Evolution of cortical neurons supporting human cognition

Human cognitive abilities are generally thought to arise from cortical expansion over the course of human brain evolution. In addition to increased neuron numbers, this cortical expansion might be driven by adaptations in the properties of single neurons and their local circuits. We review recent findings on the distinct structural, functional, and transcriptomic features of human cortical neurons and their organization in cortical microstructure. We focus on the supragranular cortical layers, which showed the most prominent expansion during human brain evolution, and the properties of their principal cells: pyramidal neurons. We argue that the evolutionary adaptations in neuronal features that accompany the expansion of the human cortex partially underlie interindividual variability in human cognitive abilities.

Ensembl 2022

Ensembl (https://www.ensembl.org) is unique in its flexible infrastructure for access to genomic data and annotation. It has been designed to efficiently deliver annotation at scale for all eukaryotic life, and it also provides deep comprehensive annotation for key species. Genomes representing a greater diversity of species are increasingly being sequenced. In response, we have focussed our recent efforts on expediting the annotation of new assemblies. Here, we report the release of the greatest annual number of newly annotated genomes in the history of Ensembl via our dedicated Ensembl Rapid Release platform (http://rapid.ensembl.org). We have also developed a new method to generate comparative analyses at scale for these assemblies and, for the first time, we have annotated non-vertebrate eukaryotes. Meanwhile, we continually improve, extend and update the annotation for our high-value reference vertebrate genomes and report the details here. We have a range of specific software tools for specific tasks, such as the Ensembl Variant Effect Predictor (VEP) and the newly developed interface for the Variant Recoder. All Ensembl data, software and tools are freely available for download and are accessible programmatically.

The Ensembl COVID-19 resource: ongoing integration of public SARS-CoV-2 data

The COVID-19 pandemic has seen unprecedented use of SARS-CoV-2 genome sequencing for epidemiological tracking and identification of emerging variants. Understanding the potential impact of these variants on the infectivity of the virus and the efficacy of emerging therapeutics and vaccines has become a cornerstone of the fight against the disease. To support the maximal use of genomic information for SARS-CoV-2 research, we launched the Ensembl COVID-19 browser; the first virus to be encompassed within the Ensembl platform. This resource incorporates a new Ensembl gene set, multiple variant sets, and annotation from several relevant resources aligned to the reference SARS-CoV-2 assembly. Since the first release in May 2020, the content has been regularly updated using our new rapid release workflow, and tools such as the Ensembl Variant Effect Predictor have been integrated. The Ensembl COVID-19 browser is freely available at https://covid-19.ensembl.org.

Verbal and General IQ Associate with Supragranular Layer Thickness and Cell Properties of the Left Temporal Cortex

The left temporal lobe is an integral part of the language system and its cortical structure and function associate with general intelligence. However, whether cortical laminar architecture and cellular properties of this brain area relate to verbal intelligence is unknown. Here, we addressed this using histological analysis and cellular recordings of neurosurgically resected temporal cortex in combination with presurgical IQ scores. We find that subjects with higher general and verbal IQ scores have thicker left (but not right) temporal cortex (Brodmann area 21, BA21). The increased thickness is due to the selective increase in layers 2 and 3 thickness, accompanied by lower neuron densities, and larger dendrites and cell body size of pyramidal neurons in these layers. Furthermore, these neurons sustain faster action potential kinetics, which improves information processing. Our results indicate that verbal mental ability associates with selective adaptations of supragranular layers and their cellular micro-architecture and function in left, but not right temporal cortex.

P–772 Blastocyst quality and perinatal outcomes in women undergoing single blastocyst transfer in frozen cycles

Study question

Is the morphological grading systems of a blastocyst associated with perinatal outcomes in women undergoing frozen-thawed single blastocyst transfer (SBT)?

Summary answer

Preferential transfer of a blastocyst based on their morphological grading systems appears to be supported by observed differences in perinatal outcomes.

What is known already

The transfer of a morphologically good quality blastocyst is associated with higher implantation and pregnancy rates as compared with a poor quality blastocyst. However to date, the association of the morphologic parameters of the blastocyst (developmental stage, inner cell mass (ICM), and trophectoderm (TE)) with the perinatal outcomes after blastocyst transfer remains unknown.

Study design, size, duration

A retrospective cohort study including 21,648 frozen-thawed SBT cycles from January 2013 to March 2019.

Participants/materials, setting, methods

6037 women with singleton delivery in Peking University Third Hospital were eligible for analysis. Multivariate logistic regression was used to test the risk of factors with the expression of crude odds ratios (OR) and adjusted OR (aOR) with 95% confidence intervals (CI).

Main results and the role of chance

Transfer of a blastocyst with grading lower than 3BB was associated with a higher chance of female baby (49% vs 43%, aOR = 1.27 (1.12, 1.43)) and a higher rate of cesarian section (C-section) (69% vs 65%, aOR = 1.17 (1.03, 1.34)). Compared with stage 4 blastocyst, transfer of a stage 3 blastocyst was associated with a higher chance of preterm delivery (PTD) (aOR = 1.77 (1.08, 2.90)). Both stage 3 and stage 6 blastocyst transfer was associated with a lower chance of female baby (aOR = 0.68 (0.48, 0.97), 0.66 (0.47, 0.93), respectively). Compared with grade A ICM blastocyst transfer, Grade B ICM and grade C ICM blastocyst transfer was associated with a lower chance of a female baby (adjusted OR = 0.84 (0.73, 0.96), 0.63 (0.48, 0.83), respectively) and a higher risk of large for gestational age (LGA) (aOR = 1.20 (1.01, 1.42), 1.46 (1.07, 1.98), respectively). Grade C ICM blastocyst transfer was associated with an increased risk of macrosomia (aOR = 1.66 (1.14, 2.42)).Grade B TE and grade C TE blastocyst transfer had a lower risk of gestational diabetes mellitus (GDM) (aOR = 0.76 (0.60, 0.98), 0.69 (0.50, 0.94), respectively) than grade A TE blastocyst transfer.

Limitations, reasons for caution

The main limitations of this study were its retrospective nature and the relative subjectivity of blastocyst scoring. The follow-up was conducted through a phone call and some patients might not report their obstetrical and neonatal outcomes, leading to a relatively lower rate of several obstetrical outcomes.

Wider implications of the findings: Transfer of a poor quality blastocyst is associated with a higher rate of C-section. The association between ICM grading and LGA and macrosomia would suggest that blastocysts with grade A ICM grading should be transferred preferentially and supports the use of current morphological grading systems for embryo prioritisation.

Trial registration number

N/A