146 research outputs found
Does hippocampal atrophy explain anterograde and retrograde amnesia following autoimmune limbic encephalitis?
Letter to the Edito
The cerebellum, internal models and prediction in 'non-motor' aspects of language: A critical review
The emergence of studies on cerebellar contributions in ‘non-motor’ aspects of predictive language processing has long been awaited by researchers investigating the neural foundations of language and cognition. Despite (i) progress in research implicating the cerebellum in language processing, (ii) the widely-accepted nature of the uniform, multi-modal computation that the cerebellum implements in the form of internal models, as well as (iii) the long tradition of psycholinguistic studies addressing prediction mechanisms, research directly addressing cerebellar contributions to ‘non-motor’ predictive language processing has only surfaced in the last five years. This paper provides the first review of this novel field, along with a critical assessment of the studies conducted so far. While encouraging, the evidence for cerebellar involvement in ‘non-motor’ aspects of predictive language processing remains inconclusive under further scrutiny. Future directions are finally discussed with respect to outstanding questions in this novel field of research
The neostriatum and response selection in overt sentence production: An fMRI study
A number of premotor and prefrontal brain areas have been recently shown to play a significant role in response selection in overt sentence production. These areas are anatomically connected to the basal ganglia, a set of subcortical structures that has been traditionally involved in response selection across behavioral domains. The putamen and the caudate, the two major inputs to the basal ganglia, have been shown to undertake motor— as well as non-motor-related selection operations in language processing. Here we investigate the role of these basal ganglia structures in sentence repetition and generation in healthy adults. Although sentence generation is known to activate prefrontal and premotor cortical areas that reciprocally connect with these two neostriatal structures, their specific contributions are not known. We present evidence suggesting that that the putamen undertakes articulation-related aspects across tasks, while the caudate selectively supports selection processes in sentence generation
Editorial: The cerebellar role in psychiatric disorders: Emerging evidence and future perspectives
First paragraph: Over the past decades, clinical, neuroimaging, anatomical, and physiological studies have established the presence of a “cognitive” and a “limbic” cerebellum—the former being represented primarily in posterolateral regions and the dentate nuclei, and the latter in the vermis and the fastigial nuclei (Schmahmann et al., 2007). The “dysmetria of thought,” following damage to the cognitive cerebellum (Schmahmann, 1998) and the neuropsychiatric impairments, following damage to the limbic cerebellum (Schmahmann et al., 2007) comprise the so called “cerebellar cognitive affective syndrome” (Schmahmann and Sherman, 1998). These findings have recently renewed interest in a cerebellar pathophysiology of a broad range of neurodevelopmental and psychiatric disorders (e.g. Hoppenbrouwers et al., 2008; Lupo et al., 2019; Van Overwalle et al., 2020)
Results of the first European Source Apportionment intercomparison for Receptor and Chemical Transport Models
In this study, the performance of the source apportionment model applications were evaluated by comparing the model results provided by 44 participants adopting a methodology based on performance indicators: z-scores and RMSEu, with pre-established acceptability criteria. Involving models based on completely different and independent input data, such as receptor models (RMs) and chemical transport models (CTMs), provided a unique opportunity to cross-validate them. In addition, comparing the modelled source chemical profiles, with those measured directly at the source contributed to corroborate the chemical profile of the tested model results. The most used RM was EPA- PMF5. RMs showed very good performance for the overall dataset (91% of z-scores accepted) and more difficulties are observed with SCE time series (72% of RMSEu accepted). Industry resulted the most problematic source for RMs due to the high variability among participants. Also the results obtained with CTMs were quite comparable to their ensemble reference using all models for the overall average (>92% of successful z-scores) while the comparability of the time series is more problematic (between 58% and 77% of the candidates’ RMSEu are accepted). In the CTM models a gap was observed between the sum of source contributions and the gravimetric PM10 mass likely due to PM underestimation in the base case. Interestingly, when only the tagged species CTM results were used in the reference, the differences between the two CTM approaches (brute force and tagged species) were evident. In this case the percentage of candidates passing the z-score and RMSEu tests were only 50% and 86%, respectively. CTMs showed good comparability with RMs for the overall dataset (83% of the z-scores accepted), more differences were observed when dealing with the time series of the single source categories. In this case the share of successful RMSEu was in the range 25% - 34%.JRC.C.5-Air and Climat
Volume reduction of caudate nucleus is associated with movement coordination deficits in patients with hippocampal atrophy due to perinatal hypoxia-ischaemia
