TY - JOUR
T1 - Disinhibition of the midbrain colliculi unmasks coordinated autonomic, Respiratory, And somatomotor responses to auditory and visual stimuli
AU - Müller-Ribeiro, Flávia C F
AU - Dampney, Roger A L
AU - McMullan, Simon
AU - Fontes, Marco A P
AU - Goodchild, Ann K.
PY - 2014/10/15
Y1 - 2014/10/15
N2 - The midbrain superior and inferior colliculi have critical roles in generating coordinated orienting or defensive behavioral responses to environmental stimuli, and it has been proposed that neurons within the colliculi can also generate appropriate cardiovascular and respiratory responses to support such behavioral responses. We have previously shown that activation of neurons within a circumscribed region in the deep layers of the superior colliculus and in the central and external nuclei of the inferior colliculus can evoke a response characterized by intense and highly synchronized bursts of renal sympathetic nerve activity and phrenic nerve activity. In this study, we tested the hypothesis that, under conditions in which collicular neurons are disinhibited, coordinated cardiovascular, somatomotor, and respiratory responses can be evoked by natural environmental stimuli. In response to natural auditory, visual, or somatosensory stimuli, powerful synchronized increases in sympathetic, respiratory, and somatomotor activity were generated following blockade of GABAA receptors in a specific region in the midbrain colliculi of anesthetized rats, but not under control conditions. Such responses still occurred after removal of most of the forebrain, including the amygdala and hypothalamus, indicating that the essential pathways mediating these coordinated responses were located within the brain stem. The temporal relationships between the different outputs suggest that they are driven by a common population of “command neurons” within the colliculi.
AB - The midbrain superior and inferior colliculi have critical roles in generating coordinated orienting or defensive behavioral responses to environmental stimuli, and it has been proposed that neurons within the colliculi can also generate appropriate cardiovascular and respiratory responses to support such behavioral responses. We have previously shown that activation of neurons within a circumscribed region in the deep layers of the superior colliculus and in the central and external nuclei of the inferior colliculus can evoke a response characterized by intense and highly synchronized bursts of renal sympathetic nerve activity and phrenic nerve activity. In this study, we tested the hypothesis that, under conditions in which collicular neurons are disinhibited, coordinated cardiovascular, somatomotor, and respiratory responses can be evoked by natural environmental stimuli. In response to natural auditory, visual, or somatosensory stimuli, powerful synchronized increases in sympathetic, respiratory, and somatomotor activity were generated following blockade of GABAA receptors in a specific region in the midbrain colliculi of anesthetized rats, but not under control conditions. Such responses still occurred after removal of most of the forebrain, including the amygdala and hypothalamus, indicating that the essential pathways mediating these coordinated responses were located within the brain stem. The temporal relationships between the different outputs suggest that they are driven by a common population of “command neurons” within the colliculi.
KW - Arterial pressure
KW - Command neuron
KW - Defensive behavior
KW - Phrenic nerve activity
KW - Sympathetic activity
UR - http://www.scopus.com/inward/record.url?scp=84908056335&partnerID=8YFLogxK
U2 - 10.1152/ajpregu.00165.2014
DO - 10.1152/ajpregu.00165.2014
M3 - Article
C2 - 25100075
AN - SCOPUS:84908056335
SN - 0363-6119
VL - 307
SP - R1025-R1035
JO - American Journal of Physiology - Regulatory Integrative and Comparative Physiology
JF - American Journal of Physiology - Regulatory Integrative and Comparative Physiology
IS - 8
ER -