Inferior Temporal Lobe Research Articles

Nε-(carboxymethyl)-lysine, White Matter, and Cognitive Function in Diabetes Patients.

To study the relationship of Nε-(carboxymethyl)-lysine level (CML) with microstructure changes of white matter (WM), and cognitive impairment in patients with type 2 diabetes mellitus (T2DM) and to discuss the potential mechanism underlying T2DM-associated cognitive impairment. The study was performed in T2DM patients (n=22) with disease course ≥5 years and age ranging from 65 to 75 years old. A control group consisted of 25 sex- and age-matched healthy volunteers. Fractional anisotropy (FA) of several WM regions was analyzed by diffusion tensor imaging scan. Plasma CML levels were measured by enzyme-linked immunosorbent assay, and cognitive function was assessed by Mini-Mental State Examination and Montreal cognitive assessment (MoCA). The total Mini-Mental State Examination score in the patient group (25.72±3.13) was significantly lower than the control group (28.16±2.45) (p<0.05). In addition, the total MoCA score in the patient group (22.15±3.56) was significantly lower than the control group 25.63±4.12) (p<0.01). In the patient group, FA values were significantly decreased in the corpus callosum, cingulate fasciculus, inferior fronto-occipital fasciculus, parietal WM, hippocampus, and temporal lobes relative to corresponding regions of healthy controls (p<0.05). Plasma CML level was negatively correlated with average FA values in the global brain (r=-0.58, p<0.01) and MoCA scores (r=-0.47, p<0.05). In T2DM, WM microstructure changes occur in older patients, and elevations in CML may play a role in the development of cognitive impairment.

Mild Perceptual Categorization Deficits Follow Bilateral Removal of Anterior Inferior Temporal Cortex in Rhesus Monkeys.

The process of seeing and recognizing objects is attributed to a set of sequentially connected brain regions stretching forward from the primary visual cortex through the temporal lobe to the anterior inferior temporal cortex, a region designated area TE. Area TE is considered the final stage for recognizing complex visual objects, e.g., faces. It has been assumed, but not tested directly, that this area would be critical for visual generalization, i.e., the ability to place objects such as cats and dogs into their correct categories. Here, we demonstrate that monkeys rapidly and seemingly effortlessly categorize large sets of complex images (cats vs dogs, cars vs trucks), surprisingly, even after removal of area TE, leaving a puzzle about how this generalization is done.

Intracranial subdural empyema after surgery for lumbar lipomyelomeningocele: A rare complication

Background:Surgery is routinely recommended for lumbar lipomyelomeningocele, especially in the setting of tethered cord syndrome. The most common complications are wound infections and cerebrospinal fluid (CSF) leak, which remain confined to the surgical site. To the best of our knowledge, there have been no prior reports relating an intracranial subdural empyema following detethering surgery. Prompt diagnosis is essential since subdural empyema is a neurosurgical emergency.Case Description:The patient was an 11-month-old male who underwent detethering surgery for a lumbar lipomyelomeningocele. This was followed by wound drainage consistent with CSF leak, requiring revision. Cultures grew three aerobes (Escherichia coli, Enterococcus, and Klebsiella) and three anaerobes (Clostridium, Veillonella, and Bacteroides). He was started on cefepime, vancomycin, and flagyl. The patient required two more wound revisions and placement of an external ventricular drain (EVD) secondary to persistent wound leakage. A subsequent magnetic resonance imaging (MRI) brain was carried out due to protracted irritability, which revealed extensive left subdural empyema along the parietooccipital region and the inferior and anterior temporal lobe. He underwent evacuation of the subdural empyema where cultures exhibited no growth. Subsequently, he progressed well. His lumbar incision continued to heal. Serial MRI brains and inflammatory markers were reassuring. He weaned off his EVD and went home to complete a 6-week course of antibiotics. Upon completion of his antibiotics, he returned for a clinic visit; he exhibited no interim fevers or wound issues; cranial imaging documented no evidence of a residual or recurrent subdural empyema.Conclusion:Intracranial subdural empyema may occur after wound complications from detethering surgery despite early initiation of broad-spectrum antibiotics. Possible etiology may be local wound infection that seeds the subdural space and travels to the cranium, leading to meningitis and subdural empyema. Such a scenario should prompt surveillance imaging of the head as undiagnosed subdural empyema may lead to devastating consequences.

