Evolution of Local Circuit Neurons in Two Sensory Thalamic Nuclei in Amniotes
Local circuit neurons are present in the thalamus of all vertebrates where they are considered inhibitory. They play an important role in computation and influence the transmission of information from the thalamus to the telencephalon. In mammals, the percentage of local circuit neurons in the dorsal lateral geniculate nucleus remains relatively constant across a variety of species. In contrast, the numbers of local circuit neurons in the ventral division of the medial geniculate body in mammals varies significantly depending on the species examined. To explain these observations, the numbers of local circuit neurons were ...
Source: Brain, Behavior and Evolution - March 27, 2023 Category: Neurology Source Type: research
Mapping human brain pathways: challenges and opportunities in the integration of scales
The human brain is composed of a complex web of pathways. Diffusion magnetic resonance (MR) tractography relies on the principle of diffusion to reconstruct brain pathways. Its tractography is broadly applicable to a range of problems as it is amenable to being studied in individuals of any age and from any species. However, it is well-known that this technique can generate biologically implausible pathways, especially in regions of the brain where multiple fibers cross. This review highlights potential mis-connections in two cortico-cortical association pathways with a focus on the aslant tract and inferior frontal occipi...
Source: Brain, Behavior and Evolution - March 27, 2023 Category: Neurology Source Type: research
The Diversity of the Brains of Ray-Finned Fishes
Brains are very plastic both in response to phenotypic diversity and to larger evolutionary trends. Differences between taxa cannot be easily attributed to either factors. Comparative morphological data on higher taxonomic levels is scarce especially in ray-finned fishes. Here we show the great diversity of brain areas of more than 150 species of ray-finned fishes by volumetric measurements using block face imaging. We found that differences among families or orders are more likely due to environmental needs than to systematic position. Most notable changes are present in the brain areas processing sensory input (chemosens...
Source: Brain, Behavior and Evolution - March 22, 2023 Category: Neurology Source Type: research
Studying the brain monoaminergic systems and neurotrophic factors in minipigs with high and low tolerance to the presence of human
Here, we present the first evidence for brain adaptation in pigs tolerant to the human presence, as a behavioral trait favoring domestication. The study was carried out on minipiglets from population bred in the Institute of Cytology and Genetics (Novosibirsk, Russia). We compared the behavior, metabolism of monoaminergic neurotransmitter systems and functional activity of the hypothalamic-pituitary-adrenal system, as well as neurotrophic markers in the brain of minipigs differing by tolerance to human presence (HT and LT - High and Low Tolerance). The piglets did not differ in the levels of activity in the open field test...
Source: Brain, Behavior and Evolution - March 13, 2023 Category: Neurology Source Type: research
Sex and Season Affect Cortical Volumes in Free-Living Western Fence Lizards, < i > Sceloporus occidentalis < /i >
This study highlights the importance of investigating sex differences and including females in studies of spatial ecology and neuroplasticity. (Source: Brain, Behavior and Evolution)
Source: Brain, Behavior and Evolution - February 16, 2023 Category: Neurology Source Type: research
Sex and season affect cortical volumes in free-living Western fence lizards, Sceloporus occidentalis
This study highlights the importance of investigating sex differences and including females in studies of spatial ecology and neuroplasticity. (Source: Brain, Behavior and Evolution)
Source: Brain, Behavior and Evolution - February 16, 2023 Category: Neurology Source Type: research
Retinal Ganglion Cell Topography and Spatial Resolution in Three Indian Pteropodid Bats
We present retinal ganglion cell topographic maps and anatomical estimates of spatial resolution in three southern Indian pteropodid species with different roosting preferences. Ganglion cell densities are between 1,000 and 2,000 cells/mm2 in the central retina and lower in the dorsal and ventral periphery. All three species have a temporal area in the retina with peak ganglion cell densities of 4,600 –6,600 cells/mm2. As a result, the foliage-roostingCynopterus sphinx and the cave-roostingRousettus leschenaultii have similar anatomical resolution (2.7 and 2.8 cycles/degree, respectively). The anatomical estimate for the...
Source: Brain, Behavior and Evolution - December 29, 2022 Category: Neurology Source Type: research
Retinal ganglion cell topography and spatial resolution in three Indian pteropodid bats
We present retinal ganglion cell topographic maps and anatomical estimates of spatial resolution in three southern Indian pteropodid species with different roosting preferences. Ganglion cell densities are between 1000 and 2000 cells/mm2 in the central retina and lower in the dorsal and ventral periphery. All three species have a temporal area in the retina with peak ganglion cell densities of 4600 to 6600 cells/mm2. As a result, the foliage-roosting Cynopterus sphinx and the cave-roosting Rousettus leschenaultii have similar anatomical resolution (2.7 and 2.8 cycles/degree, respectively). The anatomical estimate for the l...
