Distinct neuron phenotypes may serve object feature sensing in the electrosensory lobe of Gymnotus omarorum

2021 ◽  
Author(s):  
Javier Nogueira ◽  
María E. Castelló ◽  
Carolina Lescano ◽  
Ángel A. Caputi
Keyword(s):  
Stimulus Intensity ◽  
Pyramidal Neurons ◽  
Receptive Fields ◽  
Weakly Electric Fish ◽  
High Threshold ◽  
Electrophysiological Properties ◽  
Clear Cut ◽  
Low Pass ◽  
Object Feature

Early sensory relays circuits in the vertebrate medulla often adopt a cerebellum-like organization specialized for comparing primary afferent inputs with central expectations. These circuits usually have a dual output, carried by center ON and center OFF neurons responding in opposite ways to the same stimulus at the center of their receptive fields. Here we show in the electrosensory lateral line lobe of Gymnotiform weakly electric fish that basilar pyramidal neurons, representing ‘ON’ cells, and non-basilar pyramidal neurons, representing ‘OFF’ cells, have different intrinsic electrophysiological properties. We used classical anatomical techniques and electrophysiological in vitro recordings to compare these neurons. Basilar neurons are silent at rest, have a high threshold to intracellular stimulation, delayed responses to steady state depolarization and low pass responsiveness to membrane voltage variations. They respond to low intensity depolarizing stimuli with large, isolated spikes. As stimulus intensity increases the spikes are followed by a depolarizing after-potential from which phase-locked spikes often arise. Non-basilar neurons show a pacemaker-like spiking activity, smoothly modulated in frequency by slow variations of stimulus intensity. Spike frequency adaptation provides a memory of their recent firing, facilitating non-basilar response to stimulus transients. Considering anatomical and functional dimensions we conclude that basilar and non-basilar pyramidal neurons are clear-cut, different anatomo-functional phenotypes. We propose that, in addition to their role in contrast processing, basilar pyramidal neurons encode sustained global stimuli as those elicited by large or distant objects while non-basilar pyramidal neurons respond to transient stimuli due to movement textured nearby objects.

Simulations of Intrinsically Bursting Neocortical Pyramidal Neurons

1994 ◽  
Vol 6 (6) ◽  
pp. 1086-1110 ◽  
Author(s):  
Paul A. Rhodes ◽  
Charles M. Gray
Keyword(s):  
Visual Cortex ◽  
Ion Channels ◽  
Pyramidal Neurons ◽  
Compartment Model ◽  
Morphological Data ◽  
High Threshold ◽  
Simulation Results ◽  
Dendritic Branches ◽  
Neocortical Pyramidal Neurons

Neocortical layer 5 intrinsically bursting (IB) pyramidal neurons were simulated using compartment model methods. Morphological data as well as target neurophysiological responses were taken from a series of published studies on the same set of rat visual cortex pyramidal neurons (Mason, A. and Larkman, A. J., 1990. J. Neurosci. 9,1440-1447; Larkman, A. J. 1991. J. Comp. Neurol. 306, 307-319). A dendritic distribution of ion channels was found that reproduced the range of in vitro responses of layer 5 IB pyramidal neurons, including the transition from repetitive bursting to the burst/tonic spiking mode seen in these neurons as input magnitude increases. In light of available data, the simulation results suggest that in these neurons bursts are driven by an inward flow of current during a high threshold Ca2+ spike extending throughout both the basal and apical dendritic branches.

scholarly journals Optimizing computer models of corticospinal neurons to replicate in vitro dynamics

2017 ◽  
Vol 117 (1) ◽  
pp. 148-162 ◽  
Author(s):  
Samuel A. Neymotin ◽  
Benjamin A. Suter ◽  
Salvador Dura-Bernal ◽  
Gordon M. G. Shepherd ◽  
Michele Migliore ◽  
...  
Keyword(s):  
Motor Cortex ◽  
Pyramidal Neurons ◽  
Computer Models ◽  
Cortical Layer ◽  
Cortical Layers ◽  
Electrophysiological Properties ◽  
Full Reconstruction ◽  
Resonance Properties ◽  
Oscillation Frequencies

