The most typical pathological change in Alzheimer’s disease (AD) is the aggregated deposition of amyloid-β (Aβ). APOE ε3/ε3 is the most prevalent genotype in the AD population. Individuals with amyloid-PET (Aβ-PET) positivity (+) and disease progression may not be a minority in the APOE ε3/ε3 non-demented population. This study searched for accessible and available clinical models that can predict Aβ-PET (+), and assess factors that can predict clinical conversion in APOE ε3/ε3 non-demented individuals. We selected 293 non-demented individuals with APOE ε3/ε3 from the Alzheimer’s Disease Neuroimaging Initiative (ADNI) database. They were divided into Aβ-PET (+) and Aβ-PET (-) groups based on the 18F-florbetapir PET SUVR cut-off value of >1.11. Stepwise regression and the receiver operating characteristic curve (ROC) were used to search for a single or a combination of clinical variables, and to assess the accuracy of clinical markers, respectively. The Cox regression model was used to explore the risk factors associated with clinical transition. Our study found that the combination of clinical markers (Model A4: sex, education, ventricle and WMH volume; Model D5: everyday cognition study-partner total (EcogSPTotal) score, age, plasma p-tau 181 and WMH) respectively predicted Aβ-PET status in cognitively normal (CN) individuals and mild cognitive impairment (MCI) individuals. Aβ-PET (+) and EcogSPTotal score were independent predictors of clinical transition in APOE ε3/ε3 non-demented individuals. These specific factors offered an attractive and cost-effective assessment for Aβ status and clinical conversion.

Alzheimer’s disease (AD) is a progressive neurodegenerative disorder that primarily affects the hippocampus. Since hippocampal studies have highlighted a differential subregional regulation along its longitudinal axis, a more detailed analysis addressing subregional changes along the longitudinal hippocampal axis has the potential to provide new relevant biomarkers. This study included structural brain MRI data of 583 participants from the Alzheimer’s Disease Neuroimaging Initiative (ADNI). Cognitively normal (CN) subjects, mild cognitively impaired (MCI) subjects and AD patients were conveniently selected considering the age- and sex-match between clinical groups. Structural MRI acquisitions were pre-processed and analysed with a new longitudinal axis segmentation method, dividing the hippocampus in three subdivisions (anterior, intermediate, and posterior). When normalizing the volume of hippocampal sub-divisions to total hippocampus, the posterior hippocampus negatively correlates with age only in CN subjects (r = -0.31). The longitudinal ratio of hippocampal atrophy (anterior sub-division divided by the posterior one) shows a significant increase with age only in CN (r = 0.25). Overall, in AD the posterior hippocampus is predominantly atrophied early on. Consequently, the anterior/posterior hippocampal ratio is an AD differentiating metric at early disease stages with potential for diagnostic and prognostic applications.

Recent research has indicated that the relationship between age-related cognitive decline and falling may be mediated by the individual’s capacity to quickly cancel or inhibit a motor response. This longitudinal investigation demonstrates that higher white matter fibre density in the motor inhibition network paired with low physical activity was associated with falling in elderly participants. We measured the density of white matter fibre tracts connecting key nodes in the inhibitory control network in a large sample (n=414) of older adults. We modelled their self-reported frequency of falling over a four year period with white matter fibre density in pathways corresponding to the direct and hyperdirect cortical-subcortical loops implicated in the inhibitory control network. Only connectivity between right Inferior Frontal Gyrus and right Subthalamic Nucleus was associated with falling as measured cross-sectionally. The connectivity was not, however, predictive of future falling when measured two and four years later. Higher white matter fibre density was associated with falling, but only in combination with low levels of physical activity. No such relationship existed for selected control brain regions that are not implicated in the inhibitory control network. The direction of this effect was counterintuitive and warrants further longitudinal investigation into whether white matter fibre density changes over time in a manner correlated with falling, and mediated by physical activity.

