Bilateral Frontotemporal Regions Research Articles

Imaging findings in carcinomatous encephalitis secondary to malignant melanoma

BackgroundThe case of disseminated cancer cell spreading throughout the brain is called “miliary metastases” or “carcinomatous encephalitis”, a very rare and critical condition (primarily associated with lung and breast cancer) in which there are multiple plaque with a perivascular distribution, made of punctate lesions spread in all the brain. To our knowledge this represents the fourth case of melanotic miliary brain metastases described in the literature, also associated with melanin content of the lesions that is already evident on unenhanced T1-weighted images.Case presentationA 75-year-old patient with history of metastatic cutaneous melanoma (BRAF V600E mutate, PD-L1 negative) in treatment with dabrafenib and trametinib after 9 years from the diagnosis developed severe cognitive-motor slowing. Contrast-enhanced brain MRI showed miliary enhancing intra-axial brain lesions involving supra- and sub-tentorial regions and also the perivascular spaces, characterized by a bright appearance on unenhanced T1-weighted images without signal hypointensity in T2*-weighted images, as for melanotic pattern. Thus, the radiological diagnosis of “carcinomatous encephalitis” was made. Neurological examination showed an alert and cooperative subject with increased reaction time in verbal and motor responses. No ocular motility disturbances were found, and there were no motor or sensory deficits in the four limbs. The finger-to-nose test was normal, and no coordination deficit was found bilaterally. Blood tests and body temperature demonstrated no signs of ongoing infection. Electroencephalography showed slow and punctate abnormalities in bilateral fronto-temporal regions, with left prevalence. Corticosteroid therapy was started during hospitalization, improving the clinical picture. The patient was then discharged after 4 days in good clinical conditions with the indication to start second-line treatment with ipilimumab and nivolumab and to perform a whole-brain irradiation.ConclusionsBrain MRI plays a crucial role for the non-invasive diagnosis of carcinomatous encephalitis and for the differential diagnosis with other pathologies. Awareness of the existence of this disorder even in patients with melanoma is necessary to avoid diagnostic delays. Miliary brain metastases should be suspected in all melanoma patients with new neurological findings and contrast-enhanced MRI should be performed to assess the real burden of the disease.

Restricted language access during childhood affects adult brain structure in selective language regions

Due to the ubiquitous nature of language in the environment of infants, how it affects the anatomical structure of the brain language system over the lifespan is not well understood. In this study, we investigated the effects of early language experience on the adult brain by examining anatomical features of individuals born deaf with typical or restricted language experience in early childhood. Twenty-two deaf adults whose primary language was American Sign Language and were first immersed in it at ages ranging from birth to 14 y participated. The control group was 21 hearing non-signers. We acquired T1-weighted magnetic resonanceimages and used FreeSurfer [B. Fischl,Neuroimage 62, 774-781(2012)]to reconstruct the brain surface. Using an a priori regions of interest (ROI) approach, we identified 17 language and 19 somatomotor ROIs in each hemisphere from the Human Connectome Project parcellation map [M. F. Glasseretal.,Nature 536, 171-178 (2016)]. Restricted language experience in early childhood was associated with negative changes in adjusted grey matter volume and/or cortical thickness in bilateral fronto-temporal regions. No evidence of anatomical differences was observed in any of these regions when deaf signers with infant sign language experience were compared with hearing speakers with infant spoken language experience, showing that the effects of early language experience on the brain language system are supramodal.

Cerebral amyloid accumulation–related rapid mental deterioration presented with status epilepticus

