An identified neuron of the leech, a Retzius cell, has been attached to the open gate of a p-channel field-effect transistor. Action potentials, spontaneous or stimulated, modulate directly the source-drain current in silicon. The electronic signals match the shape of the action potential. The average voltage on the gate was up to 25 percent of the intracellular voltage change. Occasionally weak signals that resemble the first derivative of the action potential were observed. The junctions can be described by a model that includes capacitive coupling of the plasma membrane and the gate oxide and that accounts for variable resistance of the seal.

https://science.sciencemag.org/content/sci/252/5010/1290.full.pdf

A neuron-silicon junction: a Retzius cell of the leech on an insulated-gate field-effect transistor.

Sensor arrays are a key tool in the field of neuroscience for noninvasive recording of the activity of biological networks, such as dissociated neurons or neural tissue. A high-density sensor array complementary metal–oxide–semiconductor chip is presented with 16 K pixels, a frame rate of 2 kiloframes per second, and a pitch of 7.8 m 7.8 m for imaging of neural activity. The related circuit and system issues as well as process aspects are discussed. A mismatch-canceling calibration circuitry with current mode signal representation is used. Results from first biological experiments are presented, which prove full functionality of the chip.

A 128 × 128 CMOS bio-sensor array for extracellular recording of neural activity

The characteristics and mechanisms of synchronized firing in developing networks of cultured cortical neurons were studied using multisite recording through planar electrode arrays (PEAs). With maturation of the network (from 3 to 40 d after plating), the frequency and propagation velocity of bursts increased markedly (approximately from 0.01 to 0.5 Hz and from 5 to 100 mm/sec, respectively), and the sensitivity to extracellular magnesium concentration (0–10 mM) decreased. The source of spontaneous bursts, estimated from the relative delay of onset of activity between electrodes, varied randomly with each burst. Physical separation of synchronously bursting networks into several parts using an ultraviolet laser, divided synchronous bursting into different frequencies and phases in each part. Focal stimulation through the PEA was effective at multiple sites in eliciting bursts, which propagated over the network from the site of stimulation. Stimulated bursts exhibited both an absolute refractory period and a relative refractory period, in which partially propagating bursts could be elicited. Periodic electrical stimulation (at 1 to 30 sec intervals) produced slower propagation velocities and smaller numbers of spikes per burst at shorter stimulation intervals. These results suggest that the generation and propagation of spontaneous synchronous bursts in cultured cortical neurons is governed by the level of spontaneous presynaptic firing, by the degree of connectivity of the network, and by a distributed balance between excitation and recovery processes.

https://www.jneurosci.org/content/jneuro/15/10/6834.full.pdf

The mechanisms of generation and propagation of synchronized bursting in developing networks of cortical neurons

Sensor arrays are a key tool in the field of neuroscience for noninvasive recording of the activity of biological networks, such as dissociated neurons or neural tissue. A high-density sensor array complementary metal-oxide-semiconductor chip is presented with 16 K pixels, a frame rate of 2 kiloframes per second, and a pitch of 7.8 /spl mu/m /spl times/ 7.8 /spl mu/m for imaging of neural activity. The related circuit and system issues as well as process aspects are discussed. A mismatch-canceling calibration circuitry with current mode signal representation is used. Results from first biological experiments are presented, which prove full functionality of the chip.

A 128 /spl times/ 128 CMOS bio-sensor array for extracellular recording of neural activity

The neurochip: a new multielectrode device for stimulating and recording from cultured neurons.

Multisite hippocampal slice recording and stimulation using a 32 element microelectrode array

A passive multimicroelectrode array has been fabricated and used to record neural events from the abdominal ganglion of the marine mollusk, Aplysia californica. The array consists of a pattern of gold conductor lines on a glass substrate which is insulated with a polyimide. The 32 electrodes are 25, in diameter and are arranged in a 4 x 8 matrix on 200 um centers. The array is durable and reusable, and can be safely autoclaved. The recording environment surrounding each electrode is sufficiently uniform so as to permit spatial localization of identified cells in the ganglion. The array can record large numbers of unique and often interrelated extracellular neural potentials in relatively simple experiments.

Recording from the Aplysia Abdominal Ganglion with a Planar Microelectrode Array

The potentials recordable from the hippocampal slice using a microelectrode array are described assuming a model of neural current sources. Inverse Fourier filter techniques to compute the current source density (CSD) are described taking into account the uncertainty in knowledge of the height of the current source above the recording plane. A lower bound on the minimum necessary sampling interval is calculated as 100 ?m. Another calculation indicates it is unlikely that current sources are detectable if they are further than 250 ?m from the recording array. Inverse filters with relatively short focal distances avoid unnecessary attenuation of signals from more distant sources.

James L. Novak

Papers

Multisite hippocampal slice recording and stimulation using a 32 element microelectrode array

Recording from the Aplysia Abdominal Ganglion with a Planar Microelectrode Array

Current Source Density Estimation Using Microelectrode Array Data from the Hippocampal Slice Preparation

Two-dimensional current source density analysis of propagation delays for components of epileptiform bursts in rat hippocampal slices.

A high-speed multichannel neural data acquisition system for IBM PC compatibles