Electrophysiological responses of interfascicular neurons of the rat anterior commissure to activation from the anterior olfactory nucleus, medial frontal cortex, and posterior nucleus of the amygdala.
Interfascicular neurons (IFNs) of the anterior commissure (AC) include short-axon and projection types which receive inputs from commissural collaterals. Therefore, it was proposed that IFNs may play a role in processing nerve impulses arising from the forebrain and delivered by these collaterals [Brain Res. 931 (2002) 81-91]. To determine possible inputs from the forebrain to IFNs we performed extracellular recordings of 25 neurons from anesthetized adult rats. Short-latency evoked potentials in IFNs were elicited by electrical stimulation of the anterior olfactory, posterior amygdaloid nuclei (PA), and medial frontal cortex. The IFN responses showed three distinct patterns, namely, a single action potential (AP) followed by what appear to be spontaneous discharge; a burst of high-frequency APs, and a single AP followed by a period devoid of APs. The latter response which was elicited by stimulation of the PA, may be explained by an intervening inhibitory interneuron, perhaps GABAergic in nature. Finally, IFNs seem not to project back to any of these three forebrain areas, as we failed to demonstrate antidromic activation.
Condés-Lara
Miguel
M
Department of Developmental Biology and Neurophysiology, Instituto de Neurobiología, Universidad Nacional Autónoma de México, Campus UNAM-UAQ, Juriquilla, Apartado Postal 1-1141, Zona Centro, CP 76001 Querétaro, Qro, Mexico.
Paz
Carlos
C
Jiménez
Javier Rodríguez
JR
Martínez
Gema
G
Martínez-Lorenzana
Guadalupe
G
Larriva-Sahd
Jorge
J
D000200:Action Potentials / Q000502:physiology; D000679:Amygdala / Q000502:physiology*; D000818:Animals; D004594:Electrophysiology; D005625:Frontal Lobe / Q000502:physiology*; D008297:Male; D009434:Neural Pathways / Q000502:physiology; D009474:Neurons / Q000502:physiology*; D009833:Olfactory Pathways / Q000502:physiology*; D009836:Oligodendroglia / Q000502:physiology; D051381:Rats; D017207:Rats, Sprague-Dawley; D012686:Septal Nuclei / Q000502:physiology*