線蟲伴侶辨識的神經機制

Mate recognition is crucial to exchange genetic variations to maintain phenotypic plasticity during evolution. Precise recognition of suitable mates is mediated through sensory perceptions to recognize conspecific and reproductive mates. With computation of sensory stimuli, animals then make decision on behavioral outputs to select the suitable mates. In our current study, we have shown that C. elegans males are able to recognize suitable mates through physical contacts, and change the behavioral states to increase the chance to mate with hermaphrodites. Apart from the decision-making, we notice that the alteration of behavioral states is sustained without further stimuli, which represent the persistent state, which is the fundamental element of high cognitive functions such as emotions. We then study the neural mechanisms of decision-making and persistency of behavioral state. Starting with the simple nervous system in C. elegans, which only have 302 neurons in hermaphrodites, we anticipate these studies of decision-making and persistency of behavioral changes in mate recognition can help us to better understand the brain functions in complex organisms.?

What is the neural mechanism behind the decision-making?
Although the decision-making of animals’ behaviors has drawn a lot of attentions in neuroscience, the genes and cellular mechanisms controlling decision-making have not been satisfyingly understood. The main difficulty is that the mechanistic details are not sufficiently revealed at single cell level due to the limit of tools in animal models. We found that C. elegans males are able to recognize suitable mates through physical contact, and we want to study the underlying neural mechanisms. By using a novel cGAL-UAS system, the Chen lab disseminate the neural mechanisms of decision-making of mate recognition in C. elegans.

利用秀麗線蟲研究決策的神經機制
在神經科學領域裡，如何透過神經訊號傳遞而做出決定，是一個重要且複雜的問題，雖然科學家努力尋找其中的奧妙，但我們對於要如何做決定的神經機制以及在細胞及分子階層發生的事情，並不是完全暸解。最主要的問題是，在大多數的多細胞模式生物中，很難建立一個有效的系統，研究一個神經細胞在決定時中產生的變化，像是神經訊號的強度改變或是蛋白的產生。我們發現雄性線蟲可以有效率的透過物理性接觸辨認不同的交配對象，這讓我們開始想研究哪些神經細胞及分子機制參與在伴侶辨識中。在實驗室裡，我們利用線蟲中已經建立的cGAL-UAS系統性基因表達的基因轉殖線蟲，將可以大量且有系統的研究其中所參與的神經細胞以及其功能。

How is the behavioral state sustained by modulation of neural state?
High cognitive functions such as emotions require persistency of behavioral states in high order organisms, where sensory perceptions or behavioral outputs are altered for a certain period to meet the environmental stimuli and internal state. For example, the chance you get the candies from your parents is different, which is likely higher when they are happy.  It is a reversible change of neural states as the loss of potential stimuli is accompanied with the fade of the neural states.  This persistent state efficiently shorten the responsive time for future stimuli; however, the genetic and neural mechanisms are not fully understood. In our preliminary data, we found that males drastically change its locomotion patterns after a brief contact of hermaphrodites, and this change will sustain for at least 5 minutes. We will use advanced genetics and technology to tackle this question for the persistency of neural state in C. elegans.

研究動物持續性行為的神經調控機制
對於高階的動物體，認知功能會受到不同神經狀態下而被影響，像是我們會在不同情緒下，對於相同的感官訊息而做出不同反應，例如：在父母生氣或開心時，要糖果吃的成功率是不一樣的。而這種感官功能的變化，會持續一段時間，並在外界刺激消失後逐漸褪去。這種行為的持續性，將會有效率的縮短生物體對於外在環境的反應時間。一個有趣的問題是生物如何讓自己在接受刺激後進入持續性的行為，這也伴隨著這些持續性行為如何逐漸消散。因此，我們實驗室想要研究這些問題，在我們初步的實驗中已經發現，雄性線蟲短暫碰觸雌雄同體時會改變其行為模式，而這種行為改變會維持至少數分鐘，並回覆到先前的狀態。我們對於這種神經調控機制相當感興趣，實驗室將會利用遺傳學與新穎的神經學研究方式，去研究在線蟲行為中持續狀態的神經機制。

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