Feeding behaviour is modulated by both environmental cues and internal physiological states. Appetite is commonly boosted by the pleasant smell (or appearance) of food and destroyed by a bad taste. In reality, animals sense multiple environmental cues at the same time and it is not clear how these sensory inputs are integrated and a decision is made to regulate feeding behaviour accordingly. Here we show that feeding behaviour in Caenorhabditis elegans can be either facilitated by attractive odours or suppressed by repellents. By identifying mutants that are defective for sensory-mediated feeding regulation, we dissected a central flip-flop circuit that integrates two contradictory sensory inputs and generates bistable hormone output to regulate feeding behaviour. As feeding regulation is fundamental to animal survival, we speculate that the basic organizational logic identified here in C. elegans is likely convergent throughout different phyla.

Abstract. The sparseness of feature is an important characteristic determining feature, which directly affects the accuracy of image recognition [1] . By studying the traditional convolution neural network, we find that the learning of image features of cerebrospinal fluid cell easily overfits, but using rectie activation function instead of sigmoid activation functions, the features extracted are more sparse and have faster convergence rate in the process of training. Then features extracted are classified through a linear support vector machine. The experiments show that the improved model can enhance significantly the image recognition efficiency of cerebrospinal fluid, where two, three, four categories are respectively increased by 9.78%, 6.53%, 11.69%, and the average recognition time of a single image is also reduced 0.32s.

How neurons are capable of decoding stimulus intensity and translate this information into complex behavioral outputs is poorly defined. Here, we demonstrate that the C. elegans interneuron AIB regulates two types of behaviors: reversal initiation and feeding suppression in response to different concentrations of quinine. Low concentrations of quinine are decoded in AIB by a low-threshold, fast-inactivation glutamate receptor GLR-1 and translated into reversal initiation. In contrast, high concentrations of quinine are decoded by a high-threshold, slow-inactivation glutamate receptor GLR-5 in AIB. After activation, GLR-5 evokes sustained Ca2+ release from the inositol 1,4,5-trisphosphate (IP3)-sensitive Ca2+ stores and triggers neuropeptide secretion, which in turn activates the downstream neuron RIM and inhibits feeding. Our results reveal that distinct signal patterns in a single interneuron AIB can encode differential behavioral outputs depending on the stimulus intensity, thus highlighting the importance of functional mapping of information propagation at the single-neuron level during connectome construction.

Physiological homeostasis becomes compromised during ageing, as a result of impairment of cellular processes, including transcription and RNA splicing1–4. However, the molecular mechanisms leading to the loss of transcriptional fidelity are so far elusive, as are ways of preventing it. Here we profiled and analysed genome-wide, ageing-related changes in transcriptional processes across different organisms: nematodes, fruitflies, mice, rats and humans. The average transcriptional elongation speed (RNA polymerase II speed) increased with age in all five species. Along with these changes in elongation speed, we observed changes in splicing, including a reduction of unspliced transcripts and the formation of more circular RNAs. Two lifespan-extending interventions, dietary restriction and lowered insulin–IGF signalling, both reversed most of these ageing-related changes. Genetic variants in RNA polymerase II that reduced its speed in worms5 and flies6 increased their lifespan. Similarly, reducing the speed of RNA polymerase II by overexpressing histone components, to counter age-associated changes in nucleosome positioning, also extended lifespan in flies and the division potential of human cells. Our findings uncover fundamental molecular mechanisms underlying animal ageing and lifespan-extending interventions, and point to possible preventive measures.

Energy intake prepartum is critically important to health, milk performance, and profitability of dairy cows. The objective of this study was to determine the effect of reduced energy density of close-up diets on dry matter intake (DMI), lactation performance and energy balance (EB) in multiparous Holstein cows which were housed in a free-stall barn and fed for ad libitum intake. Thirty-nine dry cows were blocked and assigned randomly to three groups fed a high energy density diet [HD, n = 13; 6.8 MJ of net energy for lactation (NEL)/kg; 14.0% crude protein (CP) ], or a middle energy density diet (MD, n = 13; 6.2 MJ NEL/kg; 14.0% CP), or a low energy density diet (LD, n = 13; 5.4 MJ NEL/kg; 14.0% CP) from d 21 before expected day of calving. After parturition, all cows were fed the same lactation diet to d 70 in milk (DIM). The DMI and NEL intake prepartum were decreased by the reduced energy density diets (P < 0.05). The LD group consumed 1.3 kg/d (DM) more diet compared with HD group in the last 24 h before calving. The milk yield and the postpartum DMI were increased by the reduced energy density diet prepartum (P < 0.05). The changes in BCS and BW prepartum and postpartum were not affected by prepartum diets. HD group had higher milk fat content and lower lactose content compared with LD group during the first 3 wk of lactation (P < 0.05). The energy consumption for HD, MD and LD groups were 149.8%, 126.2% and 101.1% of their calculated energy requirements prepartum (P < 0.05), and 72.7%, 73.1% and 75.2% during the first 4 wk postpartum, respectively. In conclusion, the low energy density prepartum diet was effective in controlling NEL intake prepartum, and was beneficial in increasing DMI and milk yield, and alleviating negative EB postpartum.