Firing Properties and Connectivity of Neurons in the Rat Lateral Central Nucleus of the Amygdala

2004 ◽  
Vol 92 (3) ◽  
pp. 1285-1294 ◽  
Author(s):  
Mikel Lopez De Armentia ◽  
Pankaj Sah
Keyword(s):  
Action Potentials ◽  
Slow Component ◽  
Cell Types ◽  
Firing Frequency ◽  
Central Nucleus ◽  
Sk Channels ◽  
Physiological Properties ◽  
Prolonged Delay ◽  
Firing Properties ◽  
Whole Cell Recordings

Using whole cell recordings from acute slices of the rat amygdala, we have examined the physiological properties of and synaptic connectivity to neurons in the lateral sector of the central amygdala (CeA). Based on their response to depolarizing current injections, CeA neurons could be divided into three types. Adapting neurons fired action potentials at the start of the current injections at high frequency and then showed complete spike-frequency adaptation with only six to seven action potentials evoked with suprathreshold current injections. Late-firing neurons fired action potentials with a prolonged delay at threshold but then discharged continuously with larger current injections. Repetitive firers discharged at the start of the current injection at threshold and then discharged continuously with larger current injections. All three cells showed prolonged afterhyperpolarizations (AHPs) that followed trains of action potentials. The AHP was longer lasting with a larger slow component in adapting neurons. The AHP in all cell types contained a fast component that was inhibited by the SK channel blocker UCL1848. The slow component, not blocked by UCL1848, was blocked by isoprenaline and was significantly larger in adapting neurons. Blockade of SK channels increased the discharge frequency in late firers and regular-spiking neurons but had no effect on adapting neurons. Blockade of the slow AHP with isoprenaline had no effect on any cell type. All cells received a mixed glutamatergic and GABAergic input from a medial pathway. Electrical stimulation of the lateral (LA) and basolateral (BLA) nuclei evoked a large monosynaptic glutamatergic response followed by a disynaptic inhibitory postsynaptic potential. Activation of neurons in the LA and BLA by puffer application of glutamate evoked a small monosynaptic response in 13 of 55 CeA neurons. Local application of glutamate to the CeL evoked a GABAergic response in all cells. These results show that at least three types of neurons are present in the CeA that can be distinguished on their firing properties. The firing frequency of two of these cell types is determined by activation of SK channels. Cells receive a small input from the LA and BLA but may receive inputs that course through these nuclei en route to the CeA.

Single-unit analysis of different hippocampal cell types during classical conditioning of rabbit nictitating membrane response

1983 ◽  
Vol 50 (5) ◽  
pp. 1197-1219 ◽  
Author(s):  
T. W. Berger ◽  
P. C. Rinaldi ◽  
D. J. Weisz ◽  
R. F. Thompson
Keyword(s):  
Classical Conditioning ◽  
Pyramidal Cell ◽  
Action Potentials ◽  
Pyramidal Cells ◽  
Cell Types ◽  
Firing Frequency ◽  
Spontaneous Firing ◽  
Nictitating Membrane ◽  
Nictitating Membrane Response ◽  
Firing Characteristics

