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Journal of Neurology Jan 2024To investigate brain MRI abnormalities in a cohort of patients with rapidly progressive dementia (RPD) with and without a diagnosis of Creutzfeldt-Jakob disease (CJD).
OBJECTIVE
To investigate brain MRI abnormalities in a cohort of patients with rapidly progressive dementia (RPD) with and without a diagnosis of Creutzfeldt-Jakob disease (CJD).
METHODS
One hundred and seven patients with diagnosis of prion disease (60 with definite sCJD, 33 with probable sCJD and 14 with genetic prion disease) and 40 non-prion related RPD patients (npRPD) underwent brain MRI including DWI and FLAIR. MRIs were evaluated with a semiquantitative rating score, which separately considered abnormal signal extent and intensity in 22 brain regions. Clinical findings at onset, disease duration, cerebrospinal-fluid 14-3-3 and t-tau protein levels, and EEG data were recorded.
RESULTS
Among patients with definite/probable diagnosis of CJD or genetic prion disease, 2/107 had normal DWI-MRI: in one patient a 2-months follow-up DWI-MRI showed CJD-related changes while the other had autopsy-proven CJD despite no DWI abnormalities 282 days after clinical onset. CJD-related cortical changes were detected in all lobes and involvement of thalamus was common. In the npRPD groups, 6/40 patients showed DWI alterations that clustered in three different patterns: (1) minimal/doubtful signal alterations (limbic encephalitis, dementia with Lewy bodies); (2) clearly suggestive of alternative diagnoses (status epilepticus, Wernicke or metabolic encephalopathy); (3) highly suggestive of CJD (mitochondrial disease), though cortical swelling let exclude CJD.
CONCLUSIONS
In the diagnostic work-up of RPD, negative/doubtful DWI makes CJD diagnosis rather unlikely, while specific DWI patterns help differentiating CJD from alternative diagnoses. The pulvinar sign is not exclusive of the variant form.
Topics: Humans; Creutzfeldt-Jakob Syndrome; Magnetic Resonance Imaging; Brain; Prion Diseases; Thalamus
PubMed: 37698615
DOI: 10.1007/s00415-023-11962-1 -
NeuroImage Oct 2023Spatial attention is often described as a mental spotlight that enhances information processing at the attended location. Using fMRI, we investigated background...
Spatial attention is often described as a mental spotlight that enhances information processing at the attended location. Using fMRI, we investigated background connectivity between the pulvinar and V1 in relation to focused versus diffused attention allocation, in weak and strong crowding contexts. Our findings revealed that focused attention led to enhanced correlations between the pulvinar and V1. Notably, this modulation was initiated by the pulvinar, and the strength of the modulation was dependent on the saliency of the target. These findings suggest that the pulvinar initiates information reweighting to V1, which underlies attentional selection in cluttered scenes.
Topics: Humans; Pulvinar; Cognition; Diffusion
PubMed: 37619793
DOI: 10.1016/j.neuroimage.2023.120341 -
Human Brain Mapping Dec 2023Conscious visual motion information follows a cortical pathway from the retina to the lateral geniculate nucleus (LGN) and on to the primary visual cortex (V1) before...
Conscious visual motion information follows a cortical pathway from the retina to the lateral geniculate nucleus (LGN) and on to the primary visual cortex (V1) before arriving at the middle temporal visual area (MT/V5). Alternative subcortical pathways that bypass V1 are thought to convey unconscious visual information. One flows from the retina to the pulvinar (PUL) and on to medial temporal visual area (MT); while the other directly connects the LGN to MT. Evidence for these pathways comes from non-human primates and modest-sized studies in humans with brain lesions. Thus, the aim of the current study was to reconstruct these pathways in a large sample of neurotypical individuals and to determine the degree to which these pathways are myelinated, suggesting information flow is rapid. We used the publicly available 7T (N = 98; 'discovery') and 3T (N = 381; 'validation') diffusion magnetic resonance imaging datasets from the Human Connectome Project to reconstruct the PUL-MT (including all subcompartments of the PUL) and LGN-MT pathways. We found more fibre tracts with greater density in the left hemisphere. Although the left PUL-MT path was denser, the bilateral LGN-MT tracts were more heavily myelinated, suggesting faster signal transduction. We suggest that this apparent discrepancy may be due to 'adaptive myelination' caused by more frequent use of the LGN-MT pathway that leads to greater myelination and faster overall signal transmission.
