scholarly journals Long Term Amperometric Recordings in the Brain Extracellular Fluid of Freely Moving Immunocompromised NOD SCID Mice

Sensors ◽  
2017 ◽  
Vol 17 (2) ◽  
pp. 419 ◽  
Author(s):  
Caroline Reid ◽  
Niall Finnerty
Keyword(s):  
Extracellular Fluid ◽  
Scid Mice ◽  
Brain Extracellular Fluid ◽  
Freely Moving ◽  
The Brain

scholarly journals Retention Period of Amyloid β1–42 in the Brain Extracellular Fluid as the Toxicological Determinant in Freely Moving Rats

2020 ◽  
Vol 43 (12) ◽  
pp. 1975-1978
Author(s):  
Haruna Tamano ◽  
Junichi Togo ◽  
Yuichi Sato ◽  
Aoi Shioya ◽  
Munekazu Tempaku ◽  
...  
Keyword(s):  
Extracellular Fluid ◽  
Amyloid Β ◽  
Retention Period ◽  
Brain Extracellular Fluid ◽  
Freely Moving Rats ◽  
Freely Moving ◽  
The Brain

scholarly journals Kinetics of a nucleoside release from lactide-caprolactone and lactide-glycolide polymers in vitro.

2000 ◽  
Vol 47 (1) ◽  
pp. 59-64
Author(s):  
T Kryczka ◽  
P Grieb ◽  
M Bero ◽  
J Kasperczyk ◽  
P Dobrzynski
Keyword(s):  
Formation Rate ◽  
Local Treatment ◽  
Extracellular Fluid ◽  
Brain Extracellular Fluid ◽  
Artificial Cerebrospinal Fluid ◽  
Fluid Formation ◽  
Further Development ◽  
Kinetics Of ◽  
The Brain

We assessed the rate of release of a model nucleoside (adenosine, 5%, w/w) from nine different lactide-glycolide or lactide-caprolactone polymers. The polymer discs were eluted every second day with an artificial cerebrospinal fluid at the elution rate roughly approximating the brain extracellular fluid formation rate. Adenosine in eluate samples was assayed by HPLC. Three polymers exhibited a relatively constant release of adenosine for over four weeks, resulting in micromolar concentrations of nucleoside in the eluate. This points to the necessity of further development of polymers of this types as intracerebral nucleoside delivery systems for local treatment of brain tumors.

scholarly journals NeuroRoots, a bio-inspired, seamless Brain Machine Interface device for long-term recording

2018 ◽  
Author(s):  
Marc D. Ferro ◽  
Christopher M. Proctor ◽  
Alexander Gonzalez ◽  
Eric Zhao ◽  
Andrea Slezia ◽  
...  
Keyword(s):  
Neurological Diseases ◽  
Signal Amplitude ◽  
Brain Machine Interface ◽  
Behavioral Experiments ◽  
Adult Rats ◽  
Integrative Level ◽  
Machine Interface ◽  
Freely Moving ◽  
The Brain

AbstractMinimally invasive electrodes of cellular scale that approach a bio-integrative level of neural recording could enable the development of scalable brain machine interfaces that stably interface with the same neural populations over long period of time.In this paper, we designed and created NeuroRoots, a bio-mimetic multi-channel implant sharing similar dimension (10µm wide, 1.5µm thick), mechanical flexibility and spatial distribution as axon bundles in the brain. A simple approach of delivery is reported based on the assembly and controllable immobilization of the electrode onto a 35µm microwire shuttle by using capillarity and surface-tension in aqueous solution. Once implanted into targeted regions of the brain, the microwire was retracted leaving NeuroRoots in the biological tissue with minimal surgical footprint and perturbation of existing neural architectures within the tissue. NeuroRoots was implanted using a platform compatible with commercially available electrophysiology rigs and with measurements of interests in behavioral experiments in adult rats freely moving into maze. We demonstrated that NeuroRoots electrodes reliably detected action potentials for at least 7 weeks and the signal amplitude and shape remained relatively constant during long-term implantation.This research represents a step forward in the direction of developing the next generation of seamless brain-machine interface to study and modulate the activities of specific sub-populations of neurons, and to develop therapies for a plethora of neurological diseases.