Meeting physical activity recommendations may be protective against temporal lobe atrophy in older adults at risk for Alzheimer's disease

IntroductionPhysical activity (PA) is associated with brain health in older adults. However, it is unknown whether the current physical activity recommendations (PAR) impart substantive benefit. The objective of this study was to compare temporal lobe volumes between older adults who met PAR and those who did not. MethodsNinety-one enrollees from the Wisconsin Registry for Alzheimer's Prevention wore an accelerometer for seven consecutive days to quantify their PA behaviors and underwent a T-1 anatomic magnetic resonance imaging scan. Participants were categorized as either having met PAR or not based on the US Department of Health and Human Services recommendations of 150 minutes of moderate-to-vigorous physical activity per week. ResultsParticipants who met PAR possessed significantly greater inferior (η2P = .050) and anterior (η2P = .055) temporal lobe volumes compared with those who did not (P < .05). DiscussionIndividuals at-risk for AD experience accelerated rates of brain atrophy. These results suggest that regular engagement in PA at or above PAR could attenuate this decline.

Alterations in levels and ratios of n–3 and n–6 polyunsaturated fatty acids in the temporal cortex and liver of vervet monkeys from birth to early adulthood

Deficiencies in omega-3 (n–3) long chain polyunsaturated fatty acids (LC-PUFAs) and increases in the ratio of omega-6 (n–6) to n–3 LC-PUFAs in brain tissues and blood components have been associated with psychiatric and developmental disorders. Most studies have focused on n–3 LC-PUFA accumulation in the brain from birth until 2years of age, well before the symptomatic onset of such disorders. The current study addresses changes that occur in childhood and adolescence. Postmortem brain (cortical gray matter, inferior temporal lobe; n=50) and liver (n=60) from vervet monkeys fed a uniform diet from birth through young adulthood were collected from archived tissues. Lipids were extracted and fatty acid levels determined. There was a marked reduction in the ratio of n–6 LC-PUFAs, arachidonic acid (ARA) and adrenic acid (ADR), relative to the n–3 LC-PUFA, docosahexaenoic acid (DHA), in temporal cortex lipids from birth to puberty and then a more gradual decrease though adulthood. This decrease in ratio resulted from a 3-fold accumulation of DHA levels while concentrations of ARA remained constant. Early childhood through adolescence appears to be a critical period for DHA accretion in the cortex of vervet monkeys and may represent a vulnerable stage where lack of dietary n–3 LC-PUFAs impacts development in humans.

Changes in Painting Style by Poststroke Mania.

Changes in Painting Style by Poststroke Mania.

Similarly Expanded Bilateral Temporal Lobe Volumes in Female and Male Children With Autism Spectrum Disorder

BackgroundAutism spectrum disorder (ASD) is more prevalent in male than female individuals. Very few studies have examined sex modulations of brain anatomical differences between individuals with ASD and typically developing (TD) individuals, especially in children. The current study aimed to identify sex-dependent and/or sex-independent neuroanatomical mechanisms underlying ASD. MethodsMagnetic resonance imaging data were acquired from the Autism Brain Imaging Data Exchange. A 2 (diagnosis) × 2 (sex) design was used. Subjects whose ages were between 6 and 20 years were included for analysis, with matched full-scale IQ between groups for each dataset. The resulting effective numbers of subjects were 36 female subjects with ASD, 54 TD female subjects, 182 male subjects with ASD, and 172 TD male subjects. Twenty independent gray matter (GM) and 20 white matter (WM) volume sources were estimated using source-based morphometry. ResultsAmong all the independent GM and WM sources, none of them showed a significant diagnosis by sex interaction. One GM source of the bilateral inferior and middle temporal lobe showed a significantly larger volume in ASD than TD individuals and in male than in female subjects. This diagnosis effect was age sensitive and was present only in participants between 8 and 14 years of age. ConclusionsOnly sex-independent, large-scale neuroanatomical alterations could be observed in children with ASD. The directionality of bilateral temporal GM alterations was in line with the prediction of the extreme male brain hypothesis, supporting the view that similar neurobiological mechanisms may drive sexual dimorphism and the onset of ASD.

Beta-Band Oscillations Represent Auditory Beat and Its Metrical Hierarchy in Perception and Imagery.