AbstractBackgroundAmyloids are characterized by a fibrillar β‐sheet secondary structure. Cerebral accumulation of β‐amyloid peptide is proposed to be one of the toxic pathogeneses of dementia, most commonly seen in Alzheimer’s disease (AD) and cerebral amyloid angiopathy (CAA). Here we reported patients who presented with status epilepticus and rapid mental deterioration. Their amyloid PET imaging displayed diffuse deposition.MethodWe retrospectively reviewed clinical presentation, EEGs, and brain MRI from a patient group with an amyloid‐PET imaging study.ResultFour patients were admitted to the hospital with status epilepticus. Case 1, a 75‐year‐old woman, suffered an impairment of consciousness with focal jerks. Epileptic discharging from bilateral frontotemporal regions continued for days after jerking controlled. Noticeable decline in remembering and problem solving developed rapidly within two months. Case 2, a 79‐year‐old woman, had mild cognitive impairment before administered anti‐seizure medications for right leg weakness after repeated focal seizures. After that, she had a more severe decline of dementia. Case 3, an 81‐year‐old woman, got an unimprovable left hemiparesis for two weeks of a continuing left‐sided jerk. She had rapidly increasing forgetfulness. Case 4, a 61‐year‐old man, was treated as super‐refractory status epilepticus for periodical choreic movement and dystonic jerks. Medications suppressed generalized periodic epileptiform discharges temporally. After one month, the epileptic discharging turned to periodic sharp wave complexes. He expired one month later. MRIs of Case 1 and 3 showed cortical atrophy. On case 2’s MRI, corticosubcortical microhemorrahge was revealed. Case 4’s diffusion‐weighted MRI showed diffuse cortical ribbon. The amyloid PETs of Case 1, 2, and 3 demonstrated diffuse deposition with focal cortical maximum spatially responsible for generating focal ictal discharges. The nuclear imaging on Case 4 showed maximal amyloid deposition on basal ganglia.ConclusionHere we reported four patients with refractory status epilepticus before dementia. Two cases were diagnosed with AD. One patient was categorized into CAA. In Case 4, according to positive CSF‐14‐3‐3, MRI cortical ribboning, EEG features, and clinical course, probable Creutzfeldt‐Jakob disease was impressed. Amyloid deposition may contribute to the increase of cortical susceptibility to seizures. Moreover, medically refractory status epilepticus hastens mental deterioration.

Abstract 1122‐000171: Unusual Multicompartmental Intracranial Hemorrhage After Tenecteplase Administration

Introduction : The 2019 AHA/ASA updated Guidelines for the Early Management of Patients with Acute Ischemic Stroke mention tenecteplase (TNK) as a reasonable therapy in patients without contraindications for IV fibrinolysis who are also eligible to undergo mechanical thrombectomy. We describe a case of acute left MCA ischemic stroke treated with IV TNK (IV bolus of 0.25 mg/kg) followed by mechanical thrombectomy with subsequent multicompartmental intracranial hemorrhages unrelated to area of infraction. Methods : A retrospective review at a single center university hospital was performed for all intravenous TNK administrations outside of a clinical trial setting from October 2020 to July 2021. Results : A 61‐year‐old male with history of HTN and cardiomyopathy (EF<20%). Presented with sudden onset right sided weakness, aphasia and left gaze. Presenting NIHSS was 28. CT head with hyperdense left MCA sign and ASPECTS score of 10. CTA confirmed proximal left MCA M1 segment occlusion. IV TNK was given within 01:23 hours of symptoms onset. Subsequently, patient underwent emergent mechanical thrombectomy for disabling large vessel occlusion stroke. Spontaneous near complete recanalization of left MCA occlusion was noted on initial angiography run with small non flow limiting distal thrombi visualized in the distal MCA territories. Immediate post procedure CT head was negative for any intracranial hemorrhage. Patient’s exam was noted to improve to NIHSS of 2. Approximately 6 hours after the TNK administration, patient became acutely unresponsive with NIHSS of 26. With Glasgow Coma Scale 7 patient required emergent intubation. CT head revealed bilateral cerebellar intraparenchymal hemorrhages, extensive subarachnoid hemorrhage in basal cisterns and within the sulci in bilateral frontotemporal regions, as well as subdural hemorrhages along the falx and tentorial dural folds. Hypertonic saline was administered followed by emergent extraventricular drain placement. Tranexamic acid 1000 mg was given as emergent reversal, fibrinogen level was 155 mg/dL. Despite aggressive medical management and over following 24 hours, exam worsened with loss of pupillary reflexes. Patient was terminally extubated 2 days after initial presentation in accordance with his advance directives. Conclusions : Tenecteplase was a reasonable choice in this case given LVO and disabling stroke. The patient’s neurological exam improved significantly after TNK with evidence of spontaneous recanalization. However, patient’s multicompartmental intracranial hemorrhages unrelated to area of infraction were unusual in the absence of any vascular lesions to predispose hemorrhage based on CT and conventional angiography. Further observational studies are warranted to evaluate similar complications of Tenecteplase administration and their occurrence rates.

