Antidromic activity in visual radiation during evoked cortical responses

1977 ◽  
Vol 40 (1) ◽  
pp. 9-15 ◽  
Author(s):  
A. D. Rosen ◽  
E. F. Vastola
Keyword(s):  
Functional Significance ◽  
Optic Tract ◽  
Antidromic Activation ◽  
Seizure Focus ◽  
Postsynaptic Spike ◽  
Cortical Responses ◽  
Antidromic Stimulation ◽  
Variable Latency ◽  
Activation Times ◽  
Stimulation Of

1. Antidromic stimulation of the visual radiation of cats has been used to investigate the possibility that some of the activity in principal geniculate cells following an optic tract stimulus is antidromic. Single spikes were selected from two classes of poststimulus activity to condition the antidromic test spike--the undoubted orthodromic postsynaptic spike and the later spikes, occurring up to 100 ms after the optic tract stimulus. 2. In 15 of 39 cells the minimum antidromic activation times and the minimum spike-spike intervals were found to be shorter and latencies for antidromic stimulation were longer when the conditioning spikes belonged the class of late poststimulus activity. The differences are in accord with the assumption that some of the conditioning spikes were antidromic. 3. Test spikes were frequently found to have long and variable latency when the conditioning spike occurred more than 45 ms after the optic tract stimulus. Possible reasons are briefly discussed. 4. It is suggested that antidromic activity may occur in conditions of the cortex that are more physiological than those associated with a penicillin-induced seizure focus. Some possible mechanisms and functional significance are briefly discussed.

Physiological characterization of spinohypothalamic tract neurons in the lumbar enlargement of rats

1991 ◽  
Vol 66 (1) ◽  
pp. 261-284 ◽  
Author(s):  
R. Burstein ◽  
R. J. Dado ◽  
K. D. Cliffer ◽  
G. J. Giesler
Keyword(s):  
Dorsal Horn ◽  
Gray Matter ◽  
Mechanical Stimulation ◽  
Dynamic Range ◽  
Receptive Fields ◽  
Optic Tract ◽  
Antidromic Activation ◽  
Noxious Stimuli ◽  
Noxious Mechanical Stimulation ◽  
Stimulation Of

1. Ninety-six neurons in the lumbar enlargement of urethananesthetized rats were antidromically activated from the contralateral hypothalamus. The antidromic stimulating electrode was moved systematically within the hypothalamus until antidromic activation could be produced with currents of less than or equal to 50 microA (18.6 +/- 10.8 microA; mean +/- SD). The points at which antidromic activation thresholds were lowest were found in several regions of the hypothalamus but were concentrated in the optic tract and the supraoptic decussation. 2. The recording locations of 79 spinohypothalamic tract (SHT) neurons were marked and recovered. Twenty-nine were located in the superficial dorsal horn (SDH), 42 in the deep dorsal horn (DDH), 4 in the intermediate zone, and 2 in the gray matter surrounding the central canal. Two additional marks were located in the dorsal lateral funiculus (DLF). 3. The responses of 46 SHT neurons were examined during innocuous and noxious mechanical stimulation of their receptive fields. Forty-eight percent of recorded SHT neurons responded to both innocuous and noxious stimuli (wide dynamic range, WDR) and 39% responded only to noxious stimuli (high threshold, HT). Therefore 87% of SHT neurons responded preferentially or exclusively to noxious mechanical stimulation. Nine percent of SHT neurons responded exclusively to innocuous manipulation of joints and muscles. Four percent of SHT neurons responded only to innocuous tactile stimul (low threshold, LT). WDR, HT, and LT neurons were recorded widely throughout the dorsal horn; no relationship was found between the locations of recording sites in the dorsal horn and the response types of the neurons. SHT neurons that responded to stimulation of muscle, tendon, or joint were recorded deep in the gray matter. 4. The effects of heating the receptive fields were determined for 25 SHT neurons. Fourteen (56%) responded to thermal stimuli. Six (43%) of the responsive neurons responded at low frequencies to innocuous warming (38-41 degrees C) but more vigorously to noxious (greater than or equal to 45 degrees C) heating. The other eight responded only to noxious heat. Eighteen percent (3/17) of tested SHT neurons were activated by noxious cooling of their receptive fields. 5. Cutaneous receptive fields of most recorded SHT neurons were small, typically involving areas as small as two or three toes on the ipsilateral hindlimb; the largest receptive fields covered the entire paw. These findings indicate that relatively precise information about the location of innocuous and noxious stimuli is conveyed directly to the hypothalamus by SHT neurons.(ABSTRACT TRUNCATED AT 400 WORDS)

