Track topics on Twitter Track topics that are important to you
Neurodevelopmental duration plays a central role in the evolution of the retina and neocortex in mammals. In the diurnal primate eye and retina, it is necessary to scale the number of cones versus the number of rods with different exponents to defend their respective functions of spatial acuity and sensitivity in eyes of different sizes. The order of photoreceptor precursor specification, cones specified first, rods second, couples their respective cell numbers at maturity to the kinetics of embryonic stem cell proliferation. Different durations of retinogenesis change the ratio of rods to cones produced so as to defend both functions over a range of eye diameters. In the evolution of nocturnality, the same coupling of photoreceptor specification to neurogenesis is altered to fewer cones and many more rods in nocturnal eyes, by delaying the onset of retinogenesis. Similarly, the neocortex also shows coupling of the specification of laminar position with duration of neurogenesis. Overall, duration of neurogenesis directly predicts neocortex volume in most mammalian clades. In larger brains with longer neocortical neurogenesis, its organization changes progressively, differentiating the frontal pole from the occipital pole in volume of connectivity and number of neurons per unit column. This permits greater, hierarchically organized information abstraction with increasing neocortex volume. Exceptions do exist, however, in species of three separate taxa, marsupials, naked mole rats, and bats, which break the correlation of neurodevelopmental duration and brain size. Naked mole rats and bats both have small brains and unusual longevity, coupled with neurodevelopmental periods characteristic of much bigger-brained animals, raising the possibility that developmental duration and lifespan have some genetic or mechanistic control in common. The role of duration of development in mediating between the mechanistic levels of construction of retinal and cortical organization, and the different life histories associated with larger brains, such as duration of parental care, learning and overall longevity are discussed.
This article was published in the following journal.
Name: Evolution & development
Scaling relationships emerge from differential growth of body parts relative to each other. As such, scaling relationships are at least in part the product of developmental plasticity. While some of t...
The timing of developmental events is tightly regulated along a time axis for normal development. Although the RNA-binding protein Lin28a plays a crucial role in the regulation of developmental timing...
The organizer is an essential signaling center required for axial formation during vertebrate embryonic development. In the basal chordate amphioxus, the dorsal blastopore lip of the gastrula has been...
The combination of affordability, large size, and ease of access at almost every stage of development renders the chick an excellent model organism for studying vertebrate development. Not only is it ...
We report a new patient who presented with dysmorphic features and congenital heart disease. In addition, her brain magnetic resonance imaging revealed leukoencephalopathy, cavum septum pellucidum, pe...
Developmental Hip Displasia (DDH) can cause various degenerations or compensatory adaptations in the spine and knee joint, especially in the hip joint. As a result of adaptations and degen...
The purpose of this study is to examine the feasibility, acceptability and effectiveness of implementing the AAP's recommendation that clinicians provide developmental surveillance at all ...
This study is focused on developing the early integrated intervention for child brain-developmental disorders, including globe developmental delay (GDD), autism spectrum disorder (ASD), an...
Premature infants born between 28 and 33 weeks’ gestation often have significant brain damage. Brain damage can be caused by the much greater stimulation the infant receives in the neon...
This study is to determine whether scaling and root planing (SRP) followed by photodynamic disinfection results in improved outcomes that persist over time in adults with chronic periodont...
A condition characterized by long-standing brain dysfunction or damage, usually of three months duration or longer. Potential etiologies include BRAIN INFARCTION; certain NEURODEGENERATIVE DISORDERS; CRANIOCEREBRAL TRAUMA; ANOXIA, BRAIN; ENCEPHALITIS; certain NEUROTOXICITY SYNDROMES; metabolic disorders (see BRAIN DISEASES, METABOLIC); and other conditions.
A nonspecific term used to describe transient alterations or loss of consciousness following closed head injuries. The duration of UNCONSCIOUSNESS generally lasts a few seconds, but may persist for several hours. Concussions may be classified as mild, intermediate, and severe. Prolonged periods of unconsciousness (often defined as greater than 6 hours in duration) may be referred to as post-traumatic coma (COMA, POST-HEAD INJURY). (From Rowland, Merritt's Textbook of Neurology, 9th ed, p418)
Designation for several severe forms of ichthyosis, present at birth, that are characterized by hyperkeratotic scaling. Infants may be born encased in a collodion membrane which begins shedding within 24 hours. This is followed in about two weeks by persistent generalized scaling. The forms include bullous (HYPERKERATOSIS, EPIDERMOLYTIC), non-bullous (ICHTHYOSIS, LAMELLAR), wet type, and dry type.
Environments or habitats at the interface between truly terrestrial ecosystems and truly aquatic systems making them different from each yet highly dependent on both. Adaptations to low soil oxygen characterize many wetland species.
The chromosome region which is active in nucleolus formation and which functions in the synthesis of ribosomal RNA.
Ophthalmology is the branch of medicine that is devoted to the study and treatment of eye diseases. As well as mild visual defects correctable by lenses, ophthalmology is concerned with glaucoma, uveitis and other serious conditions affecting the eye, ...
Track and monitor developments in stem cell research and commercial development. Follow the tabs above to read the latest global news, research, clinical trials on stem cells and follow companies active in the stem cell industry. BioPort...