scholarly journals Implantation of Elongated Porous Silicon Neural Probe Array in Rat Cortex

2018 ◽  
Author(s):  
Mohamad Hajj-Hassan ◽  
Rayan Fayad ◽  
Soumaya Berro ◽  
Vamsy P. Chodavarapu ◽  
Sam Musallam
Keyword(s):  
Porous Silicon ◽  
Neural Tissue ◽  
Xenon Difluoride ◽  
Field Potentials ◽  
Neural Prosthetic ◽  
Rat Cortex ◽  
Numerical Studies ◽  
Neural Probe ◽  
The Brain ◽  
Probe Array

Neural microprobes represent an important component of neural prosthetic systems where implanted microprobes record the electro-potentials generated by specific thoughts in the brain and convey the signals to algorithms trained to interpret these thoughts. Here, we present novel elongated multi-site neural probe that can reach depths greater than 10mm. We hypothesize that reaching such depth allows the recording of cognitive signals required to drive cognitive prosthetics. The impedance of the recording sites on the probes was on the order of 500 kΩ at 1 kHz, which is consistent with probes used for neurophysiological recordings. The probes were made porous using Xenon Difluoride (XeF2) dry etching to improve the biocompatibility and their adherence to the surrounding neural tissue. Numerical studies were performed to determine the reliability of the porous probes. We implanted the elongated probe in rats and show that the elongated probes are capable of simultaneously recording both spikes and local field potentials (LFPs) from various recording sites.

scholarly journals Enhanced resolution of histochemical distribution of glucose-6-phosphate dehydrogenase activity in rat neural tissue by use of a semipermeable membrane.

1991 ◽  
Vol 39 (7) ◽  
pp. 937-943 ◽  
Author(s):  
M A Philbert ◽  
C M Beiswanger ◽  
T L Roscoe ◽  
D K Waters ◽  
H E Lowndes
Keyword(s):  
Vestibular Nucleus ◽  
Neural Tissue ◽  
Semipermeable Membrane ◽  
G6pd Activity ◽  
Ependymal Cells ◽  
Regional Localization ◽  
Enhanced Resolution ◽  
Membrane Technique ◽  
Glucose 6 Phosphate Dehydrogenase ◽  
The Brain

We examined the histochemical distribution of glucose-6-phosphate dehydrogenase (G6PD) activity in neural tissue using different diffusion barriers. Although polyvinyl alcohol and agar overlays permitted regional localization of G6PD, a semipermeable membrane revealed cellular differences in G6PD activity within populations of neurons. Distribution of G6PD activity in selected regions of the nervous system was examined using the membrane technique. White matter usually exhibited strong G6PD activity. The neuronal somata of the dorsal root ganglia (L4-L6) and anterior horns of the spinal lumbar enlargement demonstrated a variation in activity which was independent of somal size. Satellite cells showed intense activity when the membrane technique was used. Hippocampal pyramidal and granular cells of the dentate gyrus exhibited moderate, uniform G6PD activity, but only weak activity was seen in hippocampal and dentate molecular layers. High levels of activity were observed in the vascular endothelial cells of the brain, spinal cord, and choroid plexus, and in the ependymal cells of the spinal central canal and ventricles of the brain. The superior vestibular nucleus appeared to have little G6PD activity in either the neuron cell bodies or the surrounding parenchyma. The use of a semipermeable membrane for localization of G6PD activity in neural tissues permits enhanced resolution of neuron elements and may provide a more accurate assessment of G6PD activity in histological preparations.

scholarly journals Scalable Batch Fabrication of Ultrathin Flexible Neural Probes using Bioresorbable Silk Layer

2021 ◽  
Author(s):  
Clement Cointe ◽  
Adrian Laborde ◽  
Lionel G Nowak ◽  
David Bourrier ◽  
Christian Bergaud ◽  
...  
Keyword(s):  
Brain Research ◽  
Fabrication Technology ◽  
Neural Probes ◽  
Flexible Devices ◽  
Batch Fabrication ◽  
Neural Probe ◽  
Flexible Probe ◽  
The Brain ◽  
Design Freedom ◽  
Deep Brain

Flexible deep brain probes have been the focus of many research works and aims at achieving better compliance with the surrounding brain tissue while maintaining minimal rejection. Strategies have been explored to find the best way to implant a flexible probe in the brain, while maintaining its flexibility once positioned in the cortex. Here, we present a novel and versatile scalable batch fabrication approach to deliver ultra-thin and flexible penetrating neural probe consisting of a silk-parylene bilayer. The biodegradable silk layer provides a temporary and programmable stiffener to ensure ease of insertion of the ultrathin parylene-based flexible devices. The innovative and yet robust batch fabrication technology allows complete design freedom of the neural probe in terms of materials, size, shape and thickness. These results provide a novel technological solution for implanting ultra-flexible and ultrathin devices, which possesses great potential for brain research.