Acute sentinel hypoxia-ischaemia in neonates can target the hippocampus, mammillary bodies, thalamus, and the basal ganglia. Our previous work with paediatric patients with a history of hypoxia-ischaemia has revealed hippocampal and diencephalic damage that impacts cognitive memory. However, the structural and functional status of other brain regions vulnerable to hypoxia-ischaemia, such as the basal ganglia, has not been investigated in these patients. Furthermore, it is not known whether there are any behavioural sequelae of such damage, especially in patients with no diagnosis of neurological disorder. Based on the established role of the basal ganglia and the thalamus in movement coordination, we studied manual motor function in 20 participants exposed to neonatal hypoxia-ischaemia, and a group of 17 healthy controls of comparable age. The patients’ handwriting speed and accuracy was within the normal range (Detailed Assessment of Speed of Handwriting), and their movement adaptation learning (Rotary Pursuit task) was comparable to the control group’s performance. However, as a group, patients showed an impairment in the Grooved Pegboard task and a trend for impairment in speed of movement while performing the Rotary Pursuit task, suggesting that some patients have subtle deficits in fine, complex hand movements. Voxel-based morphometry and volumetry showed bilateral reduction in grey matter volume of the thalamus and caudate nucleus. Reduced volumes in the caudate nucleus correlated across patients with performance on the Grooved Pegboard task. In summary, the fine movement coordination deficit affecting the hand and the wrist in patients exposed to early hypoxic-ischaemic brain injury may be related to reduced volumes of the caudate nucleus, and consistent with anecdotal parental reports of clumsiness and coordination difficulties in this cohort
Beam Longitudinal Dynamics Simulation Suite BLonD
The beam longitudinal dynamics code BLonD has been developed at CERN since
2014 and has become a central tool for longitudinal beam dynamics simulations.
In this paper, we present this modular simulation suite and the various physics
models that can be included and combined by the user. We detail the reference
frame, the equations of motion, the BLonD-specific options for radio-frequency
parameters such as phase noise, fixed-field acceleration, and feedback models
for the CERN accelerators, as well as the modeling of collective effects and
synchrotron radiation. We also present various methods of generating
multi-bunch distributions matched to a given impedance model. BLonD is
furthermore a well-tested and optimized simulation suite, which is demonstrated
through examples, too
Reconstruction of primary vertices at the ATLAS experiment in Run 1 proton–proton collisions at the LHC
This paper presents the method and performance of primary vertex reconstruction in proton–proton collision data recorded by the ATLAS experiment during Run 1 of the LHC. The studies presented focus on data taken during 2012 at a centre-of-mass energy of √s=8 TeV. The performance has been measured as a function of the number of interactions per bunch crossing over a wide range, from one to seventy. The measurement of the position and size of the luminous region and its use as a constraint to improve the primary vertex resolution are discussed. A longitudinal vertex position resolution of about 30μm is achieved for events with high multiplicity of reconstructed tracks. The transverse position resolution is better than 20μm and is dominated by the precision on the size of the luminous region. An analytical model is proposed to describe the primary vertex reconstruction efficiency as a function of the number of interactions per bunch crossing and of the longitudinal size of the luminous region. Agreement between the data and the predictions of this model is better than 3% up to seventy interactions per bunch crossing
Hippocampal damage disrupts the latent decision-making processes underlying approach-avoidance conflict processing in humans
Rodent and human data implicate the hippocampus in the arbitration of approach-avoidance conflict (AAC), which arises when an organism is confronted with a stimulus associated simultaneously with reward and punishment. Yet, the precise contributions of this structure are underexplored, particularly with respect to the decision-making processes involved. We assessed humans with hippocampal damage and matched neurologically healthy controls on a computerized AAC paradigm in which participants first learned whether individual visual images were associated with the reward or loss of game points and were then asked to approach or avoid pairs of stimuli with non-conflicting or conflicting valences. To assess hippocampal involvement more broadly in response conflict, we also administered a Stroop and a Go/No-go task. On the AAC paradigm, following similar learning outcomes in individuals with hippocampal damage and matched controls, both participant groups approached positive and negative image pairs at the same rate but critically, those with hippocampal damage approached conflict pairs more often than controls. Choice and response AAC data were interrogated using the hierarchical drift diffusion model, which revealed that, compared to controls, individuals with hippocampal damage were more biased towards approach, required less evidence to make a decision during conflict trials, and were slower to accumulate evidence towards avoidance when confronted with conflicting image pairs. No significant differences were found between groups in performance accuracy or response time on the response conflict tasks. Taken together, these findings demonstrate the importance of the hippocampus to the evidence accumulation processes supporting value-based decision-making under motivational conflict
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