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Influence of the hippocampus on interneurons of the rat prefrontal cortex.
Eur J Neurosci. 2004 Jul; 20(2):514-24.EJ

Abstract

The hippocampus and prefrontal cortex (PFC), two structures implicated in learning and memory processes, are linked by a direct hippocampo-prefrontal pathway. It has been shown that PFC pyramidal cells receive monosynaptic excitatory inputs from the hippocampus and, in this study, we sought to determine the influence of the hippocampus on PFC interneurons in anesthetized rats. Extracellular recordings were coupled to juxtacellular injections of neurobiotin or biotinylated dextran amine to morphologically differentiate interneurons from pyramidal cells. In all cases, the action potentials of labeled interneurons were of shorter duration (< 0.70 ms) than those of identified pyramidal cells (> 0.70 ms). Single pulse stimulation of the hippocampal CA1/subiculum region induced an excitatory response in 70% of recorded interneurons in the prelimbic and medial-orbital areas of the PFC. In contrast to the one to two action potentials generated by pyramidal cells, an important group of interneurons fired a burst of action potentials in response to hippocampal stimulation. A large proportion of these excitatory responses was probably monosynaptic as their latency is consistent with the conduction time of the hippocampo-prefrontal pathway. In addition, when both a pyramidal cell and an interneuron were simultaneously recorded and both responded to stimulation, the interneuron consistently fired before the pyramidal cell. In conclusion, the hippocampus exerts a direct excitatory influence on PFC interneurons and is thus capable of feedforward inhibition of pyramidal cells. Hippocampal output is spatially and temporally focalized via this inhibitory process and consequently could facilitate the synchronization of a specific subset of PFC neurons with hippocampal activity.

Authors+Show Affiliations

Chaire de Neuropharmacologie, INSERM U114, Collège de France, 11 place Marcelin Berthelot, 75231 Paris Cedex 05, France.No affiliation info availableNo affiliation info availableNo affiliation info availableNo affiliation info available

Pub Type(s)

Comparative Study
Journal Article
Research Support, Non-U.S. Gov't

Language

eng

PubMed ID

15233760

Citation

Tierney, Patrick L., et al. "Influence of the Hippocampus On Interneurons of the Rat Prefrontal Cortex." The European Journal of Neuroscience, vol. 20, no. 2, 2004, pp. 514-24.
Tierney PL, Dégenètais E, Thierry AM, et al. Influence of the hippocampus on interneurons of the rat prefrontal cortex. Eur J Neurosci. 2004;20(2):514-24.
Tierney, P. L., Dégenètais, E., Thierry, A. M., Glowinski, J., & Gioanni, Y. (2004). Influence of the hippocampus on interneurons of the rat prefrontal cortex. The European Journal of Neuroscience, 20(2), 514-24.
Tierney PL, et al. Influence of the Hippocampus On Interneurons of the Rat Prefrontal Cortex. Eur J Neurosci. 2004;20(2):514-24. PubMed PMID: 15233760.
* Article titles in AMA citation format should be in sentence-case
TY - JOUR T1 - Influence of the hippocampus on interneurons of the rat prefrontal cortex. AU - Tierney,Patrick L, AU - Dégenètais,Eric, AU - Thierry,Anne-Marie, AU - Glowinski,Jacques, AU - Gioanni,Yves, PY - 2004/7/6/pubmed PY - 2004/10/1/medline PY - 2004/7/6/entrez SP - 514 EP - 24 JF - The European journal of neuroscience JO - Eur J Neurosci VL - 20 IS - 2 N2 - The hippocampus and prefrontal cortex (PFC), two structures implicated in learning and memory processes, are linked by a direct hippocampo-prefrontal pathway. It has been shown that PFC pyramidal cells receive monosynaptic excitatory inputs from the hippocampus and, in this study, we sought to determine the influence of the hippocampus on PFC interneurons in anesthetized rats. Extracellular recordings were coupled to juxtacellular injections of neurobiotin or biotinylated dextran amine to morphologically differentiate interneurons from pyramidal cells. In all cases, the action potentials of labeled interneurons were of shorter duration (< 0.70 ms) than those of identified pyramidal cells (> 0.70 ms). Single pulse stimulation of the hippocampal CA1/subiculum region induced an excitatory response in 70% of recorded interneurons in the prelimbic and medial-orbital areas of the PFC. In contrast to the one to two action potentials generated by pyramidal cells, an important group of interneurons fired a burst of action potentials in response to hippocampal stimulation. A large proportion of these excitatory responses was probably monosynaptic as their latency is consistent with the conduction time of the hippocampo-prefrontal pathway. In addition, when both a pyramidal cell and an interneuron were simultaneously recorded and both responded to stimulation, the interneuron consistently fired before the pyramidal cell. In conclusion, the hippocampus exerts a direct excitatory influence on PFC interneurons and is thus capable of feedforward inhibition of pyramidal cells. Hippocampal output is spatially and temporally focalized via this inhibitory process and consequently could facilitate the synchronization of a specific subset of PFC neurons with hippocampal activity. SN - 0953-816X UR - https://www.unboundmedicine.com/medline/citation/15233760/Influence_of_the_hippocampus_on_interneurons_of_the_rat_prefrontal_cortex_ L2 - https://onlinelibrary.wiley.com/resolve/openurl?genre=article&amp;sid=nlm:pubmed&amp;issn=0953-816X&amp;date=2004&amp;volume=20&amp;issue=2&amp;spage=514 DB - PRIME DP - Unbound Medicine ER -