scholarly journals Effects of aging on the electrophysiological properties of layer 5 pyramidal cells in the monkey prefrontal cortex

Neuroscience ◽  
2007 ◽  
Vol 150 (3) ◽  
pp. 556-562 ◽  
Author(s):  
J.I. Luebke ◽  
Y.-M. Chang
2005 ◽  
Vol 94 (5) ◽  
pp. 3009-3022 ◽  
Author(s):  
Leonid S. Krimer ◽  
Aleksey V. Zaitsev ◽  
Gabriela Czanner ◽  
Sven Kröner ◽  
Guillermo González-Burgos ◽  
...  

In primates, little is known about intrinsic electrophysiological properties of neocortical neurons and their morphological correlates. To classify inhibitory cells (interneurons) in layers 2–3 of monkey dorsolateral prefrontal cortex we used whole cell voltage recordings and intracellular labeling in slice preparation with subsequent morphological reconstructions. Regular spiking pyramidal cells have been also included in the sample. Neurons were successfully segregated into three physiological clusters: regular-, intermediate-, and fast-spiking cells using cluster analysis as a multivariate exploratory technique. When morphological types of neurons were mapped on the physiological clusters, the cluster of regular spiking cells contained all pyramidal cells, whereas the intermediate- and fast-spiking clusters consisted exclusively of interneurons. The cluster of fast-spiking cells contained all of the chandelier cells and the majority of local, medium, and wide arbor (basket) interneurons. The cluster of intermediate spiking cells predominantly consisted of cells with the morphology of neurogliaform or vertically oriented (double-bouquet) interneurons. Thus a quantitative approach enabled us to demonstrate that intrinsic electrophysiological properties of neurons in the monkey prefrontal cortex define distinct cell types, which also display distinct morphologies.


2007 ◽  
Vol 98 (5) ◽  
pp. 2622-2632 ◽  
Author(s):  
Yu-Ming Chang ◽  
Jennifer I. Luebke

Whole cell patch-clamp recordings were employed to characterize the electrophysiological properties of layer 5 pyramidal cells in slices of the prefrontal cortex (Area 46) of the rhesus monkey. Four electrophysiologically distinct cell types were discriminated based on distinctive repetitive action potential (AP) firing patterns and single AP characteristics: regular-spiking slowly adapting type-1 cells (RS1; 62%), regular-spiking slowly adapting type-2 cells (RS2; 18%), regular-spiking fast-adapting cells (FA; 15%), and intrinsically bursting cells (IB; 5%). These cells did not differ with regard to their location in layer 5 nor in their dendritic morphology. In RS1 cells, AP threshold and amplitude did not change significantly during a 2-s spike train, whereas in RS2 and FA cells, AP threshold increased significantly and AP amplitude decreased significantly during the train. In FA cells, complete adaptation of AP firing was observed within 600 ms. IB cells displayed an all-or-none burst of three to six APs, followed by RS1-type firing behavior. RS1 cells could be further subdivided into three subtypes. Low-threshold spiking (LTS) RS1 cells exhibited an initial doublet riding on a depolarizing potential at the onset of a spike train and a prominent depolarizing afterpotential (DAP); intermediate RS1 cells (IM) exhibited a DAP, but no initial doublet, and non-LTS RS1 cells exhibited neither a DAP nor an initial doublet. RS2 and FA cells did not exhibit a DAP or initial doublets. The distinctive firing patterns of these diverse layer 5 pyramidal cells may reflect different roles played by these cells in the mediation of subcortical neuronal activity by the dorsolateral PFC.


2012 ◽  
Vol 108 (2) ◽  
pp. 595-609 ◽  
Author(s):  
A. V. Zaitsev ◽  
N. V. Povysheva ◽  
G. Gonzalez-Burgos ◽  
D. A. Lewis

The activity of supragranular pyramidal neurons in the dorsolateral prefrontal cortex (DLPFC) neurons is hypothesized to be a key contributor to the cellular basis of working memory in primates. Therefore, the intrinsic membrane properties, a crucial determinant of a neuron's functional properties, are important for the role of DLPFC pyramidal neurons in working memory. The present study aimed to investigate the biophysical properties of pyramidal cells in layer 2/3 of monkey DLPFC to create an unbiased electrophysiological classification of these cells. Whole cell voltage recordings in the slice preparation were performed in 77 pyramidal cells, and 24 electrophysiological measures of their passive and active intrinsic membrane properties were analyzed. Based on the results of cluster analysis of 16 independent electrophysiological variables, 4 distinct electrophysiological classes of monkey pyramidal cells were determined. Two classes contain regular-spiking neurons with low and high excitability and constitute 52% of the pyramidal cells sampled. These subclasses of regular-spiking neurons mostly differ in their input resistance, minimum current that evoked firing, and current-to-frequency transduction properties. A third class of pyramidal cells includes low-threshold spiking cells (17%), which fire a burst of three-five spikes followed by regular firing at all suprathreshold current intensities. The last class consists of cells with an intermediate firing pattern (31%). These cells have two modes of firing response, regular spiking and bursting discharge, depending on the strength of stimulation and resting membrane potential. Our results show that diversity in the functional properties of DLPFC pyramidal cells may contribute to heterogeneous modes of information processing during working memory and other cognitive operations that engage the activity of cortical circuits in the superficial layers of the DLPFC.


2005 ◽  
Vol 93 (2) ◽  
pp. 942-953 ◽  
Author(s):  
Guillermo González-Burgos ◽  
Leonid S. Krimer ◽  
Nadya V. Povysheva ◽  
German Barrionuevo ◽  
David A. Lewis

Recent studies suggest that fast-spiking (FS) interneurons of the monkey dorsolateral prefrontal cortex (DLPFC) exhibit task-related firing during working-memory tasks. To gain further understanding of the functional role of FS neurons in monkey DLPFC, we described the in vitro electrophysiological properties of FS interneurons and their synaptic connections with pyramidal cells in layers 2/3 of areas 9 and 46. Extracellular spike duration was found to distinguish FS cells from non-FS interneuron subtypes. However, a substantial overlap in extracellular spike duration between these populations would make classification of individual interneurons difficult. FS neurons could be divided into two main morphological groups, chandelier and basket neurons, with very similar electrophysiological properties but significantly different horizontal spread of the axonal arborization. In paired cell recordings, unitary inhibitory postsynaptic potentials (IPSPs) elicited by FS neurons in pyramidal cells had rapid time course, small amplitude at resting membrane potential, and were mediated by GABAA receptors. Repetitive FS neuron stimulation, partially mimicking the sustained firing of interneurons in vivo, produced short-term depression of the unitary IPSPs, present at connections made by both basket and chandelier neurons and due at least in part to presynaptic mechanisms. These results suggest that FS neurons and their synaptic connections with pyramidal cells have homogeneous physiological properties. Thus different functional roles of basket and chandelier neurons in the DLPFC in vivo must arise from the distinct properties of the interneuronal axonal arborization or from a different functional pattern of excitatory and inhibitory connections with other components of the DLPFC neuronal network.


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