Corticospinal neurons (SPI), thick-tufted pyramidal neurons in motor cortex layer 5B that project caudally via the medullary pyramids, display distinct class-specific electrophysiological properties in vitro: strong sag with hyperpolarization, lack of adaptation, and a nearly linear frequency-current ( F– I) relationship. We used our electrophysiological data to produce a pair of large archives of SPI neuron computer models in two model classes: 1) detailed models with full reconstruction; and 2) simplified models with six compartments. We used a PRAXIS and an evolutionary multiobjective optimization (EMO) in sequence to determine ion channel conductances. EMO selected good models from each of the two model classes to form the two model archives. Archived models showed tradeoffs across fitness functions. For example, parameters that produced excellent F– I fit produced a less-optimal fit for interspike voltage trajectory. Because of these tradeoffs, there was no single best model but rather models that would be best for particular usages for either single neuron or network explorations. Further exploration of exemplar models with strong F– I fit demonstrated that both the detailed and simple models produced excellent matches to the experimental data. Although dendritic ion identities and densities cannot yet be fully determined experimentally, we explored the consequences of a demonstrated proximal to distal density gradient of Ih, demonstrating that this would lead to a gradient of resonance properties with increased resonant frequencies more distally. We suggest that this dynamical feature could serve to make the cell particularly responsive to major frequency bands that differ by cortical layer. NEW & NOTEWORTHY We developed models of motor cortex corticospinal neurons that replicate in vitro dynamics, including hyperpolarization-induced sag and realistic firing patterns. Models demonstrated resonance in response to synaptic stimulation, with resonance frequency increasing in apical dendrites with increasing distance from soma, matching the increasing oscillation frequencies spanning deep to superficial cortical layers. This gradient may enable specific corticospinal neuron dendrites to entrain to relevant oscillations in different cortical layers, contributing to appropriate motor output commands.

Actions of cholinergic agonists and antagonists on sensory nerve endings in rat skin, in vitro

1993 ◽  
Vol 70 (1) ◽  
pp. 397-405 ◽  
Author(s):  
K. H. Steen ◽  
P. W. Reeh
Keyword(s):  
Receptive Fields ◽  
Sensory Nerve ◽  
High Threshold ◽  
Rat Skin ◽  
Sensory Afferents ◽  
C Fibers ◽  
High Concentrations ◽  
Cholinergic Agonists And Antagonists ◽  
Cholinergic Effects

1. Cholinergic effects on primary sensory afferents were investigated in a superfused skin-saphenous nerve preparation of the rat that allows the application of chemicals topically to the corium side of identified receptive fields. 2. The acetylcholine analogue carbachol (carbamoylcholine) selectively excited cutaneous C-fibers of nociceptive character; in proportion, almost half of the mechanoheat sensitive ("polymodal," C-MH, n = 27), and a third of the mechanocold sensitive (C-MC, n = 10), and high-threshold mechanosensitive (C-HTM, n = 6) C-fibers were activated. 3. None of slowly and rapidly adapting A beta fibers, low and high threshold mechanoreceptive A delta fibers (n = 19) gave a response to high concentrations (< or = 10(-4) M) of carbachol. 4. The carbachol threshold concentrations of C-nociceptors ranged between 10(-7) and 10(-4) M; 10(-6) M was most frequently encountered. 5. The carbachol-induced discharges showed a dose-response relationship without obvious "ceiling" from 10(-6) to 10(-4) M. Tachyphylaxis was not prominent; the fibers mostly developed ongoing activity after exposure to carbachol. 6. Repeated carbachol treatment of C-MH units left with a marked and sustained desensitization to mechanical (von Frey) stimulation, while the heat responsiveness remained unchanged. 7. In a group of carbachol-sensitive C-nociceptors (n = 4), two units could also be excited with muscarine (10(-6) M), one with nicotine (10(-6) M), and one unit with both substances.(ABSTRACT TRUNCATED AT 250 WORDS)

scholarly journals Muscarinic Receptors Control Frequency Tuning Through the Downregulation of an A-Type Potassium Current

2007 ◽  
Vol 98 (3) ◽  
pp. 1526-1537 ◽  
Author(s):  
Lee D. Ellis ◽  
Rüdiger Krahe ◽  
Charles W. Bourque ◽  
Robert J. Dunn ◽  
Maurice J. Chacron
Keyword(s):  
Mathematical Modeling ◽  
Potassium Current ◽  
Electric Fish ◽  
Pyramidal Neurons ◽  
Frequency Tuning ◽  
Receptor Activation ◽  
Weakly Electric Fish ◽  
Weakly Electric

