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Internal state dynamics shape brainwide activity and foraging behaviour 期刊论文
NATURE, 2020, 577 (7789) : 239-+
作者:  Marques, Joao C.;  Li, Meng;  Schaak, Diane;  Robson, Drew N.;  Li, Jennifer M.
收藏  |  浏览/下载:6/0  |  提交时间:2020/07/03

The brain has persistent internal states that can modulate every aspect of an animal'  s mental experience(1-4). In complex tasks such as foraging, the internal state is dynamic(5-8). Caenorhabditis elegans alternate between local search and global dispersal(5). Rodents and primates exhibit trade-offs between exploitation and exploration(6,7). However, fundamental questions remain about how persistent states are maintained in the brain, which upstream networks drive state transitions and how state-encoding neurons exert neuromodulatory effects on sensory perception and decision-making to govern appropriate behaviour. Here, using tracking microscopy to monitor whole-brain neuronal activity at cellular resolution in freely moving zebrafish larvae(9), we show that zebrafish spontaneously alternate between two persistent internal states during foraging for live prey (Paramecia). In the exploitation state, the animal inhibits locomotion and promotes hunting, generating small, localized trajectories. In the exploration state, the animal promotes locomotion and suppresses hunting, generating long-ranging trajectories that enhance spatial dispersion. We uncover a dorsal raphe subpopulation with persistent activity that robustly encodes the exploitation state. The exploitation-state-encoding neurons, together with a multimodal trigger network that is associated with state transitions, form a stochastically activated nonlinear dynamical system. The activity of this oscillatory network correlates with a global retuning of sensorimotor transformations during foraging that leads to marked changes in both the motivation to hunt for prey and the accuracy of motor sequences during hunting. This work reveals an important hidden variable that shapes the temporal structure of motivation and decision-making.


  
An intestinal zinc sensor regulates food intake and developmental growth 期刊论文
NATURE, 2020, 580 (7802) : 263-+
作者:  Wu, Thomas D.;  39;Gorman, William E.
收藏  |  浏览/下载:14/0  |  提交时间:2020/07/03

Hodor, an intestinal zinc-gated chloride channel, controls systemic growth in Drosophila by promoting food intake and by modulating Tor signalling and lysosomal homeostasis within enterocytes.


In cells, organs and whole organisms, nutrient sensing is key to maintaining homeostasis and adapting to a fluctuating environment(1). In many animals, nutrient sensors are found within the enteroendocrine cells of the digestive system  however, less is known about nutrient sensing in their cellular siblings, the absorptive enterocytes(1). Here we use a genetic screen in Drosophila melanogaster to identify Hodor, an ionotropic receptor in enterocytes that sustains larval development, particularly in nutrient-scarce conditions. Experiments in Xenopus oocytes and flies indicate that Hodor is a pH-sensitive, zinc-gated chloride channel that mediates a previously unrecognized dietary preference for zinc. Hodor controls systemic growth from a subset of enterocytes-interstitial cells-by promoting food intake and insulin/IGF signalling. Although Hodor sustains gut luminal acidity and restrains microbial loads, its effect on systemic growth results from the modulation of Tor signalling and lysosomal homeostasis within interstitial cells. Hodor-like genes are insect-specific, and may represent targets for the control of disease vectors. Indeed, CRISPR-Cas9 genome editing revealed that the single hodor orthologue in Anopheles gambiae is an essential gene. Our findings highlight the need to consider the instructive contributions of metals-and, more generally, micronutrients-to energy homeostasis.


  
Harnessing social innovation for energy justice: A business model perspective 期刊论文
ENERGY POLICY, 2017, 107
作者:  Hiteva, Ralitsa;  Sovacool, Benjamin
收藏  |  浏览/下载:0/0  |  提交时间:2019/04/09
Business models  Social innovation  Energy justice  Value  Whole system