scholarly journals Flexible Electrocorticography Electrode Array for Epileptiform Electrical Activity Recording under Glutamate and GABA Modulation on the Primary Somatosensory Cortex of Rats

Micromachines ◽  
2020 ◽  
Vol 11 (8) ◽  
pp. 732
Author(s):  
Xinrong Li ◽  
Yilin Song ◽  
Guihua Xiao ◽  
Jingyu Xie ◽  
Yuchuan Dai ◽  
...  
Keyword(s):  
Somatosensory Cortex ◽  
Epileptiform Activity ◽  
Electrode Array ◽  
Cortical Activity ◽  
Primary Somatosensory Cortex ◽  
Platinum Black ◽  
Gamma Aminobutyric Acid ◽  
Neuronal Populations ◽  
Lower Impedance ◽  
Spike Wave

Epilepsy is a common neurological disorder. There is still a lack of methods to accurately detect cortical activity and locate lesions. In this work, a flexible electrocorticography (ECoG) electrode array based on polydimethylsiloxane (PDMS)-parylene was fabricated to detect epileptiform activity under glutamate (Glu) and gamma-aminobutyric acid (GABA) modulation on primary somatosensory cortex of rats. The electrode with a thickness of 20 μm has good flexibility to establish reliable contact with the cortex. Fourteen recording sites with a diameter of 60 μm are modified by electroplating platinum black nanoparticles, which effectively improve the performance with lower impedance, obtaining a sensitive sensing interface. The electrode enables real-time capturing changes in neural activity under drug modulation. Under Glu modulation, neuronal populations showed abnormal excitability, manifested as hypsarrhythmia rhythm and continuous or periodic spike wave epileptiform activity, with power increasing significantly. Under GABA modulation, the excitement was inhibited, with amplitude and power reduced to normal. The flexible ECoG electrode array could monitor cortical activity, providing us with an effective tool for further studying epilepsy and locating lesions.

Changes in gamma-aminobutyric acid and somatostatin in epileptic cortex associated with low-grade gliomas

1992 ◽  
Vol 77 (2) ◽  
pp. 209-216 ◽  
Author(s):  
Michael M. Haglund ◽  
Mitchel S. Berger ◽  
Dennis D. Kunkel ◽  
JoAnn E. Franck ◽  
Saadi Ghatan ◽  
...  
Keyword(s):  
Epileptiform Activity ◽  
Aminobutyric Acid ◽  
Low Grade ◽  
Tumor Infiltration ◽  
Gamma Aminobutyric Acid ◽  
Content Type ◽  
Low Grade Gliomas ◽  
Neuronal Populations ◽  
Significant Difference

✓ The role of specific neuronal populations in epileptic foci was studied by comparing epileptic and nonepileptic cortex removed from patients with low-grade gliomas. Epileptic and nearby (within 1 to 2 cm) nonepileptic temporal lobe neocortex was identified using electrocorticography. Cortical specimens taken from four patients identified as epileptic and nonepileptic were all void of tumor infiltration. Somatostatin- and γ-aminobutyric acid (GABAergic)-immunoreactive neurons were identified and counted. Although there was no significant difference in the overall cell count, the authors found a significant decrease in both somatostatin- and GABAergic-immunoreactive neurons (74% and 51 %, respectively) in the epileptic cortex compared to that in nonepileptic cortex from the same patient. It is suggested that these findings demonstrate changes in neuronal subpopulations that may account for the onset and propagation of epileptiform activity in patients with low-grade gliomas.

scholarly journals Modular Processing in the Hand Representation of Primate Primary Somatosensory Cortex Coexists With Widespread Activation

2010 ◽  
Vol 104 (6) ◽  
pp. 3136-3145 ◽  
Author(s):  
Jamie L. Reed ◽  
Hui-Xin Qi ◽  
Pierre Pouget ◽  
Mark J. Burish ◽  
A. B. Bonds ◽  
...  
Keyword(s):  
Firing Rate ◽  
Somatosensory Cortex ◽  
Receptive Fields ◽  
Electrode Array ◽  
Electrode Site ◽  
Primary Somatosensory Cortex ◽  
Local Processing ◽  
Firing Rates ◽  
Area 3B ◽  
Activation Site

