Evaluation of μECoG electrode arrays in the minipig: Experimental procedure and neurosurgical approach

Gierthmuehlen, Mortimer; Ball, Tonio; Henle, Christian; Wang, Xi; Rickert, Jörn; Raab, Markus; Freiman, Thomas M.; Kaminsky, Jan

doi:10.1016/j.jneumeth.2011.08.021

Cited by 17 publications

(19 citation statements)

References 22 publications

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“…Future analyses with different decoding algorithms, different features, or based on signals from electrodes with a higher spatial resolution such as micro-ECoG (Gierthmuehlen et al, 2011; Bouchard et al, 2013) may result in a better decoding performance. If feasible, decoding the content of IUs from single trials of neuronal activity may further aid restoration of intended speech output in paralyzed patients with articulatory impairments (Pei et al, 2011; Derix et al, 2012; Pasley et al, 2012).…”

Section: Discussionmentioning

confidence: 99%

From speech to thought: the neuronal basis of cognitive units in non-experimental, real-life communication investigated using ECoG

Derix

Iljina

Weiske

et al. 2014

Front. Hum. Neurosci.

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Exchange of thoughts by means of expressive speech is fundamental to human communication. However, the neuronal basis of real-life communication in general, and of verbal exchange of ideas in particular, has rarely been studied until now. Here, our aim was to establish an approach for exploring the neuronal processes related to cognitive “idea” units (IUs) in conditions of non-experimental speech production. We investigated whether such units corresponding to single, coherent chunks of speech with syntactically-defined borders, are useful to unravel the neuronal mechanisms underlying real-world human cognition. To this aim, we employed simultaneous electrocorticography (ECoG) and video recordings obtained in pre-neurosurgical diagnostics of epilepsy patients. We transcribed non-experimental, daily hospital conversations, identified IUs in transcriptions of the patients' speech, classified the obtained IUs according to a previously-proposed taxonomy focusing on memory content, and investigated the underlying neuronal activity. In each of our three subjects, we were able to collect a large number of IUs which could be assigned to different functional IU subclasses with a high inter-rater agreement. Robust IU-onset-related changes in spectral magnitude could be observed in high gamma frequencies (70–150 Hz) on the inferior lateral convexity and in the superior temporal cortex regardless of the IU content. A comparison of the topography of these responses with mouth motor and speech areas identified by electrocortical stimulation showed that IUs might be of use for extraoperative mapping of eloquent cortex (average sensitivity: 44.4%, average specificity: 91.1%). High gamma responses specific to memory-related IU subclasses were observed in the inferior parietal and prefrontal regions. IU-based analysis of ECoG recordings during non-experimental communication thus elicits topographically- and functionally-specific effects. We conclude that segmentation of spontaneous real-world speech in linguistically-motivated units is a promising strategy for elucidating the neuronal basis of mental processing during non-experimental communication.

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Section: Discussionmentioning

confidence: 99%

From speech to thought: the neuronal basis of cognitive units in non-experimental, real-life communication investigated using ECoG

Derix

Iljina

Weiske

et al. 2014

Front. Hum. Neurosci.

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“…This well-known problem has led to a push towards less invasive neural implants, such as electrocorticography (ECoG), and more recently, micro-ECoG (Figure 1), which sit on top of the cortical surface rather than penetrating into it (Gierthmuehlen et al, 2011; Kitzmiller et al, 2006; Thongpang et al, 2011; Viventi et al, 2011; Wang et al, 2009). These devices are thought to strike a potential balance between the spatial resolution necessary for performing brain computer interfacing (BCI) tasks and the long-term stability required for human implantation.…”

Section: Introductionmentioning

confidence: 99%

A cranial window imaging method for monitoring vascular growth around chronically implanted micro-ECoG devices

