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Tuning in the Hippocampal Theta Band In Vitro: Methodologies for Recording from the Isolated Rodent Septohippocampal Circuit
Published on: August 2, 2017
Nucleus incertus contribution to hippocampal theta rhythm generation
A Nuñez1, A Cervera-Ferri, F Olucha-Bordonau
1Departamento de Anatomia, Histología y Neurociencia Facultad de Medicina, Universidad Autónoma de Madrid, C/Arzobispo Morcillo 4, 28029 Madrid, Spain. angel.nunez@uam.es
The European Journal of Neuroscience
|July 5, 2006
Summary
The nucleus incertus (NI) plays a role in generating hippocampal theta rhythm. NI stimulation evokes theta rhythm, and NI lesions disrupt theta rhythm, suggesting it acts as a brainstem relay.
Area of Science:
- Neuroscience
- Neurophysiology
Background:
- The medial septum-diagonal band of Broca (MS/DBB) neurons are known pacemakers for hippocampal theta rhythm.
- Brainstem structures influence and modulate this theta rhythm.
Purpose of the Study:
- To investigate the contribution of the nucleus incertus (NI) to hippocampal theta rhythm generation.
- To explore the anatomical and functional connections between the NI and MS/DBB.
Main Methods:
- Recording hippocampal field activity in urethane-anesthetized rats.
- Electrical stimulation of the NI and nucleus reticularis pontis oralis (RPO).
- Unit recordings in the NI and electrolytic lesions or muscimol microinjections into the NI.
Main Results:
- NI stimulation evoked hippocampal theta rhythm and decreased delta wave amplitude.
- NI neurons exhibited non-rhythmic discharge (76%) or rhythmic activity (13-25 Hz).
- Lesions or muscimol inactivation of the NI abolished RPO-stimulated theta rhythm.
Conclusions:
- The nucleus incertus (NI) contributes to hippocampal theta rhythm generation.
- The NI may function as a relay station connecting brainstem structures to the MS/DBB for theta rhythm control.
