scholarly journals Brain Temperature Alters Contributions of Excitatory and Inhibitory Inputs to Evoked Field Potentials in the Rat Frontal Cortex

2020 ◽  
Vol 14 ◽  
Author(s):  
Mizuho Gotoh ◽  
Kazuaki Nagasaka ◽  
Mariko Nakata ◽  
Ichiro Takashima ◽  
Shinya Yamamoto
Keyword(s):  
Evoked Potentials ◽  
Frontal Cortex ◽  
Negative Correlation ◽  
Brain Temperature ◽  
Thermal Control ◽  
Control Device ◽  
Network Activity ◽  
Local Temperature ◽  
Brain Functions ◽  
Cortical Cooling

Changes in brain temperature have been reported to affect various brain functions. However, little is known about the effects of temperature on the neural activity at the network level, where multiple inputs are integrated. In this study, we recorded cortical evoked potentials while altering the local brain temperature in anesthetized rats. We delivered electrical stimulations to the midbrain dopamine area and measured the evoked potentials in the frontal cortex, the temperature of which was locally altered using a thermal control device. We focused on the maximum negative peaks, which was presumed to result mainly from polysynaptic responses, to examine the effect of local temperature on network activity. We showed that focal cortical cooling increased the amplitude of evoked potentials (negative correlation, >17°C); further cooling decreased their amplitude. This relationship would be graphically represented as an inverted-U-shaped curve. The pharmacological blockade of GABAergic inhibitory inputs eliminated the negative correlation (>17°C) and even showed a positive correlation when the concentration of GABAA receptor antagonist was sufficiently high. Blocking the glutamatergic excitatory inputs decreased the amplitude but did not cause such inversion. Our results suggest that the negative correlation between the amplitude of evoked potentials and the near-physiological local temperature is caused by the alteration of the balance of contribution between excitatory and inhibitory inputs to the evoked potentials, possibly due to higher temperature sensitivity of inhibitory inputs.

scholarly journals Study of Short Latency Somatosensory and Brain Stem Auditory Evoked Potentials Patients with Acute Ischemic Stroke Involving Middle Cerebral Artery Territory

2021 ◽  
Author(s):  
Abhishek Miryala ◽  
Mahendra Javali ◽  
Anish Mehta ◽  
Pradeep R. ◽  
Purushottam Acharya ◽  
...  
Keyword(s):  
Ischemic Stroke ◽  
Evoked Potentials ◽  
Middle Cerebral Artery ◽  
Acute Ischemic Stroke ◽  
Brain Stem ◽  
Functional Outcome ◽  
Cerebral Artery ◽  
Negative Correlation ◽  
Auditory Evoked Potentials ◽  
Positive Correlation

Abstract Background The precise timings of evoked potentials in evaluating the functional outcome of stroke have remained indistinct. Few studies in the Indian context have studied the outcome of early prognosis of stroke utilizing evoked potentials. Objective The aim of this study was to determine somatosensory evoked potentials (SSEPs) and brain stem auditory evoked potentials (BAEPs), their timing and abnormalities in acute ischemic stroke involving the middle cerebral artery (MCA) territory and to correlate SSEP and BAEP with the functional outcome (National Institutes of Health Stroke Scale (NIHSS), modified Rankin scale (mRS) and Barthel’s index) at 3 months. Methods MCA territory involved acute ischemic stroke patients (n = 30) presenting consecutively to the hospital within 3 days of symptoms onset were included. Details about clinical symptoms, neurological examination, treatment, NIHSS score, mRS scores were collected at the time of admission. All patients underwent imaging of the brain and were subjected to SSEP and BAEP on two occasions, first at 1 to 3 days and second at 4 to 7 days from the onset of stroke. At 3 months of follow-up, NIHSS, mRS, and Barthel’s index were recorded. Results P37 and N20 amplitude had a strong negative correlation (at 1–3 and 4–7 days) with NIHSS at admission, NIHSS at 3 months, mRS at admission, and mRS at 3 months and a significant positive correlation with Barthel’s index (p < 0.0001). BAEP wave V had a negative correlation (at 1–3 and 4–7 days) with NIHSS at admission, NIHSS at 3 months, mRS at admission, and mRS at 3 months and a positive correlation with Barthel’s index (p < 0.0001). Conclusion SSEP abnormalities recorded on days 4 to 7 from onset of stroke are more significant than those recorded within 1 to 3 days of onset of stroke; hence, the timing of 4 to 7 days after stroke onset can be considered as better for predicting functional outcome.

