive trajectory in aMCI. We therefore classified patients with aMCI based on their cognitive trajectory, measured by clinical dementia rating sum of boxes (CDR-SOB). Then, we compared the clinical and neuroimaging features among groups classified by cognitive trajectory.MethodsWe retrospectively recruited 278 patients with aMCI who underwent three or more timepoints of neuropsychological testing. They also had magnetic resonance imaging (MRI) including structured three-dimensional volume images. Cortical thickness was measured using surface-based methods. We performed trajectory analyses to classify our aMCI patients according to their progression and investigate their cognitive trajectory using CDR-SOB.ResultsTrajectory analyses showed that patients with aMCI were divided into three groups: stable (61.8%), slow decliner (31.7%), and fast decliner (6.5%). Changes throughout a mean follow-up duration of 3.7 years in the CDR-SOB for the subgroups of stable/slow/fast decliners were 1.3-, 6.4-, and 12-point increases, respectively. Decliners were older and carried apolipoprotein E4 (APOE4) genotypes more frequently than stable patients. Compared with the stable group, decliners showed a higher frequency of aMCI patients with both visual and verbal memory dysfunction, late stage aMCI, and multiple domain dysfunction. In addition, compared with the stable group, the slow decliners showed cortical thinning predominantly in bilateral parietotemporal areas, while the fast decliners showed cortical thinning predominantly in bilateral frontotemporal areas. Both decliner groups showed worse cognitive function in attention, language, visuospatial, memory, and frontal/executive domains than the stable group.ConclusionsOur data-driven trajectory analysis provides new insights into heterogeneous cognitive trajectories of aMCI and further suggests that baseline clinical and neuroimaging profiles might predict aMCI patients with poor prognosis.

Acute Chorea Onset after Hot Food Consumption in a Patient with Moyamoya Disease.

Acute Chorea Onset after Hot Food Consumption in a Patient with Moyamoya Disease.

Olfactory short-term memory encoding and maintenance — An event-related potential study

This study examined whether the memory encoding and short term maintenance of olfactory stimuli is associated with neurophysiological activation patterns which parallel those described for sensory modalities such as vision and auditory. We examined olfactory event-related potentials in an olfactory change detection task in twenty-four healthy adults and compared the measured activation to that found during passive olfactory stimulation.During the early olfactory post-processing phase, we found a sustained negativity over bilateral frontotemporal areas in the passive perception condition which was enhanced in the active memory task. There was no significant lateralization in either experimental condition. During the maintenance interval at the end of the delay period, we still found sustained activation over bilateral frontotemporal areas which was more negative in trials with correct – as compared to incorrect – behavioural responses. This was complemented by a general significantly stronger frontocentral activation.Summarizing, we were able to show that olfactory short term memory involves a parallel sequence of activation as found in other sensory modalities. In addition to olfactory-specific frontotemporal activations in the memory encoding phase, we found slow cortical potentials over frontocentral areas during the memory maintenance phase indicating the activation of a supramodal memory maintenance system. These findings could represent the neurophysiological underpinning of the ‘olfactory flacon’, the olfactory counter-part to the visual sketchpad and phonological loop embedded in Baddeley's working memory model.

Evaluation of cerebral ischemia using near-infrared spectroscopy with oxygen inhalation

Conventional methods presently used to evaluate cerebral hemodynamics are invasive, require physical restraint, and employ equipment that is not easily transportable. Therefore, it is difficult to take repeated measurements at the patient's bedside. An alternative method to evaluate cerebral hemodynamics was developed using near-infrared spectroscopy (NIRS) with oxygen inhalation. The bilateral fronto-temporal areas of 30 normal volunteers and 33 patients with cerebral ischemia were evaluated with the NIRS system. The subjects inhaled oxygen through a mask for 2 min at a flow rate of 8 L/min. Principal component analysis (PCA) was applied to the data, and a topogram was drawn using the calculated weights. NIRS findings were compared with those of single-photon-emission computed tomography (SPECT). In normal volunteers, no laterality of the PCA weights was observed in 25 of 30 cases (83%). In patients with cerebral ischemia, PCA weights in ischemic regions were lower than in normal regions. In 28 of 33 patients (85%) with cerebral ischemia, NIRS findings agreed with those of SPECT. The results suggest that transmission of the changes in systemic SpO2 were attenuated in ischemic regions. The method discussed here should be clinically useful because it can be used to measure cerebral ischemia easily, repeatedly, and noninvasively.

