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"Frontal Lobe"
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A case of frontal lobe seizures with ‘dancing‐like’ semiology
by
Granata, Francesca
,
Germanò, Antonio
,
Atanasio, Giorgia
in
Blood flow
,
Case Report
,
Case reports
2024
Background and purpose ‘Dancing‐like’ semiology is extremely rare and described in few case reports. It is characterized by rhythmic, oscillatory movements of the pelvis and/or limbs during which the subject appears to be dancing. It has been associated with both the frontal and temporal epileptic zone; however, the possible network involved in these fascinating seizures is unclear. Methods The case of a 45‐year‐old woman suffering from drug‐resistant focal epilepsy with multi‐day seizures of bizarre semiology is described. A structural and perfusion magnetic resonance imaging study (interictal and peri‐ictal) and video‐electroencephalograms were carried out, and several home videos were employed. A vagal stimulator was implanted. Results Home videos documented the ‘dancing’ semiology of seizures better than video‐ electroencephalogram recordings. The imaging study revealed a focal frontal polymicrogyria with a peri‐ictal cerebral blood flow increase at the perisylvian lesion foci. The combination of add‐on cenobamate and vagal nerve stimulation resulted in complete seizure freedom. Conclusion The unusual and complex dancing‐like semiology observed during our patient's seizures adds to the repertoire of fascinating complex motor manifestations of frontal lobe epilepsy.
Journal Article
Multimodal neurocognitive markers of frontal lobe epilepsy: Insights from ecological text processing
by
Moguilner, Sebastian
,
Isoardi, Roberto
,
Birba, Agustina
in
Cerebral Cortex - diagnostic imaging
,
Cerebral Cortex - pathology
,
Cerebral Cortex - physiopathology
2021
The pressing call to detect sensitive cognitive markers of frontal lobe epilepsy (FLE) remains poorly addressed. Standard frameworks prove nosologically unspecific (as they reveal deficits that also emerge across other epilepsy subtypes), possess low ecological validity, and are rarely supported by multimodal neuroimaging assessments. To bridge these gaps, we examined naturalistic action and non-action text comprehension, combined with structural and functional connectivity measures, in 19 FLE patients, 19 healthy controls, and 20 posterior cortex epilepsy (PCE) patients. Our analyses integrated inferential statistics and data-driven machine-learning classifiers. FLE patients were selectively and specifically impaired in action comprehension, irrespective of their neuropsychological profile. These deficits selectively and specifically correlated with (a) reduced integrity of the anterior thalamic radiation, a subcortical structure underlying motoric and action-language processing as well as epileptic seizure spread in this subtype; and (b) hypoconnectivity between the primary motor cortex and the left-parietal/supramarginal regions, two putative substrates of action-language comprehension. Moreover, machine-learning classifiers based on the above neurocognitive measures yielded 75% accuracy rates in discriminating individual FLE patients from both controls and PCE patients. Briefly, action-text assessments, combined with structural and functional connectivity measures, seem to capture ecological cognitive deficits that are specific to FLE, opening new avenues for discriminatory characterizations among epilepsy types.
Journal Article
Amyloid polymorphisms constitute distinct clouds of conformational variants in different etiological subtypes of Alzheimer’s disease
by
Rasmussen, Jay
,
Hammarström, Per
,
Ghetti, Bernardino
in
Alzheimer Disease - classification
,
Alzheimer Disease - genetics
,
Alzheimer Disease - metabolism
2017
The molecular architecture of amyloids formed in vivo can be interrogated using luminescent conjugated oligothiophenes (LCOs), a unique class of amyloid dyes. When bound to amyloid, LCOs yield fluorescence emission spectra that reflect the 3D structure of the protein aggregates. Given that synthetic amyloid-β peptide (Aβ) has been shown to adopt distinct structural conformations with different biological activities, we asked whether Aβ can assume structurally and functionally distinct conformations within the brain. To this end, we analyzed the LCO-stained cores of β-amyloid plaques in postmortem tissue sections from frontal, temporal, and occipital neocortices in 40 cases of familial Alzheimer’s disease (AD) or sporadic (idiopathic) AD (sAD). The spectral attributes of LCO-bound plaques varied markedly in the brain, but the mean spectral properties of the amyloid cores were generally similar in all three cortical regions of individual patients. Remarkably, the LCO amyloid spectra differed significantly among some of the familial and sAD subtypes, and between typical patients with sAD and those with posterior cortical atrophy AD. Neither the amount of Aβ nor its protease resistance correlated with LCO spectral properties. LCO spectral amyloid phenotypes could be partially conveyed to Aβ plaques induced by experimental transmission in a mouse model. These findings indicate that polymorphic Aβ-amyloid deposits within the brain cluster as clouds of conformational variants in different AD cases. Heterogeneity in the molecular architecture of pathogenic Aβ among individuals and in etiologically distinct subtypes of AD justifies further studies to assess putative links between Aβ conformation and clinical phenotype.