Topics: Animals; Humans; Adult; Motion Perception; Visual Cortex; Magnetic Resonance Imaging; Vision, Ocular; Visual Perception; Geniculate Bodies; Connectome; Visual Pathways
PubMed: 37608684
DOI: 10.1002/hbm.26467 -
Biomedicines Jun 2023Temporal interference stimulation (TIS) aims at targeting deep brain areas during transcranial electrical alternating current stimulation (tACS) by generating...
Temporal interference stimulation (TIS) aims at targeting deep brain areas during transcranial electrical alternating current stimulation (tACS) by generating interference fields at depth. Although its modulatory effects have been demonstrated in animal and human models and stimulation studies, direct experimental evidence is lacking for its utility in humans (in vivo). Herein, we directly test and compare three different structures: firstly, we perform peripheral nerve and muscle stimulation quantifying muscle twitches as readout, secondly, we stimulate peri-orbitally with phosphene perception as a surrogate marker, and thirdly, we attempt to modulate the mean power of alpha oscillations in the occipital area as measured with electroencephalography (EEG). We found strong evidence for stimulation efficacy on the modulated frequency in the PNS, but we found no evidence for its utility in the CNS. Possible reasons for failing to activate CNS targets could be comparatively higher activation thresholds here or inhibitory stimulation components to the carrier frequency interfering with the effects of the modulated signal.
PubMed: 37509455
DOI: 10.3390/biomedicines11071813 -
Frontiers in Computational Neuroscience 2023Convolutional Neural Networks (CNN) are a class of machine learning models predominately used in computer vision tasks and can achieve human-like performance through... (Review)
Review
Convolutional Neural Networks (CNN) are a class of machine learning models predominately used in computer vision tasks and can achieve human-like performance through learning from experience. Their striking similarities to the structural and functional principles of the primate visual system allow for comparisons between these artificial networks and their biological counterparts, enabling exploration of how visual functions and neural representations may emerge in the real brain from a limited set of computational principles. After considering the basic features of CNNs, we discuss the opportunities and challenges of endorsing CNNs as models of the primate visual system. Specifically, we highlight several emerging notions about the anatomical and physiological properties of the visual system that still need to be systematically integrated into current CNN models. These tenets include the implementation of parallel processing pathways from the early stages of retinal input and the reconsideration of several assumptions concerning the serial progression of information flow. We suggest design choices and architectural constraints that could facilitate a closer alignment with biology provide causal evidence of the predictive link between the artificial and biological visual systems. Adopting this principled perspective could potentially lead to new research questions and applications of CNNs beyond modeling object recognition.
PubMed: 37485400
DOI: 10.3389/fncom.2023.1153572 -
MedRxiv : the Preprint Server For... Jul 2023Motion processing deficits in schizophrenia have been linked to impairments in higher-order social-cognitive processes. The neural underpinnings are not fully understood...
BACKGROUND AND HYPOTHESIS
Motion processing deficits in schizophrenia have been linked to impairments in higher-order social-cognitive processes. The neural underpinnings are not fully understood but it has been hypothesized that middle temporal area (MT+) may serve as a bridge between purely sensory and more cognitive proceseses. We investigated the interrelationship between MT+ sensory processing deficits and impairments in higher-order processing using naturalistic videos with explicit motion and static images with implied-motion cues.
STUDY DESIGN
Functional magnetic resonance imaging was used to evaluate cortical and subcortical brain regions associated with real- and implied-motion processing in 28 individuals with schizophrenia and 20 neurotypical controls. These measures were related to face emotion recognition and motion-perception deficits, as measured behaviorally.
STUDY RESULTS
Activation of MT+ was abnormal in schizophrenia during both real- and implied-motion processing. Dysfunction of early visual cortex and pulvinar were also associated with impaired real-motion processing. During implied-motion-perception, MT+ participated in a wider network involving sensorimotor and prefrontal nodes of the human mirror neuron system, known to play a role in social-cognitive processes. Perception of both real- and implied-motion engaged the posterior superior temporal sulcus, a key node of the social brain network.