With magnetoencephalography, we examined β-band oscillatory activities around 20 Hz while participants listened to metronome beats and imagined musical meters such as a march and waltz. We demonstrated that β-band event-related desynchronization in the auditory cortex differentiates between beat positions, specifically between downbeats and the following beat. This is the first demonstration of β-band oscillations related to hierarchical and internalized timing information. Moreover, the meter representation in the β oscillations was widespread across the brain, including sensorimotor and premotor cortices, parietal lobe, and cerebellum. The results extend current understanding of the role of β oscillations in neural processing of predictive timing.

Regional white matter development in very preterm infants: perinatal predictors and early developmental outcomes.

BackgroundPreterm infants are at risk for white matter injury and adverse neurodevelopmental outcomes.MethodsSerial diffusion tensor MRI data were obtained from very preterm infants (N=78) born <30 weeks gestation imaged up to four times from 26-42 weeks postmenstrual age. Slopes were calculated for fractional anisotropy (FA) and mean diffusivity (MD) within regions of interest for infants with ≥2 scans (N=50). Sixty-five children underwent neurodevelopmental testing at age two years.ResultsFA slope for the posterior limb of the internal capsule was greater than other regions. The anterior limb of the internal capsule (ALIC), corpus callosum and optic radiations demonstrated greater FA slope with increasing gestational age. Infants with PDA had lower FA slope in the ALIC. MD slope was lower with prolonged ventilation or lack of antenatal steroids. At age 2 years, lower motor scores were associated with lower FA in the left but higher FA in the right inferior temporal lobe at term-equivalent. Better social-emotional competence was related to lower FA in the left cingulum bundle.ConclusionThis study demonstrates regional variability in the susceptibility/sensitivity of white matter maturation to perinatal factors and relationships between altered diffusion measures and developmental outcomes in preterm neonates.

Trial-level information for individual faces in the fusiform face area depends on subsequent memory

Previous research has shown that face-sensitive brain regions, such as the fusiform face area (FFA) and anterior inferior temporal lobe (aIT), not only respond selectively to face stimuli, but also respond uniquely to individual faces. A common factor in the existing literature is that face stimuli in these experiments are highly familiar to participants, usually by design. We set out to investigate to what extent familiarity correlates with the emergence of face-specific information in face-sensitive regions by testing novel faces with only a single repetition. Our results, consistent with a familiarity hypothesis, demonstrate that the FFA and aIT show face-specific information only when participants demonstrate subsequent memory for those faces. Functionally-defined regions that are not believed to process faces holistically showed no face-specific information, regardless of subsequent memory. To our knowledge, this is the first demonstration of face-specific information in face-sensitive regions for stimuli that were not highly familiar. These results contribute to our understanding of how individuating information comes to be represented in face-sensitive regions and suggest that this process can take place even after a single repetition of a particular face.

Face information processing in the left inferior temporal lobe: An ECoG case study

Functional magnetic resonance imaging (fMRI) studies have identified that the human fusiform gyrus contains specialized regions for the processing of faces, often labeled as the fusiform face areas (FFA). However, fMRI, on its own, is a correlative measurement that cannot provide evidence for the causal role of FFA in face processing. Evidence for a causal role of FFA can be acquired by using a multimodal approach that combines fMRI, electrocorticogram, electronic brain stimulation, and behavior. The current study investigated the role of the left FFA in facial information processing by directly recording event-related potentials from the inferior temporal lobes with intracranial electrodes in a patient with suspected right temporal lobe epilepsy. Our results show that, faces induced stronger blood oxygenation level dependent and electrophysiological response at the left FFA compared to other image categories; electrical stimulation through the electrode placed at the left FFA did not produce self-reports of perceptual face distortion; but electrical stimulation to the left FFA did reduce sensitivity to subtle changes in facial contours. These results suggest that the left FFA may play a causal role in the fine processing of facial shape, and may have distinct functions from the corresponding area of the right hemisphere.

