Contralateral projection of some cells of the lateral reticular nucleus

1970 ◽  
Vol 48 (8) ◽  
pp. 569-572 ◽  
Author(s):  
Eugene C. Crichlow
Keyword(s):  
Reticular Nucleus ◽  
Lateral Reticular Nucleus ◽  
Contralateral Projection ◽  
Stimulation Of

Cells of the lateral reticular nucleus were antidromically fired by stimulation of the paramedian lobules. These cells fell into three classes: those activated solely by ipsilateral paramedian stimulation, those which responded only to stimulation of the contralateral paramedian, and, finally, those cells which fired to stimulation of both paramedian lobules. These findings indicate that in addition to the known ipsilateral paramedian projection some cells of the lateral reticular nucleus send their axons to the contralateral paramedian lobule, whereas others project to both paramedian lobules.

Caudolateral areas of medulla-mediating release of ACTH in cats

1986 ◽  
Vol 251 (5) ◽  
pp. R934-R940
Author(s):  
D. A. Bereiter ◽  
D. S. Gann
Keyword(s):  
Brain Stem ◽  
Stimulus Pattern ◽  
Reticular Nucleus ◽  
Lateral Reticular Nucleus ◽  
Plasma Acth ◽  
Acth Stimulation ◽  
Afferent Information ◽  
Burst Pattern ◽  
Stimulation Of ◽  
Acth Release

The effect of electrical stimulation of the caudolateral brain stem on plasma adrenocorticotropin (ACTH) was assessed in cats anesthetized with alpha-chloralose-urethan. To examine the influence of stimulus pattern on ACTH release, an equal number of pulses was presented in a continuous pattern and in a burst pattern at each electrode site. Stimulation of the magnocellular portion (layers 4-6) of trigeminal nucleus caudalis evoked a significant (P less than 0.01) and equal peak change in plasma ACTH after continuous pattern (+121 +/- 32 pg/ml) and after burst pattern stimuli (+126 +/- 30 pg/ml, n = 21). In contrast, stimulation of more ventromedial portions (layers 7-8) of nucleus caudalis had no significant effect on plasma ACTH. Stimulation of the trigeminal lateral cervical region the caudal extent of the A1 noradrenergic cell group, or the lateral reticular nucleus evoked significant peak increases in plasma ACTH regardless of stimulus pattern. Transient changes in arterial pressure accompanied brain stem stimulation and were not correlated with the changes in ACTH. The results indicate that stimulation of trigeminal subnucleus caudalis, a brain stem region that processes nociceptor afferent information, evokes a prompt increase in plasma ACTH. Stimulation of brain stem regions that process autonomic and cardiovascular afferent information (A1 region, lateral reticular nucleus) also facilitate ACTH release. No significant influence of stimulus pattern on brain stem-evoked ACTH release was seen. The results support the hypothesis that the influence of the central nervous system on ACTH release may be processed by parallel pathways at the caudal brain stem level.

Renal and somatic input to spinal neurons antidromically activated from the ventrolateral medulla

1988 ◽  
Vol 60 (6) ◽  
pp. 1967-1981 ◽  
Author(s):  
W. S. Ammons
Keyword(s):  
Reticular Formation ◽  
Receptive Fields ◽  
Ventrolateral Medulla ◽  
Reticular Nucleus ◽  
Lateral Reticular Nucleus ◽  
Spinal Neurons ◽  
C Fiber ◽  
Somatic Input ◽  
Fiber Stimulation ◽  
Stimulation Of

1. Studies were done to characterize responses of spinal neurons backfired from the ventrolateral medulla to renal and somatic stimuli. Experiments were performed on 31 cats that were anesthetized with alpha-chloralose. Sixty-six spinal neurons were antidromically activated from the area of the lateral reticular nucleus or the ventrolateral reticular formation just rostral to the lateral reticular nucleus contralateral to the recording site. These cells could not be backfired from the medial reticular formation or from the spinothalamic tract just caudal to the thalamus. 2. Cells were located in laminae I, V, and VII of the T12-L2 segments. Antidromic conduction velocities averaged 35.9 +/- 7.2 m/s. Conduction velocities were unrelated to the projection site or laminar location of the cells. Termination sites of 21 cells were located in antidromic mapping experiments. Terminals were localized to the ventrolateral reticular formation, including the lateral reticular nucleus. 3. Responses to electrical stimulation of the renal nerves were always excitatory. Stimulation of renal A-delta-fibers excited 33 cells. These cells failed to respond to stimulation of renal C-fibers. The other 33 cells responded to both A-delta- and C-fiber stimulation. Latencies to A-delta-fiber stimulation averaged 9 +/- 2 ms, whereas latencies to C-fiber stimulation averaged 57 +/- 10 ms. 4. Renal mechanoreceptors were activated by occlusion of the renal vein or upper portion of the ureter. Renal vein occlusion excited 14 of 32 cells tested. Activity increased from 6 +/- 2 to 14 +/- 4 spike/s. Ureteral occlusion increased activity of 19 of 32 cells from 7 +/- 2 to 16 +/- 5 spikes/s. Cells responding to one of the mechanical stimuli were significantly more likely to receive A-delta-and C-fiber input compared with nonresponding cells. Nonresponders were more likely than responders to receive only A-delta input. 5. All cells received somatic input in addition to renal input. Twelve cells were classified as wide dynamic range, 46 as high threshold, and 8 as Deep. Somatic receptive fields most often included skin and muscle of the left flank and abdomen. Thirty-two cells had bilateral receptive fields, and 22 had inhibitory fields in addition to excitatory fields. 6. These data show that spinal neurons projecting to the ventrolateral medulla receive convergent inputs from the kidney and somatic structures. These cells may participate in a variety of functions including autonomic reflexes of renal origin.

