Convergence of pyramidal and medial brain stem descending pathways onto macaque cervical spinal interneurons.
We investigated the control of spinal interneurons by corticospinal and medial brain stem descending tracts in two macaque monkeys. Stimulating electrodes were implanted in the left pyramidal tract (PT), and the right medial longitudinal fasciculus (MLF), which contains reticulospinal, vestibulospinal, and some tectospinal fibers. Single unit discharge was recorded from 163 interneurons in the intermediate zone of the right spinal cord (segmental levels C(6)-C(8)) in the awake state; inputs from descending pathways were assessed from the responses to stimulation through the PT and MLF electrodes. Convergent input from both pathways was the most common finding (71/163 cells); responses to PT and MLF stimulation were of similar amplitude. Interneuron discharge was also recorded while the animal performed a reach and grasp task with the right hand; the output connections of the recorded cells were determined by delivering intraspinal microstimulation (ISMS) at the recording sites. Convergent input from MLF/PT stimulation was also common when analysis was restricted to cells that increased their rate during grasp (14/23 cells) or to cells recorded at sites where ISMS elicited finger or wrist movements (23/57 cells). We conclude that medial brain stem and corticospinal descending pathways have largely overlapping effects on spinal interneurons, including those involved in the control of the hand. This may imply a more important role for the brain stem in coordinating hand movements in primates than commonly assumed; brain stem pathways could contribute to the restoration of function seen after lesions to the corticospinal tract.
Riddle
C Nicholas
CN
Department of Physiology, Development and Neuroscience, University of Cambridge, Cambridge, UK.
Baker
Stuart N
SN
D000200:Action Potentials; D000818:Animals; D001132:Arm / Q000502:physiology*; D001933:Brain Stem / Q000502:physiology*; D002574:Cervical Vertebrae; D004558:Electric Stimulation; D004567:Electrodes, Implanted; D004576:Electromyography; D005260:Female; D005385:Fingers / Q000502:physiology; D007839:Functional Laterality; D007395:Interneurons / Q000502:physiology*; D008253:Macaca mulatta; D009043:Motor Activity / Q000502:physiology; D018482:Muscle, Skeletal / Q000502:physiology; D009434:Neural Pathways / Q000502:physiology; D011712:Pyramidal Tracts / Q000502:physiology*; D013116:Spinal Cord / Q000502:physiology*; D014953:Wrist / Q000502:physiology
Prog Neurobiol. 1987;28(2):161-95
3544055
J Neurosci. 2007 Jul 25;27(30):8053-8
17652596
Exp Brain Res. 1978 Sep 15;33(1):101-30
699994
J Physiol. 1994 Sep 15;479 ( Pt 3):463-73
7837102
J Comp Neurol. 1977 Jun 1;173(3):583-612
404340
J Neurosci. 1993 Feb;13(2):467-91
8426224
J Physiol. 1994 Oct 1;480 ( Pt 1):191-202
7853222
J Comp Neurol. 1985 Dec 1;242(1):56-92
2416786
J Neurophysiol. 1999 Dec;82(6):3580-5
10601484
Exp Neurol. 1964 Mar;9:212-27
14130538
J Comp Neurol. 1997 Jan 13;377(2):234-50
8986883
Biofizika. 1970 Jan-Feb;15(1):171-8
5457895
Exp Brain Res. 1977 Sep 28;29(3-4):323-46
913521
J Neurosci Methods. 1993 Sep;49(3):175-9
8271837
Exp Brain Res. 1985;59(2):353-64
4029309
J Neurosci. 2004 Sep 8;24(36):7804-13
15356191
J Physiol. 1992 Mar;448:397-412
1593472
J Comp Neurol. 1999 Aug 2;410(3):413-30
10404409
Prog Brain Res. 1964;12:222-45
14202441
J Physiol. 1999 Aug 1;518 ( Pt 3):895-906
10420023
J Neurophysiol. 2000 Aug;84(2):698-709
10938297
Exp Brain Res. 1981;42(3-4):269-81
7238671
J Physiol. 1962 Apr;161:91-111
14461967
Electroencephalogr Clin Neurophysiol. 1978 Aug;45(2):302-4
78843
Exp Brain Res. 2004 Jul;157(2):225-33
15024538
J Neurophysiol. 2008 Apr;99(4):2012-20
18234981
J Neurosci Methods. 1982 May;5(4):317-25
6285087
J Neurophysiol. 2006 Dec;96(6):2995-3005
16943320
Exp Brain Res. 1998 Dec;123(4):397-411
9870600
J Neurophysiol. 2004 Jul;92(1):83-95
15014106
J Physiol. 1975 Aug;249(3):617-36
1177108
J Neurophysiol. 2001 Oct;86(4):1573-86
11600621
Exp Brain Res. 2004 Dec;159(3):284-300
15221165
Brain Res Rev. 2008 Jan;57(1):134-46
17936363
J Neurophysiol. 2004 Nov;92(5):3142-7
15175371
J Neurophysiol. 2001 Feb;85(2):679-98
11160503
Brain. 1990 Dec;113 ( Pt 6):1843-56
2276047
Science. 1960 Jul 1;132(3418):38-40
14413009
J Neurophysiol. 1986 Jul;56(1):184-95
3746394
J Neurophysiol. 1998 Nov;80(5):2475-94
9819257
Brain. 1968 Mar;91(1):1-14
4966862
J Neurophysiol. 2006 Jun;95(6):3674-85
16495365
Brain. 1968 Mar;91(1):15-36
4966860
Brain. 1960 Mar;83:161-84
14413010
J Comp Neurol. 1962 Feb;118:107-37
14461005
J Physiol. 1993 Sep;469:213-43
8271199
J Neurophysiol. 2006 Nov;96(5):2229-52
16837662
J Neurophysiol. 2000 May;83(5):3147-53
10805709
J Neurosci. 2003 Mar 1;23(5):1867-78
12629191
Exp Brain Res. 2006 Aug;173(1):25-39
16506008
J Neurophysiol. 1945 Nov;8:387-92
21004991
Adv Neurol. 2001;87:25-40
11347228
J Neurophysiol. 2004 Apr;91(4):1722-33
14668295
Brain Res. 1985 Aug 12;340(2):341-54
4027655
J Neurosci. 2009 Apr 15;29(15):4993-9
19369568
J Neurophysiol. 1986 Feb;55(2):375-401
3950696
Exp Brain Res. 1976 Dec 22;26(5):509-19
1010004
J Neurosci. 1993 Dec;13(12):5105-18
7504721
J Comp Neurol. 1964 Jun;122:355-67
14184859
Brain Res. 1967 Oct;6(2):275-324
6060511
J Neurophysiol. 1968 Mar;31(2):166-75
4879854
J Neurophysiol. 2007 Jan;97(1):110-20
16971685
J Physiol. 1998 Aug 15;511 ( Pt 1):191-212
9679174
J Neurophysiol. 2006 Feb;95(2):1194-206
16424458