The human brain encodes gender differences. This fact has been gradually expanded from the realm of the hypothalamus and sexual behavior to the whole brain with its different lobes, structures, and functions, by the influence of the constantly advancing neuroscientific and imag-ing research. However, less is known about sex differences in the brains of neonates and infants, despite their relevance to various sex-linked diseases that develop early in life. In this review, we provide a synopsis of the literature evidence on sex differences in the brains of neonates and infants at the morphological, structural, and network levels. We also briefly overview the pre-sent evidence on the sex bias in some brain disorders affecting infants and neonates.

MECP2 duplication syndrome (MDS) is an X-linked neurodevelopmental disorder caused by the gain of dose of at least the genes MECP2 and IRAK1 and is characterised by intellectual disability (ID), developmental delay, hypotonia, epilepsy and recurrent infections. It mainly affects males, and females can be affected or asymptomatic carriers. Rett syndrome (RTT) is mainly triggered by loss of function mutations in MECP2 and is a well described syndrome that presents ID, epilepsy, lack of purposeful hand use and impaired speech, among others. As a result of implementing omics technology, altered biological pathways in human RTT samples have been reported, but such molecular characterisation has not been performed in MDS patients. We gathered human skin fibroblasts from 17 patients with MDS, 10 MECP2 duplication carrier mothers and 21 RTT patients, and performed multi-omics (RNAseq and proteomics) analysis. Here, we provide a thorough description and compare the shared and specific dysregulated biological processes between the cohorts. We also highlight the genes TMOD2, SRGAP1, COPS2, CNPY2, IGF2BP1, MOB2, VASP, FZD7, ECSIT and KIF3B as biomarker and therapeutic target candidates due to their implication in neuronal functions. Defining the RNA and protein profiles has shown that our four cohorts are less alike than expected by their shared phenotypes.

Having a multitude of choices can be advantageous, yet an abundance of options can be detrimental to the decision-making process. Based on existing research, the present study combined electroencephalogram and self-reported methodologies to investigate the neural mechanisms underlying the phenomenon of choice overload. Behavioral data suggested that an increase in the number of options led to negative evaluations and avoidance of choice tendencies, even in the absence of time pressure. Event-related potential results indicated that the large choice set interfered with the early visual process, as evidenced by the small P1 amplitude, and failed to attract more attentional resources in the early stage, as evidenced by the small amplitude of P2 and N2. However, the LPC amplitude was increased in the late stage, suggesting greater investment of attentional resources and higher emotional arousal. Multivariate pattern analysis revealed that the difference between small and large choice set began at around 120ms and the early and late stages were characterized by opposite activation patterns. This suggested that too many options interfered with early processing and necessitate continued processing at a later stage. In summary, both behavioral and ERP results confirm the choice overload effect, and it was observed that individuals tend to subjectively exaggerate the choice overload effect.

Differences between autistic and non-autistic individuals in perception of the temporal relationships between sights and sounds are theorized to underlie difficulties in integrating relevant sensory information. These, in turn, are thought to contribute to problems with speech perception and higher level social behaviors. However, the literature establishing this connection often involves limited sample sizes and focuses almost entirely on children. To determine whether these differences persist into adulthood, we compared 469 autistic and 373 non-autistic adults (aged 17 to 75 years). Participants completed an online version of the McGurk/MacDonald paradigm, a multisensory illusion indicative of the ability to integrate audiovisual speech stimuli. Audiovisual asynchrony was manipulated, and participants responded both to the syllable they perceived (revealing their susceptibility to the illusion) and to whether or not the audio and video were synchronized (allowing insight into temporal processing). In contrast with prior research with smaller, younger samples, we detected no evidence of impaired temporal or multisensory processing in autistic adults. Instead, we found that in both groups, multisensory integration correlated strongly with age. This contradicts prior presumptions that differences in multisensory perception persist and even increase in magnitude over the lifespan of autistic individuals. It also suggests that the compensatory role multisensory integration may play as the individual senses decline with age is intact. These findings challenge existing theories and provide an optimistic perspective on autistic development. They also underline the importance of expanding autism research to better reflect the age range of the autistic population.