Function of lateral reticular nucleus in central cardiovascular regulation in the cat

1977 ◽  
Vol 232 (2) ◽  
pp. H157-H166
Author(s):  
M. R. Thomas ◽  
R. F. Ulrichsen ◽  
F. R. Calaresu
Keyword(s):  
Pressor Response ◽  
Cardiovascular Responses ◽  
Cardiovascular Regulation ◽  
Reticular Nucleus ◽  
Lateral Reticular Nucleus ◽  
Functional Connections ◽  
Cervical Vagotomy ◽  
The Right ◽  
Stimulation Of

The role of the lateral reticular nucleus (LRN) in central cardiovascular regulation was investigated in cats. In 15 cerebellectomized and nine intact chloralosed cats stimulation of 115 histologically verified sites in the LRN elicited increases in arterial pressure and heart rate; the latter was abolished by propranolol but not by bilateral cervical vagotomy. The pressor response was significantly greater in intact animals. Electrical activity was recorded from the right inferior cardiac nerve (ICN) during stimulation fo the LRN and of a vasomotor region in the posteromedial hypothalamus (PMH). Stimulation of sites in the LRN and in the PMH, on both sides, elicited a response in the right ICN that was consistently abolished during baroreceptor excitation. Medullary transection 3 mm rostral to the LRN did not abolish the ICN response to LRN stimulation. The conclusions are drawn that stimulation of the LRN elicits cardiovascular responses probably due to excitation of groups of neurons in this nucleus located in a descending sympathetic pathway originating in the PMH and that these responses can be inhibited by excitation of baroreceptors. In view of the known functional connections of the LRN with the somatomotor system it is suggested that this nucleus may play a major role in somatosympathetic reflexes.

c-Fos expression in the medulla induced by static muscle contraction in cats

1997 ◽  
Vol 272 (1) ◽  
pp. H48-H56 ◽  
Author(s):  
J. Li ◽  
G. A. Hand ◽  
J. T. Potts ◽  
L. B. Wilson ◽  
J. H. Mitchell
Keyword(s):  
Muscle Contraction ◽  
Vestibular Nucleus ◽  
Rostral Ventrolateral Medulla ◽  
Ventrolateral Medulla ◽  
Reticular Nucleus ◽  
Lateral Reticular Nucleus ◽  
Double Labeling ◽  
Exercise Pressor Reflex ◽  
Pressor Reflex ◽  
Stimulation Of

In this study, we examined Fos-like immunoreactivity (FLI) in the medulla after static muscle contraction induced by stimulation of L7 and S1 ventral roots of the spinal cord in anesthetized cats. The results show that FLI increases in the lateral reticular nucleus, nucleus of the solitary tract, lateral tegmental field, vestibular nucleus, subretrofacial nucleus, and A1 region of the medulla in comparison with these same areas in sham-operated animals (P < 0.05 in each region). In the rostral ventrolateral medulla, FLI distribution in neurons containing phenylethanolamine-N-methyltransferase (PNMT, the synthetic enzyme for epinephrine) was also observed utilizing double-labeling methods. The majority of neurons with PNMT also expressed FLI (66 +/- 4%). These data are in contrast to the results from sham-operated animals showing that 24 +/- 3% of the neurons costained with PNMT (P < 0.05). Our findings indicate that expression of FLI can be used to identify neurons activated during static muscle contraction and support previous studies implicating the ventrolateral medulla as a critical region for expression of the exercise pressor reflex. Furthermore, neurons in the rostral ventrolateral medulla containing PNMT were activated during static muscle contraction.

scholarly journals Synaptic properties of the feedback connections from the thalamic reticular nucleus to the dorsal lateral geniculate nucleus

2020 ◽  
Vol 124 (2) ◽  
pp. 404-417 ◽  
Author(s):  
Peter W. Campbell ◽  
Gubbi Govindaiah ◽  
Sean P. Masterson ◽  
Martha E. Bickford ◽  
William Guido
Keyword(s):  
Lateral Geniculate Nucleus ◽  
Dorsal Lateral Geniculate Nucleus ◽  
Thalamic Reticular Nucleus ◽  
Reticular Nucleus ◽  
Lateral Geniculate ◽  
Dependent Form ◽  
Dorsal Lateral Geniculate ◽  
Feedback Connections ◽  
Spike Firing ◽  
Stimulation Of

The thalamic reticular nucleus (TRN) modulates thalamocortical transmission through inhibition. In mouse, TRN terminals in the dorsal lateral geniculate nucleus (dLGN) form synapses with relay neurons but not interneurons. Stimulation of TRN terminals in dLGN leads to a frequency-dependent form of inhibition, with higher rates of stimulation leading to a greater suppression of spike firing. Thus, TRN inhibition appears more dynamic than previously recognized, having a graded rather than an all-or-none impact on thalamocortical transmission.

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