Spinal and Supraspinal Effects of Long-Term Stimulation of Sensorimotor Cortex in Rats

2007 ◽  
Vol 98 (2) ◽  
pp. 878-887 ◽  
Author(s):  
Xiang Yang Chen ◽  
Shreejith Pillai ◽  
Yi Chen ◽  
Yu Wang ◽  
Lu Chen ◽  
...  
Keyword(s):  
Spinal Cord ◽  
Operant Conditioning ◽  
Sensorimotor Cortex ◽  
H Reflex ◽  
Freely Moving ◽  
Activity Dependent ◽  
Spinal Cord Function ◽  
The Brain ◽  
Stimulation Of

Sensorimotor cortex (SMC) modifies spinal cord reflex function throughout life and is essential for operant conditioning of the H-reflex. To further explore this long-term SMC influence over spinal cord function and its possible clinical uses, we assessed the effect of long-term SMC stimulation on the soleus H-reflex. In freely moving rats, the soleus H-reflex was measured 24 h/day for 12 wk. The soleus background EMG and M response associated with H-reflex elicitation were kept stable throughout. SMC stimulation was delivered in a 20-day-on/20-day-off/20-day-on protocol in which a train of biphasic 1-ms pulses at 25 Hz for 1 s was delivered every 10 s for the on-days. The SMC stimulus was automatically adjusted to maintain a constant descending volley. H-reflex size gradually increased during the 20 on-days, stayed high during the 20 off-days, and rose further during the next 20 on-days. In addition, the SMC stimulus needed to maintain a stable descending volley rose steadily over days. It fell during the 20 off-days and rose again when stimulation resumed. These results suggest that SMC stimulation, like H-reflex operant conditioning, induces activity-dependent plasticity in both the brain and the spinal cord and that the plasticity responsible for the H-reflex increase persists longer after the end of SMC stimulation than that underlying the change in the SMC response to stimulation.

scholarly journals Striking Differences in Glucose and Lactate Levels between Brain Extracellular Fluid and Plasma in Conscious Human Subjects: Effects of Hyperglycemia and Hypoglycemia

2002 ◽  
Vol 22 (3) ◽  
pp. 271-279 ◽  
Author(s):  
Walid M. Abi-Saab ◽  
David G. Maggs ◽  
Tim Jones ◽  
Ralph Jacob ◽  
Vinod Srihari ◽  
...  
Keyword(s):  
Human Subjects ◽  
Intractable Epilepsy ◽  
Extracellular Fluid ◽  
Intracerebral Microdialysis ◽  
Brain Extracellular Fluid ◽  
Lactate Levels ◽  
A Site ◽  
Clamp Study ◽  
The Relationship ◽  
The Brain

Brain levels of glucose and lactate in the extracellular fluid (ECF), which reflects the environment to which neurons are exposed, have never been studied in humans under conditions of varying glycemia. The authors used intracerebral microdialysis in conscious human subjects undergoing electro-physiologic evaluation for medically intractable epilepsy and measured ECF levels of glucose and lactate under basal conditions and during a hyperglycemia–hypoglycemia clamp study. Only measurements from nonepileptogenic areas were included. Under basal conditions, the authors found the metabolic milieu in the brain to be strikingly different from that in the circulation. In contrast to plasma, lactate levels in brain ECF were threefold higher than glucose. Results from complementary studies in rats were consistent with the human data. During the hyperglycemia–hypoglycemia clamp study the relationship between plasma and brain ECF levels of glucose remained similar, but changes in brain ECF glucose lagged approximately 30 minutes behind changes in plasma. The data demonstrate that the brain is exposed to substantially lower levels of glucose and higher levels of lactate than those in plasma; moreover, the brain appears to be a site of significant anaerobic glycolysis, raising the possibility that glucose-derived lactate is an important fuel for the brain.

scholarly journals Volume Transmission and Pain Perception

2003 ◽  
Vol 3 ◽  
pp. 677-683 ◽  
Author(s):  
Gilberto C. Castañeda-Hernàndez ◽  
Paul Bach-y-Rita
Keyword(s):  
Pain Perception ◽  
Brain Plasticity ◽  
Extracellular Fluid ◽  
Multiple Roles ◽  
Target Cells ◽  
Volume Transmission ◽  
Brain Extracellular Fluid ◽  
Extrasynaptic Receptors ◽  
Drug Actions ◽  
The Brain

Volume transmission (VT) is the diffusion through the brain extracellular fluid of neurotransmitters released at points that may be remote from the target cells with the resulting activation of extrasynaptic receptors. VT appears to play multiple roles in the brain in normal and abnormal activity, brain plasticity and drug actions. The relevance of VT to pain perception has been explored in this review.

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