Apolipoprotein-E4 (ApoE4) carriers show altered small-world properties in the default mode network of the brain

Apolipoprotein-E (ApoE), specifically the e4 allele, has been identified as a risk factor for Alzheimer’s disease (AD). The prevalence of the gene in 25% to 30% of the population necessitates careful examination of its role in neuroregulation and its impact on distributed brain networks. In this study, large-scale and small-world anatomical cortical networks are assessed in cognitive normal (CN) subjects with differing apolipoprotein-E4 (ApoE4) gene expression. The large-scale anatomical networks are estimated from cortical thickness measurements derived from magnetic resonance imaging in 147 CN subjects examined in relation to the ApoE4 genotype (e4+ carriers (n = 41) versus e4− non-carriers (n = 106)). Brain networks were constructed by thresholding anatomical cortical thickness correlation matrices of 68 bilateral brain regions analyzed using well-established graph theoretical approaches. Compared to non-carriers, carriers showed increased interregional correlation coefficients in regions such as the precentral, superior frontal and inferior temporal lobes, and most of the altered connections were intra-hemispheric and limited primarily to the right hemisphere. The number of long-length anatomic connections in carriers (26.1%) was significantly higher compared to non-carriers (17.9%). Carriers showed a reduced amount of short connections in the frontal lobe as compared to non-carriers, but an increased presence of long-range connections was observed in the frontal lobe. Furthermore, ApoE4 carriers demonstrated abnormal small-world architecture in the cortical networks with increased clustering coefficient and path lengths as compared to non-carriers, suggesting a less optimal topological organization of their brain networks. Finally, as compared to non-carriers, ApoE4 carriers demonstrated higher betweenness in regions such as middle temporal, parahippocampal gyrus, posterior cingulate and insula of the default mode network, also seen in subjects with AD and mild cognitive impairment. The results suggest that the complex morphological cortical connectivity patterns are altered in ApoE4 carriers, providing evidence for disruption of integrity in large-scale anatomical brain networks in asymptomatic ApoE4 carriers.

Dual-echo fMRI can detect activations in inferior temporal lobe during intelligible speech comprehension

The neural basis of speech comprehension has been investigated intensively during the past few decades. Incoming auditory signals are analysed for speech-like patterns and meaningful information can be extracted by mapping these sounds onto stored semantic representations. Investigation into the neural basis of speech comprehension has largely focused on the temporal lobe, in particular the superior and posterior regions. The ventral anterior temporal lobe (vATL), which includes the inferior temporal gyrus (ITG) and temporal fusiform gyrus (TFG) is consistently omitted in fMRI studies. In contrast, PET studies have shown the involvement of these ventral temporal regions. One crucial factor is the signal loss experienced using conventional echo planar imaging (EPI) for fMRI, at tissue interfaces such as the vATL. One method to overcome this signal loss is to employ a dual-echo EPI technique. The aim of this study was to use intelligible and unintelligible (spectrally rotated) sentences to determine if the vATL could be detected during a passive speech comprehension task using a dual-echo acquisition. A whole brain analysis for an intelligibility contrast showed bilateral superior temporal lobe activations and a cluster of activation within the left vATL. Converging evidence implicates the same ventral temporal regions during semantic processing tasks, which include language processing. The specific role of the ventral temporal region during intelligible speech processing cannot be determined from this data alone, but the converging evidence from PET, MEG, TMS and neuropsychology strongly suggest that it contains the stored semantic representations, which are activated by the speech decoding process.

The alterations in regional homogeneity of parieto-cingulate and temporo-cerebellum regions of first-episode medication-naïve depression patients.

This study surveyed the characteristics of the indicator for the synchrony of brain activities, regional homogeneity (ReHo), in patients who were diagnosed with major depressive disorder (MDD) without co-morbidities. Forty-four patients with MDD and twenty-seven normal controls were enrolled in our study. The ReHo outputs of patients and controls were compared by a nonparametric permutation-based method with global brain volume, age, and gender as covariates. In addition, the correlations between the clinical variables (such as depression severity, anxiety severity, illness duration) and ReHo values were also estimated in each group and across both groups. The patients with MDD had lower ReHo values than the controls for the cognitive division of right anterior cingulate cortex and the left inferior parietal lobule. In contrast, the patients had higher values of ReHo than controls for the right inferior temporal lobe and the right cerebellum. Additionally, the ReHo values were negatively correlated with the depression severity and with illness duration in the right anterior cingulate cortex. MDD patients had significant alterations in the ReHo of the parieto-cingulate and temporo-cerebellum regions with opposite trends.

Increased cerebral water content in hemodialysis patients.