The functional role of cholinergic input in the modulation of sensory responses was studied using a combination of in vivo and in vitro electrophysiology supplemented by mathematical modeling. The electrosensory system of weakly electric fish recognizes different environmental stimuli by their unique alteration of a self-generated electric field. Variations in the patterns of stimuli are primarily distinguished based on their frequency. Pyramidal neurons in the electrosensory lateral line lobe (ELL) are often tuned to respond to specific input frequencies. Alterations in the tuning of the pyramidal neurons may allow weakly electric fish to preferentially select for certain stimuli. Here we show that muscarinic receptor activation in vivo enhances the excitability, burst firing, and subsequently the response of pyramidal cells to naturalistic sensory input. Through a combination of in vitro electrophysiology and mathematical modeling, we reveal that this enhanced excitability and bursting likely results from the down-regulation of an A-type potassium current. Further, we provide an explanation of the mechanism by which these currents can mediate frequency tuning.

scholarly journals Diversity amongst human cortical pyramidal neurons revealed via their sag currents and frequency preferences

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Homeira Moradi Chameh ◽  
Scott Rich ◽  
Lihua Wang ◽  
Fu-Der Chen ◽  
Liang Zhang ◽  
...  
Keyword(s):  
Pyramidal Neurons ◽  
Pyramidal Cells ◽  
Theta Oscillations ◽  
Cortical Layers ◽  
Electrophysiological Properties ◽  
Theta Frequency ◽  
Subthreshold Resonance ◽  
Cortical Pyramidal Neurons ◽  
Whole Cell Recordings

AbstractIn the human neocortex coherent interlaminar theta oscillations are driven by deep cortical layers, suggesting neurons in these layers exhibit distinct electrophysiological properties. To characterize this potential distinctiveness, we use in vitro whole-cell recordings from cortical layers 2 and 3 (L2&3), layer 3c (L3c) and layer 5 (L5) of the human cortex. Across all layers we observe notable heterogeneity, indicating human cortical pyramidal neurons are an electrophysiologically diverse population. L5 pyramidal cells are the most excitable of these neurons and exhibit the most prominent sag current (abolished by blockade of the hyperpolarization activated cation current, Ih). While subthreshold resonance is more common in L3c and L5, we rarely observe this resonance at frequencies greater than 2 Hz. However, the frequency dependent gain of L5 neurons reveals they are most adept at tracking both delta and theta frequency inputs, a unique feature that may indirectly be important for the generation of cortical theta oscillations.

Electrophysiological characteristics of lumbar spinal cord neurons backfired from lateral reticular nucleus in the rat

1984 ◽  
Vol 52 (4) ◽  
pp. 595-611 ◽  
Author(s):  
D. Menetrey ◽  
J. de Pommery ◽  
J. M. Besson
Keyword(s):  
Spinal Cord ◽  
Dorsal Horn ◽  
Receptive Fields ◽  
Reticular Nucleus ◽  
Lumbar Spinal Cord ◽  
High Threshold ◽  
Lateral Reticular Nucleus ◽  
Spinal Cord Neurons ◽  
Electrophysiological Properties ◽  
Lumbar Spinal

Spinal neurons antidromically activated from either the lateral reticular nucleus (LRN) or immediately adjacent areas were identified in the rat lumbar spinal cord. In agreement with previous anatomical work (60), these neurons were widely distributed in both the dorsal and ventral horns of the spinal cord and could be subdivided into three main groups according to their location: a) deep ventromedial (DVM) cells, which project more substantially to the LRN than to other supraspinal targets; b) cells of the median portion of the neck of the dorsal horn (mNDH), which project exclusively to the LRN; c) cells lying in other parts of the dorsal horn (superficial layers, nucleus proprius, reticular extension of the neck), by their location, they are indistinguishable from cells projecting to other supraspinal targets. The probability is high that the DVM and mNDH cells contribute exclusively, or at least preferentially, to the lateral component of the spinoreticular tract (lSRT), defined as the direct spinal pathway to the LRN. Although electrophysiological properties of cells were clearly related to their spinal location, several subpopulations could be recognized in each of the three main groups. The majority of DVM neurons were in lamina VII, with some in laminae VI, VIII, and X. With the exception of a few lamina X cells, the DVM neurons had high conduction velocities. Four subpopulations of these neurons were recognized. a) Innocuous proprioceptive cells responded to small changes in joint position, some showing convergence of nonnoxious cutaneous inputs. b) High-threshold cells (approximately 50% of DVM cells). Seventy-five percent of these cells were excited from bilateral receptive fields (mostly symmetric) with noxious cutaneous pinching that extended to subcutaneous tissues. Their evoked responses had long-lasting postdischarges that continued up to several minutes after cessation of the stimulus. c) Inhibited cells had no demonstrable excitatory receptive fields and a high ongoing activity that was tonically depressed by pressure or pinch; poststimulus effects of long duration were observed. d) Cells with no resting discharge and demonstrable excitatory peripheral receptive fields. mNDH cells had recording sites at the medial border of the internal portion of the reticular area of the neck of the dorsal horn.(ABSTRACT TRUNCATED AT 400 WORDS)

