Compressive Sensing system for recording of ECoG signals in-vivo

Figure 1.1. Energy a power costs for a typical biosensor configuration [4, 5, 6 7, 8].In applications such an implantable neural recording arrays, as the number of microelectrodewithin the arrays have increased in order to simultaneously understand the dynamics of manyneurons at almost single neuron scale, the data reduction becomes mandatory in order to beable to transmit the recorded data. As a matter of fact, in recent years the advance in thedevelopment of multichannels microprobes, for recording neural activity, has supposed asignificant milestone towards integrated microimplanted wireless devices for clinical applicationsin the study of chronic illness, such as epilepsy.In Fig.1.2 it is depicted an example of an array for neural data acquisition which has beendeveloped by researchers from the University of Utah [9]. It is possible to observe theintegration density of the platinum-tipped silicon microelectrodes over a volume of 4 x 4 x 1.5mm 3 , which have been implemented in a matrix of 10 x 10 microelectrodes. It has to be takeninto consideration that independently from the resolution, when multielectrodes are placed in thebrain it is common for some electrodes to detect spikes from several distinct neurons whileother electrodes may see no resolvable spikes.Figure 1.2. Integrated Neural Interface (INI) developed by University of Utah [9]. The 10 x 10microelectode array has been implemented with an inter-probe distance of 400μm.Neural signals acquisition systems, as ECoG and Action Potentials (AP), play a challenging rolein the biomedical applications development which has been introduced along this chapterbecause of the saving in area and power which have to be mandatorily achieved in order toimplant the chips in human brains.26