Neural-recording systems

Rearce, T. M., WiUiams, J. J., Kmzel, S. R, Gidden, M. J., and Williams, J. C., Dynamic control of extraceUnlar environment in in vitro neural recording systems, LEEE Trans Neural Syst Rehabil Eng, 13, 207, 2005. 

R.R. Harrison et al., "A low-power integrated circuit for a wireless 100-electrode neural recording system," IEEE. Solid-State Circuits, vol. 42, no. 1, pp. 123-133, Jan. 2007. 

Recording 128-Channel Wireless Neural-Recording System. 307... 

These applications, by nature, impose serious limitations on power and area in the design of neural-recording systems. Researchers have developed several kinds of neural-recording systems [23-27], and those systems are generally composed of preamplifiers to amplify the small extracellular potentials, low-pass filters to reject the high frequency noise, multiplexers, and analog-to-digital converters (ADCs) followed by the wireless telemetry circuits to transmit data out of the body. 

Figure 12 shows the general architecture of the multichannel neural-recording system. The total number of channels is N =2") and the total number of ADCs is... 

Fig. 12 General architecture of the multichannel neural-recording system...

Figure 13 shows the schematic of the preamplifier, which is composed of an operational transconductance amplifier (OTA) and a feedback network. A capacitive negative-feedback amplifier is widely used in neural-recording systems [28] because there is usually a DC offset of 1—2 V across the electrode-tissue interface [29]. The gain of the amplifier is determined by the ratio of the two capacitances in the feedback network. 

Table 3 is the calculated area of the neural-recording system with various channel numbers and ADCs. As shown, the total chip area increases as the number of ADCs does, which is a straightforward conclusion. Therefore, there must be an optimal multiplexing ratio that makes the system s power-area product minimum. Table 4 is the power-area product based on Tables 2 and 3. From Table 4, we can deter-... 

Unlike other UWB applications, power amplifiers are not necessary due to the low transmitted power and short distance range in neural-recording systems. Instead, a wideband-matching filter is used to regulate the transmitted power. 

A multichannel neural-recording system is used in neuroscience experiments to study complex neural networks of animals in their natural environments [130]. It is also a critical component in brain-computer interface used for cortical-controlled neural prosthetics, which has a wide range of applications such as upper and lower limb prostheses [131-134], bladder and bowel movement control for spinal cord injury (SCI) patients [135-136], respiration control for SCI patients [137], and hand grasping function restoration [138]. 

To support these applications, a neural-recording system has to meet challenging requirements imposed by the environment. First, it should be able to record a large number of channels simultaneously and high-resolution recording can advance fundamental neuroscience studies and has the potential to improve the performance of neural prosthetic devices. Second, a wireless telemetry that transmits recorded neu-... 

Chae M, Liu W, Sivaprakasam M (2008) Design optimization for integrated neural recording systems. IEEE J Solid-State Circ 43 1931-1939... 

Dagtekin M, Liu W, Bashirullah R (2001) A multichannel chopper modulated neural recording system. Proc IEEE EMBS Int Conf 757-760. 

Liu W, Sivaprakasam M, Wang G, Chae MS (2006) A neural recording system for monitoring shark behavior In Proc. IEEE Int. Symp. Circuits and Systems, May 21-24, 2006, pp. 4123 236. 

Santhanam G, Linderman MD, GUja V, Afshar A, Ryu SI, Meng T, Shenoy K (2007) HermesB A continuous neural recording system for freely behaving primates. IEEE Tran Biomed Eng 54(11) 2037-2050, Nov. 2007. 

Yuce MR, Liu W, Chae MS, Kim JS (2007) A wideband telemetry unit for multi-channel neural recording systems. Ultra-Wideband, 2007. IEEE International Conference on ICUWB 2007, pp. 612-617, 24-26 Sept. 2007. 

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