A hollow microlattice based ultralight active thermal control device and its fabrication techniques and thermal performances

2021 ◽  
Author(s):  
Wenjun Xu ◽  
Longquan Liu ◽  
Junming Chen ◽  
Xinying Lv ◽  
Yongtao Yao
Keyword(s):  
Phase Change ◽  
Phase Change Material ◽  
Forced Convection ◽  
Liquid State ◽  
High Efficiency ◽  
Thermal Control ◽  
Test System ◽  
Control Device ◽  
Active Cooling ◽  
Change Material

Abstract This paper introduces a new thermal control device which has not only low weight and high efficiency but also passive and active cooling capabilities. The thermal control device mainly consists of hollow graphene-enhanced-metallic microlattice material, phase change material (PCM) and a peristatic pump. The PCM is inside the spatial-interconnected millimeter-scale diameter tubes, which are the basic constitution of the hollow microlattice material, in addition, the peristatic pump was connected with the tubes and used to force the liquid-state PCM to circulate inside the interconnected thin tubes. Thus, the proposed thermal control device takes combined advantages of the ultralight and high thermal transfer properties of the hollow graphene-enhanced-metallic microlattice materials, the thermal storage capability of the PCM and forced convection of the PCM driven by the peristatic pump as the PCM is in liquid state. The manufacturing process of the active thermal control device was also developed and proposed, which mainly includes additive manufacturing, composite electroless plating, polymer etching, liquid phase change material injecting and the peristatic pump connecting. In addition to that, a thermal test system was built and the effective thermal conductivities of the thermal control device in passive cooling and with active cooling modes were experimentally studied. The thermal control device can absorb heat and actively dissipate heat by means of forced convection. Consequently, the proposed active thermal control device can be used to guarantee the electronic components and spacecrafts operate in a specific temperature range.

Effects of Cooling “Association Cortex” on Visual Evoked Potentials

1967 ◽  
Vol 20 (2) ◽  
pp. 377-378 ◽  
Author(s):  
Arthur A. Uyeda ◽  
Joaquin M. Fuster
Keyword(s):  
Evoked Potentials ◽  
Frontal Cortex ◽  
Visual Evoked Potentials ◽  
Striate Cortex ◽  
Evoked Response ◽  
Association Cortex ◽  
Long Latency ◽  
Cortical Association Areas ◽  
Visual Evoked

Cryogenic probes were implanted in monkeys for cooling cortical “association areas” in unanesthetized state. Cooling was obtained by attaching special D.C. operated thermodes to the probes. When the parastriate and the lateral frontal cortex were cooled to 5° C, the amplitude of averaged visual evoked potentials recorded from the striate cortex was depressed. The change is conspicuous in long latency components of evoked response.

Design of a thermal control device suitable for airborne remote sensors

2014 ◽  
Vol 73 (1) ◽  
pp. 894-898
Author(s):  
Liu Weiyi ◽  
Ge Ming ◽  
Xu Yulei ◽  
Xu Yongsen ◽  
Cheng Zhifeng ◽  
...  
Keyword(s):  
Thermal Control ◽  
Control Device ◽  
Remote Sensors

scholarly journals Satellite Thermal Control Device Enhanced by Latent Heat of the Phase Change Material

2016 ◽  
Vol 44 (10) ◽  
pp. 887-894
Author(s):  
Tae Su Kim ◽  
Yoon Sub Shin ◽  
Taig Young Kim ◽  
Jung-gi Seo ◽  
Bum-Seok Hyun ◽  
...  
Keyword(s):  
Phase Change ◽  
Phase Change Material ◽  
Latent Heat ◽  
Thermal Control ◽  
Control Device ◽  
Change Material

scholarly journals Gated feedforward inhibition in the frontal cortex releases goal-directed action