Interval Coding. I. Burst Interspike Intervals as Indicators of Stimulus Intensity

2007 ◽  
Vol 97 (4) ◽  
pp. 2731-2743 ◽  
Author(s):  
Anne-Marie M. Oswald ◽  
Brent Doiron ◽  
Leonard Maler
Keyword(s):  
Stimulus Intensity ◽  
Information Transfer ◽  
Pyramidal Cells ◽  
Sensory Stimulation ◽  
Weakly Electric Fish ◽  
Interspike Intervals ◽  
Direct Stimulation ◽  
Distinct Features ◽  
Weakly Electric

Short interspike intervals such as those that occur during burst firing are hypothesized to be distinct features of the neural code. Although a number of correlations between the occurrence of burst events and aspects of the stimulus have been identified, the relationship between burst characteristics and information transfer is uncertain. Pyramidal cells in the electrosensory lobe of the weakly electric fish, Apteronotus leptorhynchus, respond to dynamic broadband electrosensory stimuli with bursts and isolated spikes. In the present study, we mimic synaptic input during sensory stimulation by direct stimulation of electrosensory pyramidal cells with broadband current in vitro. The pyramidal cells respond to this stimulus with burst interspike intervals (ISIs) that are reliably and precisely correlated with the intensity of stimulus upstrokes. We found burst ISIs must differ by a minimum of 2 ms to discriminate, with low error, differences in stimulus intensity. Based on these results, we define and quantify a candidate interval code for the processing of sensory input. Finally, we demonstrate that interval coding is restricted to short ISIs such as those generated in burst events and that the proposed interval code is distinct from rate and timing codes.

Electrophysiology of the mammillary complex in vitro. II. Medial mammillary neurons

1992 ◽  
Vol 68 (4) ◽  
pp. 1321-1331 ◽  
Author(s):  
A. Alonso ◽  
R. R. Llinas
Keyword(s):  
Low Frequency ◽  
Input Resistance ◽  
Resting Potential ◽  
High Threshold ◽  
Potential Oscillations ◽  
Electrophysiological Properties ◽  
Voltage Dependent ◽  
Low Threshold ◽  
Membrane Potential Oscillations

1. The electrophysiological properties of guinea pig medial mammillary body (MMB) neurons were studied using an in vitro slice preparation. 2. The neurons (n = 80) had an average resting potential of -57 +/- 5.5 (SD) mV, an input resistance of 176 +/- 83 M omega, and a spike amplitude of 58 +/- 15.7 mV. Most of the neurons were silent at rest (n = 52), but some fired spontaneous single spikes (n = 16) or spike bursts (n = 14). 3. The main electrophysiological characteristic of MMB neurons was the ability to generate Ca(2+)-dependent regenerative events, which resulted in very robust burst responses. However, this regenerative event was not the same for all neurons, ranging from typical low-threshold Ca2+ spikes (LTSs) to intermediate-threshold plateau potentials (ITPs). 4. The ITPs were distinct from the LTSs in that they lasted > or = 100 ms and were not inactivated at membrane potentials at or positive to -55 mV. 5. Some cells with a prominent ITP and no LTS (n = 36) displayed repetitive, usually rhythmic, bursting (n = 14). This ITP could be powerful enough to maintain rhythmic membrane potential oscillations after pharmacological block of Na+ conductances. 6. A group of 32 MMB neurons displayed complex bursting that was generated by activation of both LTSs and ITPs. This was established on the basis of their distinct time- and voltage-dependent characteristics. In a group of neurons (n = 14), the burst responses were exclusively generated by an LTS; however, a Ca(2+)-dependent plateau potential contributed to the generation of rebound-triggered oscillatory firing. 7. In addition to the Ca(2+)-dependent LTS and/or ITP, MMB neurons always displayed high-threshold Ca2+ spikes after reduction of K+ conductances with tetraethylammonium. 8. MMB neurons display one of the richer varieties of voltage-dependent Ca2+ conductances so far encountered in mammalian CNS. We propose that the very prominent endogenous bursting and oscillatory properties of MB neurons allow this nuclear complex to function as an oscillatory relay for the transmission of low-frequency rhythmic activities throughout the limbic circuit.