Neurons in the hand representation of primary somatosensory cortex (area 3b) are known to have discretely localized receptive fields; and these neurons form modules that can be visualized histologically as distinct digit and palm representations. Despite these indicators of the importance of local processing in area 3b, widespread interactions between stimuli presented to locations across the hand have been reported. We investigated the relationship of neuron firing rate with distance from the site of maximum activation in cortex by recording from a 100-electrode array with electrodes spaced 400 μm apart, implanted into the area 3b hand representation in anesthetized owl monkeys. For each stimulated location on the hand, the electrode site where neurons had the highest peak firing rate was defined as the peak activation site. The lesser firing rates of neurons at all other electrode sites in the grid were compared with the firing rates of neurons at the peak activation site. On average, peak firing rates of neurons decreased rapidly with distance away from the peak activation site. The effect of distance on the variance of firing rates was highly significant ( P < 0.0001). However, individual neurons retained high firing rates for distances over 3 mm. The clear decline in firing rate with distance from the most activated location indicates that local processing is emphasized in area 3b, while the distance of neurons with reduced but maintained firing rates ≤3–4 mm from the site of best activation demonstrated widespread activation in primary somatosensory cortex.

Functional role of GABA in cat primary somatosensory cortex: shaping receptive fields of cortical neurons

1984 ◽  
Vol 52 (6) ◽  
pp. 1066-1093 ◽  
Author(s):  
R. W. Dykes ◽  
P. Landry ◽  
R. Metherate ◽  
T. P. Hicks
Keyword(s):  
Receptive Field ◽  
Somatosensory Cortex ◽  
Cortical Neurons ◽  
Receptive Fields ◽  
Field Size ◽  
Primary Somatosensory Cortex ◽  
Gamma Aminobutyric Acid ◽  
Receptive Field Size ◽  
Thalamic Stimulation ◽  
Somatosensory Neurons

Extracellular recordings of 209 neurons were obtained with carbon fiber-containing multibarrel micropipettes. The cells were isolated in the primary somatosensory cortex of cats anesthetized with barbiturate and classified according to the nature of their response to natural stimuli, the nature of the surrounding multiunit responses to the same stimuli, the response to thalamic stimulation, and their depth in the cortex. To study factors controlling the excitability of somatosensory neurons, their receptive fields were examined in the presence of iontophoretically administered gamma-aminobutyric acid (GABA), glutamate, and bicuculline methiodide (BMI). Even when the neurons were depolarized to perithreshold levels with glutamate, or when local inhibitory influences mediated by GABA were antagonized by BMI, the apparent specificity for one class of afferent input was maintained. Neurons responding to stimulation of either cutaneous or deep receptors maintained their modality specificity, and neurons in cutaneous rapidly adapting regions never took on slowly adapting properties. When ejected at currents that did not elicit action potentials, glutamate lowered the threshold for activation by cutaneous stimuli but did not enlarge the receptive field. With larger ejecting currents, the neurons developed an on-going discharge, but even at these higher doses, glutamate did not produce an increase in the receptive-field size. Some neurons in regions of cortex exhibiting slowly adapting multiunit responses were relatively insensitive to glutamate. These cells required four to five times more glutamate to evoke discharges than did most neurons. Other cells, previously unresponsive to somatic stimuli, could be shown to possess distinct cutaneous receptive fields when either glutamate or BMI was ejected in their vicinity. Iontophoretically administered BMI altered the firing pattern of somatosensory neurons, causing them to discharge in bursts of 3-15 impulses. BMI enlarged the receptive-field size of neurons in regions displaying rapidly adapting multiunit background discharges but not in those regions with slowly adapting multiunit discharges. This differential effect of BMI, suggesting that GABA controls receptive-field size in rapidly adapting regions, also indicates that neurons in rapidly adapting regions differ pharmacologically from those in other submodality regions. In all cortical regions, BMI blocked the poststimulus inhibitory period that normally followed thalamic stimulation.(ABSTRACT TRUNCATED AT 400 WORDS)

Sign in / Sign up

Export Citation Format

Share Document