Electrophysiological characterization of rat nucleus incertus neurons – in vivo studies using multi-channel recording technique

• Autorzy: Trenk A. , Walczak M. , Blasiak T.
• Języki publikacji: EN

Abstrakty

EN

The nucleus incertus (NI) is a brainstem structure formed of GABAergic projection neurons. It is located in the dorsal tegmental pons, below the fourth ventri‑ cle. Axons of NI neurons innervate numerous brain re‑ gions, including the septo-hippocampal system. Previ‑ ous studies have shown that the NI is one of the key el‑ ements involved in the induction of hippocampal theta oscillations. More recently, theta oscillations in the lo‑ cal field potential of the NI were described. Neverthe‑ less, the electrophysiological characteristics of NI neu‑ rons and the involvement of the NI in the mechanisms of theta rhythm generation are unclear. Therefore, the aim of our research is to determine the comprehensive classification of NI neurons in relation to hippocampal theta oscillations. We have performed in vivo electro‑ physiology experiments on 12 urethane anaesthetised Sprague Dawley rats. Under this anaesthetic condition one can observe spontaneous cyclical alternations of brain states (activation and slow wave activity; SWA), characterized by the dominance of different EEG waves (theta and delta oscillations, respectively). Neuronal activity was recorded extracellularly using a 32-chan‑nel recording system in combination with acute micro‑ electrode arrays. Theta rhythm and slow wave activity were recorded from stratum lacunosum-moleculare of hippocampal CA1 field. Our results have revealed that electrical activity of NI neurons (n=147) is brain state dependent. Based on the preference to fire in a specific phase of hippocampal theta rhythm, two main groups of NI neurons could be distinguished: theta phaselocked cells (45%, 66/147) and theta phase-independent cells (55%, 81/147). a majority of theta phase-locked NI neurons fired action potentials in bursts occurring at the rising phase of hippocampal theta oscillation (the‑ ta bursting neurons; 68%, 45/66). Firing rate of theta phase-locked neurons was higher during brain activa‑ tion compared to SWA state. Firing of theta phase-in‑ dependent NI neurons was more heterogeneous and included cells with higher firing rates either during theta oscillations or SWA. Using the multi-channel re‑ cording technique, we have shown that the patterns of NI neuronal activity are more complex than previously described. The resulting in-depth electrophysiological characterization of NI neurons help us to better under‑ stand the mechanisms underlying the formation and synchronization of theta oscillations. Funding: NSC, Poland UMO-2014/15/B/NZ4/04896.

• Wydawca: -
• Czasopismo: Acta Neurobiologiae Experimentalis
• Rocznik: 2018
• Tom: 78
• Numer: Suppl.1
• Opis fizyczny: p.17-18

Twórcy

autor

Trenk A.

• Department of Neurophysiology and Chronobiology, Institute of Zoology and Biomedical Research, Jagiellonian University, Krakow, Poland

autor

Walczak M.

• Department of Neurophysiology and Chronobiology, Institute of Zoology and Biomedical Research, Jagiellonian University, Krakow, Poland

autor

Blasiak T.

• Department of Neurophysiology and Chronobiology, Institute of Zoology and Biomedical Research, Jagiellonian University, Krakow, Poland