Inhibition and Rhythmic Activity of the Circular Muscles of Calliactis Parasitica (Couch)

1960 ◽  
Vol 37 (4) ◽  
pp. 812-831
Author(s):  
D. W. EWER
Keyword(s):  
Electrical Stimulation ◽  
Spontaneous Activity ◽  
Low Frequency ◽  
Rhythmic Activity ◽  
Inhibitory Effect ◽  
Low Frequency Stimulation ◽  
Double Response ◽  
Frequency Stimulation ◽  
Spontaneous Contractions ◽  
Stimulation Of

1. The responses to electrical stimulation of isolated rings of the column and pedal disk of Calliactis are described. Such rings make slow spontaneous contractions which are frequently rhythmical, the interval between contractions normally being 7-20 min. 2. Continuous low-frequency stimulation inhibits spontaneous activity of rings from the pedal disk and also of fresh rings from more adoral regions of the column. Older rings from the mid-column respond to such stimulation by a tetanic contraction. 3. The latency of response to electrical stimulation of pedal rings is of the order of 120 sec. This latency is not affected by stimulation frequency but is prolonged by increase in the number of shocks applied. 4. Stimulation of a pedal ring at the onset of a contraction prevents the further development of this contraction, while stimulation as a contraction reaches its maximum is followed by more rapid relaxation than in unstimulated controls. 5. Mid-column rings when freshly prepared show a latency of the order of 120 sec. As the preparation ages, a double response to stimulation appears; the first response has a latency of about 30-40 sec. and presently becomes the only type of response shown. 6. If two sets of stimuli are applied to a mid-column ring, the magnitude of response to the second set increases as the time between stimulations increases. With long intervals an almost total contraction is obtained in response to a single shock. 7. The effect of intercalated stimuli upon the rhythm of spontaneous activity is studied. The effect is very variable and it is suggested that this is the result of electrical stimulation having both an excitatory and an inhibitory effect. 8. The very long latent periods characteristic of pedal rings and the rhythmic activity of these preparations are interpreted as interactions of excitation and inhibition.

Pyriform Responses to Electrical Stimulation of Olfactory Fila, Bulb and Tract

1957 ◽  
Vol 189 (2) ◽  
pp. 395-400 ◽  
Author(s):  
Paul D. MacLean ◽  
Burton S. Rosner ◽  
Franklin Robinson
Keyword(s):  
Electrical Stimulation ◽  
Olfactory Bulb ◽  
Low Frequency ◽  
Posttetanic Potentiation ◽  
Evoked Responses ◽  
Pyriform Cortex ◽  
Low Frequency Stimulation ◽  
Frequency Stimulation ◽  
Repetitive Electrical Stimulation ◽  
Stimulation Of

Single shock stimulation of the olfactory fila in anesthetized animals evokes slow potentials from the olfactory bulb and pyriform cortex. Conduction velocity in the fila is estimated at 0.4 m/sec. Repetitive electrical stimulation of fila, bulb or tract, produces four phenomena in the pyriform cortex: a) gradual recruitment with low frequency stimulation (3–30/sec.); b) alternation in size of evoked responses at frequencies of 6/sec. and above; c) decline in amplitude of responses with frequencies above 20/sec. (‘decrementation’); and d) posttetanic potentiation after stimulation of the olfactory bulb or tract. Potentiation may persist for several minutes following tetanization of the tract. Recruitment and decrementation are observed in the bulb also upon stimulation of the fila.

Effects of low-frequency stimulation of the superior colliculus on spontaneous and visually guided saccades

1993 ◽  
Vol 69 (3) ◽  
pp. 953-964 ◽  
Author(s):  
P. W. Glimcher ◽  
D. L. Sparks
Keyword(s):  
Superior Colliculus ◽  
Time Course ◽  
Low Frequency ◽  
Arbitrary Point ◽  
Visually Guided ◽  
Spontaneous Movements ◽  
Low Frequency Stimulation ◽  
Frequency Stimulation ◽  
Stimulation Current ◽  
Stimulation Of

1. The first experiment of this study determined the effects of low-frequency stimulation of the monkey superior colliculus on spontaneous saccades in the dark. Stimulation trains, subthreshold for eliciting short-latency fixed-vector saccades, were highly effective at biasing the metrics (direction and amplitude) of spontaneous movements. During low-frequency stimulation, the distribution of saccade metrics was biased toward the direction and amplitude of movements induced by suprathreshold stimulation of the same collicular location. 2. Low-frequency stimulation biased the distribution of saccade metrics but did not initiate movements. The distribution of intervals between stimulation onset and the onset of the next saccade did not differ significantly from the distribution of intervals between an arbitrary point in time and the onset of the next saccade under unstimulated conditions. 3. Results of our second experiment indicate that low-frequency stimulation also influenced the metrics of visually guided saccades. The magnitude of the stimulation-induced bias increased as stimulation current or frequency was increased. 4. The time course of these effects was analyzed by terminating stimulation immediately before, during, or after visually guided saccades. Stimulation trains terminated at the onset of a movement were as effective as stimulation trains that continued throughout the movement. No effects were observed if stimulation ended 40–60 ms before the movement began. 5. These results show that low-frequency collicular stimulation can influence the direction and amplitude of spontaneous or visually guided saccades without initiating a movement. These data are compatible with the hypothesis that the collicular activity responsible for specifying the horizontal and vertical amplitude of a saccade differs from the type of collicular activity that initiates a saccade.