Journal Article
Structure of pathological TDP-43 filaments from ALS with FTLD
by
Arai, Makoto
,
Murzin, Alexey G.
,
Arseni, Diana
in
101/28
,
631/378/1689/1285
,
631/378/1689/132
2022
The abnormal aggregation of TAR DNA-binding protein 43 kDa (TDP-43) in neurons and glia is the defining pathological hallmark of the neurodegenerative disease amyotrophic lateral sclerosis (ALS) and multiple forms of frontotemporal lobar degeneration (FTLD)
1
,
2
. It is also common in other diseases, including Alzheimer’s and Parkinson’s. No disease-modifying therapies exist for these conditions and early diagnosis is not possible. The structures of pathological TDP-43 aggregates are unknown. Here we used cryo-electron microscopy to determine the structures of aggregated TDP-43 in the frontal and motor cortices of an individual who had ALS with FTLD and from the frontal cortex of a second individual with the same diagnosis. An identical amyloid-like filament structure comprising a single protofilament was found in both brain regions and individuals. The ordered filament core spans residues 282–360 in the TDP-43 low-complexity domain and adopts a previously undescribed double-spiral-shaped fold, which shows no similarity to those of TDP-43 filaments formed in vitro
3
,
4
. An abundance of glycine and neutral polar residues facilitates numerous turns and restricts β-strand length, which results in an absence of β-sheet stacking that is associated with cross-β amyloid structure. An uneven distribution of residues gives rise to structurally and chemically distinct surfaces that face external densities and suggest possible ligand-binding sites. This work enhances our understanding of the molecular pathogenesis of ALS and FTLD and informs the development of diagnostic and therapeutic agents that target aggregated TDP-43.
Cryo-electron microscopy of aggregated TDP-43 from postmortem brain tissue of individuals who had ALS with FTLD reveals a filament structure with distinct features to other neuropathological protein filaments, such as those of tau and α-synuclein.
Journal Article
Frontostriatal salience network expansion in individuals in depression
2024
Decades of neuroimaging studies have shown modest differences in brain structure and connectivity in depression, hindering mechanistic insights or the identification of risk factors for disease onset
1
. Furthermore, whereas depression is episodic, few longitudinal neuroimaging studies exist, limiting understanding of mechanisms that drive mood-state transitions. The emerging field of precision functional mapping has used densely sampled longitudinal neuroimaging data to show behaviourally meaningful differences in brain network topography and connectivity between and in healthy individuals
2
–
4
, but this approach has not been applied in depression. Here, using precision functional mapping and several samples of deeply sampled individuals, we found that the frontostriatal salience network is expanded nearly twofold in the cortex of most individuals with depression. This effect was replicable in several samples and caused primarily by network border shifts, with three distinct modes of encroachment occurring in different individuals. Salience network expansion was stable over time, unaffected by mood state and detectable in children before the onset of depression later in adolescence. Longitudinal analyses of individuals scanned up to 62 times over 1.5 years identified connectivity changes in frontostriatal circuits that tracked fluctuations in specific symptoms and predicted future anhedonia symptoms. Together, these findings identify a trait-like brain network topology that may confer risk for depression and mood-state-dependent connectivity changes in frontostriatal circuits that predict the emergence and remission of depressive symptoms over time.
Precision functional mapping shows that the frontostriatal salience network occupies nearly twice as much of the cortex in people with depression, and this was unaffected by mood changes and detected in children before onset of symptoms.
Journal Article
Control of working memory by phase–amplitude coupling of human hippocampal neurons
by
Kyzar, Michael
,
Reed, Chrystal M.