Source: Brain, Behavior and Evolution - December 29, 2022 Category: Neurology Source Type: research
Molecular Diversity of Neuron Types in the Salamander Amygdala and Implications for Amygdalar Evolution
The amygdala is a complex brain structure in the vertebrate telencephalon, essential for regulating social behaviors, emotions, and (social) cognition. In contrast to the vast majority of neuron types described in the many nuclei of the mammalian amygdala, little is known about the neuronal diversity in non-mammals, making reconstruction of its evolution particularly difficult. Here, we characterize glutamatergic neuron types in the amygdala of the urodele amphibianPleurodeles waltl. Our single-cell RNA sequencing data indicate the existence of at least ten distinct types and subtypes of glutamatergic neurons in the salama...
Source: Brain, Behavior and Evolution - December 27, 2022 Category: Neurology Source Type: research
Molecular diversity of neuron types in the salamander amygdala and implications for amygdalar evolution
The amygdala is a complex brain structure in the vertebrate telencephalon, essential for regulating social behaviors, emotions and (social) cognition. In contrast to the vast majority of neuron types described in the many nuclei of the mammalian amygdala, little is known about the neuronal diversity in non-mammals, making reconstruction of its evolution particularly difficult. Here, we characterize glutamatergic neuron types in the amygdala of the urodele amphibian Pleurodeles waltl. Our single-cell RNA sequencing data indicate the existence of at least ten distinct types and subtypes of glutamatergic neurons in the salama...
Source: Brain, Behavior and Evolution - December 27, 2022 Category: Neurology Source Type: research
Climate Change Influences Brain Size in Humans
Brain size evolution in hominins constitutes a crucial evolutionary trend, yet the underlying mechanisms behind those changes are not well understood. Here, climate change is considered as an environmental factor using multiple paleoclimate records testing temperature, humidity, and precipitation against changes to brain size in 298Homo specimens over the past fifty thousand years. Across regional and global paleoclimate records, brain size inHomo averaged significantly lower during periods of climate warming as compared to cooler periods. Geological epochs displayed similar patterns, with Holocene warming periods comprisi...
Source: Brain, Behavior and Evolution - December 27, 2022 Category: Neurology Source Type: research
Climate Change Influences Brain Size in Humans
Brain size evolution in hominins constitutes a crucial evolutionary trend, yet the underlying mechanisms behind those changes are not well understood. Here, climate change is considered as an environmental factor using four paleoclimate records testing temperature, humidity, and precipitation against changes to brain size in 298 Homo specimens over the past fifty thousand years. Across regional and global paleoclimate records, brain size in Homo averaged significantly lower during periods of climate warming as compared to cooler periods. Geological epochs displayed similar patterns, with Holocene warming periods comprising...
Source: Brain, Behavior and Evolution - December 27, 2022 Category: Neurology Source Type: research
Endocranial Casts of < b > < i > Camelops hesternus < /i > < /b > and < b > < i > Palaeolama < /i > < /b > sp.: New Insights into the Recent History of the Camelid Brain
Endocranial casts are capable of capturing the general brain form in extinct mammals due to the high fidelity of the endocranial cavity and the brain in this clade. Camelids, the clade including extant camels, llamas, and alpacas, today display high levels of gyrification and brain complexity. The evolutionary history of the camelid brain has been described as involving unique neocortical growth dynamics which may have led to its current state. However, these inferences are based on their fossil endocast record from approximately ∼40 Mya (Eocene) to ∼11 Mya (Miocene), with a gap in this record for the last ∼10 millio...
Source: Brain, Behavior and Evolution - December 27, 2022 Category: Neurology Source Type: research
Endocranial Casts of < b > < i > Camelops hesternus < /i > < /b > and < b > < i > Palaeolama < /i > < /b > sp.: New Insights into the Recent History of the Camelid Brain
Endocranial casts are capable of capturing the general brain form in extinct mammals due to the high fidelity of the endocranial cavity and the brain in this clade. Camelids, the clade including extant camels, llamas, and alpacas, today display high levels of gyrification and brain complexity. The evolutionary history of the camelid brain has been described as involving unique neocortical growth dynamics which may have led to its current state. However, these inferences are based on their fossil endocast record from approximately ∼40 Mya (Eocene) to ∼11 Mya (Miocene), with a gap in this record for the last ∼10 millio...
Source: Brain, Behavior and Evolution - December 27, 2022 Category: Neurology Source Type: research
