GSTDTAP

浏览/检索结果: 共3条,第1-3条 帮助

限定条件                            
已选(0)清除 条数/页:   排序方式:
UNPRECEDENTED SPREAD OF URBAN SPRAWL 期刊论文
NATURE, 2020, 581 (7807) : 123-123
作者:  Powell, Kendall;  Mondino, Anna;  Nemhauser, Jennifer;  Salas, Rafael Carazo;  Gunawardane, Ru;  Di Nicolantonio, Federica
收藏  |  浏览/下载:6/0  |  提交时间:2020/07/03

Molecular analysis indicates that the baffling soft-bodied creature was a vertebrate.


Molecular analysis indicates that the baffling soft-bodied creature was a vertebrate.


  
Dating the skull from Broken Hill, Zambia, and its position in human evolution 期刊论文
NATURE, 2020, 580 (7803) : 372-+
作者:  Mergner, Julia;  Frejno, Martin;  List, Markus;  Papacek, Michael;  Chen, Xia;  Chaudhary, Ajeet;  Samaras, Patroklos;  Richter, Sandra;  Shikata, Hiromasa;  Messerer, Maxim;  Lang, Daniel;  Altmann, Stefan;  Cyprys, Philipp;  Zolg, Daniel P.;  Mathieson, Toby;  Bantscheff, Marcus
收藏  |  浏览/下载:5/0  |  提交时间:2020/07/03

The cranium from Broken Hill (Kabwe) was recovered from cave deposits in 1921, during metal ore mining in what is now Zambia(1). It is one of the best-preserved skulls of a fossil hominin, and was initially designated as the type specimen of Homo rhodesiensis, but recently it has often been included in the taxon Homo heidelbergensis(2-4). However, the original site has since been completely quarried away, and-although the cranium is often estimated to be around 500 thousand years old(5-7)-its unsystematic recovery impedes its accurate dating and placement in human evolution. Here we carried out analyses directly on the skull and found a best age estimate of 299 +/- 25 thousand years (mean +/- 2s). The result suggests that later Middle Pleistocene Africa contained multiple contemporaneous hominin lineages (that is, Homo sapiens(8,9), H. heidelbergensis/H. rhodesiensis and Homo naledi(10,11)), similar to Eurasia, where Homo neanderthalensis, the Denisovans, Homo floresiensis, Homo luzonensis and perhaps also Homo heidelbergensis and Homo erectus(12) were found contemporaneously. The age estimate also raises further questions about the mode of evolution of H. sapiens in Africa and whether H. heidelbergensis/H. rhodesiensis was a direct ancestor of our species(13,14).


  
Dopamine D2 receptors in discrimination learning and spine enlargement 期刊论文
NATURE, 2020, 579 (7800) : 555-+
作者:  Luo, Zhaochu;  Hrabec, Ales;  Dao, Trong Phuong;  Sala, Giacomo;  Finizio, Simone;  Feng, Junxiao;  Mayr, Sina;  Raabe, Joerg;  Gambardella, Pietro;  Heyderman, Laura J.
收藏  |  浏览/下载:24/0  |  提交时间:2020/07/03

Detection of dopamine dips by neurons that express dopamine D2 receptors in the striatum is used to refine generalized reward conditioning mediated by dopamine D1 receptors.


Dopamine D2 receptors (D2Rs) are densely expressed in the striatum and have been linked to neuropsychiatric disorders such as schizophrenia(1,2). High-affinity binding of dopamine suggests that D2Rs detect transient reductions in dopamine concentration (the dopamine dip) during punishment learning(3-5). However, the nature and cellular basis of D2R-dependent behaviour are unclear. Here we show that tone reward conditioning induces marked stimulus generalization in a manner that depends on dopamine D1 receptors (D1Rs) in the nucleus accumbens (NAc) of mice, and that discrimination learning refines the conditioning using a dopamine dip. In NAc slices, a narrow dopamine dip (as short as 0.4 s) was detected by D2Rs to disinhibit adenosine A(2A) receptor (A(2A)R)-mediated enlargement of dendritic spines in D2R-expressing spiny projection neurons (D2-SPNs). Plasticity-related signalling by Ca2+/calmodulin-dependent protein kinase II and A(2A)Rs in the NAc was required for discrimination learning. By contrast, extinction learning did not involve dopamine dips or D2-SPNs. Treatment with methamphetamine, which dysregulates dopamine signalling, impaired discrimination learning and spine enlargement, and these impairments were reversed by a D2R antagonist. Our data show that D2Rs refine the generalized reward learning mediated by D1Rs.