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ELife Jun 2024Downregulating emotional overreactions toward threats is fundamental for developing treatments for anxiety and post-traumatic disorders. The prefrontal cortex (PFC) is...
Downregulating emotional overreactions toward threats is fundamental for developing treatments for anxiety and post-traumatic disorders. The prefrontal cortex (PFC) is critical for top-down modulatory processes, and despite previous studies adopting repetitive transcranial magnetic stimulation (rTMS) over this region provided encouraging results in enhancing extinction, no studies have hitherto explored the effects of stimulating the medial anterior PFC (aPFC, encompassing the Brodmann area 10) on threat memory and generalization. Here we showed that rTMS over the aPFC applied before threat memory retrieval immediately decreases implicit reactions to learned and novel stimuli in humans. These effects enduringly persisted 1 week later in the absence of rTMS. No effects were detected on explicit recognition. Critically, rTMS over the aPFC resulted in a more pronounced reduction of defensive responses compared to rTMS targeting the dorsolateral PFC. These findings reveal a previously unexplored prefrontal region, the modulation of which can efficiently and durably inhibit implicit reactions to learned threats. This represents a significant advancement toward the long-term deactivation of exaggerated responses to threats.
Topics: Humans; Fear; Prefrontal Cortex; Transcranial Magnetic Stimulation; Male; Young Adult; Female; Adult; Extinction, Psychological
PubMed: 38913410
DOI: 10.7554/eLife.85951 -
International Journal of Nanomedicine 2024Autism Spectrum Disorder (ASD) is a neurodevelopmental condition that affects social interaction and communication and can cause stereotypic behavior. Fullerenols, a...
BACKGROUND
Autism Spectrum Disorder (ASD) is a neurodevelopmental condition that affects social interaction and communication and can cause stereotypic behavior. Fullerenols, a type of carbon nanomaterial known for its neuroprotective properties, have not yet been studied for their potential in treating ASD. We aimed to investigate its role in improving autistic behaviors in BTBR TItpr3/J (BTBR) mice and its underlying mechanism, which could provide reliable clues for future ASD treatments.
METHODS
Our research involved treating C57BL/6J (C57) and BTBR mice with either 0.9% NaCl or fullerenols (10 mg/kg) daily for one week at seven weeks of age. We then conducted ASD-related behavioral tests in the eighth week and used RNA-seq to screen for vital pathways in the mouse hippocampus. Additionally, we used real-time quantitative PCR (RT-qPCR) to verify related pathway genes and evaluated the number of stem cells in the hippocampal dentate gyrus (DG) by Immunofluorescence staining.
RESULTS
Our findings revealed that fullerenols treatment significantly improved the related ASD-like behaviors of BTBR mice, manifested by enhanced social ability and improved cognitive deficits. Immunofluorescence results showed that fullerenols treatment increased the number of DCX and SOX2/GFAP cells in the DG region of BTBR mice, indicating an expanded neural progenitor cell (NPC) pool of BTBR mice. RNA-seq analysis of the mouse hippocampus showed that VEGFA was involved in the rescued hippocampal neurogenesis by fullerenols treatment.
CONCLUSION
In conclusion, our findings suggest that fullerenols treatment improves ASD-like behavior in BTBR mice by upregulating VEGFA, making nanoparticle- fullerenols a promising drug for ASD treatment.
Topics: Animals; Mice, Inbred C57BL; Mice; Fullerenes; Autism Spectrum Disorder; Cognitive Dysfunction; Disease Models, Animal; Male; Doublecortin Protein; Social Behavior; Behavior, Animal; Hippocampus; Vascular Endothelial Growth Factor A; Neuroprotective Agents; Neurogenesis; Autistic Disorder
PubMed: 38911505
DOI: 10.2147/IJN.S459511 -
BMC Neurology Jun 2024After spinal cord injury (SCI), a large number of survivors suffer from severe motor dysfunction (MD). Although the injury site is in the spinal cord, excitability...
