培養神経回路網の自発活動の長期的観測と解析  [in Japanese] Long-term recording and analysis of spontaneous activity in cultured cortical networks  [in Japanese]

64微小電極アレイ基板上で培養されたラット大脳皮質神経回路網の活動電位を長期的に安定して測定するため、インキュベータ内に測定基板を直接設置した。コンタミネーションを防ぐため培養液の注入用と排出用の2本のチューブを取り付け、培養液を遠隔的に交換できるシステムを構築し、予め50日間培養された神経回路網をこのシステムに設置してから一ケ月以上に渡る長期的な同一回路網からの自発活動電位の記録に成功した。信号解析については、まず各電極でスパイクソーティングを行った上で分離されたスパイクの多電極に渡る発火時間のマッチングを取ることで神経細胞の伝搬経路の推定を行った。さらに単一の細胞の多電極での信号伝搬延パターンを用い発火時間を精度良く求め、発火パターンの長期的な変化を調査した。

Activity-dependent synaptic modification is considered to be the basis of plasticity in developmental as well as matured neural networks. To test this hypothesis, we constructed a long-term recording and stimulation system for cultured neural networks using substrates with 64 embedded electrode arrays. Rat cortical neurons were cultured on the electrode-array substrates and the substrates were kept in an incubator. Electrical connection and medium exchange systems were directly attached to the substrates. We could avoid contamination problems by the medium exchange system with sterilized suction and injection tubes and thus more than one-month continuous observation of spontaneous activity was achieved. After signal processing, gradual changes in inter-spike and inter-burst intervals were observed.