scholarly journals Repeated cocaine exposure increases fast-spiking interneuron excitability in the rat medial prefrontal cortex

2013 ◽  
Vol 109 (11) ◽  
pp. 2781-2792 ◽  
Author(s):  
Emilie Campanac ◽  
Dax A. Hoffman
Keyword(s):  
Prefrontal Cortex ◽  
Medial Prefrontal Cortex ◽  
Pyramidal Neurons ◽  
Input Resistance ◽  
Compensatory Mechanism ◽  
Cocaine Exposure ◽  
Membrane Excitability ◽  
Chronic Cocaine ◽  
Fast Spiking ◽  
Circuit Output

The medial prefrontal cortex plays a key role in cocaine addiction. However, how chronic cocaine exposure affects cortical networks remains unclear. Most studies have focused on layer 5 pyramidal neurons (the circuit output), while the response of local GABAergic interneurons to cocaine remains poorly understood. Here, we recorded from fast-spiking interneurons (FS-IN) after repeated cocaine exposure and found altered membrane excitability. After cocaine withdrawal, FS-IN showed an increase in the number of spikes evoked by positive current injection, increased input resistance, and decreased hyperpolarization-activated current. We also observed a reduction in miniature excitatory postsynaptic currents, whereas miniature inhibitory postsynaptic current activity was unaffected. We show that, in animals with cocaine history, dopamine receptor D2 activation is less effective in increasing FS-IN intrinsic excitability. Interestingly, these alterations are only observed 1 wk or more after the last cocaine exposure. This suggests that the dampening of D2-receptor-mediated response may be a compensatory mechanism to rein down the excitability of FS-IN.

scholarly journals Layer- and subregion-specific differences in the neurophysiological properties of rat medial prefrontal cortex pyramidal neurons

2018 ◽  
Vol 119 (1) ◽  
pp. 177-191 ◽  
Author(s):  
Chenghui Song ◽  
James R. Moyer
Keyword(s):  
Prefrontal Cortex ◽  
Medial Prefrontal Cortex ◽  
Pyramidal Neurons ◽  
Conditioned Fear ◽  
Input Resistance ◽  
Underlying Mechanism ◽  
Fear Memory ◽  
Membrane Properties ◽  
Spike Threshold ◽  
Memory Acquisition

Medial prefrontal cortex (mPFC) is critical for the expression of long-term conditioned fear. However, the neural circuits involving fear memory acquisition and retrieval are still unclear. Two subregions within mPFC that have received a lot of attention are the prelimbic (PL) and infralimbic (IL) cortices (e.g., Santini E, Quirk GJ, Porter JT. J Neurosci 28: 4028–4036, 2008; Song C, Ehlers VL, Moyer JR Jr. J Neurosci 35: 13511–13524, 2015). Interestingly, PL and IL may play distinct roles during fear memory acquisition and retrieval but the underlying mechanism is poorly understood. One possibility is that the intrinsic membrane properties differ between these subregions. Thus, the current study was carried out to characterize the basic membrane properties of mPFC neurons in different layers and subregions. We found that pyramidal neurons in L2/3 were more hyperpolarized and less excitable than in L5. This was observed in both IL and PL and was associated with an enhanced h-current in L5 neurons. Within L2/3, IL neurons were more excitable than those in PL, which may be due to a lower spike threshold and higher input resistance in IL neurons. Within L5, the intrinsic excitability was comparable between neurons obtained in IL and PL. Thus, the heterogeneity in physiological properties of mPFC neurons may underlie the observed subregion-specific contribution of mPFC in cognitive function and emotional control, such as fear memory expression. NEW & NOTEWORTHY This is the first study to demonstrate that medial prefrontal cortical (mPFC) neurons are heterogeneous in both a layer- and a subregion-specific manner. Specifically, L5 neurons are more depolarized and more excitable than those neurons in L2/3, which is likely due to variations in h-current. Also, infralimbic neurons are more excitable than those of prelimbic neurons in layer 2/3, which may be due to differences in certain intrinsic properties, including input resistance and spike threshold.

scholarly journals Cocaine Exposure Modulates Perineuronal Nets and Synaptic Excitability of Fast-Spiking Interneurons in the Medial Prefrontal Cortex

eNeuro ◽  
2018 ◽  
Vol 5 (5) ◽  
pp. ENEURO.0221-18.2018 ◽  
Author(s):  
Megan L. Slaker ◽  
Emily T. Jorgensen ◽  
Deborah M. Hegarty ◽  
Xinyue Liu ◽  
Yan Kong ◽  
...  
Keyword(s):  
Prefrontal Cortex ◽  
Medial Prefrontal Cortex ◽  
Perineuronal Nets ◽  
Cocaine Exposure ◽  
Fast Spiking

scholarly journals Functional properties of GABA synaptic inputs onto GABA neurons in monkey prefrontal cortex

2015 ◽  
Vol 113 (6) ◽  
pp. 1850-1861 ◽  
Author(s):  
Diana C. Rotaru ◽  
Cameron Olezene ◽  
Takeaki Miyamae ◽  
Nadezhda V. Povysheva ◽  
Aleksey V. Zaitsev ◽  
...  
Keyword(s):  
Prefrontal Cortex ◽  
Input Resistance ◽  
Synaptic Inputs ◽  
Gaba Neurons ◽  
Decay Times ◽  
Cortical Interneurons ◽  
Dorsolateral Prefrontal ◽  
Gaba Neuron ◽  
Fast Spiking ◽  
Monkey Prefrontal Cortex

In rodent cortex GABAA receptor (GABAAR)-mediated synapses are a significant source of input onto GABA neurons, and the properties of these inputs vary among GABA neuron subtypes that differ in molecular markers and firing patterns. Some features of cortical interneurons are different between rodents and primates, but it is not known whether inhibition of GABA neurons is prominent in the primate cortex and, if so, whether these inputs show heterogeneity across GABA neuron subtypes. We thus studied GABAAR-mediated miniature synaptic events in GABAergic interneurons in layer 3 of monkey dorsolateral prefrontal cortex (DLPFC). Interneurons were identified on the basis of their firing pattern as fast spiking (FS), regular spiking (RS), burst spiking (BS), or irregular spiking (IS). Miniature synaptic events were common in all of the recorded interneurons, and the frequency of these events was highest in FS neurons. The amplitude and kinetics of miniature inhibitory postsynaptic potentials (mIPSPs) also differed between DLPFC interneuron subtypes in a manner correlated with their input resistance and membrane time constant. FS neurons had the fastest mIPSP decay times and the strongest effects of the GABAAR modulator zolpidem, suggesting that the distinctive properties of inhibitory synaptic inputs onto FS cells are in part conferred by GABAARs containing α1 subunits. Moreover, mIPSCs differed between FS and RS interneurons in a manner consistent with the mIPSP findings. These results show that in the monkey DLPFC GABAAR-mediated synaptic inputs are prominent in layer 3 interneurons and may differentially regulate the activity of different interneuron subtypes.

scholarly journals Development of inhibitory synaptic inputs on layer 2/3 pyramidal neurons in the rat medial prefrontal cortex

2018 ◽  
Author(s):  
Mari A. Virtanen ◽  
Claudia Marvine Lacoh ◽  
Hubert Fiumelli ◽  
Markus Kosel ◽  
Shiva Tyagarajan ◽  
...  
Keyword(s):  
Prefrontal Cortex ◽  
Medial Prefrontal Cortex ◽  
Pyramidal Neurons ◽  
Synaptic Inputs ◽  
Layer 2
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