BACKGROUND
After spinal cord injury (SCI), a large number of survivors suffer from severe motor dysfunction (MD). Although the injury site is in the spinal cord, excitability significantly decreases in the primary motor cortex (M1), especially in the lower extremity (LE) area. Unfortunately, M1 LE area-targeted repetitive transcranial magnetic stimulation (rTMS) has not achieved significant motor improvement in individuals with SCI. A recent study reported that the M1 hand area in individuals with SCl contains a compositional code (the movement-coding component of neural activity) that links matching movements from the upper extremities (UE) and the LE. However, the correlation between bilateral M1 hand area excitability and overall functional recovery is unknown.
OBJECTIVE
To clarify the changes in the excitability of the bilateral M1 hand area after SCI and its correlation with motor recovery, we aim to specify the therapeutic parameters of rTMS for SCI motor rehabilitation.
METHODS
This study is a 12-month prospective cohort study. The neurophysiological and overall functional status of the participants will be assessed. The primary outcomes included single-pulse and paired-pulse TMS. The second outcome included functional near-infrared spectroscopy (fNIRS) measurements. Overall functional status included total motor score, modified Ashworth scale score, ASIA Impairment Scale grade, spinal cord independence measure and modified Barthel index. The data will be recorded for individuals with SCI at disease durations of 1 month, 2 months, 4 months, 6 months and 12 months. The matched healthy controls will be measured during the same period of time after recruitment.
DISCUSSION
The present study is the first to analyze the role of bilateral M1 hand area excitability changes in the evaluation and prediction of overall functional recovery (including motor function and activities of daily living) after SCI, which will further expand the traditional theory of the predominant role of M1, optimize the current rTMS treatment, and explore the brain-computer interface design for individuals with SCI.
TRIAL REGISTRATION NUMBER
ChiCTR2300068831.
Topics: Humans; Spinal Cord Injuries; Recovery of Function; Hand; Transcranial Magnetic Stimulation; Motor Cortex; Prospective Studies; Evoked Potentials, Motor; Male; Adult; Female; Cohort Studies; Middle Aged; Spectroscopy, Near-Infrared
PubMed: 38909175
DOI: 10.1186/s12883-024-03705-0 -
Nature Communications Jun 2024Psychedelics have experienced renewed interest following positive clinical effects, however the neurobiological mechanisms underlying effects remain unclear. The...
Psychedelics have experienced renewed interest following positive clinical effects, however the neurobiological mechanisms underlying effects remain unclear. The paraventricular nucleus of the hypothalamus (PVN) plays an integral role in stress response, autonomic function, social behavior, and other affective processes. We investigated the effect of psilocin, the psychoactive metabolite of psilocybin, on PVN reactivity in Sprague Dawley rats. Psilocin increased stimulus-independent PVN activity as measured by c-Fos expression in male and female rats. Psilocin increased PVN reactivity to an aversive air-puff stimulus in males but not females. Reactivity was restored at 2- and 7-days post-injection with no group differences. Additionally, prior psilocin injection did not affect PVN reactivity following acute restraint stress. Experimental groups sub-classified by baseline threat responding indicate that increased male PVN reactivity is driven by active threat responders. These findings identify the PVN as a significant site of psychedelic drug action with implications for threat responding behavior.
Topics: Animals; Paraventricular Hypothalamic Nucleus; Male; Psilocybin; Rats, Sprague-Dawley; Female; Rats; Hallucinogens; Proto-Oncogene Proteins c-fos; Behavior, Animal; Stress, Psychological
PubMed: 38909051
DOI: 10.1038/s41467-024-49741-9 -
Nature Communications Jun 2024Metacognitive evaluations of confidence provide an estimate of decision accuracy that could guide learning in the absence of explicit feedback. We examine how humans...
Metacognitive evaluations of confidence provide an estimate of decision accuracy that could guide learning in the absence of explicit feedback. We examine how humans might learn from this implicit feedback in direct comparison with that of explicit feedback, using simultaneous EEG-fMRI. Participants performed a motion direction discrimination task where stimulus difficulty was increased to maintain performance, with intermixed explicit- and no-feedback trials. We isolate single-trial estimates of post-decision confidence using EEG decoding, and find these neural signatures re-emerge at the time of feedback together with separable signatures of explicit feedback. We identified these signatures of implicit versus explicit feedback along a dorsal-ventral gradient in the striatum, a finding uniquely enabled by an EEG-fMRI fusion. These two signals appear to integrate into an aggregate representation in the external globus pallidus, which could broadcast updates to improve cortical decision processing via the thalamus and insular cortex, irrespective of the source of feedback.
