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2022 ◽  
Author(s):  
Philip Kennedy ◽  
A. Ganesh ◽  
A.J. Cervantes

Abstract Summary The motivation of someone who is locked-in, that is, paralyzed and mute, is to find relief for their loss of function. The data presented in this report is part of an attempt to restore one of those lost functions, namely, speech. An essential feature of the development of a speech prosthetic is optimal decoding of patterns of recorded neural signals during silent or covert speech, that is, speaking ‘inside the head’ with no audible output due to the paralysis of the articulators. The aim of this paper is to illustrate the importance of both fast and slow single unit firings recorded from an individual with locked-in syndrome and from an intact participant speaking silently. Long duration electrodes were implanted in the motor speech cortex for up to 13 years in the locked-in participant. The data herein provide evidence that slow firing single units are essential for optimal decoding accuracy. Additional evidence indicates that slow firing single units can be conditioned in the locked-in participant five years after implantation, further supporting their role in decoding.


2021 ◽  
Author(s):  
Jason E Chung ◽  
Kristin K Sellers ◽  
Matthew K Leonard ◽  
Laura Gwilliams ◽  
Duo Xu ◽  
...  

A fundamental unit of neural computation is the action potential. While significant advances have been made in the ability to sample action potentials of large numbers of individual neurons in animal models, translation of these methodologies to humans has been lacking due to clinical time constraints, electrical noise in the operating room, and reliability of the methodology. Here we present a reliable method for intraoperative recording of dozens of neurons in humans using the Neuropixels probe, yielding up to ~100 simultaneously-recorded single-units (n=596 across 11 recordings in 8 participants). Most single-units were active within 1 minute of reaching target depth, compatible with clinical time constraints. Cell pairs active close in time were spatially closer in most recordings, demonstrating the power to resolve complex cortical dynamics. Altogether, this approach provides access to population single-unit activity across the depth of human neocortex at scales previously only accessible in animal models.


Author(s):  
Chantal McMahon ◽  
David P Kowalski ◽  
Alexander J Krupka ◽  
Michel A Lemay

We explored the relationship between population interneuronal network activation and motor output in the adult, in-vivo, air stepping, spinal cat. By simultaneously measuring the activity of large numbers of spinal interneurons, we explored ensembles of coherently firing interneurons and their relation to motor output. Additionally, the networks were analyzed in relation to their spatial distribution along the lumbar enlargement for evidence of localized groups driving particular phases of the locomotor step cycle. We simultaneously recorded hindlimb EMG activity during stepping and extracellular signals from 128 channels across two polytrodes inserted within lamina V-VII of two separate lumbar segments. Results indicated that spinal interneurons participate in one of two ensembles that are highly correlated with the flexor or the extensor muscle bursts during stepping. Interestingly, less than half of the isolated single units were significantly unimodally tuned during the step cycle while >97% of the single units of the ensembles were significantly correlated with muscle activity. These results show the importance of population scale analysis in neural studies of behavior as there is a much greater correlation between muscle activity and ensemble firing than between muscle activity and individual neurons. Finally, we show that there is no correlation between interneurons' rostrocaudal locations within the lumbar enlargement and their preferred phase of firing or ensemble participation. These findings indicate that spinal interneurons of lamina V-VII encoding for different phases of the locomotor cycle are spread throughout the lumbar enlargement in the adult spinal cord.


PLoS ONE ◽  
2021 ◽  
Vol 16 (11) ◽  
pp. e0259055
Author(s):  
Mutsumi Kenmochi ◽  
Kentaro Ochi ◽  
Hirotsugu Kinoshita ◽  
Yasuhiro Miyamoto ◽  
Izumi Koizuka

Objective To investigate the effect of systemic administration of salicylate as a tinnitus inducing drug in the auditory cortex of guinea pigs. Methods Extracellular recording of spikes of the primary auditory cortex and dorsocaudal areas in healthy male albino Hartley guinea pigs was continuously performed (pre- and post-salicylate). Results We recorded 160 single units in the primary auditory cortex from five guinea pigs and 156 single units in the dorsocaudal area from another five guinea pigs. The threshold was significantly elevated after the administration of salicylate in both the primary auditory cortex and dorsocaudal areas. The Q10dB value was significantly increased in the primary auditory cortex, whereas it has significantly decreased in the dorsocaudal area. Spontaneous firing activity was significantly decreased in the primary auditory cortex, whereas it has significantly increased in the dorsocaudal area. Conclusion Salicylate induces significant changes in single units of both stimulated and spontaneous activity in the auditory cortex of guinea pigs. The spontaneous activity changed differently depending on its cortical areas, which may be due to the neural elements that generate tinnitus.


Author(s):  
Mariane A. Mendoza ◽  
Maria Virginia S. Buera ◽  
Frederick Ray I. Gomez ◽  
Allen Jay D. Kumawit

Singulation is a process in a semiconductor industry where high dense strips were singulated into single units. Jig saw singulation was the updated technology where strips were seated and vacuumed on a rubber nest jig during singulation. Jig saw singulation is also practical for high volume manufacturing as it demands minimal indirect materials. To cut the strips, jig alignment with the strip was measured by the machine to ensure that the rubber nest jig will not be cut and damaged while the strip is being singulated. However, with the different upstream process that the strip undergone, machine prompt frequent jig alignment errors when the machine detected that the strip saw street has high displacement with the recorded alignment of the saw street of rubber nest jig. Through this study, the authors have driven to understand the jig alignment errors occurrences as well as the assistance that can be made for the strip to be processed. The authors also included the study of the risks that might be imposed on both rubber nest jig and the affected strips, as well as the recommendations when jig alignment errors were encountered.