Joint action (JA) is a continuous process of motor co-regulation based on the integration of contextual (top-down) and kinematic (bottom-up) cues from partners. The fine equilibrium between excitation and inhibition in sensorimotor circuits is, thus, central to such a dynamic process of action selection and execution. In a bimanual task adapted to become a unimanual JA task, the participant held a bottle (JA), while a confederate had to reach and unscrew either that bottle or another stabilized by a mechanical clamp (No_JA). Prior knowledge was manipulated in each trial such that the participant knew (K) or not (no_K) the target bottle in advance. Online transcranial magnetic stimulation (TMS) was administered at action-relevant landmarks to explore corticospinal excitability (CSE) and inhibition (cortical silent period - cSP). CSE was modulated early on before the action started, if prior information was available. In contrast, cSP modulation emerged later during the reaching action, regardless of prior information. These two indexes could thus reflect the concurrent elaboration of contextual priors (top-down) and the online sampling of partner’s kinematic cues (bottom-up). Furthermore, participants selected either one of two possible behavioural strategies, preferring early or late force exertion on the bottle. One translates into a reduced risk of motor coordination failure and the other into reduced metabolic expenditure. Each strategy was characterised by a specific excitatory/inhibitory profile. In conclusion, the study of excitatory/inhibitory balance paves the way for the neurophysiological determination of individual differences in the combination of top-down and bottom-up processing during JA coordination.

Parkinson’s disease (PD) is a neurodegenerative disorder characterized by the loss of dopaminergic neurons in the substantia nigra, leading to various motor and non-motor symptoms. Several cellular and molecular mechanisms such as alpha-synuclein (α-syn) accumulation, mitochondrial dysfunction, oxidative stress, and neuroinflammation are involved in the pathogenesis of this disease. MicroRNAs (miRNAs) play important roles in post-transcriptional gene regulation. They are typically about 21-25 nucleotides in length and are involved in the regulation of gene expression by binding to the messenger RNA (mRNA) molecules. miRNAs like miR-221 play important roles in various biological processes, including development, cell proliferation, differentiation, and apoptosis. miR-221 is also implicated in promoting neuronal survival against oxidative stress and in promoting neurite outgrowth and neuronal differentiation. Additionally, the role of miR-221 in PD has been investigated in several studies. According to the results of this study; 1) miR-221 protects against oxidative stress in 6-hydroxydopamine-induced PC12 cells; 2) miR-221 prevents Bax/caspase-3 signaling activation by stopping Bim; 3) miR-221 has moderate predictive power for PD; 4) miR-221 directly targets PTEN, and PTEN over-expression eliminates the protective action of miR-221 on p-AKT expression in PC12 cells; 5) miRNA-221, by manipulating the Akt signaling pathway, performs in controlling cell viability and apoptosis in PD. This review study suggests that miR-221 has the potential to be used as a clinical biomarker for PD diagnosis and stage assignment.