Topics: Humans; Decision Making; Male; Magnetic Resonance Imaging; Female; Adult; Basal Ganglia; Young Adult; Learning; Electroencephalography; Brain Mapping
PubMed: 38909014
DOI: 10.1038/s41467-024-49538-w -
Medicina 2024The frontal aslant tract (FAT) connects the supplementary motor area (SMA) with the pars opercularis. Its role in language and its implications in glioma surgery remain...
The frontal aslant tract (FAT) connects the supplementary motor area (SMA) with the pars opercularis. Its role in language and its implications in glioma surgery remain under discussion. We present an anatomosurgical study of three cases with surgical resolution. Three patients with gliomas in the left frontal lobe were operated on using an awake patient protocol with cortical and subcortical mapping techniques, conducting motor and language evaluations. Tractography was performed using DSI Studio software. All three patients showed intraoperative language inhibition through subcortical stimulation of the FAT. Resection involving the FAT correlated with language deficits in all cases and movement initiation deficits in two cases. All patients recovered from their deficits at six months postoperatively. In conclusion, the tract has been successfully reconstructed, showing both anatomical and functional complexity, supporting the idea of its mapping and preservation in glioma surgery. Future interdisciplinary studies are necessary to determine the transient or permanent nature of the deficits.
Topics: Humans; Brain Neoplasms; Glioma; Male; Frontal Lobe; Middle Aged; Female; Adult; Neurosurgical Procedures; Brain Mapping; Motor Cortex; Diffusion Tensor Imaging
PubMed: 38907981
DOI: No ID Found -
Scientific Reports Jun 2024Head-fixation of mice enables high-resolution monitoring of neuronal activity coupled with precise control of environmental stimuli. Virtual reality can be used to...
Head-fixation of mice enables high-resolution monitoring of neuronal activity coupled with precise control of environmental stimuli. Virtual reality can be used to emulate the visual experience of movement during head fixation, but a low inertia floating real-world environment (mobile homecage, MHC) has the potential to engage more sensory modalities and provide a richer experimental environment for complex behavioral tasks. However, it is not known whether mice react to this adapted environment in a similar manner to real environments, or whether the MHC can be used to implement validated, maze-based behavioral tasks. Here, we show that hippocampal place cell representations are intact in the MHC and that the system allows relatively long (20 min) whole-cell patch clamp recordings from dorsal CA1 pyramidal neurons, revealing sub-threshold membrane potential dynamics. Furthermore, mice learn the location of a liquid reward within an adapted T-maze guided by 2-dimensional spatial navigation cues and relearn the location when spatial contingencies are reversed. Bilateral infusions of scopolamine show that this learning is hippocampus-dependent and requires intact cholinergic signalling. Therefore, we characterize the MHC system as an experimental tool to study sub-threshold membrane potential dynamics that underpin complex navigation behaviors.
Topics: Animals; Mice; Spatial Navigation; Maze Learning; Male; Hippocampus; Pyramidal Cells; Mice, Inbred C57BL; Membrane Potentials; CA1 Region, Hippocampal; Virtual Reality; Scopolamine; Patch-Clamp Techniques
PubMed: 38906952
DOI: 10.1038/s41598-024-64807-w -
Science Advances Jun 2024The suprachiasmatic nucleus (SCN) sets the phase of oscillation throughout the brain and body. Anatomical evidence reveals a portal system linking the SCN and the...