Little information is available on the impact of hemodialysis on cerebral water homeostasis and its distribution in chronic kidney disease. We used a neuropsychological test battery, structural magnetic resonance imaging (MRI) and a novel technique for quantitative measurement of localized water content using 3T MRI to investigate ten hemodialysis patients (HD) on a dialysis-free day and after hemodialysis (2.4±2.2 hours), and a matched healthy control group with the same time interval. Neuropsychological testing revealed mainly attentional and executive cognitive dysfunction in HD. Voxel-based-morphometry showed only marginal alterations in the right inferior medial temporal lobe white matter in HD compared to controls. Marked increases in global brain water content were found in the white matter, specifically in parietal areas, in HD patients compared to controls. Although the global water content in the gray matter did not differ between the two groups, regional increases of brain water content in particular in parieto-temporal gray matter areas were observed in HD patients. No relevant brain hydration changes were revealed before and after hemodialysis. Whereas longer duration of dialysis vintage was associated with increased water content in parieto-temporal-occipital regions, lower intradialytic weight changes were negatively correlated with brain water content in these areas in HD patients. Worse cognitive performance on an attention task correlated with increased hydration in frontal white matter. In conclusion, long-term HD is associated with altered brain tissue water homeostasis mainly in parietal white matter regions, whereas the attentional domain in the cognitive dysfunction profile in HD could be linked to increased frontal white matter water content.

Navigating toward a novel environment from a route or survey perspective: neural correlates and context-dependent connectivity.

When we move toward a novel environment we may learn it in different ways, i.e., by walking around or studying a map. Both types of learning seem to be very effective in daily life navigation and correspond to two different types of mental representation of space: route and survey representation. In the present study, we investigated the neural basis of route and survey perspectives during learning and retrieval of novel environments. The study was carried out over 5days, during which participants learned two paths from a different perspective (i.e., route learning and survey learning). Then participants had to retrieve these paths using a survey or route perspective during fMRI scans, on the first and fifth day. We found that the left inferior temporal lobe and right angular gyrus (AG) were activated more during recall of paths learned in a survey perspective than in a route perspective. We also found a session by perspective interaction effect on neural activity in brain areas classically involved in navigation such as the parahippocampal place area (PPA) and the retrosplenial cortex (RSC). A set of frontal, parietal and temporal areas showed different patterns of activity according to the type of retrieval perspective. We tested the context-dependent connectivity of right PPA, RSC and AG, finding that these areas showed different patterns of connectivity in relation to the learning and recalling perspective. Our results shed more light on the segregation of neural circuits involved in the acquisition of a novel environment and navigational strategies.

Voxel-based analysis of normal cerebral [18F]FDG uptake during childhood using statistical parametric mapping

The changing pattern of relative cerebral 18F-fluoro-2-deoxy-D-glucose (FDG) uptake that occurs during normal childhood development is not completely understood. Using SPM8 we undertook a voxel-based analysis of dedicated cerebral FDG scans in 28 children ranging in age from 11months to 16years to examine the effects of age on regional FDG uptake. The subjects included were children with suspected or proven extracranial malignancies without central nervous system metastases and no previous or current therapies or medical conditions likely to interfere with cerebral metabolism. The included cerebral FDG scans were considered to represent normal cerebral FDG distribution in a child of their age at the time of the scan. When normalised to whole brain mean uptake, the voxel-based analysis showed increasing FDG uptake with age in the premotor and prefrontal cortices, insula cortex, cingulate cortex, basal ganglia, thalamus, cerebellum and in small areas of the inferior temporal lobes and left Heschl's gyrus. These findings correlate with previous published analysis of the same data that used qualitative and maximal standardised uptake value (SUVmax) analysis techniques. This data provides more regionally specific information and further supports the conclusion that relative cerebral FDG uptake in children has not reached a typical adult pattern by approximately one year of age but in fact changes throughout childhood. The results speak to the importance of using age-matched data or adjusting for age in the statistical analysis of studies comparing paediatric cerebral FDG scans to a control dataset to avoid bias due to different age distributions in the groups of subjects studied. The areas of increasing FDG uptake with age probably relate to underlying neuronal processes linked to normal neurodevelopment including key resting state networks.