A multiparametric MRI study of structural brain damage in dementia with lewy bodies: A comparison with Alzheimer's disease

IntroductionDifferential diagnosis between dementia with Lewy bodies (DLB) and Alzheimer's disease (AD) is crucial for an adequate patients' management but might be challenging. We investigated with advanced MRI techniques gray (GM) and white matter (WM) damage in DLB patients compared to those with AD. Methods24 DLB patients, 26 age- and disease severity-matched AD patients, and 20 age and sex-matched controls performed clinical and neuropsychological assessment, and brain structural and diffusion-tensor MRI. We measured GM atrophy using voxel-based morphometry, WM hyperintensities (WMH) using a local thresholding segmentation technique, and normal-appearing WM (NAWM) damage using tract-based spatial statistic. ResultsDLB and AD patients exhibited mild-to-moderate-stage dementia. Compared to controls, GM damage was diffuse in AD, while limited to bilateral thalamus and temporal regions in DLB. Compared to DLB, AD patients exhibited GM atrophy in bilateral fronto-temporal and occipital regions. DLB and AD patients showed higher WMH load than controls, with no differences among each other. WMH in DLB were diffuse with relative prevalence in posterior parietal-occipital regions. Compared to controls, both DLB and AD patients showed reduced microstructural integrity of the main supratentorial and infratentorial NAWM tracts. AD patients exhibited greater posterior NAWM damage than DLB. ConclusionsDLB showed prominent WM degeneration compared to the limited GM atrophy, while in AD both tissue compartments were severely involved. In DLB, NAWM microstructural degeneration was independent of WMH, thus revealing two possible underlying processes. Different pathophysiological mechanisms are likely to drive GM and WM damage distribution in DLB and AD.

Deep Neural Network to Differentiate Brain Activity Between Patients With First-Episode Schizophrenia and Healthy Individuals: A Multi-Channel Near Infrared Spectroscopy Study

Backgrounds: Reduced brain cortical activity over the frontotemporal regions measured by near infrared spectroscopy (NIRS) has been reported in patients with first-episode schizophrenia (FES). This study aimed to differentiate between patients with FES and healthy controls (HCs) on basis of the frontotemporal activity measured by NIRS with a support vector machine (SVM) and deep neural network (DNN) classifier. In addition, we compared the accuracy of performance of SVM and DNN.Methods: In total, 33 FES patients and 34 HCs were recruited. Their brain cortical activities were measured using NIRS while performing letter and category versions of verbal fluency tests (VFTs). The integral and centroid values of brain cortical activity in the bilateral frontotemporal regions during the VFTs were selected as features in SVM and DNN classifier.Results: Compared to HCs, FES patients displayed reduced brain cortical activity over the bilateral frontotemporal regions during both types of VFTs. Regarding the classifier performance, SVM reached an accuracy of 68.6%, sensitivity of 70.1%, and specificity of 64.6%, while DNN reached an accuracy of 79.7%, sensitivity of 88.8%, and specificity of 74.9% in the classification of FES patients and HCs.Conclusions: Compared to findings of previous structural neuroimaging studies, we found that using DNN to measure the NIRS signals during the VFTs to differentiate between FES patients and HCs could achieve a higher accuracy, indicating that NIRS can be used as a potential marker to classify FES patients from HCs. Future additional independent datasets are needed to confirm the validity of our model.

Voltage‐gated potassium channel complex (VGKC) antibody encephalitis in a Filipino adult: A reversible cause of early‐onset neurocognitive disorder

AbstractBackgroundVoltage‐gated potassium channels (VGKCs) are cell‐surface proteins with several functions in the central nervous system. VGKC antibody encephalitis is caused by antibodies against the cell‐surface antigens that are part of the VGKC complex, which are highly concentrated in the limbic lobes and the hippocampus.Case PresentationWe report a case of a 46‐year‐old Filipino female who presented with subacute onset of memory loss, behavioral changes, and focal motor seizures. On cranial magnetic resonance imaging, there were increased signal intensities on both medial temporal lobes but no intracranial tumor, restricted diffusion, or meningeal enhancement. Electroencephalography showed focal slowing on bilateral frontotemporal regions and blood test revealed hyponatremia. Cerebrospinal fluid analysis revealed high titers for antibodies against VGKC complex. Pulse intravenous steroid therapy was administered and oral steroids and azathioprine were continued as outpatient. The patient showed significant response with marked improvement of memory without any recurrence of seizure episodes.ConclusionThis case highlights VGKC antibody encephalitis as an important diagnostic consideration in patients presenting with subacute onset of memory loss, behavioral changes, and seizures. With prompt initiation of immunosuppressive therapy, neurocognitive changes can be potentially reversed.

