When the Ostrich-Algorithm Fails: Blanking Method Affects Spike Train Statistics

Abstract

Modern electroceuticals are bound to employ the usage of electrical high frequency (130–180 Hz) stimulation carried out under closed loop control, most prominent in the case of movement disorders. However, particular challenges are faced when electrical recordings of neuronal tissue are carried out during high frequency electrical stimulation, both in-vivo and in-vitro. This stimulation produces undesired artifacts and can render the recorded signal only partially useful. The extent of these artifacts is often reduced by temporarily grounding the recording input during stimulation pulses. In the following study, we quantify the effects of this method, “blanking,” on the spike count and spike train statistics. Starting from a theoretical standpoint, we calculate a loss in the absolute number of action potentials, depending on: width of the blanking window, frequency of stimulation, and intrinsic neuronal activity. These calculations were then corroborated by actual high signal to noise ratio (SNR) single cell recordings. We state that, for clinically relevant frequencies of 130 Hz (used for movement disorders) and realistic blanking windows of 2 ms, up to 27% of actual existing spikes are lost. We strongly advice cautioned use of the blanking method when spike rate quantification is attempted.Impact statementBlanking (artifact removal by temporarily grounding input), depending on recording parameters, can lead to significant spike loss. Very careful use of blanking circuits is advised.

Human organotypic brain slice culture: a novel framework for environmental research in neuro-oncology

“…The sections were initially perfused with physiological artificial cerebro spinal fluid (aCSF) (concentration in mM: 11 mM glucose, 25 mM NaHC0 3 , 126 mM NaCl, 3.5 mM KCl, 1.2 mM NaH 2 PO 4 , 1.3 mM MgCl 2 , and 2 mM CaCl 2 ) at 3 ml/min during the stabilization and baseline phase (60 min) followed by a high K + aCSF (11 mM glucose, 25 mM NaHCO 3 , 126 mM NaCl, 7 mM KCl, 1.2 mM NaH 2 PO 4 , and 2 mM CaCl 2 ) perfused into the system for 60 min. The high K + aCSF was used to evoke activity from the tissue, which was then further analyzed offline using a custom MATLAB (Mathworks Inc.) script, as reported previously (Joseph et al, 2018). Briefly, after high-pass filtering of the data (300 Hz), four parameters were used to classify a threshold crossing event as an action potential: amplitude, falling and rising slopes of depolarization/repolarization, the hyperpolarization amplitude, and the time delay between the depolarization peak and hyperpolarization peak.…”

Advances in Neural Recording and Stimulation Integrated Circuits

“…However, the large stimulation pulse causes the artifact that is subsequently picked up by the recording amplifier as a false AP, and a false stimulation will be triggered. This situation is even worse in the multi-channel neural recording and stimulation circuit (Ng et al, 2012;Joseph et al, 2018).…”