TY - JOUR
T1 - Locus coeruleus modulation of the motor thalamus
T2 - Inhibition in nuclei ventralis lateralis and ventralis anterior
AU - Rivner, Michael
AU - Sutin, Jerome
N1 - Funding Information:
Abbreviations: VL-VA-ventralis lateralis-ventralis anterior nuclei of the thalamus, BC-brachium conjunctivum, LC-locus coeruleus, CM-centrum medianum. ’ This work was supported by grant R-29-77 from the United Cerebral Palsy Research and Educational Foundation, Inc.. grant NS-14778 from the National Institutes of Health, and the Helen Miller Endowment award to Emory University School of Medicine. We are grateful to Ms. Geraldine Luttrell for her able technical assistance. The present address of Dr. Rivner is Department of Neurology, Medical College of Georgia, Augusta, Georgia 30912.
PY - 1981/9
Y1 - 1981/9
N2 - Single-cell recordings were made from 693 cells in thalamic nuclei ventralis lateralis and ventralis anterior (VL-VA). Cells were identified as thalamocortical projection cells by antidromic firing from motor cortex or classified according to responsiveness to stimulation of the brachium conjunctivum (BC), entopeduncular nucleus, and motor cortx. Only 14% of the cells tested responded to entopeduncular nucleus stimulation, whereas BC and motor cortex (orthodromic) stimulation each evoked responses in 31% of the VL-VA cells tested. The most common sources of convergent input to VL-VA cells were motor cortex and BC. In 30% of the VL-VA population tested, spontaneous firing was inhibited by stimulation of the locus coeruleus (LC). This inhibition had a long latency to onset which varied from cell to cell (100 to 1000 ms or more) and a long duration (mean = 1183 ms). The inhibition of spontaneous firing by LC was associated with a variable effect upon BC-evoked excitatory responses in VL-VA cells. In some cases, BC evoked responses were suppressed, but not abolished. In other cells, the excitatory response to BC was unaffected despite complete cessation of VL-VA cell spontaneous firing after LC stimulation. The inhibitory action of LC was not limited to any class of VL-VA cells, but occurred most frequently in neurons receiving an input from the BC. The LC inhibition of VL-VA is not related to changes in systemic blood pressure or an action at the level of the cerebellar cortex. However, LC also produces inhibitory and excitatory effects in centrum medianum neurons, which could account for some of the long-latency responses observed in VL-VA. This electrophysiological study of the action of locus coeruleus upon cellular activity in the motor thalamus argues against involvement in phasic movement and associated postural adjustments. Rather, the locus coeruleus projection to thalamus has properties which suggest a role in longer-term tonic regulation of motor activity.
AB - Single-cell recordings were made from 693 cells in thalamic nuclei ventralis lateralis and ventralis anterior (VL-VA). Cells were identified as thalamocortical projection cells by antidromic firing from motor cortex or classified according to responsiveness to stimulation of the brachium conjunctivum (BC), entopeduncular nucleus, and motor cortx. Only 14% of the cells tested responded to entopeduncular nucleus stimulation, whereas BC and motor cortex (orthodromic) stimulation each evoked responses in 31% of the VL-VA cells tested. The most common sources of convergent input to VL-VA cells were motor cortex and BC. In 30% of the VL-VA population tested, spontaneous firing was inhibited by stimulation of the locus coeruleus (LC). This inhibition had a long latency to onset which varied from cell to cell (100 to 1000 ms or more) and a long duration (mean = 1183 ms). The inhibition of spontaneous firing by LC was associated with a variable effect upon BC-evoked excitatory responses in VL-VA cells. In some cases, BC evoked responses were suppressed, but not abolished. In other cells, the excitatory response to BC was unaffected despite complete cessation of VL-VA cell spontaneous firing after LC stimulation. The inhibitory action of LC was not limited to any class of VL-VA cells, but occurred most frequently in neurons receiving an input from the BC. The LC inhibition of VL-VA is not related to changes in systemic blood pressure or an action at the level of the cerebellar cortex. However, LC also produces inhibitory and excitatory effects in centrum medianum neurons, which could account for some of the long-latency responses observed in VL-VA. This electrophysiological study of the action of locus coeruleus upon cellular activity in the motor thalamus argues against involvement in phasic movement and associated postural adjustments. Rather, the locus coeruleus projection to thalamus has properties which suggest a role in longer-term tonic regulation of motor activity.
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U2 - 10.1016/0014-4886(81)90203-X
DO - 10.1016/0014-4886(81)90203-X
M3 - Article
C2 - 7262261
AN - SCOPUS:0019440579
SN - 0014-4886
VL - 73
SP - 651
EP - 673
JO - Experimental Neurology
JF - Experimental Neurology
IS - 3
ER -