HIV-associated neurocognitive disorder and HIV-associated myelopathy in a patient with a preserved CD4, but high viral load-a rarely reported phenomenon: a case report and literature review

BackgroundDespite widespread use of combination antiretroviral therapy (cART), HIV-associated neurocognitive disorder (HAND) and HIV-associated myelopathy (HAM) are not showing significant reduction in there occurrence. The HAM is a progressive myelopathy that often occur synchronously with severe form of the HAND in patients’ having advanced immunosuppression. However, co-existence of less severe form of the HAND and HAM in patient with relatively preserved CD4 cells is rarely reported clinical entity in post cART era.Case presentationWe report a 16-year old male, acquired HIV infection vertically, was on second line regimen because of virological failure since 3 years. His current CD4 lymphocyte count is 835 cells/uL with viral RNA level of 33,008 copies/mL. Currently presented with progressive forgetfulness, gait imbalance, and a frequent staring episodes without loss of postural tone. Neurological examination was pertinent for cognitive dysfunction with score of 6 on International HIV Dementia Scale (motor speed = 3, psychomotor speed = 2, and memory recall = 1). Lower limbs power is 4−/5, increased deep tendon reflexes, and unsteady gait. Brain MRI revealed diffuse both cortical and white matter T2 and FLAIR hyperintense lesions. Thoracic MRI showed abnormal T2 signal prolongation spanning from mid thoracic cord to conus. Electroencephalography study showed severe generalized slowing with evidence of focal dysrhythmia in bilateral frontotemporal regions. Unremarkable serum vitamin B 12 level (286 ng/mL). Virological failure with the HAND, HAM and seizure was considered. Dolutegravir +3TC + ATV/r regimen and valproate for seizure disorder was started. On 6 months follow up evaluation, he is clinically stable with significant improvement of his symptoms related to seizure disorders and modest improvement of his cognitive dysfunction, as he is now attending his school regularly. However, less improvement was observed reading his gait abnormality.ConclusionThis case supports the current understanding regarding the persistent occurrence of HIV-associated neurocognitive disorder and HIV-associated myelopathy even decades after introduction of cART. Therefore, it’s important to screen HIV+ patients for the HAND and HAM even if they have relatively preserved immunity. Because patient can be easily shifted to ART drugs with better CNS penetrating potential to achieve acceptable virological suppression level, to observe sound clinical improvement.

The Neural Time Course of Semantic Ambiguity Resolution in Speech Comprehension.

Semantically ambiguous words challenge speech comprehension, particularly when listeners must select a less frequent (subordinate) meaning at disambiguation. Using combined magnetoencephalography (MEG) and EEG, we measured neural responses associated with distinct cognitive operations during semantic ambiguity resolution in spoken sentences: (i) initial activation and selection of meanings in response to an ambiguous word and (ii) sentence reinterpretation in response to subsequent disambiguation to a subordinate meaning. Ambiguous words elicited an increased neural response approximately 400-800 msec after their acoustic offset compared with unambiguous control words in left frontotemporal MEG sensors, corresponding to sources in bilateral frontotemporal brain regions. This response may reflect increased demands on processes by which multiple alternative meanings are activated and maintained until later selection. Disambiguating words heard after an ambiguous word were associated with marginally increased neural activity over bilateral temporal MEG sensors and a central cluster of EEG electrodes, which localized to similar bilateral frontal and left temporal regions. This later neural response may reflect effortful semantic integration or elicitation of prediction errors that guide reinterpretation of previously selected word meanings. Across participants, the amplitude of the ambiguity response showed a marginal positive correlation with comprehension scores, suggesting that sentence comprehension benefits from additional processing around the time of an ambiguous word. Better comprehenders may have increased availability of subordinate meanings, perhaps due to higher quality lexical representations and reflected in a positive correlation between vocabulary size and comprehension success.