Extracellular single-unit recordings from neurons in the CA1 and CA3 regions of the dorsal hippocampus were monitored during classical conditioning of the rabbit nictitating membrane response. Neurons were classified as different cell types using response to fornix stimulation (i.e., antidromic or orthodromic activation) and spontaneous firing characteristics as criteria. Results showed that hippocampal pyramidal neurons exhibit learning-related neural plasticity that develops gradually over the course of classical conditioning. The learning-dependent pyramidal cell response is characterized by an increase in frequency of firing within conditioning trials and a within-trial pattern of discharge that correlates strongly with amplitude-time course of the behavioral response. In contrast, pyramidal cell activity recorded from control animals given unpaired presentations of the conditioned and unconditioned stimulus (CS and UCS) does not show enhanced discharge rates with repeated stimulation. Previous studies of hippocampal cellular electrophysiology have described what has been termed a theta-cell (19-21, 45), the activity of which correlates with slow-wave theta rhythm generated in the hippocampus. Neurons classified as theta-cells in the present study exhibit responses during conditioning that are distinctly different than pyramidal cells. theta-Cells respond during paired conditioning trials with a rhythmic bursting; the between-burst interval occurs at or near 8 Hz. In addition, two different types of theta-cells were distinguishable. One type of theta-cell increases firing frequency above pretrial levels while displaying the theta bursting pattern. The other type decreases firing frequency below pretrial rates while showing a theta-locked discharge. In addition to pyramidal and theta-neurons, several other cell types recorded in or near the pyramidal cell layer could be distinguished. One cell type was distinctive in that it could be activated with a short, invariant latency following fornix stimulation, but spontaneous action potentials of such neurons could not be collided with fornix shock-induced action potentials. These neurons exhibit a different profile of spontaneous firing characteristics than those of antidromically identified pyramidal cells. Nevertheless, neurons in this noncollidable category display the same learning-dependent response as pyramidal cells. It is suggested that the noncollidable neurons represent a subpopulation of pyramidal cells that do not project an axon via the fornix but project, instead, to other limbic cortical regions.(ABSTRACT TRUNCATED AT 400 WORDS)

Electrophysiological Differences Between Neurogliaform Cells From Monkey and Rat Prefrontal Cortex

2007 ◽  
Vol 97 (2) ◽  
pp. 1030-1039 ◽  
Author(s):  
N. V. Povysheva ◽  
A. V. Zaitsev ◽  
S. Kröner ◽  
O. A. Krimer ◽  
D. C. Rotaru ◽  
...  
Keyword(s):  
Prefrontal Cortex ◽  
Input Resistance ◽  
Firing Frequency ◽  
Morphological Features ◽  
Inhibitory Neurons ◽  
Physiological Properties ◽  
Cortical Circuit ◽  
Current Steps ◽  
Constituent Elements ◽  
Whole Cell Recordings

Current dogma holds that a canonical cortical circuit is formed by cellular elements that are basically identical across species. However, detailed and direct comparisons between species of specific elements of this circuit are limited in number. In this study, we compared the morphological and physiological properties of neurogliaform (NGF) inhibitory neurons in the prefrontal cortex (PFC) of macaque monkeys and rats. In both species, NGF cells were readily identified based on their distinctive morphological features. Indeed, monkey NGF cells had only a few morphological features that differed from rat, including a larger soma, a greater number of dendrites, and a more compact axonal field. In contrast, whole cell recordings of the responses to injected current steps revealed important differences between monkey and rat NGF cells. Monkey NGF cells consistently generated a short-latency first spike riding on an initial depolarizing hump, whereas in rat NGF cells, the first spike appeared after a substantial delay riding on a depolarizing ramp not seen in monkey NGF cells. Thus although rat NGF cells are traditionally classified as late-spiking cells, monkey NGF cells did not meet this physiological criterion. In addition, NGF cells in monkey appeared to be more excitable than those in rat because they displayed a higher input resistance, a lower spike threshold, and a higher firing frequency. Finally, NGF cells in monkey showed a more prominent spike-frequency adaptation as compared with rat. Our findings indicate that the canonical cortical circuit differs in at least some aspects of its constituent elements across species.

Layer V Neurons in Mouse Cortex Projecting to Different Targets Have Distinct Physiological Properties

2007 ◽  
Vol 98 (6) ◽  
pp. 3330-3340 ◽  
Author(s):  
Alexis M. Hattox ◽  
Sacha B. Nelson
Keyword(s):  
Cortical Neurons ◽  
Pyramidal Neurons ◽  
Projection Neuron ◽  
Target Form ◽  
Trigeminal Neurons ◽  
Physiological Properties ◽  
Mouse Cortex ◽  
Layer V ◽  
Firing Properties ◽  
Whole Cell Recordings

Layer V pyramidal neurons are anatomically and physiologically heterogeneous and project to multiple intracortical and subcortical targets. However, because most physiological studies of layer V pyramidal neurons have been carried out on unidentified cells, we know little about how anatomical and physiological properties relate to subcortical projection site. Here we combine neuroanatomical tract tracing with whole cell recordings in mouse somatosensory cortex to test whether neurons with the same projection target form discrete subpopulations and whether they have stereotyped physiological properties. Our findings indicate that corticothalamic and -trigeminal neurons are two largely nonoverlapping subpopulations, whereas callosal and corticostriatal neurons overlap extensively. The morphology as well as the intrinsic membrane and firing properties of corticothalamic and corticotrigeminal neurons differ from those of callosal and corticostriatal neurons. In addition, we find that each class of projection neuron exhibits a unique compliment of hyperpolarizing and depolarizing afterpotentials that further suggests that cortical neurons with different subcortical targets are distinct from one another.