Aims: The initial phase of multiple sclerosis (MS), often known as clinically isolated syndrome (CIS), is a critical period for identifying individuals at high risk of progressing to full-blown MS and initiating timely treatment. In this study, we aimed to evaluate the prognostic value of CXCL13 and IL-8 as potential markers for CIS patients’ conversion to MS. Methods: Our study encompassed patients with CIS, those with relapsing-remitting MS (RRMS), and control subjects, with sample analysis conducted on both cerebrospinal fluid (CSF) and serum. Patients were categorized into four groups: CIS-CIS (no MS development within two years), CIS-RRMS (conversion to RRMS within two years), RRMS (already diagnosed), and a control group (CG) with non-inflammatory CNS disorders. Results: Results showed significantly elevated levels of CXCL13 in CSF across all patient groups compared to the CG (p < 0.0001, Kruskal-Wallis test). Although CXCL13 concentrations were slightly higher in the CIS-RRMS group, statistical significance was not reached. Similarly, significantly higher levels of IL-8 were detected in CSF samples from all patient groups compared to the CG (p < 0.0001, Kruskal-Wallis test), with comparable levels among patient groups. ROC analysis in the CIS-RRMS group identified both CXCL13 (AUC = 0.959) and IL-8 (AUC = 0.939) in CSF as significant predictors of CIS to RRMS conversion. Conclusion: In conclusion, our study suggests a trend toward elevated CXCL13 levels in CIS patients progressing to RRMS. These findings emphasize the importance of identifying prognostic markers to guide appropriate treatment strategies for individuals in the early stages of MS.

Millions of people suffer from dopamine-related disorders spanning disturbances in movement, cognition and emotion, often attributed to changes in striatal dopamine function. Understanding how dopamine signaling in the striatum and basal ganglia shapes human behavior is fundamental to advancing the treatment of affected patients. Dopaminergic neurons innervate large scale brain networks and many different roles for dopamine signals have been proposed, such as invigoration of movement and tracking of reward contingencies. The canonical circuit architecture of cortico-striatal loops sparks the question, whether dopamine signals in the basal ganglia serve an overarching computational principle which could provide new insights into symptom generation in psychiatry to neurology. Here, we review the perspective that dopamine could bidirectionally control neural population dynamics, increasing, or decreasing their strength and likelihood to reoccur in the future, a process previously termed neural reinforcement. We outline how the basal ganglia pathways could drive strengthening and weakening of circuit dynamics and discuss the implication of this hypothesis on the understanding of motor signs of Parkinson’s disease (PD), the most frequent dopaminergic disorder. We propose that loss of dopamine in PD may lead to a pathological brain state where repetition of neural activity leads to weakening and instability, possibly explanatory for the fact that movement in PD deteriorates with repetition, as defined by the sequence effect or decrement of movement. Finally, we speculate on how therapeutic interventions such as deep brain stimulation (DBS) may be able to reinstate reinforcement signals and thereby improve treatment strategies of PD in the future.

The emergence of compulsive drug seeking habits, a hallmark feature of substance use disorder, has been shown to be predicated on the engagement of dorsolateral striatum (DLS) control over behaviour, which is underpinned by a dopamine-dependent functional coupling of the nucleus accumbens and the DLS. However, the mechanisms by which this coupling occurs have not been fully elucidated. The striatum is tiled by a syncytium of astrocytes that express the dopamine transporter (DAT), whose expression is altered in individuals with a heroin use disorder. Thus, astrocytes are uniquely placed functionally to bridge dopamine-dependent mechanisms across the striatum. Thus, here we tested the hypothesis that exposure to heroin, which does not interact with DAT, influences its expression in astrocytes across the striatum before the development of DLS-dependent incentive heroin seeking habits. Using Western-blot, qPCR and RNAscope we measured DAT protein and mRNA levels in whole tissue, cultured or in situ astrocytes from striatal territories of rats with a well-established cue-controlled heroin seeking habit and rats trained to respond for heroin or food under continuous reinforcement. Incentive heroin seeking habits were associated with a reduction in DAT protein levels in the anterior DLS (aDLS) that was preceded by a heroin-induced reduction in DAT mRNA and protein content in astrocytes across the striatum. aDLS astrocytes were also shown to be uniquely susceptible to direct dopamine- and opioid-induced downregulation of DAT expression. These results suggest that astrocytes may critically regulate the striatal dopaminergic adaptations that lead to the development of incentive habits for heroin.

