Search results for "Neurosciences. Biological psychiatry. Neuropsychiatry"

Context-dependent minimisation of prediction errors involves temporal-frontal activation

2020

According to the predictive coding model of perception, the brain constantly generates predictions of the upcoming sensory inputs. Perception is realised through a hierarchical generative model which aims at minimising the discrepancy between predictions and the incoming sensory inputs (i.e., prediction errors). Notably, prediction errors are weighted depending on precision of prior information. However, it remains unclear whether and how the brain monitors prior precision when minimising prediction errors in different contexts. The current study used magnetoencephalography (MEG) to address this question. We presented participants with repetition of two non-predicted probes embedded in cont…

Influence of ADAM10 on prion protein processing and scrapie infectiosity in vivo.

2009

Abstract Both the cellular prion protein (PrPc) and the amyloid precursor protein (APP) are physiologically subjected to complex proteolytic processing events. While for APP the proteinases involved – alpha-, beta- and gamma-secretase – have been identified in vitro and in vivo, the cleavage of PrPc by now has been linked only to the shedding activity of the metalloproteinase ADAM10 and/or ADAM17 in cell culture. Here we show that neuronal overexpression of the alpha-secretase ADAM10 in mice reduces all PrPc species detected in the brain instead of leading to enhanced amounts of specific cleavage products of PrPc. Additionally, the incubation time of mice after scrapie infection is signific…

Familial Hemiplegic Migraine with an ATP1A4 Mutation: Clinical Spectrum and Carbamazepine Efficacy

2020

An Italian family with familial hemiplegic migraine (FHM) with the absence of mutations in the known genes associated with this disorder, namely ATP1A2, ATP1A3, CACNA1A, and SCN1A, has recently been reported. Soon afterward, whole exome sequencing allowed the identification of the carrier status of a heterozygous ATP1A4 mutation c.1798 C >T, in four affected members of this family. Here we compare the clinical symptoms of the affected family members with those from the other FHM families linked to mutations in the known genes associated with this disorder. A further two-year follow-up, including clinical response to carbamazepine administered to the proband and the maternal grandmother due …

Stochastic model predicts evolving preferences in the Iowa gambling task

2014

Learning under uncertainty is a common task that people face in their daily life. This process relies on the cognitive ability to adjust behavior to environmental demands. Although the biological underpinnings of those cognitive processes have been extensively studied, there has been little work in formal models seeking to capture the fundamental dynamic of learning under uncertainty. In the present work, we aimed to understand the basic cognitive mechanisms of outcome processing involved in decisions under uncertainty and to evaluate the relevance of previous experiences in enhancing learning processes within such uncertain context. We propose a formal model that emulates the behavior of p…

Polyglutamine toxicity induces rod photoreceptor division, morphological transformation or death in Spinocerebellar ataxia 7 mouse retina

2010

In neurodegenerative disorders caused by polyglutamine (polyQ) expansion, polyQ toxicity is thought to trigger a linear cascade of successive degenerative events leading to neuronal death. To understand how neurons cope with polyQ toxicity, we studied a Spinocerebellar ataxia 7 (SCA7) mouse which expresses polyQ-expanded ATXN7 only in rod photoreceptors. We show that in response to polyQ toxicity, SCA7 rods go through a range of radically different cell fates, including apoptotic and non-apoptotic cell death, cell migration, morphological transformation into a round cell or, most remarkably, cell division. The temporal profile of retinal remodeling indicates that some degenerative pathways …

Wild-type Cu/Zn superoxide dismutase (SOD1) does not facilitate, but impedes the formation of protein aggregates of amyotrophic lateral sclerosis cau…

2009

Aggregation of Cu/Zn superoxide dismutase (SOD1) is a hallmark of a subset of familial amyotrophic lateral sclerosis (ALS) cases. The expression of wild-type SOD1 [SOD(hWT)] surprisingly exacerbates the phenotype of mutant SOD1 in vivo. Here we studied whether SOD1(hWT) may affect mutant SOD1 aggregation by employing fluorescence microscopy techniques combined with lifetime-based Förster resonance energy transfer (FRET). Only a very minor fraction of SOD1(hWT) was observed in aggregates induced by mutant SOD1(G37R), SOD1(G85R) or SOD1(G93C). Quite in contrast, co-expression of SOD(hWT) reduced the amount of mutant SOD1 in the aggregate fraction. Furthermore, we did not detect endogenous mou…

Longitudinal CSF proteome profiling in mice to uncover the acute and sustained mechanisms of action of rapid acting antidepressant (2R,6R)-hydroxynor…

2021

Delayed onset of antidepressant action is a shortcoming in depression treatment. Ketamine and its metabolite (2R,6R)-hydroxynorketamine (HNK) have emerged as promising rapid-acting antidepressants. However, their mechanism of action remains unknown. In this study, we first described the anxious and depression-prone inbred mouse strain, DBA/2J, as an animal model to assess the antidepressant-like effects of ketamine and HNK in vivo. To decode the molecular mechanisms mediating HNK's rapid antidepressant effects, a longitudinal cerebrospinal fluid (CSF) proteome profiling of its acute and sustained effects was conducted using an unbiased, hypothesis-free mass spectrometry-based proteomics app…

Indirect assessment of an interpretation bias in humans: Neurophysiological and behavioral correlates

2013

Affective state can influence cognition leading to biased information processing, interpretation, attention, and memory. Such bias has been reported to be essential for the onset and maintenance of different psychopathologies, particularly affective disorders. However, empirical evidence has been very heterogeneous and little is known about the neurophysiological mechanisms underlying cognitive bias and its time-course. We therefore investigated the interpretation of ambiguous stimuli as indicators of biased information processing with an ambiguous cue-conditioning paradigm. In an acquisition phase, participants learned to discriminate two tones of different frequency, which acquired emotio…

A range of pulses commonly used for human transcranial ultrasound stimulation are clearly audible.

2021

Does the Relation between Rapid Automatized Naming and Reading Depend on Age or on Reading Level? A Behavioral and ERP Study

2018

Reading predictors evolve through age: phonological awareness is the best predictor of reading abilities at the beginning of reading acquisition while Rapid Automatized Naming (RAN) becomes the best reading predictor in more experienced readers (around 9–10 years old). Those developmental changes in the relationship between RAN and reading have so far been explained in term of participants' age. However, it should be noted that in the previous experiments age always co-vary with participants reading level. It is thus not clear whether RAN-reading relationship is developmental in nature or related to the reading system itself. This study investigates whether the behavioral changes in the rel…