Transmural action potential and ionic current remodeling in ventricles of failing canine hearts

2002 ◽  
Vol 283 (3) ◽  
pp. H1031-H1041 ◽  
Author(s):  
Gui-Rong Li ◽  
Chu-Pak Lau ◽  
Anique Ducharme ◽  
Jean-Claude Tardif ◽  
Stanley Nattel
Keyword(s):  
Left Ventricle ◽  
Action Potential ◽  
Action Potentials ◽  
Slow Component ◽  
Ionic Current ◽  
Ionic Currents ◽  
Cell Types ◽  
Delayed Rectifier ◽  
Cardiac Repolarization ◽  
Early Afterdepolarizations

Heart failure (HF) produces important alterations in currents underlying cardiac repolarization, but the transmural distribution of such changes is unknown. We therefore recorded action potentials and ionic currents in cells isolated from the endocardium, midmyocardium, and epicardium of the left ventricle from dogs with and without tachypacing-induced HF. HF greatly increased action potential duration (APD) but attenuated APD heterogeneity in the three regions. Early afterdepolarizations (EADs) were observed in all cell types of failing hearts but not in controls. Inward rectifier K+ current ( I K1) was homogeneously reduced by ∼41% (at −60 mV) in the three cell types. Transient outward K+ current ( I to1) was decreased by 43–45% at +30 mV, and the slow component of the delayed rectifier K+ current ( I Ks) was significantly downregulated by 57%, 49%, and 58%, respectively, in epicardial, midmyocardial, and endocardial cells, whereas the rapid component of the delayed rectifier K+ current was not altered. The results indicate that HF remodels electrophysiology in all layers of the left ventricle, and the downregulation of I K1, I to1, and I Ks increases APD and favors occurrence of EADs.

Comparative electrophysiology of pyramidal and sparsely spiny stellate neurons of the neocortex

1985 ◽  
Vol 54 (4) ◽  
pp. 782-806 ◽  
Author(s):  
D. A. McCormick ◽  
B. W. Connors ◽  
J. W. Lighthall ◽  
D. A. Prince
Keyword(s):  
Action Potentials ◽  
Maximum Rate ◽  
Lucifer Yellow ◽  
Cell Types ◽  
Anterior Cingulate ◽  
Electrophysiological Properties ◽  
Physiological Properties ◽  
Fast Spiking ◽  
Tonic Current

Slices of sensorimotor and anterior cingulate cortex from guinea pigs were maintained in vitro and bathed in a normal physiological medium. Electrophysiological properties of neurons were assessed with intracellular recording techniques. Some neurons were identified morphologically by intracellular injection of the fluorescent dye Lucifer yellow CH. Three distinct neuronal classes of electrophysiological behavior were observed; these were termed regular spiking, bursting, and fast spiking. The physiological properties of neurons from sensorimotor and anterior cingulate areas did not differ significantly. Regular-spiking cells were characterized by action potentials with a mean duration of 0.80 ms at one-half amplitude, a ratio of maximum rate of spike rise to maximum rate of fall of 4.12, and a prominent afterhyperpolarization following a train of spikes. The primary slope of initial spike frequency versus injected current intensity was 241 Hz/nA. During prolonged suprathreshold current pulses the frequency of firing adapted strongly. When local synaptic pathways were activated, all cells were transiently excited and then strongly inhibited. Bursting cells were distinguished by their ability to generate endogenous, all-or-none bursts of three to five action potentials. Their properties were otherwise very similar to regular-spiking cells. The ability to generate a burst was eliminated when the membrane was depolarized to near the firing threshold with tonic current. By contrast, hyperpolarization of regular-spiking (i.e., nonbursting) cells did not uncover latent bursting tendencies. The action potentials of fast-spiking cells were much briefer (mean of 0.32 ms) than those of the other cell types.(ABSTRACT TRUNCATED AT 250 WORDS)