Schendel

Thongpang

Brodnick

et al. 2013

Journal of Neuroscience Methods

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Implantable neural micro-electrode arrays have the potential to restore lost sensory or motor function to many different areas of the body. However, the invasiveness of these implants often results in scar tissue formation, which can have detrimental effects on recorded signal quality and longevity. Traditional histological techniques can be employed to study the tissue reaction to implanted micro-electrode arrays, but these techniques require removal of the brain from the skull, often causing damage to the meninges and cortical surface. This is especially unfavorable when studying the tissue response to electrode arrays such as the micro-electrocorticography (micro-ECoG) device, which sits on the surface of the cerebral cortex. In order to better understand the biological changes occurring around these types of devices, a cranial window implantation scheme has been developed, through which the tissue response can be studied in vivo over the entire implantation period. Rats were implanted with epidural micro-ECoG arrays, over which glass coverslips were placed and sealed to the skull, creating cranial windows. Vascular growth around the devices was monitored for one month after implantation. It was found that blood vessels grew through holes in the micro-ECoG substrate, spreading over the top of the device. Micro-hematomas were observed at varying time points after device implantation in every animal, and tissue growth between the micro-ECoG array and the window occurred in several cases. Use of the cranial window imaging technique with these devices enabled the observation of tissue changes that would normally go unnoticed with a standard device implantation scheme.

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“…Laser‐fabricated tailored electrodes (Schuettler et al, ; Henle et al, ), µECoG‐based micromachining techniques using polymer substrates (Rubehn et al, ) or on dissolvable silk (Kim et al, ) or silicon‐based foldable grids (Viventi et al, ), have broken completely new ground in BMI research, and all these techniques have to be tested and certified for human use. Therefore, there is a great demand for suitable, practical, and readily available animal models to evaluate the safety and efficiency of such new techniques to record brain activity (Gierthmuehlen et al, ; Charvet et al, ) and to broaden the knowledge of cortical (micro‐)neurophysiology for neuroscience and BMI. Ideally, such an animal model should have the following properties.…”

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confidence: 99%

“…The minipig has a convenient size, but its frontal sinus is extended over the most of the skull and thus is inevitably opened during the surgical approach to most parts of the cortex. This makes the minipig interesting for acute experiments, but chronic implantation is impaired by the clinical fact that the risk of postoperative infection is dramatically increased by the large opened frontal sinus (Gierthmuehlen et al, ). The minipig qualifies for chronic implantation only if the dura is left intact and the target cortical area is located occipitally so that the frontal sinus is not opened during the approach (Laube et al, ; Sachs et al, ).…”

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confidence: 99%

Mapping of sheep sensory cortex with a novel microelectrocorticography grid

Gierthmuehlen

Wang

Gkogkidis

et al. 2014

J of Comparative Neurology

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Microelectrocorticography (µECoG) provides insights into the cortical organization with high temporal and spatial resolution desirable for better understanding of neural information processing. Here we evaluated the use of µECoG for detailed cortical recording of somatosensory evoked potentials (SEPs) in an ovine model. The approach to the cortex was planned using an MRI-based 3D model of the sheep's brain. We describe a minimally extended surgical procedure allowing placement of two different µECoG grids on the somatosensory cortex. With this small craniotomy, the frontal sinus was kept intact, thus keeping the surgical site sterile and making this approach suitable for chronic implantations. We evaluated the procedure for chronic implantation of an encapsulated µECoG recording system. During acute and chronic recordings, significant SEP responses in the triangle between the ansate, diagonal, and coronal sulcus were identified in all animals. Stimulation of the nose, upper lip, lower lip, and chin caused a somatotopic lateral-to-medial, ipsilateral response pattern. With repetitive recordings of SEPs, this somatotopic pattern was reliably recorded for up to 16 weeks. The findings of this study confirm the previously postulated ipsilateral, somatotopic organization of the sheep's sensory cortex. High gamma band activity was spatially most specific in the comparison of different frequency components of the somatosensory evoked response. This study provides a basis for further acute and chronic investigations of the sheep's sensory cortex by characterizing its exact position, its functional properties, and the surgical approach with respect to macroanatomical landmarks.

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Evaluation of μECoG electrode arrays in the minipig: Experimental procedure and neurosurgical approach

Cited by 17 publications

References 22 publications

From speech to thought: the neuronal basis of cognitive units in non-experimental, real-life communication investigated using ECoG

From speech to thought: the neuronal basis of cognitive units in non-experimental, real-life communication investigated using ECoG

A cranial window imaging method for monitoring vascular growth around chronically implanted micro-ECoG devices

Mapping of sheep sensory cortex with a novel microelectrocorticography grid

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