A low-cost, 61-channel &amp;#x00B5;ECoG array for use in rodents

Woods, Virginia; Wang, Charles; Bossi, Silvia; Insanally, Michele N.; Trumpis, Michael; Froemke, Robert C.; Viventi, Jonathan

doi:10.1109/ner.2015.7146687

Cited by 9 publications

(7 citation statements)

References 19 publications

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“…We designed a flexible μECoG array with 61 passive electrodes spaced 406 μm apart (figure 1(a)) [15]. The arrays were fabricated using the following standard flexible printed circuit board processing techniques by Microconnex Flex Circuits (Snoqualmie, WA).…”

Section: Methodsmentioning

confidence: 99%

A low-cost, multiplexedμECoG system for high-density recordings in freely moving rodents

et al. 2016

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Objective Micro-electrocorticography (μECoG) offers a minimally invasive neural interface with high spatial resolution over large areas of cortex. However, electrode arrays with many contacts that are individually wired to external recording systems are cumbersome and make recordings in freely-behaving rodents challenging. We report a novel high-density 60-electrode system for μECoG recording in freely-moving rats. Approach Multiplexed headstages overcome the problem of wiring complexity by combining signals from many electrodes to a smaller number of connections We have developed a low-cost, multiplexed recording system with 60 contacts at 406 μm spacing. We characterized the quality of the electrode signals using multiple metrics that tracked spatial variation, evoked-response detectability, and decoding value. Performance of the system was validated both in anesthetized animals and freely-moving awake animals. Main results We recorded μECoG signals over the primary auditory cortex, measuring responses to acoustic stimuli across all channels. Single-trial responses had high signal-to-noise ratios (up to 25 dB under anesthesia), and were used to rapidly measure network topography within ~10 seconds by constructing all single-channel receptive fields in parallel. We characterized evoked potential amplitudes and spatial correlations across the array in the anesthetized and awake animals. Recording quality in awake animals was stable for at least 30 days. Finally, we used these responses to accurately decode auditory stimuli on single trials. Significance This study introduces (1) a μECoG recording system based on practical hardware design and (2) a rigorous analytical method for characterizing the signal characteristics of μECoG electrode arrays. This methodology can be applied to evaluate the fidelity and lifetime of any μECoG electrode array. Our μECoG-based recording system is accessible and will be useful for studies of perception and decision-making in rodents, particularly over the entire time course of behavioral training and learning.

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Section: Methodsmentioning

confidence: 99%

A low-cost, multiplexedμECoG system for high-density recordings in freely moving rodents

et al. 2016

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“…Electrochemical cleaning of the electrodes is recommended prior to plating, e.g. by injecting 500 µA for 60 s in deionized water as in [5], or 750 µA for 5 s [71].…”

Section: ) Methods For Interfacial Impedance Reductionmentioning

confidence: 99%

Bioimpedance Sensors: A Tutorial

Kassanos

2021

IEEE Sensors J.

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Electrical bioimpedance entails the measurement of the electrical properties of tissues as a function of frequency. It is thus a spectroscopic technique. It has been applied in a plethora of biomedical applications for diagnostic and monitoring purposes. In this tutorial, the basics of electrical bioimpedance sensor design will be discussed. The electrode/electrolyte interface is thoroughly described, as well as methods for its modelling with equivalent circuits and computational tools. The design optimization and modelling of bipolar and tetrapolar bioimpedance sensors is presented in detail, based on the sensitivity theorem. Analytical and numerical modelling approaches for electric field simulations based on conformal mapping, point electrode approximations and the finite element method (FEM) are also elaborated. Finally, current trends on bioimpedance sensors are discussed followed by an overview of instrumentation methods for bioimpedance measurements, covering aspects of voltage signal excitations, current sources, voltage measurement front-end topologies and methods for computing the electrical impedance.

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“…Neural activity was recorded using a 61-channel ECoG array [48]. The flexible (~30 μm thin) ECoG array comprised 203-μm diameter circular electrodes arranged on an 8 × 8 square grid, with three of the four corner positions unoccupied, and a 406-μm spacing between neighboring electrodes.…”

Section: Ecog Recording Apparatusmentioning

confidence: 99%

The precedence effect in spatial hearing manifests in cortical neural population responses

Auksztulewicz

Chan

et al. 2022

BMC Biol

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Background To localize sound sources accurately in a reverberant environment, human binaural hearing strongly favors analyzing the initial wave front of sounds. Behavioral studies of this “precedence effect” have so far largely been confined to human subjects, limiting the scope of complementary physiological approaches. Similarly, physiological studies have mostly looked at neural responses in the inferior colliculus, the main relay point between the inner ear and the auditory cortex, or used modeling of cochlear auditory transduction in an attempt to identify likely underlying mechanisms. Studies capable of providing a direct comparison of neural coding and behavioral measures of sound localization under the precedence effect are lacking. Results We adapted a “temporal weighting function” paradigm previously developed to quantify the precedence effect in human for use in laboratory rats. The animals learned to lateralize click trains in which each click in the train had a different interaural time difference. Computing the “perceptual weight” of each click in the train revealed a strong onset bias, very similar to that reported for humans. Follow-on electrocorticographic recording experiments revealed that onset weighting of interaural time differences is a robust feature of the cortical population response, but interestingly, it often fails to manifest at individual cortical recording sites. Conclusion While previous studies suggested that the precedence effect may be caused by early processing mechanisms in the cochlea or inhibitory circuitry in the brainstem and midbrain, our results indicate that the precedence effect is not fully developed at the level of individual recording sites in the auditory cortex, but robust and consistent precedence effects are observable only in the auditory cortex at the level of cortical population responses. This indicates that the precedence effect emerges at later cortical processing stages and is a significantly “higher order” feature than has hitherto been assumed.

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A low-cost, 61-channel µECoG array for use in rodents

Cited by 9 publications

References 19 publications

A low-cost, multiplexedμECoG system for high-density recordings in freely moving rodents

A low-cost, multiplexedμECoG system for high-density recordings in freely moving rodents

Bioimpedance Sensors: A Tutorial

The precedence effect in spatial hearing manifests in cortical neural population responses

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