The dorsal subiculum is the primary source of hippocampal projections to the rat retrosplenial cortex. Although, both regions are implicated in spatial memory and navigation, the significance of their direct interconnections remains poorly understood. The present study selectively disrupted dorsal subiculum projections to retrosplenial cortex with inhibitory designer-receptors exclusively activated by designer drugs (iDREADDs), activated locally by clozapine. iDREADDs were injected in the dorsal subiculum in adult male rats (N=14), where they were transported anterogradely to granular retrosplenial cortex. In a separate control group, GFP expressing adeno-associated virus was injected into the dorsal subiculum (N=8). Both groups received behavioural sessions preceded either by intracerebral infusions of clozapine or saline within retrosplenial cortex. Behavioural testing involved reinforced T-maze alternation, with five test variations that differentially taxed intra-maze, extra-maze, and egocentric strategies. Disruption of the subiculum to retrosplenial projections impaired spatial working memory whenever the test variant created a conflict between cue-types, associated with a switch between different strategies. These findings suggest that the direct projections from the dorsal subiculum to the granular retrosplenial cortex help to maintain the flexible integration of different spatial cue-types.

Astrocytes, glial cells in the central nervous system, perform a multitude of homeostatic functions and are in constant bidirectional communication with neuronal cells, a concept named the tripartite synapse, however their role in the dopamine homeostasis remains unexplored. The aim of this study was to clarify the pharmacological and molecular characteristics of dopamine transport in cultured cortical astrocytes of adult rats. In addition, we were interested in the expression of mRNA of dopamine transporters as well as dopamine receptors D1 and D2 and in the effect of dopaminergic drugs on the expression of these transporters and receptors. We have found that astrocytes possess both Na+-dependent and Na+-independent transporters. Uptake of radiolabelled dopamine was time-, temperature- and concentration-dependent and was inhibited by decynium-22, a plasma membrane monoamine transporter inhibitor, tricyclic antidepressants desipramine and nortriptyline, both inhibitors of the norepinephrine transporter. Results of transporter mRNA expression indicate that the main transporters involved in cortical astrocyte dopamine uptake are the norepinephrine transporter and plasma membrane monoamine transporter. Both dopamine receptor subtypes were identified in cortical astrocyte cultures. 24-hour treatment of astrocyte cultures with apomorphine, a D1/D2 agonist, induced upregulation of D1 receptor, norepinephrine transporter and plasma membrane monoamine transporter, whereas the latter was downregulated by haloperidol and L-DOPA. Astrocytes take up dopamine by multiple transporters and express dopamine receptors, which are sensitive to dopaminergic drugs. The findings of this study could open a promising area of research for the fine-tuning of existing therapeutic strategies.

Several midbrain nuclei degenerate in Parkinson’s Disease. Many of these nuclei share the common characteristics that are thought to contribute to their selective vulnerability, including pacemaking activity and high levels of calcium influx. In addition to the well-characterized dopaminergic neurons of the substantia nigra pars compacta (SNc), the cholinergic neurons of the pedunculopontine nucleus (PPN) also degenerate in PD. It is well established that the low-threshold L-type calcium current is a main contributor to tonic calcium in SNc dopaminergic neurons and is hypothesized to contribute to their selective vulnerability. However, it is not yet clear whether the vulnerable PPN cholinergic neurons share this property. Therefore, we used two-photon dendritic calcium imaging and whole-cell electrophysiology to evaluate the role of L-type calcium channels in the tonic and phasic activity of PPN neurons and the corresponding dendritic calcium signal and directly compare these characteristics to SNc neurons. We found that blocking L-type channels reduces tonic firing rate and dendritic calcium levels in SNc neurons. By contrast, the calcium load in PPN neurons during pacemaking did not depend on L-type channels. However, we find that blocking L-type channels reduces phasic calcium influx in PPN dendrites. Together, these findings show that L-type calcium channels play different roles in the activity of SNc and PPN neurons, and suggest that low-threshold L-type channels are not responsible for tonic calcium levels in PPN cholinergic neurons and are therefore not likely to be a source of selective vulnerability in these cells.