Domain-general and domain-specific computations in single word processing

Language comprehension relies on a multitude of domain-general and domain-specific cognitive operations. This study asks whether the domain-specific grammatical computations are obligatorily invoked whenever we process linguistic inputs. Using fMRI and three complementary measures of neural activity, we tested how domain-general and domain-specific demands of single word comprehension engage cortical language networks, and whether the left frontotemporal network (commonly taken to support domain-specific grammatical computations) automatically processes grammatical information present in inflectionally complex words. In a natural listening task, participants were presented with words that manipulated domain-general and domain-specific processing demands in a 2 × 2 manner. The results showed that only domain-general demands of mapping words onto their representations consistently engaged the language processing system during single word comprehension, triggering increased activity and connectivity in bilateral frontotemporal regions, as well as bilateral encoding across multivoxel activity patterns. In contrast, inflectional complexity failed to activate left frontotemporal regions in this task, implying that domain-specific grammatical processing in the left hemisphere is not automatically triggered when the processing context does not specifically require such analysis. This suggests that cortical computations invoked by language processing critically depend on the current communicative goals and demands, underlining the importance of domain-general processes in language comprehension, and arguing against the strong domain-specific view of the LH network function.

Community violence exposure in early adolescence: Longitudinal associations with hippocampal and amygdala volume and resting state connectivity.

Community violence exposure is a common stressor, known to compromise youth cognitive and emotional development. In a diverse, urban sample of 22 adolescents, participants reported on community violence exposure (witnessing a beating or illegal drug use, hearing gun shots, or other forms of community violence) in early adolescence (average age 12.99), and underwent a neuroimaging scan 3-5 years later (average age 16.92). Community violence exposure in early adolescence predicted smaller manually traced left and right hippocampal and amygdala volumes in a model controlling for age, gender, and concurrent community violence exposure, measured in late adolescence. Community violence continued to predict hippocampus (but not amygdala) volumes after we also controlled for family aggression exposure in early adolescence. Community violence exposure was also associated with stronger resting state connectivity between the right hippocampus (using the manually traced structure as a seed region) and bilateral frontotemporal regions including the superior temporal gyrus and insula. These resting state connectivity results held after controlling for concurrent community violence exposure, SES, and family aggression. Although this is the first study focusing on community violence in conjunction with brain structure and function, these results dovetail with other research linking childhood adversity with smaller subcortical volumes in adolescence and adulthood, and with altered frontolimbic resting state connectivity. Our findings suggest that even community-level exposure to neighborhood violence can have detectable neural correlates in adolescents.

Hypofunction of left dorsolateral prefrontal cortex in depression during verbal fluency task: A multi-channel near-infrared spectroscopy study

BackgroundPrevious functional neuroimaging studies of depression have demonstrated frontotemporal dysfunction, including the dorsolateral prefrontal cortex, while patients perform working memory and language comprehension tasks. Recent near-infrared spectroscopy (NIRS) studies have shown frontotemporal hypofunction in depression by verbal fluency task, but the regions of impairment affecting respective depressive symptoms still remain unclear. We investigated frontotemporal function during word production task in depression with multi-channel NIRS. Further, we aimed to clarify whether any depressive symptoms affect frontotemporal dysfunction. MethodsOne hundred seventy-seven major depressive patients and 50 healthy control volunteers participated in this study. Their cerebral activations were compared during verbal fluency task. ResultsAlthough performance was not significantly different, hypoactivation in the bilateral frontotemporal regions was significantly observed in depressed patients, compared with controls. Left lateral frontotemporal activation was significantly reduced in the group with mandatory symptom, which is depressed mood, or loss of interest or pleasure, compared with the group that still has residual depressive symptoms in spite MDD having been remitted. Limitationthe MDD group had significantly higher age and education level than the controls. ConclusionsOur findings indicate hypofunction of the bilateral frontotemporal regions in depression during verbal fluency task. Further, hypofunction of these regions in the left hemisphere by this task could reflect whether the subjects recovered from depressed mood, or loss of interest or pleasure.

Differential Effects of the Factor Structure of the Wechsler Memory Scale-Revised on the Cortical Thickness and Complexity of Patients Aged Over 75 Years in a Memory Clinic Setting.