Ventricular and Cerebrospinal Fluid System

2017 ◽  
pp. 409-434
Author(s):  
Eduardo E. Benarroch ◽  
Jeremy K. Cutsforth-Gregory ◽  
Kelly D. Flemming
Keyword(s):  
Cerebrospinal Fluid ◽  
Neural Tissue ◽  
Local Environment ◽  
System P ◽  
Neurologic Disorders ◽  
Unique System ◽  
The Central Nervous System ◽  
Protective Structures ◽  
And Function ◽  
The Brain

The meninges, ventricular system, subarachnoid space, and cerebrospinal fluid (CSF) constitute a functionally unique system that has an important role in maintaining a stable environment within which the central nervous system can function. The membranes that constitute the meninges serve as supportive and protective structures for neural tissue. The CSF itself provides a cushioning effect during rapid movement of the head and mechanical buoyancy to the brain. In addition to providing a pathway for the removal of brain metabolites, it functions as a chemical reservoir that protects the local environment of the brain from changes that may occur in the blood, thus ensuring the brain’s continued undisturbed performance. The CSF system is present at the supratentorial, posterior fossa, and spinal levels. Because of this extensive anatomical distribution and function, pathologic alterations of the CSF system can occur in many neurologic disorders.

Spinomuscular Coherence in Monkeys Performing a Precision Grip Task

2008 ◽  
Vol 99 (4) ◽  
pp. 2012-2020 ◽  
Author(s):  
Tomohiko Takei ◽  
Kazuhiko Seki
Keyword(s):  
Spinal Cord ◽  
Sensorimotor Integration ◽  
Unique Feature ◽  
Cervical Spinal Cord ◽  
Precision Grip ◽  
Muscle Physiology ◽  
Field Potentials ◽  
Spinal Interneurons ◽  
Arm Muscles ◽  
The Brain

We recorded local field potentials (LFPs) from cervical spinal cord (C5–C8) in monkeys performing a precision grip task and examined their coherence with electromyographic (EMG) activities (spinomuscular coherence) recorded from hand and arm muscles. Among 164 LFP-EMG pairs, significant coherence was found in 34 pairs (21%). We classified the coherence into two groups based on its frequency range, narrowband coherence, and broadband coherence. The narrowband coherence was restricted to discrete frequencies in the range of 14–55 Hz and was widespread throughout the superficial and deep gray matter. In contrast, the broadband coherence distributed between 10 and 95 Hz and was found only in the ventral half of the spinal cord. The narrowband coherence suggests that oscillations, which have been described in many motor control areas of the brain, could also pass though spinal interneurons to affect motor output and sensorimotor integration. On the other hand, the broadband coherence could be a unique feature of spinal motoneuron-muscle physiology.

scholarly journals Repositioning N-Acetylcysteine (NAC): NAC-Loaded Electrospun Drug Delivery Scaffolding for Potential Neural Tissue Engineering Application

Pharmaceutics ◽  
2020 ◽  
Vol 12 (10) ◽  
pp. 934
Author(s):  
Gillian D. Mahumane ◽  
Pradeep Kumar ◽  
Viness Pillay ◽  
Yahya E. Choonara
Keyword(s):  
Cell Viability ◽  
Engineering Application ◽  
Neural Tissue ◽  
Modern Medicine ◽  
Burst Release ◽  
Tissue Engineering Application ◽  
Glioblastoma Multiform ◽  
Pheochromocytoma Pc12 ◽  
The Brain

Traumatic brain injury (TBI) presents a serious challenge for modern medicine due to the poor regenerative capabilities of the brain, complex pathophysiology, and lack of effective treatment for TBI to date. Tissue-engineered scaffolds have shown some experimental success in vivo; unfortunately, none have yielded consummate results of clinical efficacy. N-acetylcysteine has shown neuroprotective potential. To this end, we developed a N-acetylcysteine (NAC)-loaded poly(lactic-co-glycolic acid) (PLGA) electrospun system for potential neural tissue application for TBI. Scanning electron microscopy showed nanofiber diameters ranging 72–542 nm and 124–592 nm for NAC-free and NAC-loaded PLGA nanofibers, respectively. NAC loading was obtained at 28%, and drug entrapment efficacy was obtained at 84%. A biphasic NAC release pattern that featured an initial burst release (13.9%) stage and a later sustained release stage was noted, thus enabling the prolonged replenishing of NAC and drastically improving cell viability and proliferation. This was evidenced by a significantly higher cell viability and proliferation on NAC-loaded nanofibers for rat pheochromocytoma (PC12) and human glioblastoma multiform (A172) cell lines in comparison to PLGA-only nanofibers. The increased cell viability and cell proliferation on NAC-loaded nanofiber substantiates for the repositioning of NAC as a pharmacological agent in neural tissue regeneration applications.