2020 ◽  
Author(s):  
Jae-Hyun Kim ◽  
Dong-Hyun Ma ◽  
Eunji Jung ◽  
Ilsong Choi ◽  
Seung-Hee Lee
Keyword(s):  
Frontal Cortex ◽  
Sensory Neurons ◽  
Motor Neurons ◽  
Anterior Cingulate ◽  
Network Activity ◽  
Striatal Neurons ◽  
Strong Suppression ◽  
Directed Action ◽  
Feedforward Inhibition ◽  
Motor Signals

Cortical circuits process sensory information and generate motor signals in animals performing perceptual tasks. However, it is still unclear how sensory inputs generate motor signals in the cortex to initiate goal-directed action. Here, we identified a visual-to-motor inhibitory circuit in the anterior cingulate cortex (ACC) that induced action initiation in mice performing visual Go/No-go tasks. Interestingly, higher activity in sensory neurons and faster suppression in motor neurons of the ACC predicted faster reaction times. Notably, optogenetic activation of visual inputs in the ACC evoked strong suppression of neighboring motor neurons by activating fast-spiking sensory neurons and drove task-relevant actions in mice via activating striatal neurons. Finally, the ACC network activity maintained low during spontaneous and perceptual actions and increased during action cancellation in response to the stop signals. Collectively, our data demonstrate that visual salience in the frontal cortex exerts gated feedforward inhibition to release goal-directed actions.

scholarly journals Frontal Cortex Neuron Type Classification with Deep Learning and Recurrence Plot

2021 ◽  
Vol 38 (3) ◽  
pp. 807-819
Author(s):  
Fatma Özcan ◽  
Ahmet Alkan
Keyword(s):  
Deep Learning ◽  
Frontal Cortex ◽  
Recurrence Plot ◽  
Image Features ◽  
Spike Timing ◽  
Nerve Cells ◽  
Network Activity ◽  
Cell Type ◽  
Spike Sequences ◽  
Type Classification

One of the goals of neural decoding in neuroscience is to create Brain-Computer Interfaces (BCI) that use nerve signals. In this context, we are interested in the activity of nerve cells. It is possible to classify nerve cells as excitatory or inhibitors by evaluating individual extra-cellular measurements taken from the frontal cortex of rats. Classification of neurons with only spike timing values has not been studied before, with deep learning, without knowing all of the wave properties and the intercellular interactions. In this study, inter-spike interval values of individual neuronal spike sequences were converted into recurrence plot images to analyze as point processing, image features were extracted using the pre-trained AlexNet with CNN deep learning method, and frontal cortex nerve cell type classification was made. Kernel classification, SVM, Naive Bayes, Ensemble, decision trees classification methods were used. The accuracy, sensitivity and specificity evaluate the proposed methods. A success of more than 81% has been achieved. Thus, the cell type is defined automatically. It has been observed that the ISI properties of spike trains can carry out information on cell type and thus neural network activity. Under these circumstances, these values are significant and important for neuroscientists.

scholarly journals Development of Auto Thermal Control Device For Space Air - Conditioning

2021 ◽  
pp. 193-204
Author(s):  
Akinde Olusola Kunle ◽  
Maduako Kingsley Obinna ◽  
Akande, Kunle Akinyinka ◽  
Adeaga Oyetunde Adeoye
Keyword(s):  
Temperature Coefficient ◽  
Room Temperature ◽  
Negative Temperature Coefficient ◽  
Negative Temperature ◽  
Thermal Control ◽  
Positive Temperature Coefficient ◽  
Control Device ◽  
Thermal Source ◽  
Positive Temperature ◽  
Ntc Thermistor

Auto Thermal Control device is an electronic based device which employs the application of temperature sensors to controlling household appliances without human interference directly. In this work, thermal source is used to regulate electrical fan and room heater depending on ambient temperature. The room heater, which is adjusted to a set temperature, switches ‘ON’ when the temperature of a room is low (cold). While the same is switches ‘OFF’ with increase in the room temperature. This triggers ‘ON’ an electric fan at different speeds, and thus cools the room. A temperature sensor, tthermistor, monitors change in room temperature. Two types of thermistor exists: Positive Temperature Coefficient, PTC. An increasee in the resistance of PTC results in increasee in temperature). In the Negative Temperature Coefficient, NTC; a decreasee in resistance yields to temperature increase. This article explored a NTC thermistor. The design could be a ready product in the market of the developing nation where environmental automation is yet fully deployed.

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