Electrophysiological characterization of the rat nucleus incertus neurons in relation to hippocampal theta oscillations

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

Abstrakty

EN

INTRODUCTION: The nucleus incertus (NI) is a bilateral structure located adjacent to the midline of the brainstem, below the fourth ventricle. NI is formed of GABAergic neurons strongly innervating theta pacemaker regions of the brain. Previously, it has been shown that activation of NI induces hippocampal theta rhythms, whereas inactivation impairs it. The NI itself is a part of a network working at theta frequency. However, the electrophysiological characteristics of NI neurons and their involvement in the mechanisms of theta rhythm generation are unclear. AIM(S): Our goal was to determine the classification of NI neurons based on their electrophysiological properties in relation to hippocampal theta oscillations. METHOD(S): The experiments were conducted on Sprague-Dawley rats under urethane anaesthesia that induces cyclic alternations of brain states (dominance of theta oscillations or slow waves). Neuronal activity was recorded extracellularly using a 32-channel recording system in combination with acute microelectrode arrays. At the same time, theta rhythm and slow wave activity were recorded from the stratum lacunosum‑moleculare layer of the hippocampal CA1 field. RESULTS: We have shown that the level and pattern of NI neuronal firing is brain state dependent. Two main groups of NI neurons could be distinguished: theta‑phase locked cells (46%, 66/145), and theta‑phase independent cells (54%, 79/145). A majority of theta‑phase locked NI neurons are characterized by rhythmic bursting with a strong preference to fire action potentials at the rising phase of hippocampal theta oscillation (theta bursting neurons; 68%, 45/66). CONCLUSIONS: We have discovered that NI neuronal activity patterns are more complex than has been previously described. Almost a third of all recorded NI neurons exhibit a theta-bursting pattern of firing, suggesting that the NI not only modulates theta oscillations but is itself an oscillator.

• Wydawca: -
• Czasopismo: Acta Neurobiologiae Experimentalis
• Rocznik: 2019
• Tom: 79
• Numer: Suppl.1
• Opis fizyczny: p.LXXXIX

Twórcy

autor

Trenk A.

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

autor

Walczak M.

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

autor

Blasiak T.

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