scholarly journals The Effects of Propofol on Local Field Potential Spectra, Action Potential Firing Rate, and Their Temporal Relationship in Humans and Felines

2013 ◽  
Vol 7 ◽  
Author(s):  
Sara J. Hanrahan ◽  
Bradley Greger ◽  
Rebecca A. Parker ◽  
Takahiro Ogura ◽  
Shinju Obara ◽  
...  
Keyword(s):  
Action Potential ◽  
Firing Rate ◽  
Local Field ◽  
Local Field Potential ◽  
Temporal Relationship ◽  
Field Potential ◽  
Action Potential Firing ◽  
Potential Firing

Cultured olfactory interneurons from Limax maximus: optical and electrophysiological studies of transmitter-evoked responses

1993 ◽  
Vol 69 (6) ◽  
pp. 1940-1947 ◽  
Author(s):  
L. D. Rhines ◽  
P. G. Sokolove ◽  
J. Flores ◽  
D. W. Tank ◽  
A. Gelperin
Keyword(s):  
Action Potential ◽  
Intracellular Calcium ◽  
Local Field ◽  
Local Field Potential ◽  
Field Potential ◽  
Optical Measurements ◽  
Optical Studies ◽  
Isolated Cells ◽  
Fura 2 ◽  
Limax Maximus

1. The olfactory processing network in the procerebral (PC) lobe of the terrestrial mollusk Limax maximus exhibits a coherent oscillation of local field potential that is modulated by odor input. To understand the cellular basis of this oscillation, we developed a cell culture preparation of isolated PC neurons and studied the responses of isolated cells to stimulation with neurotransmitters known to be present in the PC lobe. 2. The distribution of PC soma diameters suggests at least two different populations of neurons. Approximately 95% of isolated cells had soma diameters of 7-8 microns, with the remaining cells having larger diameters (10-15 microns). 3. Extracellular measurements of action potentials and optical measurements of intracellular calcium concentrations in fura-2-loaded cells were made. Serotonin and dopamine excited PC neurons and promoted transitions from steady to bursty activity. Both amines elicited increases in intracellular calcium, presumably concomitant with the increase in action-potential frequency. 4. Glutamate suppressed action-potential firing and reduced intracellular calcium. This effect was seen most clearly when glutamate was applied to cells excited by high potassium medium. Quisqualate is an effective glutamate agonist in this system, whereas kainate is not. 5. Combined with anatomic and biochemical data and with studies of the effects of these neurotransmitters on the oscillating local field potential of the intact PC network, the data from isolated PC neurons are consistent with the hypothesis that dopamine and serotonin modulate network dynamics, whereas glutamate is involved in generating the basic oscillation of local field potential in the PC. 6. The optical studies of fura-2-loaded cells showed that several treatments that increase the rate of action-potential production lead to elevations in intracellular calcium. Optical studies of intracellular calcium may be useful for multisite measurements of activity in the intact, oscillating PC lobe network.

scholarly journals Temporal coupling of field potentials and action potentials in the neocortex

2017 ◽  
Author(s):  
Brendon O. Watson ◽  
Mingxin Ding ◽  
György Buzsáki
Keyword(s):  
Action Potential ◽  
Action Potentials ◽  
Field Potential ◽  
Electromyographic Activity ◽  
Action Potential Firing ◽  
Firing Rates ◽  
Potential Firing ◽  
Temporal Coupling ◽  
Potential Activity ◽  
The Relationship

AbstractThe local field potential (LFP) is an aggregate measure of group neuronal activity and is often correlated with the action potentials of single neurons. In recent years investigators have found that action potential firing rates increase during elevations in power high-frequency band oscillations (50-200 Hz range). However action potentials also contribute to the LFP signal itself, making the spike–LFP relationship complex. Here we examine the relationship between spike rates and LFPs in varying frequency bands in rat neocortical recordings. We find that 50-180Hz oscillations correlate most consistently with high firing rates, but that other LFPs bands also carry information relating to spiking, including in some cases anti-correlations. Relatedly, we find that spiking itself and electromyographic activity contribute to LFP power in these bands. The relationship between spike rates and LFP power varies between brain states and between individual cells. Finally, we create an improved oscillation-based predictor of action potential activity by specifically utilizing information from across the entire recorded frequency spectrum of LFP. The findings illustrate both caveats and improvements to be taken into account in attempts to infer spiking activity from LFP.

scholarly journals Microelectrode recording findings within the tractography-defined ventral intermediate nucleus