The Wechsler Memory Scale-Revised (WMS-R) is one of the internationally well-known batteries for memory assessment in a general memory clinic setting. Several factor structures of the WMS-R for patients aged under 74 have been proposed. However, little is known about the factor structure of the WMS-R for patients aged over 75 years and its neurological significance. Thus, we conducted exploratory factor analysis to determine the factor structure of the WMS-R for patients aged over 75 years in a memory clinic setting. Regional cerebral blood flow (rCBF) was calculated from single-photon emission computed tomography data. Cortical thickness and cortical fractal dimension, as the marker of cortical complexity, were calculated from high resolution magnetic resonance imaging data. We found that the four factors appeared to be the most appropriate solution to the model, including recognition memory, paired associate memory, visual-and-working memory, and attention as factors. Patients with mild cognitive impairments showed significantly higher factor scores for paired associate memory, visual-and-working memory, and attention than patients with Alzheimer's disease. Regarding the neuroimaging data, the factor scores for paired associate memory positively correlated with rCBF in the left pericallosal and hippocampal regions. Moreover, the factor score for paired associate memory showed most robust correlations with the cortical thickness in the limbic system, whereas the factor score for attention correlated with the cortical thickness in the bilateral precuneus. Furthermore, each factor score correlated with the cortical fractal dimension in the bilateral frontotemporal regions. Interestingly, the factor scores for the visual-and-working memory and attention selectively correlated with the cortical fractal dimension in the right posterior cingulate cortex and right precuneus cortex, respectively. These findings demonstrate that recognition memory, paired associate memory, visual-and-working memory, and attention can be crucial factors for interpreting the WMS-R results of elderly patients aged over 75 years in a memory clinic setting. Considering these findings, the results of WMS-R in elderly patients aged over 75 years in a memory clinic setting should be cautiously interpreted.

Reduced left precentral regional responses in patients with major depressive disorder and history of suicide attempts

Previous neuroimaging studies have revealed frontal and temporal functional abnormalities in patients with major depressive disorder (MDD) and a history of suicidal behavior. However, it is unknown whether multi-channel near-infrared spectroscopy (NIRS) signal changes among individuals with MDD are associated with a history of suicide attempts and a diathesis for suicidal behavior (impulsivity, hopelessness, and aggression). Therefore, we aimed to explore frontotemporal hemodynamic responses in depressed patients with a history of suicide attempts using 52-channel NIRS. We recruited 30 patients with MDD and a history of suicidal behavior (suicide attempters; SAs), 38 patient controls without suicidal behavior (non-attempters; NAs), and 40 healthy controls (HCs) matched by age, gender ratio, and estimated IQ. Regional hemodynamic responses during a verbal fluency task (VFT) were monitored using NIRS. Our results showed that severities of depression, impulsivity, aggression, and hopelessness were similar between SAs and NAs. Both patient groups had significantly reduced activation compared with HCs in the bilateral frontotemporal regions. Post hoc analyses revealed that SAs exhibited a smaller hemodynamic response in the left precentral gyrus than NAs and HCs. Furthermore, the reduced response in the left inferior frontal gyrus was negatively correlated with impulsivity level and hemodynamic responses in the right middle frontal gyrus were negatively associated with hopelessness and aggression in SAs but not in NAs and HCs. Our findings suggest that MDD patients with a history of suicide attempts demonstrate patterns of VFT-induced NIRS signal changes different from those demonstrated by individuals without a history of suicidal behaviors, even in cases where clinical symptoms are similar. NIRS has a relatively high time resolution, which may help visually differentiate SAs from NAs.

Perceived Occupational Stress is associated with Decreased Cortical Activity of the Prefrontal Cortex: A Multichannel Near-infrared Spectroscopy Study.

Despite an increasing number of reports on the associations between chronic occupational stress and structural and functional changes of the brain, the underlying neural correlates of perceived occupational stress is still not clear. Perceived stress reflects the extents to which situations are appraised as stressful at a given point in one’s life. Using near-infrared spectroscopy, we investigated the associations between perceived occupational stress and cortical activity over the bilateral frontotemporal regions during a verbal fluency test. Sixty-eight participants (17 men, 51 women), 20–62 years of age were recruited. Perceived occupational stress was measured using the Chinese version of Job Content Questionnaire, and the Chinese version of the Copenhagen Burnout Inventory. We found statistically significant negative associations between occupational burnout and brain cortical activity over the fronto-polar and dorsolateral prefrontal cortex during the VFT (r = −0.343 to −0.464). In conclusion, our research demonstrated a possible neural basis of perceived occupational stress that are distributed across the prefrontal cortex.

Duration of Untreated Psychosis and Brain Function during Verbal Fluency Testing in First-Episode Schizophrenia: A Near-Infrared Spectroscopy Study.

