蛔蟲的神經系統(tǒng)只有302個具有已知突觸連接的神經細胞，然而它卻執(zhí)行很多與更復雜的生物相似的功能,。這使得它非常適合讓神經科學家來研究神經回路是怎樣組織的,。Chalasani等人對一種決定蛔蟲覓食行為的神經回路進行了解剖研究。該回路允許探測氣味的神經元激發(fā)或抑制下游的中間神經元,，它們控制一致的爬行和轉身行為,。將遺傳學和鈣成像技術結合起來,，可以對信息從環(huán)境中通過傳感神經元向控制趨化性和覓食的中間神經元的流動進行跟蹤。這一神經回路與哺乳動物視網膜中用來探測光的神經回路具有非常驚人的同源性,，這是關于信息處理的保留策略或融合策略的一個明顯例子,。
原始出處:
Nature 450, 63-70 (1 November 2007) | doi:10.1038/nature06292; Received 14 August 2007; Accepted 24 September 2007
Dissecting a circuit for olfactory behaviour in Caenorhabditis elegans
Sreekanth H. Chalasani1, Nikos Chronis1, Makoto Tsunozaki1, Jesse M. Gray1, Daniel Ramot2, Miriam B. Goodman2 & Cornelia I. Bargmann1
Howard Hughes Medical Institute, Laboratory of Neural Circuits and Behaviour, The Rockefeller University, New York, New York 10065, USA
Program in Neurobiology and Department of Molecular and Cellular Physiology, Stanford University, Stanford, California 94305, USA
Correspondence to: Cornelia I. Bargmann1 Correspondence and requests for materials should be addressed to C.I.B. (Email: [email protected]).
Abstract
Although many properties of the nervous system are shared among animals and systems, it is not known whether different neuronal circuits use common strategies to guide behaviour. Here we characterize information processing by Caenorhabditis elegans olfactory neurons (AWC) and interneurons (AIB and AIY) that control food- and odour-evoked behaviours. Using calcium imaging and mutations that affect specific neuronal connections, we show that AWC neurons are activated by odour removal and activate the AIB interneurons through AMPA-type glutamate receptors. The level of calcium in AIB interneurons is elevated for several minutes after odour removal, a neuronal correlate to the prolonged behavioural response to odour withdrawal. The AWC neuron inhibits AIY interneurons through glutamate-gated chloride channels; odour presentation relieves this inhibition and results in activation of AIY interneurons. The opposite regulation of AIY and AIB interneurons generates a coordinated behavioural response. Information processing by this circuit resembles information flow from vertebrate photoreceptors to 'OFF' bipolar and 'ON' bipolar neurons, indicating a conserved or convergent strategy for sensory information processing.