The suprachiasmatic nucleus (SCN) sets the phase of oscillation throughout the brain and body. Anatomical evidence reveals a portal system linking the SCN and the organum vasculosum of the lamina terminalis (OVLT), begging the question of the direction of blood flow and the nature of diffusible signals that flow in this specialized vasculature. Using a combination of anatomical and in vivo two-photon imaging approaches, we unequivocally show that blood flows unidirectionally from the SCN to the OVLT, that blood flow rate displays daily oscillations with a higher rate at night than in the day, and that circulating vasopressin can access portal vessels. These findings highlight a previously unknown central nervous system communication pathway, which, like that of the pituitary portal system, could allow neurosecretions to reach nearby target sites in OVLT, avoiding dilution in the systemic blood. In both of these brain portal pathways, the target sites relay signals broadly to both the brain and the rest of the body.
Topics: Suprachiasmatic Nucleus; Animals; Mice; Hypothalamus; Brain; Portal System; Male; Vasopressins; Cerebrovascular Circulation; Circadian Rhythm
PubMed: 38905332
DOI: 10.1126/sciadv.adn8350 -
PloS One 2024Visual processing relies on the identification of both local and global features of visual stimuli. While well investigated at the behavioral level, the underlying brain...
Visual processing relies on the identification of both local and global features of visual stimuli. While well investigated at the behavioral level, the underlying brain mechanisms are less clear, especially in the context of aging. Using fMRI, we aimed to investigate the neural correlates underlying local and global processing in early and late adulthood. We recruited 77 healthy adults aged 19-77 who completed a visual search task based on 2-level hierarchical stimuli made of squares and/or circles. Participants were instructed to detect a target (a square) at either a local (small) or global (large) level of a hierarchical geometrical form, in the presence or absence of other hierarchical geometrical forms (distractors). At the behavioral level, we revealed high accuracy for all participants, but older participants were slower to detect local targets, specifically in presence of distractors. At the brain level, while both local and global processing were associated with occipital activation, local processing also recruited the anterior insula and dorsal anterior cingulate cortex, that are core regions of the salience network. However, while the presence of distractors in the local condition elicited specifically stronger activation within the right anterior insula for the young group, it was not observed for older participants. In addition, older participants showed less activation than younger participants in the occipital cortex, especially for the most complex conditions. Our findings suggest that the brain correlates underlying local and global processing change with aging, especially for complex visual patterns. These results are discussed in terms of top-down reduction effects from the salience network on primary visual areas, that may lead to specific difficulties to process local visual details in older adults.
Topics: Humans; Adult; Male; Female; Middle Aged; Magnetic Resonance Imaging; Aged; Young Adult; Brain Mapping; Visual Perception; Photic Stimulation; Brain; Aging; Reaction Time; Occipital Lobe
PubMed: 38905236
DOI: 10.1371/journal.pone.0303796 -
PloS One 2024Defining the brain mechanisms underlying initial emotional evaluation is a key but unexplored clue to understanding affective processing. Event-related potentials...
Defining the brain mechanisms underlying initial emotional evaluation is a key but unexplored clue to understanding affective processing. Event-related potentials (ERPs), especially suited for investigating this issue, were recorded in two experiments (n = 36 and n = 35). We presented emotionally negative (spiders) and neutral (wheels) silhouettes homogenized regarding their visual parameters. In Experiment 1, stimuli appeared at fixation or in the periphery (200 trials per condition and location), the former eliciting a N40 (39 milliseconds) and a P80 (or C1: 80 milliseconds) component, and the latter only a P80. In Experiment 2, stimuli were presented only at fixation (500 trials per condition). Again, an N40 (45 milliseconds) was observed, followed by a P100 (or P1: 105 milliseconds). Analyses revealed significantly greater N40-C1P1 peak-to-peak amplitudes for spiders in both experiments, and ANCOVAs showed that these effects were not explained by C1P1 alone, but that processes underlying N40 significantly contributed. Source analyses pointed to V1 as an N40 focus (more clearly in Experiment 2). Sources for C1P1 included V1 (P80) and V2/LOC (P80 and P100). These results and their timing point to low-order structures (such as visual thalamic nuclei or superior colliculi) or the visual cortex itself, as candidates for initial evaluation structures.
Topics: Humans; Emotions; Male; Female; Adult; Photic Stimulation; Young Adult; Electroencephalography; Evoked Potentials; Evoked Potentials, Visual; Visual Perception; Brain; Visual Cortex
PubMed: 38905211
DOI: 10.1371/journal.pone.0299677