CONCLUSIONS
The findings support concepts of MT+ as a bridge between visual sensory areas and higher-order brain regions especially in relationship to face emotion recognition and social cognition. Our data argue for greater focus on MT+ contributions to social-cognitive processing, in addition to its well-documented role in visual motion processing.
PubMed: 37461678
DOI: 10.1101/2023.07.07.23292259 -
Journal of Affective Disorders Nov 2023American youth are seriously impacted by depression and suicide. The Texas Youth Depression and Suicide Research Network (TX-YDSRN) Participant Registry Study was...
BACKGROUND
American youth are seriously impacted by depression and suicide. The Texas Youth Depression and Suicide Research Network (TX-YDSRN) Participant Registry Study was initiated in 2020 to develop predictive models for treatment outcomes in youth with depression and/or suicidality. This report presents the study rationale, design and baseline characteristics of the first 1000 participants.
METHODS
TX-YDSRN consists of the Network Hub (coordinating center), 12 medical school "Nodes" (manage/implement study), each with 1-5 primary care, inpatient, and/or outpatient Sub-Sites (recruitment, data collection). Participants are 8-20-year-olds who receive treatment or screen positive for depression and/or suicidality. Baseline data include mood and suicidality symptoms, associated comorbidities, treatment history, services used, and social determinants of health. Subsequent assessments occur every two months for 24 months.
RESULTS
Among 1000 participants, 68.7 % were 12-17 years, 24.6 % were ≥ 18 years, and 6.7 % were < 12. Overall, 36.8 % were non-Hispanic Caucasian, 73.4 % were female, and 79.9 % had a primary depressive disorder. Nearly half of the sample reported ≥1 suicide attempt, with rates similar in youth 12-17 years old (49.9 %) and those 18 years and older (45.5 %); 29.9 % of children <12 reported at least one suicide attempt. Depression and anxiety scores were in the moderate-severe range for all age groups (Patient Health Questionnaire for Adolescents [PHQ-A]: 12.9 ± 6.4; Generalized Anxiety Disorder [GAD-7]: 11.3 ± 5.9).
LIMITATIONS
The sample includes youth who are receiving depression care at enrollment and may not be representative of non-diagnosed, non-treatment seeking youth.
CONCLUSIONS
The TX-YDSRN is one of the largest prospective longitudinal cohort registries designed to develop predictive models for outcome trajectories based on disorder heterogeneity, social determinants of health, and treatment availability.
Topics: Child; Humans; Adolescent; Female; Male; Depression; Texas; Prospective Studies; Delivery of Health Care; Registries
PubMed: 37459975
DOI: 10.1016/j.jad.2023.07.035 -
Journal of Clinical Neurology (Seoul,... Nov 2023We aimed to determine whether structural brain connectivity is significantly associated with the response to sumatriptan in patients with migraine.
BACKGROUND AND PURPOSE
We aimed to determine whether structural brain connectivity is significantly associated with the response to sumatriptan in patients with migraine.
METHODS
We retrospectively enrolled patients with newly diagnosed migraine who underwent brain diffusion-tensor imaging (DTI) at the time of diagnosis, with regular follow-up for at least 6 months after the initial diagnosis. Patients were classified into good- and poor-responder groups according to their response to sumatriptan. We analyzed the structural connectivity using DTI by applying graph theory using DSI Studio software.
RESULTS
We enrolled 59 patients (35 good responders and 24 poor responders) and 30 healthy controls. Global structural connectivity differed significantly between patients with migraine and healthy controls, while local structural connectivity differed significantly between good and poor responders. The betweenness centrality was lower in good responders than in poor responders in the left lateral geniculate thalamic nucleus (26.078 vs. 41.371, =0.039) and right medial mediodorsal magnocellular thalamic nucleus (60.856 vs. 90.378, =0.021), whereas was higher in good responders in the left lateral pulvinar thalamic nucleus (98.365 vs. 50.347, =0.003) and right medial pulvinar thalamic nucleus (216.047 vs. 156.651, =0.036).
CONCLUSIONS
We found that structural connectivity in patients with migraine differed from that in healthy controls. Moreover, the local structural connectivity varied with the response to sumatriptan, which suggests that structural connectivity is a useful factor for predicting how a patient will respond to sumatriptan.
PubMed: 37455509
DOI: 10.3988/jcn.2022.0479