Chemogenetic Modulation of Preoptic Neurons Decreases Body Temperature and Heart Rate.

The preoptic area of the hypothalamus is critical for regulation of brain-body interaction, including circuits that control vital signs such as body temperature and heart rate. The preoptic area contains approximately 70 molecularly distinct cell types. The gene is expressed in a subset of preoptic area cell types.

A novel rat model of Dravet syndrome recapitulates clinical hallmarks.

Dravet syndrome (DS) is a debilitating infantile epileptic encephalopathy characterized by seizures induced by high body temperature (hyperthermia), sudden unexpected death in epilepsy (SUDEP), cognitive impairment, and behavioral disturbances. The most common cause of DS is haploinsufficiency of the SCN1A gene, which encodes the voltage-gated sodium channel Na1.1.

Cortical synapses of the world's smallest mammal: An FIB/SEM study in the Etruscan shrew.

The main aim of the present study was to determine if synapses from the exceptionally small brain of the Etruscan shrew show any peculiarities compared to the much larger human brain. We analyzed the cortical synaptic density and a variety of structural characteristics of 7,239 3D reconstructed synapses, using using Focused Ion Beam/Scanning Electron Microscopy (FIB/SEM). We found that some of the general synaptic characteristics are remarkably similar to those found in the human cerebral cortex.

Modular microcircuit organization of the presubicular head-direction map.

Our internal sense of direction is thought to rely on the activity of head-direction (HD) neurons. We find that the mouse dorsal presubiculum (PreS), a key structure in the cortical representation of HD, displays a modular "patch-matrix" organization, which is conserved across species (including human). Calbindin-positive layer 2 neurons within the "matrix" form modular recurrent microcircuits, while inputs from the anterodorsal and laterodorsal thalamic nuclei are non-overlapping and target the "patch" and "matrix" compartments, respectively.

Developmental Patterning and Neurogenetic Gradients of Positive Neurons in the Rat Claustrum and Lateral Cortex.

The claustrum is an enigmatic brain structure thought to be important for conscious sensations. Recent studies have focused on gene expression patterns, connectivity, and function of the claustrum, but relatively little is known about its development. Interestingly, claustrum-enriched genes, including the previously identified marker , are not only expressed in the classical claustrum complex, but also embedded within lateral neocortical regions in rodents.

Seasonal plasticity in the adult somatosensory cortex.

Seasonal cycles govern life on earth, from setting the time for the mating season to influencing migrations and governing physiological conditions like hibernation. The effect of such changing conditions on behavior is well-appreciated, but their impact on the brain remains virtually unknown. We investigate long-term seasonal changes in the mammalian brain, known as Dehnel's effect, where animals exhibit plasticity in body and brain sizes to counter metabolic demands in winter.

Estrus-Cycle Regulation of Cortical Inhibition.

Female mammals experience cyclical changes in sexual receptivity known as the estrus cycle. Little is known about how estrus affects the cortex, although alterations in sensation, cognition and the cyclical occurrence of epilepsy suggest brain-wide processing changes. We performed in vivo juxtacellular and whole-cell recordings in somatosensory cortex of female rats and found that the estrus cycle potently altered cortical inhibition.

Evolution of pallium, hippocampus, and cortical cell types revealed by single-cell transcriptomics in reptiles.

Computations in the mammalian cortex are carried out by glutamatergic and γ-aminobutyric acid-releasing (GABAergic) neurons forming specialized circuits and areas. Here we asked how these neurons and areas evolved in amniotes. We built a gene expression atlas of the pallium of two reptilian species using large-scale single-cell messenger RNA sequencing.

Structural modularity and grid activity in the medial entorhinal cortex.

Following the groundbreaking discovery of grid cells, the medial entorhinal cortex (MEC) has become the focus of intense anatomical, physiological, and computational investigations. Whether and how grid activity maps onto cell types and cortical architecture is still an open question. Fundamental similarities in microcircuits, function, and connectivity suggest a homology between rodent MEC and human posteromedial entorhinal cortex.

On the Value of Reptilian Brains to Map the Evolution of the Hippocampal Formation.

Our ability to navigate through the world depends on the function of the hippocampus. This old cortical structure plays a critical role in spatial navigation in mammals and in a variety of processes, including declarative and episodic memory and social behavior. Intense research has revealed much about hippocampal anatomy, physiology, and computation; yet, even intensely studied phenomena such as the shaping of place cell activity or the function of hippocampal firing patterns during sleep remain incompletely understood.

Complementary Modular Microcircuits of the Rat Medial Entorhinal Cortex.

The parahippocampal region is organized into different areas, with the medial entorhinal cortex (MEC), presubiculum and parasubiculum prominent in spatial memory. Here, we also describe a region at the extremity of the MEC and bordering the subicular complex, the medial-most part of the entorhinal cortex. While the subdivisions of hippocampus proper form more or less continuous cell sheets, the superficial layers of the parahippocampal region have a distinct modular architecture.

Conserved size and periodicity of pyramidal patches in layer 2 of medial/caudal entorhinal cortex.

To understand the structural basis of grid cell activity, we compare medial entorhinal cortex architecture in layer 2 across five mammalian species (Etruscan shrews, mice, rats, Egyptian fruit bats, and humans), bridging ∼100 million years of evolutionary diversity. Principal neurons in layer 2 are divided into two distinct cell types, pyramidal and stellate, based on morphology, immunoreactivity, and functional properties. We confirm the existence of patches of calbindin-positive pyramidal cells across these species, arranged periodically according to analyses techniques like spatial autocorrelation, grid scores, and modifiable areal unit analysis.