Visual input to commissural neurons of the cat's superior colliculus

1991 ◽  
Vol 7 (4) ◽  
pp. 389-393 ◽  
Author(s):  
James T. McIlwain
Keyword(s):  
Superior Colliculus ◽  
Action Potentials ◽  
Optic Tract ◽  
Extracellular Recording ◽  
Response Latencies ◽  
Antidromic Activation ◽  
Commissural Neurons ◽  
Direct Input ◽  
Y Cells ◽  
Stimulation Of

AbstractCells projecting into the commissure of the cat's superior colliculus were identified during extracellular recording by antidromic activation. Electrical stimulation of the ipsilateral optic tract evoked action potentials in the majority of commissural neurons. Response latencies of 1.4 ± 0.5 ms (mean ± S.D.) in a few cells indicated that some commissural neurons receive direct input from the axons of retinal Y–cells. Most commissural cells responded 5.9 ± 1.9 ms (mean ± S.D.) following optic tract shock, implying that the responsible pathway was composed of more slowly conducting axons or did not proceed directly to the colliculus. Results of previous studies of retinal inputs to cells in the deep tectal layers suggest that the later responses were mediated by an indirect Y pathway through the visual cortex.

Human intracranially-recorded cortical responses evoked by painful electrical stimulation of the sural nerve

NeuroImage ◽  
2007 ◽  
Vol 34 (2) ◽  
pp. 743-763 ◽  
Author(s):  
R. Dowman ◽  
T. Darcey ◽  
H. Barkan ◽  
V. Thadani ◽  
D. Roberts
Keyword(s):  
Electrical Stimulation ◽  
Sural Nerve ◽  
Cortical Responses ◽  
Stimulation Of

Stimulation of the Hippocampus and the Seizure Focus

2009 ◽  
pp. 2839-2852
Author(s):  
A. L. Velasco ◽  
F. Velasco ◽  
M. Velasco ◽  
G. Castro ◽  
J. D. Carrillo-Ruiz ◽  
...  
Keyword(s):  
Seizure Focus ◽  
Stimulation Of

Distribution of vagal cardioinhibitory neurons in the medulla of the cat

1980 ◽  
Vol 238 (1) ◽  
pp. R57-R64 ◽  
Author(s):  
J. Ciriello ◽  
F. R. Calaresu
Keyword(s):  
Nucleus Tractus Solitarius ◽  
Border Region ◽  
Nucleus Ambiguus ◽  
Motor Nucleus ◽  
Dorsal Motor Nucleus ◽  
Antidromic Stimulation ◽  
Low Threshold ◽  
Vagal Bradycardia ◽  
Medullary Nuclei ◽  
Stimulation Of

Experiments were done in cats anesthetized with chloralose, paralyzed and artificially ventilated cats to obtain electrophysiological evidence on the medullary site of origin of vagal cardioinhibitory fibers. The regions of the nucleus ambiguus (AMB), dorsal motor nucleus of the vagus (DMV), nucleus tractus solitarius (NTS), and external cuneate nucleus (ECN) were systematically explored for units responding both to antidromic stimulation of the cardiac branches of the vagus (CBV) and to orthodromic stimulation of the carotid sinus and aortic depressor nerves. Eighty-six single units conforming to these criteria were found in the medulla: 30 in the AMB, 26 in the DMV, 12 in the NTS, 8 in the NTS-DMV border region, and 10 in the ECN. Antidromically evoked spikes had durations of 0.5--2.5 ms and followed stimulation frequencies of 20--500 Hz. The axons of these units conducted at velocities of 3.3--20.8 m/s. The specificity of activation of medullary units by cardioinhibitory fibers was tested in 11 units, which were found to respond consistently with an antidromic spike to stimulation of CBV but not to stimulation of the thoracic vagus. In eight spinal animals low threshold (less than 15 microA) sites eliciting vagal bradycardia were found in the same medullary nuclei where cardioinhibitory units had been located. These results indicate that vagal cardioinhibitory axons, originate in at least three medullary nuclei, the AMB, DMV, and NTS. Unit activity from the ECN may have been recorded from carioinhibitory fibers because of the short duration of the spike potentials.

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