A longer duration of untreated psychosis (DUP) has been associated with poor clinical outcomes in patients with schizophrenia (SZ); however, it remains unclear whether this is due to neurotoxic effects of psychosis. The purpose of this study was to use near-infrared spectroscopy (NIRS) to investigate the influence of DUP on brain function using two verbal fluency tests (VFTs) in patients with first-episode SZ (FES). A total of 28 FES patients and 29 healthy controls (HC) underwent NIRS during VFTs. Group comparisons of cortical activity were made using two-tailed t-tests and the false discovery rate method. We then examined the associations between DUP and hemodynamic changes in each channel to identify any effects of DUP on brain cortical activity. During the letter VFT, the HC group exhibited significantly greater cortical activations over bilateral frontotemporal regions compared to FES patients. However, this distinction was not observed while performing a category version of the VFT. In addition, no associations between DUP and brain cortical activity were observed in the FES group during either VFT. In conclusion, we did not find an association between DUP and frontotemporal cortical activities. This might be because neurodevelopmental disturbances result in neurocognitive deficits long before psychotic symptoms onset.

Decreased Cerebral Blood Flow in Chronic Pediatric Mild TBI: An MRI Perfusion Study

We evaluated cerebral blood flow (CBF) in chronic pediatric mild traumatic brain injury (mTBI) using arterial spin labeling (ASL) magnetic resonance imaging perfusion. mTBI patients showed lower CBF than controls in bilateral frontotemporal regions, with no between-group cognitive differences. Findings suggest ASL may be useful to assess functional abnormalities in pediatric mTBI.

Language-specific cortical activation patterns for verbal fluency tasks in Japanese as assessed by multichannel functional near-infrared spectroscopy

In Japan, verbal fluency tasks are commonly utilized as a standard paradigm for neuropsychological testing of cognitive and linguistic abilities. The Japanese “letter fluency task” is a mora/letter fluency task based on the phonological and orthographical characteristics of the Japanese language. Whether there are similar activation patterns across languages or a Japanese-specific mora/letter fluency pattern is not certain. We investigated the neural correlates of overt mora/letter and category fluency tasks in healthy Japanese. The category fluency task activated the bilateral fronto-temporal language-related regions with left-superior lateralization, while the mora/letter fluency task led to wider activation including the inferior parietal regions (left and right supramarginal gyrus). Specific bilateral supramarginal activation during the mora/letter fluency task in Japanese was distinct from that of similar letter fluency tasks in syllable-alphabet-based languages: this might be due to the requirement of additional phonological processing and working memory, or due to increased cognitive load in general.

Decreased Right Temporal Activation and Increased Interhemispheric Connectivity in Response to Speech in Preterm Infants at Term-Equivalent Age

Preterm infants are at increased risk of language-related problems later in life; however, few studies have examined the effects of preterm birth on cerebral responses to speech at very early developmental stages. This study examined cerebral activation and functional connectivity in response to infant-directed speech (IDS) and adult-directed speech (ADS) in full-term neonates and preterm infants at term-equivalent age using 94-channel near-infrared spectroscopy. The results showed that compared with ADS, IDS increased activity in larger brain areas such as the bilateral frontotemporal, temporal, and temporoparietal regions, both in full-term and preterm infants. Preterm infants exhibited decreased activity in response to speech stimuli in the right temporal region compared with full-term infants, although the significance was low. Moreover, preterm infants exhibited increased interhemispheric connectivity compared with full-term controls, especially in the temporal and temporoparietal regions. These differences suggest that preterm infants may follow different developmental trajectories from those born at term owing to differences in intrauterine and extrauterine development.

Functional neuroimages of cortical myoclonus altered by levetiracetam in a patient with sialidosis

Levetiracetam can suppress sialidosis-related myoclonus but its effects on cerebral metabolism warrant elucidation. In this report, fluorodeoxyglucose-positron emission tomography was conducted before and after levetiracetam in a sialidosis patient. By subtracting the drug “off” from “on” signals, regions of enhanced metabolism were shown to be allocated mostly in the bilateral fronto-temporal regions whereas regions of reduced metabolism were distributed mainly in the occipital areas. Imaging changes suggest that the effects of levetiracetam may be different in different brain regions. The drug may also elicit fronto-temporal inhibitory impulses to suppress the vigorous myoclonus in sialidosis.