Robust Changes of Afferent-Induced Excitation in the Rat Spinal Dorsal Horn After Conditioning High-Frequency Stimulation

2000 ◽  
Vol 83 (4) ◽  
pp. 2412-2420 ◽  
Author(s):  
Hiroshi Ikeda ◽  
Tatsuya Asai ◽  
Kazuyuki Murase
Keyword(s):  
Dorsal Horn ◽  
High Frequency ◽  
Low Frequency ◽  
Single Pulse ◽  
High Frequency Stimulation ◽  
Neuronal Excitation ◽  
Low Frequency Stimulation ◽  
Frequency Stimulation ◽  
Stimulation Of

We investigated the neuronal plasticity in the spinal dorsal horn and its relationship with spinal inhibitory networks using an optical-imaging method that detects neuronal excitation. High-intensity single-pulse stimulation of the dorsal root activating both A and C fibers evoked an optical response in the lamina II (the substantia gelatinosa) of the dorsal horn in transverse slices of 12- to 25-day-old rat spinal cords stained with a voltage-sensitive dye, RH-482. The optical response, reflecting the net neuronal excitation along the slice-depth, was depressed by 28% for more than 1 h after a high-frequency conditioning stimulation of A fibers in the dorsal root (3 tetani of 100 Hz for 1 s with an interval of 10 s). The depression was not induced in a perfusion solution containing an NMDA antagonist,dl-2-amino-5-phosphonovaleric acid (AP5; 30 μM). In a solution containing the inhibitory amino acid antagonists bicuculline (1 μM) and strychnine (3 μM), and also in a low Cl−solution, the excitation evoked by the single-pulse stimulation was enhanced after the high-frequency stimulation by 31 and 18%, respectively. The enhanced response after conditioning was depotentiated by a low-frequency stimulation of A fibers (0.2–1 Hz for 10 min). Furthermore, once the low-frequency stimulation was applied, the high-frequency conditioning could not potentiate the excitation. Inhibitory transmissions thus regulate the mode of synaptic plasticity in the lamina II most likely at afferent terminals. The high-frequency conditioning elicits a long-term depression (LTD) of synaptic efficacy under a greater activity of inhibitory amino acids, but it results in a long-term potentiation (LTP) when inhibition is reduced. The low-frequency preconditioning inhibits the potentiation induction and maintenance by the high-frequency conditioning. These mechanisms might underlie robust changes of nociception, such as hypersensitivity after injury or inflammation and pain relief after electrical or cutaneous stimulation.

Gnashing induced by electrical stimulation of rabbit brain cortex

1961 ◽  
Vol 200 (5) ◽  
pp. 916-918 ◽  
Author(s):  
Yojiro Kawamura ◽  
Shusaku Tsukamoto ◽  
Kiyokatsu Miyoshi
Keyword(s):  
Electrical Stimulation ◽  
High Frequency ◽  
Brain Cortex ◽  
Low Frequency ◽  
Rabbit Brain ◽  
Lower Jaw ◽  
Low Frequency Stimulation ◽  
Frequency Stimulation ◽  
Chewing Movement ◽  
Experimentally Induced

Gnashing was induced in rabbits by high-frequency cortical stimulation. The frequencies ranged from 60 to 1000 cycle/sec. Strictly circumscribed anteromedial cortical areas were responsive to stimulation. These loci are similar to those which induced chewing movements with low-frequency stimulation (30 cycle/ sec). Electrical stimulation within the above-described range induced gnashing of a constant rhythm of 3–4 cycle/sec that was almost independent of the stimulation frequency. The rate of experimentally induced gnashing is slower than the rate of experimentally induced chewing movements of 5–6 cycle/sec. Gnashing motion of the lower jaw consisted of the vertical and dominant lateral movements; the lateral deflection was more predominant than that of the chewing movement. Gnashing was readily induced with low-frequency stimulation after topical application of a 0.5% solution of strychnine nitrate on the cortical jaw motor area.

Low-frequency stimulation of the ventral hippocampus facilitates extinction of contextual fear

2013 ◽  
Vol 101 ◽  
pp. 39-45 ◽  
Author(s):  
Carine Cleren ◽  
Isabelle Tallarida ◽  
Emilie Le Guiniec ◽  
François Janin ◽  
Ophélie Nachon ◽  
...  
Keyword(s):  
Low Frequency ◽  
Ventral Hippocampus ◽  
Contextual Fear ◽  
Low Frequency Stimulation ◽  
Frequency Stimulation ◽  
Stimulation Of
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