Fabrication of the Silicon-Based Three-Dimension Neural Probe Arrays

2014 ◽  
Vol 609-610 ◽  
pp. 758-768 ◽  
Author(s):  
Yi Wei Zhuang ◽  
Zheng Xi Cheng ◽  
Xue Min Zhang ◽  
Hong Hui Yuan
Keyword(s):  
Flip Chip ◽  
Fabrication Process ◽  
Three Dimension ◽  
Sprague Dawley ◽  
Nerve Signal ◽  
Biological Compatibility ◽  
Neural Probe ◽  
Silicon Based ◽  
Probe Array

The neural probe array is an important tool for getting the neural signals. Giving consideration to the biological compatibility and the demand of integrating in circuit, new fabrication process of a silicon-based three-dimension neural probe array was reported. The idea about milling in mechanical process and the method of structure for transfer were introduced in the fabrication. The 10*10 scale silicon-based three-dimension probe arrays integrated in the readout circuit directly were fabricated by means of flip chip and multi-blade mixing dicing techniques. In the entire fabrication process, no any high-temperature process and silicon wet etching process, which would damage the circuit, were included. Using the fabrication process above, the 10*10 scale silicon-based probe arrays with centre-to-centre separation of 400 μm were achieved. In the probe arrays, whose good rate was more than 95%, the width of a single probe was 100 μm, the tip angle was 25o, and the height was more than 1.4 mm. Through the fabrication process, it was not only reducing the pin count greatly, but also simplifying the interface effectively. By the in vivo experiment of the Sprague Dawley rat, the corresponding nerve signal was obtained.

scholarly journals Generation of field potentials and modulation of their dynamics through volume integration of cortical activity

2015 ◽  
Vol 113 (1) ◽  
pp. 339-351 ◽  
Author(s):  
Yoshinao Kajikawa ◽  
Charles E. Schroeder
Keyword(s):  
Current Source ◽  
Quantitative Description ◽  
Critical Issue ◽  
Synaptic Activity ◽  
Field Potentials ◽  
Cortical Layers ◽  
Physiological Processes ◽  
Volume Conductor Model ◽  
The Relationship ◽  
The Brain

Field potentials (FPs) recorded within the brain, often called “local field potentials” (LFPs), are useful measures of net synaptic activity in a neuronal ensemble. However, due to volume conduction, FPs spread beyond regions of underlying synaptic activity, and thus an “LFP” signal may not accurately reflect the temporal patterns of synaptic activity in the immediately surrounding neuron population. To better understand the physiological processes reflected in FPs, we explored the relationship between the FP and its membrane current generators using current source density (CSD) analysis in conjunction with a volume conductor model. The model provides a quantitative description of the spatiotemporal summation of immediate local and more distant membrane currents to produce the FP. By applying the model to FPs in the macaque auditory cortex, we have investigated a critical issue that has broad implications for FP research. We have shown that FP responses in particular cortical layers are differentially susceptible to activity in other layers. Activity in the supragranular layers has the strongest contribution to FPs in other cortical layers, and infragranular FPs are most susceptible to contributions from other layers. To define the physiological processes generating FPs recorded in loci of relatively weak synaptic activity, strong effects produced by synaptic events in the vicinity have to be taken into account. While outlining limitations and caveats inherent to FP measurements, our results also suggest specific peak and frequency band components of FPs can be related to activity in specific cortical layers. These results may help improving the interpretability of FPs.

Dexterous Finger Movements in Primate Without Monosynaptic Corticomotoneuronal Excitation

2004 ◽  
Vol 92 (5) ◽  
pp. 3142-3147 ◽  
Author(s):  
Shigeto Sasaki ◽  
Tadashi Isa ◽  
Lars-Gunnar Pettersson ◽  
Bror Alstermark ◽  
Kimisato Naito ◽  
...  
Keyword(s):  
Precision Grip ◽  
Field Potentials ◽  
Finger Movements ◽  
Complete Transection ◽  
Electrophysiological Recordings ◽  
Upper Cervical ◽  
Propriospinal Neurons ◽  
The Brain ◽  
Observation Period ◽  
Made In

It is generally accepted that the precision grip and independent finger movements (IFMs) in monkey and man are controlled by the direct (monosynaptic) corticomotoneuronal (CM) pathway. This view is based on previous observations that pyramidotomy causes near permanent deficits of IFMs. However, in addition to the direct CM pathway, pyramidotomy interrupts several corticofugal connections to the brain stem and upper cervical segments. Indirect (oligosynaptic) CM pathways, which are phylogenetically older, have been considered to be of little or no importance in prehension. In three adult macaque monkeys, complete transection of the direct CM pathway was made in C4/C5, which is rostral to the forelimb segments (C6–Th1). Electrophysiological recordings revealed lack of the direct lateral corticospinal tract (LCST) volley, monosynaptic extracellular field potentials in the motor nuclei, and monosynaptic CM excitation. However, a disynaptic volley, disynaptic field potentials and disynaptic CM excitation mediated via C3–C4 propriospinal neurons remained after the lesion. Thus the lesion interrupted the monosynaptic CM pathway and oligosynaptic LCST pathways mediated by interneurons in the forelimb segments. Precision grip and IFMs were observed already after 1–28 days postoperatively. Weakness in force and deficits in preshaping remained for an observation period of 3 mo. Indirect CM pathways may be important for neuro-rehabilitation.

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