,
Rutishauser, Ueli
in
631/378/1595/1554
,
631/378/1595/1636
,
631/378/2649
2024
Retaining information in working memory is a demanding process that relies on cognitive control to protect memoranda-specific persistent activity from interference
1
,
2
. However, how cognitive control regulates working memory storage is unclear. Here we show that interactions of frontal control and hippocampal persistent activity are coordinated by theta–gamma phase–amplitude coupling (TG-PAC). We recorded single neurons in the human medial temporal and frontal lobe while patients maintained multiple items in their working memory. In the hippocampus, TG-PAC was indicative of working memory load and quality. We identified cells that selectively spiked during nonlinear interactions of theta phase and gamma amplitude. The spike timing of these PAC neurons was coordinated with frontal theta activity when cognitive control demand was high. By introducing noise correlations with persistently active neurons in the hippocampus, PAC neurons shaped the geometry of the population code. This led to higher-fidelity representations of working memory content that were associated with improved behaviour. Our results support a multicomponent architecture of working memory
1
,
2
, with frontal control managing maintenance of working memory content in storage-related areas
3
–
5
. Within this framework, hippocampal TG-PAC integrates cognitive control and working memory storage across brain areas, thereby suggesting a potential mechanism for top-down control over sensory-driven processes.
Hippocampal theta–gamma phase–amplitude coupling integrates cognitive control and working memory storage across brain areas in humans.
Journal Article
Initial regional cytoarchitectonic differences in dorsal and orbitobasal human developing frontal cortex revealed by spatial transcriptomics
by
Kopić, Janja
,
Millen, Kathleen J.
,
Krasić, Jure
in
Biomedical and Life Sciences
,
Biomedicine
,
Brain architecture
2024
Early development of the human fetal cerebral cortex involves a set of precisely coordinated molecular processes that remains rather underexplored. Previous studies indicate that the laminar identity and the molecular specification of cortical neurons driven by genetic programming, as well as associated histogenetic events begin during early fetal development. Our recent study discovered unique regional cytoarchitectonic features in the developing human frontal lobe, including migratory waves of postmitotic neurons in the dorsal frontal cortex and the “double plate” feature in orbitobasal cortex (Kopić et al. in Cells 12:231, 2023). Notably, neurons of these two cytoarchitectonic features typically express deep projection neuron (DPN) markers (TBR1, TLE4, SOX5). This paper aims to conduct an in-depth investigation of these cytoarchitectonic features at the transcriptomic level, whilst preserving spatial information. Here, we employed NanoString GeoMx
™
Digital Spatial Profiler (DSP) technology to examine gene expression differences in the transient cortical compartments of the dorsal and ventral regions of the developing frontal lobe, focusing specifically on 15 post-conceptional weeks (PCW), that is a critical period for subplate formation. We identified multiple differentially expressed genes between the transient cellular compartments of the dorsal and orbitobasal regions of the developing human frontal cortex. These new findings additionally confirm that regional patterning and specification of the prospective higher-order association prefrontal cortex emerges early in fetal development, contributing to the highly organized cortical architecture of the human brain.
Journal Article
Novel tau filament fold in corticobasal degeneration
2020
Corticobasal degeneration (CBD) is a neurodegenerative tauopathy—a class of disorders in which the tau protein forms insoluble inclusions in the brain—that is characterized by motor and cognitive disturbances
1
–
3
. The H1 haplotype of
MAPT
(the tau gene) is present in cases of CBD at a higher frequency than in controls
4
,
5
, and genome-wide association studies have identified additional risk factors
6
. By histology, astrocytic plaques are diagnostic of CBD
7
,
8
; by SDS–PAGE, so too are detergent-insoluble, 37 kDa fragments of tau
9
. Like progressive supranuclear palsy, globular glial tauopathy and argyrophilic grain disease
10
, CBD is characterized by abundant filamentous tau inclusions that are made of isoforms with four microtubule-binding repeats
11
–
15
. This distinguishes such ‘4R’ tauopathies from Pick’s disease (the filaments of which are made of three-repeat (3R) tau isoforms) and from Alzheimer’s disease and chronic traumatic encephalopathy (CTE) (in which both 3R and 4R isoforms are found in the filaments)
16
. Here we use cryo-electron microscopy to analyse the structures of tau filaments extracted from the brains of three individuals with CBD. These filaments were identical between cases, but distinct from those seen in Alzheimer’s disease, Pick’s disease and CTE
17
–
19
. The core of a CBD filament comprises residues lysine 274 to glutamate 380 of tau, spanning the last residue of the R1 repeat, the whole of the R2, R3 and R4 repeats, and 12 amino acids after R4. The core adopts a previously unseen four-layered fold, which encloses a large nonproteinaceous density. This density is surrounded by the side chains of lysine residues 290 and 294 from R2 and lysine 370 from the sequence after R4.