2017 ◽  
Vol 126 (5) ◽  
pp. 1669-1675 ◽  
Author(s):  
Nicolas Kon Kam King ◽  
Vibhor Krishna ◽  
Diellor Basha ◽  
Gavin Elias ◽  
Francesco Sammartino ◽  
...  
Keyword(s):  
Firing Rate ◽  
Local Field ◽  
Local Field Potential ◽  
Structural Connectivity ◽  
Field Potential ◽  
Area Under The Curve ◽  
Microelectrode Recording ◽  
Intermediate Nucleus ◽  
Beta Power ◽  
Ventral Intermediate Nucleus

OBJECTIVEThe ventral intermediate nucleus (VIM) of the thalamus is not visible on structural MRI. Therefore, direct VIM targeting methods for stereotactic tremor surgery are desirable. The authors previously described a direct targeting method for visualizing the VIM and its structural connectivity using deterministic tractography. In this combined electrophysiology and imaging study, the authors investigated the electrophysiology within this tractography-defined VIM (T-VIM).METHODSThalamic neurons were classified based on their relative location to the T-VIM: dorsal, within, and ventral to the T-VIM. The authors identified the movement-responsive cells (kinesthetic and tremor cells), performed spike analysis (firing rate and burst index), and local field potential analysis (area under the curve for 13–30 Hz). Tremor efficacy in response to microstimulation along the electrode trajectory was also assessed in relation to the T-VIM.RESULTSSeventy-three cells from a total of 9 microelectrode tracks were included for this analysis. Movement-responsive cells (20 kinesthetic cells and 26 tremor cells) were identified throughout the electrode trajectories. The mean firing rate and burst index of cells (n = 27) within the T-VIM are 18.8 ± 9.8 Hz and 4.5 ± 5.4, respectively. Significant local field potential beta power was identified within the T-VIM (area under the curve for 13–30 Hz = 6.6 ± 7.7) with a trend toward higher beta power in the dorsal T-VIM. The most significant reduction in tremor was also observed in the dorsal T-VIM.CONCLUSIONSThe electrophysiological findings within the VIM thalamus defined by tractography, or T-VIM, correspond with the known microelectrode recording characteristics of the VIM in patients with tremor.

BK channel activation by L-type Ca2+ channels CaV1.2 and CaV1.3 during the subthreshold phase of an action potential

2021 ◽  
Author(s):  
Amber E Plante ◽  
Joshua P Whitt ◽  
Andrea L. Meredith
Keyword(s):  
Membrane Potential ◽  
Action Potential ◽  
Firing Rate ◽  
Low Voltage ◽  
Bk Channels ◽  
Bk Channel ◽  
Action Potential Firing ◽  
Channel Activation ◽  
Potential Firing ◽  
Current Activation

Mammalian circadian (24-hour) rhythms are timed by the pattern of spontaneous action potential firing in the suprachiasmatic nucleus (SCN). This oscillation in firing is produced through circadian regulation of several membrane currents, including large-conductance Ca2+- and voltage-activated K+ (BK) and L-type Ca2+ channel (LTCC) currents. During the day, steady-state BK currents depend mostly on LTCCs for activation, while at night, they depend predominantly on RyRs. However, the contribution of these Ca2+ channels to BK channel activation during action potential firing has not been thoroughly investigated. In this study, we used a pharmacological approach to determine that both LTCCs and RyRs contribute to the baseline membrane potential of SCN action potential waveforms, as well as action potential-evoked BK current, during the day and night, respectively. Since the baseline membrane potential is a major determinant of circadian firing rate, we focused on the LTCCs contributing to low voltage activation of BK channels during the subthreshold phase. For these experiments, two LTCC subtypes found in SCN (CaV1.2 and CaV1.3) were co-expressed with BK channels in heterologous cells, where their differential contributions could be separately measured. CaV1.3 channels produced currents that were shifted to more hyperpolarized potentials compared to CaV1.2, resulting in increased subthreshold Ca2+ and BK currents during an action potential command. These results show that while multiple Ca2+ sources in SCN can contribute to the activation of BK current during an action potential, specific BK-CaV1.3 partnerships may optimize the subthreshold BK current activation that is critical for firing rate regulation.

scholarly journals Cyclic AMP Signaling Control of Action Potential Firing Rate and Molecular Circadian Pacemaking in the Suprachiasmatic Nucleus