Sepsis is a life-threatening organ dysfunction that results from dysregulated host response to infection. Multiple organ system dysfunction syndromes are prevalent among septic patients and are essential hallmarks of sepsis diagnosis. These syndromes involve failure of the pulmonary, hepatic, circulatory, renal, gastrointestinal and central nervous systems. Neurological dysfunction is part of this syndrome and has gained research attention recently [1]. Sepsis induces neuroinflammation, BBB disruption, cerebral hypoxia, neuronal mitochondrial dysfunction and cell death causing sepsis-associated encephalopathy (SAE). These pathological consequences lead to short- and long-term neurobehavioral deficits. Till now there is no specific treatment that directly improves SAE and its associated behavioral impairments. In this review, we discuss the underlying mechanisms of sepsis-induced brain injury with a focus on the latest progress regarding neuroprotective effects of SIRT1 (silent mating type information regulation-2 homologue-1). SIRT1 is an NAD+-dependent class III protein deacetylase. It is able to modulate multiple downstream signals (including NF-κB, HMGB, AMPK, PGC1α and FoxO) which are involved in the development of SAE by its deacetylation activity. There are multiple recent studies showing the neuroprotective effects of SIRT1 in neuroinflammation related diseases. The proposed neuroprotective action of SIRT1 is meant to bring a promising therapeutic strategy for managing SAE and ameliorating its related behavioural deficits.

Psychopathy is characterized by glibness and superficial charm, as well as a lack of empathy, guilt, and remorse, and is often accompanied by antisocial behavior. The cerebral bases of this syndrome have been mostly studied in violent subjects or those with a criminal history. However, the antisocial component of psychopathy is not central to its conceptualization and, in fact, psychopathic traits are present in well-adjusted, non-criminal individuals within the general population. Interestingly, certain psychopathy characteristics appear to be particularly pronounced in some groups or professions. Importantly, as these so-called adaptive or successful psychopaths do not show antisocial tendencies or have significant psychiatric comorbidities, they may represent an ideal population to study this trait. Here we investigated such a group, specifically elite female judo athletes, and compared them to matched non-athletes. Participants completed psychopathy, anger, perspective-taking and empathic concern questionnaires and underwent structural magnetic resonance imaging (MRI). Grey matter density (GMD) was computed using voxel-based morphometry from the T1-weighted images. Athletes scored significantly higher in primary psychopathy and anger, and lower in empathy and perspective taking. They also exhibited smaller GMD in the right Temporal Pole, left Occipital Cortex, and left Amygdala/Hippocampus. GMD values for the latter cluster significantly correlated with primary psychopathy scores across both groups. These results confirm and extend previous findings to a little-studied population and provide support for the conceptualization of psychopathy as a dimensional personality trait which, not only is not necessarily associated with antisocial behavior, but may potentially have adaptive value.

Aims: to systematically review the prevalence of DCD in individuals born preterm; explore this prevalence according to gestational age and different assessments cut-offs; and compare to full-term peers. Methods: The eligibility criteria was observational and experimental studies reporting the prevalence of DCD in preterm individuals. A systematic search was performed in databases from inception until March 2022. The selection was performed by two independent reviewers. Study quality assessment was performed using the checklists from Joanna Briggs Institute (JBI). Data analysis were performed on Excel and Review Manager Software 5.4. Results: Among the 1774 studies identified, 32 matched the eligibility criteria. The pooled estimates of DCD rate in preterm was 21% (95% CI 17.8–24.3). The estimate rates were higher as gestational age decreased, and preterm children are two times more likely to have DCD than their full-term peers RR 2.2 (95% IC 1.77–2.79). Interpretation: The limitation was high heterogeneity between studies: the assessment tools and cut-off points, as well as the age at assessment, were diverse. This study provided evidence that preterm children are at higher risk for DCD than full-term children, and the risks increased as gestational age decreased.