Stimulation with a Low-Amplitude, Digitized Synaptic Signal to Invoke Robust Activity within Neuronal Networks on Multielectrode Arrays

Abstract

Multielectrode arrays (MEAs) are used for analysis of neuronal activity. Here we report two variations on commonly accepted techniques that increase the precision of extracellular electrical stimulation: (i) the use of a low-amplitude recorded spontaneous synaptic signal as a stimulus waveform and (ii) the use of a specific electrode within the array adjacent to the stimulus electrode as a hard-grounded stimulus signal return path. Both modifications remained compatible with manipulation of neuronal networks. In addition, localized stimulation with the low-amplitude synaptic signal allowed selective stimulation or inhibition of otherwise spontaneous signals. These findings indicate that minimizing the area of the culture impacted by external stimulation allows modulation of signaling patterns within subpopulations of neurons in culture. The simple modifications described herein may be useful for precise monitoring and manipulation of neuronal networks.

Accelerated establishment of mature signaling patterns following stimulation of developing neuronal networks: “learning” versus “plasticity”

“…This approach allows spreading of the signal to large numbers of neurons that are not synaptically connected (Brewer et al, 2009; Wagenaar et al, 2004). By contrast, our use herein of a recorded synaptic signal, coupled with confinement to a localized cluster of electrodes for stimulation and recording, presents a more physiological model of synaptic input (Zemianek et al, 2012).…”

“…Neuronal networks were recorded for 30 s periods via a DT9814 data acquisition system (Data Translation; Marlborough, MA) using a MEA‐1060‐INV amplifier (Multichannel). Signals were quantified manually and with an algorithm that distinguishes bona‐fide activity from baseline disturbances (Serra et al, 2008a; Wagenaar et al, 2005; Zemianek et al, 2012). Data were captured at 3.125 kHz simultaneously accessing 16 channels and 12.5 kHz accessing 4 channels; the latter was used to validate the use of undersampling for the purpose of observing more channels.…”

“…Spontaneous signals and signals resulting from stimulation were classified as “spikes” if they appeared as individual signals separated by other signals by a minimum of 0.7 s, and “bursts” if they consisted of clusters of at least 3 spikes within a 0.7 s period prior to returning to baseline (Serra et al, 2008a; Zemianek et al, 2012).…”

“…Many studies utilizing external network stimulation utilize a relatively high‐amplitude, biphasic “spike” or series of such spikes (Brewer et al, 2009; Jimbo et al, 1998; Wagenaar et al, 2004, 2005, 2006), coupled with the use of a distal “bath ground” electrode. This regimen results in simultaneous stimulation of virtually the entire culture (Zemianek et al, 2012 and references therein). Herein, in our attempt to model the onset of sensory input, we instead set out to stimulate localized regions of the networks, and to utilize a physiological signal.…”

Understanding the temporal evolution of neuronal connectivity in cultured networks using statistical analysis

“…Over the past few decades, MEAs have been frequently used to investigate the mechanisms that take place at the network level among cultured neurons and to answer fundamental questions regarding the cellular basis of learning, memory and synaptic developmental plasticity [1]. MEAs allow researchers to carry out long-term (up to a few months) non-invasive neural recordings using experimental setups that are easier to control and less complex than similar in-vivo systems.…”