Cyro-electron microscopy of tau filaments from people with corticobasal degeneration reveals a previously unseen four-layered fold, distinct from the filament structures seen in Alzheimer’s disease, Pick’s disease and chronic traumatic encephalopathy.
Journal Article
Cell-specific histone modification maps in the human frontal lobe link schizophrenia risk to the neuronal epigenome
by
Kavanagh, David H
,
Kundakovic, Marija
,
Peters, Mette A
in
Brain mapping
,
Chromatin
,
Cortex (cingulate)
2018
Risk variants for schizophrenia affect more than 100 genomic loci, yet cell- and tissue-specific roles underlying disease liability remain poorly characterized. We have generated for two cortical areas implicated in psychosis, the dorsolateral prefrontal cortex and anterior cingulate cortex, 157 reference maps from neuronal, neuron-depleted and bulk tissue chromatin for two histone marks associated with active promoters and enhancers, H3-trimethyl-Lys4 (H3K4me3) and H3-acetyl-Lys27 (H3K27ac). Differences between neuronal and neuron-depleted chromatin states were the major axis of variation in histone modification profiles, followed by substantial variability across subjects and cortical areas. Thousands of significant histone quantitative trait loci were identified in neuronal and neuron-depleted samples. Risk variants for schizophrenia, depressive symptoms and neuroticism were significantly over-represented in neuronal H3K4me3 and H3K27ac landscapes. Our Resource, sponsored by PsychENCODE and CommonMind, highlights the critical role of cell-type-specific signatures at regulatory and disease-associated noncoding sequences in the human frontal lobe.
Journal Article
Multi-modal neuroimaging of dual-task walking: Structural MRI and fNIRS analysis reveals prefrontal grey matter volume moderation of brain activation in older adults
2019
It has been well established over the last two decades that walking is not merely an automatic, motoric activity; it also utilizes executive function circuits, which play an increasingly important role in walking for older people and those with mobility and cognitive deficits. Dual-task walking, such as walking while performing a cognitive task, is a necessary skill for everyday functioning, and has been shown to activate prefrontal lobe areas in healthy older people. Another well-established point in healthy aging is the loss of grey matter, and in particular loss of frontal lobe grey matter volume. However, the relationship between increased frontal lobe activity during dual-task walking and loss of frontal grey matter in healthy aging remains unknown.
In the current study, we combined oxygenated hemoglobin (HbO2) data from functional near-infrared spectroscopy (fNIRS), taken during dual-task walking, with structural MRI volumetrics in a cohort of healthy older subjects to identify this relationship. We studied fifty-five relatively healthy, older participants (≥65 years) during two separate sessions: fNIRS to measure HbO2 changes between single-task (i.e., normal walking) and dual-task walking-while-talking, and high-resolution, structural MRI to measure frontal lobe grey matter volumes. Linear mixed effects modeling was utilized to determine the moderation effect of grey matter volume on the change in prefrontal oxygenated hemoglobin between the two walking tasks, while controlling for covariates including task performance. We found a highly significant interaction effect between frontal grey matter volume and task on HbO2 levels (p < 0.0001). Specifically, increased HbO2 levels during dual-task compared to single-task walking were associated with reduced frontal grey matter volume. Regional analysis identified bilateral superior and rostral middle gyri as the primary areas driving these results. The findings provide support for the concept of neural inefficiency: in the absence of behavioral gains, grey matter loss in relatively healthy, older individuals leads to over-activation of frontal lobe during a cognitively demanding walking task with established clinical and predictive utility.
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•The relationship of frontal activity during walking to grey matter volume in aging was explored.•Frontal lobe volumetrics and fNIRS-oxyhemoglobin assessed during walking were measured.•Lower frontal grey matter volume was associated with increased frontal lobe activity.•Grey matter loss in aging may result in inefficient activation of frontal circuits while walking.
Journal Article