* Systematic, cross-cortex variation in neuron numbers in rodents and primates.
- Uniformity, local variability, and systematic variation in neuron numbers per unit of cortical surface area across species and cortical areas have been claimed to characterize the isocortex. Resolving these claims has been difficult, because species, techniques, and cortical areas vary across studies. We present a stereological assessment of neuron numbers in layers II-IV and V-VI per unit of cortical surface area across the isocortex in rodents (hamster, Mesocricetus auratus; agouti, Dasyprocta azarae; paca, Cuniculus paca) and primates (owl monkey, Aotus trivigratus; tamarin, Saguinus midas; capuchin, Cebus apella); these chosen to vary systematically in cortical size. The contributions of species, cortical areas, and techniques (stereology, "isotropic fractionator") to neuron estimates were assessed. Neurons per unit of cortical surface area increase across the rostro-caudal (RC) axis in primates (varying by a factor of 1.64-2.13 across the rostral and caudal poles) but less in rodents (varying by a factor of 1.15-1.54). Layer II-IV neurons account for most of this variation. When integrated into the context of species variation, and this RC gradient in neuron numbers, conflicts between studies can be accounted for. The RC variation in isocortical neurons in adulthood mirrors the gradients in neurogenesis duration in development.
Overview of noun study
The noun study has 10 senses (first 8 from tagged texts)
1. (90) survey, study -- (a detailed critical inspection)
2. (17) study, work -- (applying the mind to learning and understanding a subject (especially by
reading); "mastering a second language requires a lot of work"; "no schools offer graduate study in
interior design")
3. (6) report, study, written report -- (a written document describing the findings of some
individual or group; "this accords with the recent study by Hill and Dale")
4. (6) study -- (a state of deep mental absorption; "she is in a deep study")
5. (6) study -- (a room used for reading and writing and studying; "he knocked lightly on the closed
door of the study")
6. (3) discipline, subject, subject area, subject field, field, field of study, study, bailiwick --
(a branch of knowledge; "in what discipline is his doctorate?"; "teachers should be well trained in
their subject"; "anthropology is the study of human beings")
7. (2) sketch, study -- (preliminary drawing for later elaboration; "he made several studies before
starting to paint")
8. (1) cogitation, study -- (attentive consideration and meditation; "after much cogitation he
rejected the offer")
9. study -- (someone who memorizes quickly and easily (as the lines for a part in a play); "he is a
quick study")
10. study -- (a composition intended to develop one aspect of the performer's technique; "a study in
spiccato bowing")
Overview of verb study
The verb study has 6 senses (first 6 from tagged texts)
1. (73) analyze, analyse, study, examine, canvass, canvas -- (consider in detail and subject to an
analysis in order to discover essential features or meaning; "analyze a sonnet by Shakespeare";
"analyze the evidence in a criminal trial"; "analyze your real motives")
2. (17) study -- (be a student; follow a course of study; be enrolled at an institute of learning)
3. (15) study, consider -- (give careful consideration to; "consider the possibility of moving")
4. (13) learn, study, read, take -- (be a student of a certain subject; "She is reading for the bar
exam")
5. (5) study, hit the books -- (learn by reading books; "He is studying geology in his room"; "I
have an exam next week; I must hit the books now")
6. (2) study, meditate, contemplate -- (think intently and at length, as for spiritual purposes; "He
is meditating in his study")
--- WordNet end ---