Laminar fate specification in the cerebral cortex

The cerebral cortex is composed of hundreds of different types of neurons, which underlie its ability to perform highly complex neural processes. How this astonishing cell diversity is generated during development constitutes a major challenge in developmental neurosciences, with important implications for neurological diseases. Here we review some recent and exciting advances in this field, from the description of the cellular processes at the origin of cortical neuron diversity, to the dissection of the molecular logic underlying fate selection in cortical neurons

Entropy production and time asymmetry in nonequilibrium fluctuations

The time-reversal symmetry of nonequilibrium fluctuations is experimentally investigated in two out-of-equilibrium systems namely, a Brownian particle in a trap moving at constant speed and an electric circuit with an imposed mean current. The dynamical randomness of their nonequilibrium fluctuations is characterized in terms of the standard and time-reversed entropies per unit time of dynamical systems theory. We present experimental results showing that their difference equals the thermodynamic entropy production in units of Boltzmann's constant

Quantification of EEG reactivity in comatose patients

OBJECTIVE: EEG reactivity is an important predictor of outcome in comatose patients. However, visual analysis of reactivity is prone to subjectivity and may benefit from quantitative approaches. METHODS: In EEG segments recorded during reactivity testing in 59 comatose patients, 13 quantitative EEG parameters were used to compare the spectral characteristics of 1-minute segments before and after the onset of stimulation (spectral temporal symmetry). Reactivity was quantified with probability values estimated using combinations of these parameters. The accuracy of probability values as a reactivity classifier was evaluated against the consensus assessment of three expert clinical electroencephalographers using visual analysis. RESULTS: The binary classifier assessing spectral temporal symmetry in four frequency bands (delta, theta, alpha and beta) showed best accuracy (Median AUC: 0.95) and was accompanied by substantial agreement with the individual opinion of experts (Gwet’s AC1: 65–70%), at least as good as inter-expert agreement (AC1: 55%). Probability values also reflected the degree of reactivity, as measured by the inter-experts’ agreement regarding reactivity for each individual case. CONCLUSION: Automated quantitative EEG approaches based on probabilistic description of spectral temporal symmetry reliably quantify EEG reactivity. SIGNIFICANCE: Quantitative EEG may be useful for evaluating reactivity in comatose patients, offering increased objectivity

Electromagnetic Field Coupling to Transmission Lines: A Model for the Risers

In this paper, an improved model of the vertical risers of a transmission line is proposed and validated. The proposed improved model, which can be readily implemented in the frame of a classical transmission line formulation, provides accurate results at frequencies much higher than the upper frequency limit of the classical transmission line theory. For example, for the assessed line (with a height above the ground of 10 cm), the improved model is still fairly accurate at around 1 GHz, whereas the classical model starts to deviate from the accurate solution at around 150 MHz

Role of Epileptic Activity in Older Adults With Delirium, a Prospective Continuous EEG Study

Background/Objectives: Delirium occurs in up to 50 % of hospitalized old patients and is associated with increased morbidity and mortality. Acute medical conditions favor delirium, but the pathophysiology is unclear. Preliminary evidence from retrospective and prospective studies suggests that a substantial minority of old patients with unexplained delirium have non-convulsive seizures or status epilepticus (NCSE). Yet, seeking epileptic activity only in unexplained cases of delirium might result in misinterpretation of its actual prevalence. We aimed to systematically investigate the role of epileptic activity in all older patients with delirium regardless of the underlying etiology.Design, Setting: Prospective observational study in a tertiary medical center. Adults >65 years with delirium underwent at least 24 h of continuous electro-encephalographic monitoring (cEEG). Background patterns and ictal and interictal epileptic discharges were identified, as well as clinical and biological characteristics.Participants: Fifty patients were included in the study.Results: NCSE was found in 6 (12%) patients and interictal discharges in 15 (30%). There was no difference in the prevalence of epileptic activity rates between delirium associated with an acute medical condition and delirium of unknown etiology.Conclusion: Epileptic activity may play a substantial role in the pathophysiology of delirium by altering brain functioning and neuronal metabolism. No clinical or biological marker was found to distinguish delirious patients with or without epileptic activity, underlining the importance of cEEG in this context

