Related by context. Frequent words. (Click for all words.) 56 mice 55 guinea pigs 54 rats 51 humans 51 monkeys 48 experiments 48 dopamine neurons 48 brains 48 experimenters 46 guinea pig 46 GDNF 46 livers 46 diabetic mice 45 digestive tracts 45 gerbils 45 genetically engineered mice 45 glia 45 hamsters 45 ESCs 45 rhesus monkeys 44 transgenic mice 44 astrocytes 44 pancreatic cells 44 cultured cells 44 mutant mice 44 leptin 43 rodents 43 petri dishes 43 automatons 43 scientists 43 metabolisms 43 mice genetically engineered 43 neurobiologist 43 neuronal cells 43 hormones 43 yeast cells 43 fruit flies 43 reprogrammed cells 43 genetically altered 42 psychopaths 42 laboratory experiments 42 iPSCs 42 mutants 42 roundworms 42 genetically modified mice 42 Transgenic 42 researchers 41 mammalian cells 41 biochemically 41 cyborgs 41 boffins 41 dopamine receptors 41 knockout mice 41 mice rats 41 brain 41 Humans 41 macaque monkeys 41 gonads 41 ES cells 41 human beings 41 transgenic animals 41 humanoids 40 biochemist 40 ex vivo 40 neuroscientist 40 experiment 40 rat 40 tadpoles 40 zebrafish 40 Experiments 40 glutamine 40 retinal cells 40 androids 40 mutant 40 parasitic worms 40 sociopaths 40 bone marrow stem cells 40 monkey 40 mouse embryos 40 islet cells 40 Petri dish 40 genetically engineered 40 robots 40 rhesus macaques 40 habituation 39 stem cells 39 deficient mice 39 exoskeletons 39 C. elegans 39 orexin 39 nerve cells 39 parasites 39 amoebas 39 germ cells 39 cells 39 testes 39 neurons 39 Petri dishes 39 serotonin 39 BDNF 39 motor neurons