Non-NMDA and NMDA receptors in the synaptic pathway between area postrema and nucleus tractus solitarius

1998 ◽  
Vol 275 (4) ◽  
pp. H1236-H1246 ◽  
Author(s):  
Maria Luz Aylwin ◽  
John M. Horowitz ◽  
Ann C. Bonham
Keyword(s):  
Nmda Receptor ◽  
Nmda Receptors ◽  
Action Potentials ◽  
Nucleus Tractus Solitarius ◽  
Area Postrema ◽  
Slow Component ◽  
Nmda Receptor Antagonist ◽  
Afferent Information ◽  
Whole Cell Recordings

Area postrema (AP) modulates cardiovascular function through excitatory projections to neurons in nucleus tractus solitarius (NTS), which also process primary sensory (including cardiovascular-related) input via the solitary tract (TS). The neurotransmitter(s) and their receptors in the AP-NTS pathway have not been fully characterized. We used whole cell recordings in voltage- and current-clamp modes in the rat brain stem slice to examine the role of ionotropic glutamatergic receptors and α2-adrenergic receptors in the pathway from AP to NTS neurons receiving visceral afferent information via the TS. In neurons voltage clamped at potentials from −100 to +80 mV, AP stimulation (0.2 Hz) evoked excitatory postsynaptic currents having a fast component blocked by the non- N-methyl-d-aspartate (NMDA) receptor antagonist 1,2,3,4-tetrahydro-6-nitro-2,3-dioxobenzoquinoxaline-7-sulfonamide (NBQX; 3 μM, n = 7) and a slow component blocked by the NMDA receptor antagonistdl-2-amino-5-phosphonovaleric acid (APV; 50 μM, n = 8). Although NBQX (3 μM, n = 14) abolished AP-evoked action potentials, APV (50 μM, n = 9 or 500 μM, n = 6) or yohimbine, (200 nM, n = 5 or 2 μM, n = 10) did not. Thus, although AP stimulation activates both non-NMDA and NMDA receptors on NTS neurons receiving TS input, only non-NMDA receptors are required for synaptic transmission.

scholarly journals Effect of knockout of α 2 δ-1 on action potentials in mouse sensory neurons

2016 ◽  
Vol 371 (1700) ◽  
pp. 20150430 ◽  
Author(s):  
Wojciech Margas ◽  
Laurent Ferron ◽  
Manuela Nieto-Rostro ◽  
Arnold Schwartz ◽  
Annette C. Dolphin
Keyword(s):  
Calcium Channels ◽  
Calcium Channel ◽  
Sensory Neurons ◽  
Knockout Mice ◽  
Action Potentials ◽  
Firing Frequency ◽  
Cold Sensitivity ◽  
Sk Channels ◽  
Voltage Gated ◽  
Intracellular Ca

Gene deletion of the voltage-gated calcium channel auxiliary subunit α 2 δ-1 has been shown previously to have a cardiovascular phenotype, and a reduction in mechano- and cold sensitivity, coupled with delayed development of neuropathic allodynia. We have also previously shown that dorsal root ganglion (DRG) neuron calcium channel currents were significantly reduced in α 2 δ-1 knockout mice. To extend our findings in these sensory neurons, we have examined here the properties of action potentials (APs) in DRG neurons from α 2 δ-1 knockout mice in comparison to their wild-type (WT) littermates, in order to dissect how the calcium channels that are affected by α 2 δ-1 knockout are involved in setting the duration of individual APs and their firing frequency. Our main findings are that there is reduced Ca 2+ entry on single AP stimulation, particularly in the axon proximal segment, reduced AP duration and reduced firing frequency to a 400 ms stimulation in α 2 δ-1 knockout neurons, consistent with the expected role of voltage-gated calcium channels in these events. Furthermore, lower intracellular Ca 2+ buffering also resulted in reduced AP duration, and a lower frequency of AP firing in WT neurons, mimicking the effect of α 2 δ-1 knockout. By contrast, we did not obtain any consistent evidence for the involvement of Ca 2+ -activation of large conductance calcium-activated potassium (BK) and small conductance calcium-activated potassium (SK) channels in these events. In conclusion, the reduced Ca 2+ elevation as a result of single AP stimulation is likely to result from the reduced duration of the AP in α 2 δ-1 knockout sensory neurons. This article is part of the themed issue ‘Evolution brings Ca 2+ and ATP together to control life and death’.

