The Journal of Neuroscience, March 15, 2001, 21(6):2159-2165
Parabrachial Internal Lateral Neurons Convey Nociceptive Messages
from the Deep Laminas of the Dorsal Horn to the Intralaminar
Thalamus
Laurence
Bourgeais,
Lénaïc
Monconduit,
Luis
Villanueva, and
Jean-François
Bernard
Institut National de la Santé et de la Recherche
Médicale U-161, F-75014 Paris, France
This study investigates the physiological properties of
parabrachial internal lateral (PBil) neurons that project to the
paracentral thalamic (PC) nucleus using antidromic activation and
single-unit recording techniques in anesthetized rat. We reported here
that most of these neurons responded exclusively to the nociceptive stimulation of large receptive fields with a sustained firing that
often outlasted the stimulus up to several minutes. These responses
were depressed by intravenous morphine.
Our results demonstrated a novel spino-PBil-PC pathway, which
transmits nociceptive messages to the PC nucleus, which in turn projects to the prefrontal cortex. Recent clinical imaging studies showed the important participation of prefrontal cortex in emotional response to pain. This spino-PBil-PC pathway may explain how
nociceptive messages reach the prefrontal cortex and thus trigger
unbearable aversive aspects of pain.
Key words:
parabrachial area; thalamus; intralaminar nuclei; paracentral nucleus; dorsal horn; nociception
Copyright © 2001 Society for Neuroscience 0270-6474/01/2162159-07$05.00/0