Frontotemporal abnormal gyration with infantile spasms in identical twins

We describe the case of 10-year-old twin girls, who were born to nonconsanguineous parents and showed pes equinovarus, infantile spasms, and severe psychomotor retardation. Neither patient showed marked microcephaly. Neuroimaging revealed a simplified gyral pattern in the bilateral frontotemporal areas, a reduced volume of cerebral white matter, and a thin corpus callosum in both patients. The cerebral cortex presented with significant thickness in the anterior temporal region at the age of 10 years, which suggest that the simplified gyri can evolve into the pachygyria during postnatal period. These cases may represent a hereditary brain malformation with a distinct pattern of abnormal cortical gyration. The age-dependent change in appearance of dysgenetic cortex should be further explored in cases with brain malformations.

Repetition suppression and semantic enhancement: An investigation of the neural correlates of priming

The priming of a stimulus by another has become an important tool for exploring the neural underpinnings of conceptual representations. However, priming effects can derive from many different types of relationships and it is important to distinguish between them in order to be able to develop theoretical accounts of the representation of conceptual knowledge. While it is well known that repetition priming (the repeated presentation of the same stimulus) is associated with a reduced neural response, called repetition suppression (RS), the neural correlates of semantic priming (when two stimuli are related in meaning but not identical) are not so well established. We compared the neural correlates of repetition and semantic priming using written words, independently manipulating form and meaning. In an fMRI study, subjects saw single words and made a concrete–abstract decision. Two consecutive words were identical ( town– town) or varied along a continuum of semantic relatedness, from highly related ( cord– string) to unrelated ( face– sail). We found distinct patterns of activation for repetition and semantic priming. Repetition priming was associated with RS in LIFG, bilateral parahippocampal gyrus and R fusiform gyrus. We also observed increased activation for word repetition in the RMFG and RMTG/STG, which may reflect recognition of item's earlier presentation. There was no evidence of suppression for semantic relatedness. Semantic priming was associated with enhanced activation in multiple bilateral fronto-temporal areas, i.e. semantic enhancement. The results suggest that repetition and semantic priming in visual word recognition depend on distinct cognitive processes and neural substrates.

Familial frontotemporal dementia with a P301L tau mutation in Japan

We have reported the family line with frontotemporal dementia (FTD) in Japan. This family line has so far included four patients. Patient II-1 (man) had a 10 year history of slowly progressive personality and behavioral changes and died at the age of 56. His neuropathological examination showed severe atrophy of the bilateral frontal and temporal cortices with neuronal loss, gliosis and superficial spongiosis. Pick bodies were not found. The neuropathological diagnosis was atypical Pick’s disease without Pick bodies or Pick-type in FTD. Patient III-2 is patient II-1’s oldest daughter and was taken ill with personality change at the age of 52. She died at the age of 68. Patient III-4 is patient II-1’s second daughter. Her onset with strange speech and behavior was at the age of 59. Patient III-5 is patient II-1’s oldest son. He also had onset with personality change at the age of 54 and had the P301L mutation in tau. In all III generation cases CT/MRI revealed circumscribed frontotemporal atrophy. Patient III-5’s PET/SPECT showed signs of hypoperfusion or hypometabolism in the bilateral frontotemporal areas. This is the first report of familial FTD with the P301L mutation in Japan.