我們取出未出生幼鼠( prenatal Wistar rats )的大腦皮質層 細胞( Cortical neurons )培養，形成由許多不同形狀、不同大小 的神經元群落( Neuronal clusters )交錯聯結而成的二維神經網 路系統。利用鈣離子指示計( Ca2+ indicator )螢光染色顯微技 術，我們可以研究二維神經網路系統之集體發火動力學行為。 藉由調控培養液中鎂離子的濃度，我們可以觀測二維神 經網路系統中同步與非同步發火的動力學行為。當培養液中 沒有鎂離子時，二維神經網路系統展現同步發火的現象；相 反地，當培養液中有鎂離子存在時，二維神經網路系統展現 出非同步發火的現象。 透過非線性動力學的分析手法，如：奇異吸子的重建 ( Attractor reconstruction ) 與發火時間間隔的機率分佈 ( Probability distribution of inter-spike interval )，我們可以探討 二維神經網路系統中的時空動力學行為。此外，我們建構了 一個簡單清楚的物理模型解釋二維神經網路系統中的動力學 行為。 We experimentally investigate the dynamical behaviors of a 2D neuronal network system. The incubated cortical neurons, extracted from prenatal Wistar rats, develop into network in forms of clusters in a wide distribution of sizes and connectivities. The firing activities are detected by measuring the fluorescence emission of the calcium indicator through optical microscopy. Synchronous and asynchronous firings are observed by tuning the Magnesium ion concentrations of the medium. The neuronal network exhibit synchronous firing under zero Magnesium ion condition while transition to asynchronous firing when the Magnesium ion is present. We investigate the spatio-temporal dynamics by measuring the probability distribution of the inter-spike interval (ISI) and reconstructing the attractor. A physical model is presented to explain the observations
