These kinds of research have been focused on recording electrical signals from living brains or cells, called neural spikes, for studying the activity of the brain or neuron cells. A component of instrumentation development for cell study is also included in this research [1,2]. Many researchers have demonstrated good results in the field that measures extracellular signals from individual neurons for over 50 years [3�C5]. Also, it became possible to measure reaction signals from tens to hundreds of neurons [6], but in all this research, there exists a limitation that the neurons cannot be observed while acquiring signals from them. To overcome this limitation, studies using two-photon or multi-photon microscopy as imaging tools have been underway since the late 1990s [7�C9].
Such non-linear microscopies are becoming standard tools for defining molecular mechanisms in the field of cell-based engineering and bio-medical research. Most of all, multi-photon microscope (MPM) is a type of laser-scanning microscope that excites a fluorescent material to a thin raster-scanned plane using a ��non-linear�� excitation state [10]. Ten years after the first report on MPM, it has been applied to various imaging fields, and nowadays it has become an imaging modality used to observe thick tissues or living animals.Barbashov et al. and Alexander et al. reported the multiphoton excitation of nerve cells using femtosecond laser radiation [11,12]. Ryan et al.
showed their experimental results with signals recorded from the visual cortex using a microelectrode array and a single electrode [13].
Because just using the MPM system Cilengitide or extracellular recording is confined to imaging or electrical signal recording, a complex system which can perform simultaneous measurements of the neuron images and the electrical signals Entinostat could improve the reliability of experimental results. If a planar multi-electrode array is applied to culturing neuron cells and compatible with an imaging modality, simultaneous acquisition of the neuron images and electrical signals could be done. Also, by using a specific calcium dye, the system can have additional merit if we can analyze the activity of calcium channels from cultured neuron cells.
A multi-signal acquisition system that performs a simultaneous measurement of electrical signals, fluorescence images and changes would have an important role in neuroscience. Shew et al. already reported about a system which performs the simultaneous measurement of neural activity using a complex multi-electrode array and a two-photon microscope [14]. They focused on the large-scale field potential signals to single-neuron activity in small scale-group cells from rat brain slices.