2011 ◽  
Vol 26 (3) ◽  
pp. 210-220 ◽  
Author(s):  
Susan E. Atkinson ◽  
Elizabeth S. Maywood ◽  
Johanna E. Chesham ◽  
Christian Wozny ◽  
Christopher S. Colwell ◽  
...  
Keyword(s):  
Cyclic Amp ◽  
Action Potential ◽  
Firing Rate ◽  
Suprachiasmatic Nucleus ◽  
Action Potential Firing ◽  
Potential Firing ◽  
Cyclic Amp Signaling

Synchronization of neurons during local field potential oscillations in sensorimotor cortex of awake monkeys

1996 ◽  
Vol 76 (6) ◽  
pp. 3968-3982 ◽  
Author(s):  
V. N. Murthy ◽  
E. E. Fetz
Keyword(s):  
Firing Rate ◽  
Local Field ◽  
Sensorimotor Cortex ◽  
Local Field Potential ◽  
Field Potential ◽  
Peak Latency ◽  
Peak Amplitude ◽  
Firing Rates ◽  
Multiple Units ◽  
40 Hz

1. The neural activity associated with 20- to 40-Hz oscillations in sensorimotor cortex of awake monkeys was investigated by recording action potentials of single and multiple units. At a given site, activity of many units became synchronized with local field potential (LFP) oscillations. Cycle-triggered histograms (CTHs) of unit spikes aligned on cycles of LFP oscillations indicated that about two thirds of the recorded units (n = 268) were entrained with LFP oscillations. On average, units had the highest probability of spiking 2.7 ms before peak LFP negativity, corresponding to a -27.6 degrees phase shift relative to the negative peak of the LFP. 2. The average relative modulation amplitude (RMA), defined as the ratio of amplitude of oscillatory component of CTH and the baseline multiplied by 100, was 45 +/- 27% (mean +/- SD). The RMAs of single units did not differ significantly from those of multiple units. 3. Phase shifts and RMAs did not vary systematically with the cortical depth of recorded units. 4. Autocorrelation histograms (ACHs) of entrained units exhibited clear 20- to 40-Hz periodicity if they were compiled with spikes that occurred during oscillatory episodes in LFPs. ACHs of spikes outside oscillatory episodes usually did not show periodicity. Global ACHs of all spikes typically showed weak or no evidence of periodic activity. 5. Cross-correlation histograms (CCHs) between pairs of units complied with all spikes, whether they occurred during or outside LFP oscillations, seldom revealed significant features (19 of 134 pairs or 14%). However, CCHs compiled with spikes that occurred during oscillatory episodes (OS-CCHs) had significant features in 67 of 134 pairs recorded ipsilaterally; in these 67 cases, units at both sites showed modulation in CTHs. 6. The latencies of the OS-CCH peaks (taking the medial unit as reference) were normally distributed about a mean of -0.5 +/- 13 ms. Normalized peak height of CCHs (peak/baseline x 100) was, on average, 14.3 +/- 11.2%. Peak latency and normalized peak amplitude did not change significantly with horizontal separation of recorded precentral pairs up to 14 mm. 7. Units in the left and right hemispheres could become synchronized during oscillations. Significant features in OS-CCH were detected in 22 of 42 pairs of units recorded bilaterally. The average peak latency was 0.2 +/- 8.0 ms and the average normalized peak amplitude was 10 +/- 8%. These parameters did not differ significantly from those for ipsilateral OS-CCHs. 8. Oscillations tended to affect both the temporal structure and net rate of unit firing. For each unit, the firing rate was clamped to a narrow range of frequencies during oscillatory episodes. The coefficient of variation (SD/mean) of firing rates was significantly reduced during oscillatory episodes compared with prior rates (P < 0.001, paired t-test). However, the overall mean firing rate of each unit during all oscillatory episodes did not differ from its average rate immediately before the episodes. Thus oscillatory episodes tended to clamp mean firing rates to the cells' average rates outside episodes. 9. The strength of synchronization between units during oscillatory episodes was unrelated to their involvement in the task. For pairs of precentral units recorded ipsilaterally, the probability of occurrence of significant features in the OS-CCH was slightly larger when both units of the pair were task related (33 of 56 pairs or 59%) than when only one unit was task related (20 of 39 pairs or 51%) or neither unit was task related (7 of 16 or 44%). However, these differences were not statistically significant. The magnitude of the correlation peak and the latency to peak were also not significantly different for the three cases. 10. These results suggest that units across wide regions can become transiently synchronized specifically during LFP oscillations, even if their spikes are uncorrelated during nonoscillatory periods.

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