摘要:
嗅覺在動物的很多行為表現扮演著重要的角色,像是動物生存的基本功能，例如:求偶、避敵、覓食以及像是學習與記憶這類比較高等的功能。在果蠅中，嗅覺受體神經細胞會感知到特殊的氣味並將這個氣味訊息藉由他的神經突觸末梢將訊息在特定的嗅球傳遞給投射神經細胞的樹突。這樣的模式顯然形成一種在觸角突這個空間上嗅覺訊息的特異性分布。為了去了解這些嗅覺訊息是如何被傳遞到高等腦區最後進而造成行為的改變，於是我開始專注在這些嗅覺訊息在蕈狀體這個高等腦區的呈現模式。在這個實驗裡，我藉由MARCM技術並在nc82和DID染色的協助下，分別去掃描紀錄在蕈狀體杯狀結構中128個不同的投射神經他的空間分布情形。除此之外，我們也依據蕈狀體神經的發育及出生時期的不同來將蕈狀體杯狀結構區分成17個區域。而投射神經與蕈狀體杯狀結構相連性的分析也暗示我們每個投射神經只會跟五類蕈狀體細胞其中的一類有所連接。在疊合分析中，我們也發現bouton在蕈狀體杯狀結構中四個樹突區域有著不一樣的特異性分布狀況。綜合以上告訴我們一件事: 在角突觸的神經細胞會將氣味訊息進行編碼，並送到蕈狀體之後再進行解碼的工作；而這些具有特異性的氣味傳遞模式是藉由每個投射神經只會跟五類蕈狀體細胞其中的一類有所連接所達成的。

Summary
Olfaction plays an essential role in animal behaviors including courtship, avoidance, and food searching as well as higher functions such as learning and memory. In Drosophila, olfactory receptor neurons (ORNs) sense and deliver specific odorant stimuli to specific glomeruli where their axons contact with dendrites of projection neurons (PNs) forming a stereotyped spatial map in the antennal lobe. To understand how this olfactory map is translated in the higher brain centers to ultimately elicit corresponding behaviors, I address the olfactory representation in the mushroom body (MB), an olfactory learning center. Using genetic mosaic MARCM system, I mapped spatial distributions of 128 individual PNs in the MB calyx. We have recently shown that KC dendrites in the calyx are segregated into 17 domains as a result of lineage development and sequential birth. PN/KC connectivity likelihood assignment indicates that with only few exceptions each PN connects to neurons of only one of the five KC classes (□,□□'/□'□□pioneer □/□□ early □/□ and late□□/□□neurons□.
Colocalization analysis also shows that each PN gives different numbers of terminal boutons to the four vertical clonal divisions in a stereotypical manner. These data suggest that neural coding of olfactory stimuli in the antennal lobe is transformed and decoded in the MB by the selective connectivity between each PN and specific types of KCs.

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