Author(s):  
Allen Jay D. Kumawit ◽  
Maria Virginia S. Buera ◽  
Mariane A. Mendoza ◽  
Frederick Ray I. Gomez

After singulation process where the strips are being cut into single units, unit tray loading comes next. Unit tray loading is the process where the singulated units will be picked up from the table and then place it in a tray pocket. Z-picker assembly executes the pick and placing activity through vacuum suction. Vacuum pads were installed on the Z-picker’s vacuum pad holder area, and it contacts with the unit. Vacuum pads come with different design depending on dimension and configuration of the device in process. Pick and place process is prone for unit dislodge as it transfers the unit from one place to another. These unit dislodges will result to missing units and will be accounted for yield loss. In this study, the authors were driven to understand the Z-picker mechanism together with the effect of vacuum pad designs, aiming to find the best match that would lessen the occurrence of unit dislodges.


Author(s):  
Anthony V. Incognito ◽  
André L. Teixeira ◽  
Brooke M. Shafer ◽  
Massimo Nardone ◽  
Tyler D. Vermeulen ◽  
...  

A small proportion of postganglionic muscle sympathetic single units can be inhibited during sympathoexcitatory stressors in humans. However, whether these responses are dependent on the specific stressor or the level of sympathoexcitation remains unclear. We hypothesize that, when matched by sympathoexcitatory magnitude, different stressors can evoke similar proportions of inhibited single units. Multiunit and single-unit muscle sympathetic nerve activity (MSNA) were recorded in seven healthy, young males at baseline and during: 1) rhythmic handgrip exercise (40% of maximum voluntary contraction) and 2) acute isocapnic hypoxia (partial pressure of end-tidal O2: 47±3 mmHg). Single units were classified as activated, nonresponsive, or inhibited if the spike frequency was above, within, or below the baseline variability, respectively. By design, rhythmic handgrip and isocapnic hypoxia similarly increased multiunit total MSNA (D273±208 vs. D254±193 AU, P=0.84) and single-unit spike frequency (D8±10 vs. D12±13 spikes/min, P=0.12). Among 19 identified single units, the proportion of activated (47% vs. 68%) non-responsive (32% vs. 16%) and inhibited (21% vs. 16%) single units were not different between rhythmic handgrip and isocapnic hypoxia (P=0.42). However, only 9 (47%) single units behaved with concordant response patterns across both stressors (7 activated, 1 non-responsive, and 1 inhibited during both stressors). During the 1-min epoch with the highest increase in total MSNA during hypoxia (D595±282 AU, P<0.01) only 1 single unit was inhibited. These findings suggest that the proportion of muscle sympathetic single units inhibited during stress are associated with the level of sympathoexcitation and not the stressor per se in healthy young males.


2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Junghwa Lee ◽  
Bobae An ◽  
Sukwoo Choi

AbstractThe balance between activities of fear neurons and extinction neurons in the basolateral nucleus of the basal amygdala (BAL) has been hypothesized to encode fear states after extinction. However, it remains unclear whether these neurons are solely responsible for encoding fear states. In this study, we stably recorded single-unit activities in the BAL during fear conditioning and extinction for 3 days, providing a comprehensive view on how different BAL neurons respond during fear learning. We found BAL neurons that showed excitatory responses to the conditioned stimulus (CS) after fear conditioning (‘conditioning-potentiated neurons’) and another population that showed excitatory responses to the CS after extinction (‘extinction-potentiated neurons’). Interestingly, we also found BAL neurons that developed inhibitory responses to the CS after fear conditioning (‘conditioning-inhibited neurons’) or after extinction (‘extinction-inhibited neurons’). BAL neurons that showed excitatory responses to the CS displayed various functional connectivity with each other, whereas less connectivity was observed among neurons with inhibitory responses to the CS. Intriguingly, we found correlative neuronal activities between conditioning-potentiated neurons and neurons with inhibitory responses to the CS. Our findings suggest that distinct BAL neurons, which are responsive to the CS with excitation or inhibition, encode various facets of fear conditioning and extinction.


Author(s):  
Mariane Mendoza ◽  
Maria Virginia Buera ◽  
Frederick Ray Gomez

Tape saw singulation is the process where a strip was mounted on the tape attached on the frame and then sawn into single units. Circular tape saw singulation only caters one panel of the two-paneled strip which was found to be consuming with the machine capacity and resources. Driven by continuously growing volumes of customer demands at the Philippines for the past two years, it was a challenge for the machine to maximize its capacity while minimizing the cost and resources. Opportunity was found on exploring the idea of dual work piece where two strip panels were catered by one circular tape frame. Dual work piece application would not only maximize the machine capability and capacity but also reduce the cost of resources consumed per strip loading. In this study, the authors have explored the workability of dual work piece cutting where two panels can be catered on one circular frame instead of the current one panel per circular frame. Dual Work Piece application was found to be effective to achieve the goal of maximizing the machine capacity while trimming down the expenses by 50% that was brought about by the resources demanded to process the strips at singulation. With the results of the study, it was recommended for the dual work piece cutting be applied and explored on growing semiconductor industry.


2021 ◽  
Vol 404 ◽  
pp. 113176
Author(s):  
Adam T. Brockett ◽  
Daniela Vázquez ◽  
Matthew R. Roesch

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