Chemosensitivity of fine afferents from rat skin in vitro

1990 ◽  
Vol 63 (4) ◽  
pp. 887-901 ◽  
Author(s):  
E. Lang ◽  
A. Novak ◽  
P. W. Reeh ◽  
H. O. Handwerker
Keyword(s):  
Calcium Concentration ◽  
Receptive Fields ◽  
Nerve Fibers ◽  
High Threshold ◽  
Rat Skin ◽  
Test Protocol ◽  
Heat Stimulation ◽  
C Fibers ◽  
Slow Development

1. Properties of sensory receptors with slowly conducting nerve fibers (less than 10 m/s) were studied using a rat skin-saphenous nerve in vitro preparation where receptive fields of identified single units can be isolated and superfused at the corium side with defined chemical solutions. 2. With mechanical search stimuli, 150 slowly adapting units were identified, 88% C-fibers, and the remainder, A delta-fibers. The majority of these units (65%) were categorized as mechano-heat sensitive ("polymodal") with controlled radiant heat stimulation. The remaining units were classified as low- or high-threshold mechanoreceptors according to their von Frey thresholds. 3. Bradykinin (BK), in concentrations of 10(-8) to 10(-4) M, was repeatedly applied for 1 min at 10-min intervals. Fifty-six percent of the polymodal C-fibers responded to BK (up to 10(-5) M), in contrast to 17% of the heat-insensitive units (P less than 0.01). No correlation between BK sensitivity and conduction velocity or von Frey threshold was found. 4. The BK "threshold concentrations" to excite C- and A delta-fibers were about equally distributed over a range from 10(-8) to 10(-5) M. 5. There was a large interindividual variability in pattern and magnitude of the response to BK. Intraindividually, a marked tachyphylaxis upon repeated BK stimulation was observed. 6. In fibers with a slow development of tachyphylaxis, the effects of conditioning application of different chemicals on BK responsiveness were studied. Norepinephrine in 10(-7) M concentration did not produce a significant effect, whereas 10(-5) M and 10(-4) M seemed to increase the BK responses. 7. Prostaglandin E2 (10(-6) M) caused a weak sensitization to BK on average (n.s.), but serotonin (10(-6) M) was clearly effective (P less than 0.05). 8. The strongest sensitization to BK (P = 0.01) resulted from conditioning heat stimulation, which also uncovered a responsiveness in some units initially insensitive to BK. 9. In some experiments the calcium concentration in the superfusate of receptive fields was lowered to 0.3 mM, which induced ongoing activity in C-fibers and markedly increased the BK responses in two polymodal units tested. Increasing the calcium concentration to 3.0 mM reversed these effects. 10. After completing the BK test protocol, polymodal C-fibers were exposed to other chemicals.(ABSTRACT TRUNCATED AT 400 WORDS)

In Vivo Demonstration of a Late Depolarizing Postsynaptic Potential in CA1 Pyramidal Neurons

2005 ◽  
Vol 93 (3) ◽  
pp. 1326-1335 ◽  
Author(s):  
Yuan Fan ◽  
Bende Zou ◽  
Yiwen Ruan ◽  
Zhiping Pang ◽  
Zao C. Xu
Keyword(s):  
Nmda Receptor ◽  
Pyramidal Neurons ◽  
Receptor Blocker ◽  
Spine Density ◽  
Adult Rats ◽  
Electrophysiological Properties ◽  
Ca1 Pyramidal Neurons ◽  
Postsynaptic Potential

Previous studies have shown that GABA can have a depolarizing and excitatory action through GABAA receptors in mature CNS neurons in vitro. However, it remains unknown whether this occurs under physiological conditions. In this study, using intracellular recording and staining in vivo technique, we show a late depolarizing postsynaptic potential (L-PSP) in CA1 pyramidal neurons of adult Wistar rats under halothane anesthesia. This L-PSP was elicited in ∼70% of the recorded neurons on stimulation of the Schaffer collaterals or the contralateral commissural path. The size of L-PSP was linearly correlated to the decay time constant but not the rising slope of the initial excitatory PSP (EPSP). Intravenous administration of the N-methyl-d-aspartate (NMDA) receptor blocker MK-801 and the GABAA receptor blocker picrotoxin significantly reduced the size of the L-PSP. The spine density and apical dendritic branching length of the neurons that displayed L-PSPs was significantly greater than those that do not. These results indicate that NMDA receptor and GABAA receptor-mediated depolarizing postsynaptic potentials can be revealed in CA1 pyramidal neurons of adult rats in vivo, supporting the physiological relevance of GABAA-mediated depolarization in normal neuronal information processing. The difference in electrophysiological properties and morphological features between neurons that display the L-PSP and the other neurons suggest that they might represent two different subtypes of CA1 pyramidal neurons.

Sign in / Sign up

Export Citation Format

Share Document