Azoospermie non obstructive : auto-immunité, génétique, histologie testiculaire et résultats d’une prise en charge endocrinienne dans une série prospective de 29 patients

peer reviewedIntroduction : L’azoospermie non obstructive (NOA) est l’absence de spermatozoïdes dans l’éjaculat, secondaire à une anomalie de la spermatogenèse. L’étiologie de cette atteinte est souvent méconnue. Patients et Méthodes : Depuis 2020, nous suivons une série de 29 hommes( (32 ans) avec NOA, consultant pour une infertilité primaire. Ils ont bénéficié d’un bilan endocrinien et urologique, incluant une échographie testiculaire, un spermogramme, une bactériologie et une sérologie virales. Une première étude du caryotype, CFTR et micro délétions AZF(29 patients) a été suivie d’un panel de 130 gènes d’hypogonadisme (10 patients). Résultats : Une auto-immunité thyroïdienne a été retrouvée chez 14/29. Des anomalies génétiques sont présentes chez 11/29 cas incluant : XXY (1cas), délétion AZF (2cas), CFTR (2 cas), une mutation hétérozygote connexine 30-26, associant une surdité congénitale (1 cas), 2 mutations non décrites du récepteur aux androgènes, une mutation SRD5A2, maladie de Wilson (1cas), CYP21A2 (1cas). L’histologie testiculaire retrouve un arrêt de la spermatogenèse chez 11/14 cas et un Sertoli only syndrome chez 3/14 cas, avec une orchite localisée (auto-immune ?) chez 2 cas. Après stimulation de 3 à 6 mois par clomifène 50 mg/j (26 cas), létrozol 2.5mg/j (5 cas), et supplémentation par hydrocortisone (1 cas) ou lévothyroxine (13 cas), on observe à ce jour une faible production de spermatozoïdes chez 6/29 patients. Conclusions : L’auto-immunité et les causes génétiques incluant la voie des androgènes sont des mécanismes sous-estimés chez les patients avec NOA. Une prise en charge endocrinienne est susceptible d’améliorer la fertilité chez des patients soigneusement étudiés.Introduction: Non-obstructive azoospermia (NOA) is the absence of spermatozoa in the ejaculate, secondary to an abnormality of spermatogenesis. The etiology of this disease is often unknown. Patients and Methods: Since 2020, we followed a series of 29 men (with NOA, consultant for primary infertility). They underwent an endocrine and urological assessment, including testicular ultrasound, spermogram, bacteriology and viral serology. A first study of karyotype, CFTR and AZF microdeletions (29 patients) was followed by a panel of 130 hypogonadism genes (10 patients). Results: Thyroid autoimmunity was found in 14/29 patients. Genetic abnormalities were present in 11/29 cases including: XXY (1 case), AZF deletion (2 cases), CFTR (2 cases), a heterozygous connectin 30-26 mutation, associating congenital deafness (1 case), 2 undescribed androgen receptor mutations, an SRD5A2 mutation, Wilson's disease (1 case), CYP21A2 (1 case). Testicular histology showed arrest of spermatogenesis in 11/14 cases and Sertoli only syndrome in 3/14 cases, with localized orchitis (autoimmune?) in 2 cases. After stimulation of 3 to 6 months with clomiphene 50 mg/day (26 cases), letrozol 2.5 mg/day (5 cases), and supplementation with hydrocortisone (1 case) or levothyroxine (13 cases), low sperm production has been observed to date in 6/29 patients. Conclusions: Autoimmunity and genetic causes including the androgen pathway are underestimated mechanisms in patients with NOA. Endocrine management has the potential to improve fertility in patients who have been carefully studied