scholarly journals Human Nav1.8: enhanced persistent and ramp currents contribute to distinct firing properties of human DRG neurons

2015 ◽  
Vol 113 (9) ◽  
pp. 3172-3185 ◽  
Author(s):  
Chongyang Han ◽  
Mark Estacion ◽  
Jianying Huang ◽  
Dymtro Vasylyev ◽  
Peng Zhao ◽  
...  
Keyword(s):  
Action Potentials ◽  
Firing Frequency ◽  
Inactivation Kinetics ◽  
Drg Neurons ◽  
Current Clamp ◽  
Single Action ◽  
Ion Channel Properties ◽  
Firing Properties ◽  
Species Specific ◽  
Channel Properties

Although species-specific differences in ion channel properties are well-documented, little has been known about the properties of the human Nav1.8 channel, an important contributor to pain signaling. Here we show, using techniques that include voltage clamp, current clamp, and dynamic clamp in dorsal root ganglion (DRG) neurons, that human Nav1.8 channels display slower inactivation kinetics and produce larger persistent current and ramp current than previously reported in other species. DRG neurons expressing human Nav1.8 channels unexpectedly produce significantly longer-lasting action potentials, including action potentials with half-widths in some cells >10 ms, and increased firing frequency compared with the narrower and usually single action potentials generated by DRG neurons expressing rat Nav1.8 channels. We also show that native human DRG neurons recapitulate these properties of Nav1.8 current and the long-lasting action potentials. Together, our results demonstrate strikingly distinct properties of human Nav1.8, which contribute to the firing properties of human DRG neurons.

scholarly journals Morphological and Physiological Characterization of Layer VI Corticofugal Neurons of Mouse Primary Visual Cortex

2003 ◽  
Vol 89 (5) ◽  
pp. 2854-2867 ◽  
Author(s):  
Joshua C. Brumberg ◽  
Farid Hamzei-Sichani ◽  
Rafael Yuste
Keyword(s):  
Visual Cortex ◽  
Primary Visual Cortex ◽  
Action Potentials ◽  
Three Dimensional ◽  
Cell Types ◽  
Dorsal Lateral Geniculate Nucleus ◽  
Morphological Properties ◽  
Feedback Connection ◽  
Physiological Characterization ◽  
Layer Vi

Layer VI is the origin of the massive feedback connection from the cortex to the thalamus, yet its complement of cell types and their connections is poorly understood. The physiological and morphological properties of corticofugal neurons of layer VI of mouse primary visual cortex were investigated in slices loaded with the Ca2+indicator fura-2AM. To identify corticofugal neurons, electrical stimulation of the white matter (WM) was done in conjunction with calcium imaging to detect neurons that responded with changes in intracellular Ca2+ concentrations in response to the stimulation. Subsequent whole cell recordings confirmed that they discharged antidromic action potentials after WM stimulation. Antidromically activated neurons were more excitable and had different spiking properties than neighboring nonantidromic neurons, although both groups had similar input resistances. Furthermore, antidromic neurons possessed narrower action potentials and smaller afterhyperpolarizations. Additionally, three-dimensional reconstructions indicated that antidromically activated neurons had a distinct morphology with longer apical dendrites and fewer nonprimary dendrites than nonantidromic cells. To identify the antidromic neurons, rhodamine microspheres were injected into the dorsal lateral geniculate nucleus of the thalamus and allowed to retrogradely transport back to the somata of the layer VI cortico-geniculate neurons. Physiological and anatomical analysis indicated that most antidromic neurons were likely to be cortico-geniculate neurons. Our results show that cortico-thalamic neurons represent a specific functional and morphological class of layer VI neurons.

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