Comparison between the cranial magnetic resonance imaging features of neuromyelitis optica spectrum disorder versus multiple sclerosis in Taiwanese patients.

BackgroundNeuromyelitis optica spectrum disorder (NMOSD) and multiple sclerosis (MS) are inflammatory diseases of the central nervous system with different pathogenesis, brain lesion patterns, and treatment strategies. However, it is still difficult to distinguish these two disease entities by neuroimaging studies. Herein, we attempt to differentiate NMOSD from MS by comparing brain lesion patterns on magnetic resonance imaging (MRI).MethodsThe medical records and cranial MRI studies of patients with NMOSD diagnosed according to the 2006 Wingerchuk criteria and the presence of anti-aquaporin 4 (anti-AQP4) antibodies, and patients with MS diagnosed according to the Poser criteria, were retrospectively reviewed.ResultsTwenty-five NMOSD and 29 MS patients were recruited. The NMOSD patients became wheelchair dependent earlier than MS patients (log rank test; P = 0.036). Linear ependymal (28% vs. 0%, P = 0.003) and punctate lesions (64% vs. 28%, P = 0.013) were more frequently seen in NMOSD patients. Ten NMOSD patients (40%) had brain lesions that did not meet the Matthews criteria (MS were separated from NMOSD by the presence of at least 1 lesion adjacent to the body of the lateral ventricle and in the inferior temporal lobe; or the presence of a subcortical U-fiber lesion or a Dawson finger-type lesion). The different image patterns of NMOSD didn’t correlate with the clinical prognosis. However, NMOSD patients with more (≧10) brain lesions at onset became wheelchair dependence earlier than those with fewer (<10) brain lesions (log rank test; P < 0.001).ConclusionsThe diagnostic sensitivity of NMOSD criteria can be increased to 56% by combining the presence of linear ependymal lesions with unmet the Matthews criteria. The prognoses of NMOSD and MS are different. A specific imaging marker, the linear ependymal lesion, was present in some NMOSD patients. The diagnosis of NMOSD can be improved by following the evolution of this imaging feature when anti-AQP4 antibody test results are not available.

Preserved mid-fusiform activation for visual words in a patient with a visual word recognition impairment

Previous functional imaging studies have highlighted the role of left ventral temporal cortex in processing written word forms. We explored activation and anatomical connectivity of this region in HE, a professional writer with alexia as a result of stroke affecting primarily white matter in the left inferior temporal lobe. We used a one-back visual recognition task and functional Magnetic Resonance Imaging to elicit automatic activation to various orthographic and non-orthographic stimuli. Surprisingly, HE showed cortical activation in the left mid-fusiform area during the presentation of words and word-like stimuli, suggesting that this region׳s role in processing visual words is intact despite his severely impaired reading. Diffusion Tensor Imaging data further suggest that HE shows an anatomical disconnection between the ventral temporal cortex and posterior middle temporal cortex. Together, these findings suggest that activation of word-specific regions of mid-fusiform gyrus is not sufficient to yield the conscious experience of reading in the absence of activity in downstream regions of the classical reading network.

Neural correlates of spelling difficulties in Alzheimer’s disease

Alzheimer’s disease (AD) is associated with a general cognitive decline that affects the memory and language domains. Thus, an oral production deficit with a lexical-semantic origin has been widely observed in these patients. Their written production capacities, however, have been much less studied. We assessed the spelling abilities of 22 AD patients and a group of matched healthy controls with a test battery including written picture naming and word and pseudoword dictation tests, as well as text dictation and spontaneous writing tasks. The results of the AD patients in the discriminative tasks were then entered into voxel-based morphometry analyses along with their grey matter volumes. The patient group presented a selective impairment for word dictation, which contrasted with a spared capacity to spell pseudowords, and showed more difficulties for words with arbitrary and rule-based orthography. Moreover, they also produced less complete syntactic units in the spontaneous writing task. These results point out the lexical-semantic, as opposed to sublexical, nature of the spelling deficit associated to AD. In addition, we recognized a mainly left-lateralized cortical network, including areas in the posterior inferior temporal lobe and the superior region of the parietal cortex, which might be responsible for this impairment. Other regions, such as the putamen, were also associated to the deficit. The results of this study, hence, improve our understanding of the neuropsychological and neuroanatomical mechanisms that underlie the cognitive symptoms associated to AD.