On the Effective Stimulus in Olfaction

1974 ◽  
Author(s):  
Leif T. Svennsson
Keyword(s):  
Effective Stimulus

Effects of Auditory Stimulus Context on the Representation of Frequency in the Gerbil Inferior Colliculus

2001 ◽  
Vol 86 (3) ◽  
pp. 1113-1130 ◽  
Author(s):  
B. J. Malone ◽  
M. N. Semple
Keyword(s):  
Inferior Colliculus ◽  
Duty Cycle ◽  
Selective Adaptation ◽  
Stimulus Context ◽  
Effective Stimulus ◽  
Spatial Stimulus ◽  
Interaural Phase ◽  
Wide Range ◽  
Conditioned Responses ◽  
Frequency Changes

Prior studies of dynamic conditioning have focused on modulation of binaural localization cues, revealing that the responses of inferior colliculus (IC) neurons to particular values of interaural phase and level disparities depend critically on the context in which they occur. Here we show that monaural frequency transitions, which do not simulate azimuthal motion, also condition the responses of IC neurons. We characterized single-unit responses to two frequency transition stimuli: a glide stimulus comprising two tones linked by a linear frequency sweep (origin-sweep-target) and a step stimulus consisting of one tone followed immediately by another (origin-target). Using sets of glide and step stimuli converging on a common target, we constructed conditioned response functions (RFs) depicting the variability in the response to an identical stimulus as a function of the preceding origin frequency. For nearly all cells, the response to the target depended on the origin frequency, even for origins outside the excitatory frequency response area of the cell. Results from conditioned RFs based on long (2–4 s) and short (200 ms) duration step stimuli indicate that conditioning effects can be induced in the absence of the dynamic sweep, and by stimuli of relatively short duration. Because IC neurons are tuned to frequency, changes in the origin frequency often change the “effective” stimulus duty cycle. In many cases, the enhancement of the target response appeared related to the decrease in the “effective” stimulus duty cycle rather than to the prior presentation of a particular origin frequency. Although this implies that nonselective adaptive mechanisms are responsible for conditioned responses, slightly more than half of IC neurons in each paradigm responded significantly differently to targets following origins that elicited statistically indistinguishable responses. The prevailing influence of stimulus context when discharge history is controlled demonstrates that not all the mechanisms governing conditioning depend on the discharge history of the recorded neuron. Selective adaptation among the neuron's variously tuned afferents may help engender stimulus-specific conditioning. The demonstration that conditioning effects reflect sensitivity to spectral as well as spatial stimulus contrast has broad implications for the processing of a wide range of dynamic acoustic signals and sound sequences.

Characteristics of an inspiration-augmenting reflex in anesthetized cats

1962 ◽  
Vol 17 (4) ◽  
pp. 683-688 ◽  
Author(s):  
Leslie B. Reynolds
Keyword(s):  
Mechanical Properties ◽  
Functional Residual Capacity ◽  
Lung Compliance ◽  
Respiratory Cycle ◽  
Effective Stimulus ◽  
Deep Breath ◽  
Residual Capacity

Overinflation or release from deflation of the lungs in anesthetized cats induced a vagally mediated, inspiration-augmenting reflex, characterized by a sudden phrenic motor discharge and an increase in rate and depth of inspiration. It resulted in an increase in end-expiratory volume and lung compliance. In a series of sinusoidal inflations, the reflex could exhibit summation to occur on any single inflation, but having occurred, was temporarily refractory to further inflations. The spontaneous deep breath was shown to be the same reflex, being vagally mediated, and similarly related to changes in mechanical properties of the lungs. The effective stimulus was shown to be a function of velocity and duration of inflation, while the refractoriness shown by the reflex was related to the accompanying increase in end-expiratory volume. The inspiration-augmenting reflex, by increasing functional residual capacity and compliance, was presumed to open alveolar units. It may interact with the Hering-Breuer inspiration-limiting reflex in controlling the respiratory cycle. Submitted on January 8, 1962

Cooling the vascular bed of an organ makes anoxia a less effective stimulus

1987 ◽  
Vol 104 (3) ◽  
pp. 1205-1208
Author(s):  
B. I. Tkachenko ◽  
A. A. Nurmatov ◽  
Yu. A. Kudryashov
Keyword(s):  
Effective Stimulus ◽  
Vascular Bed

Effects of tracheal irritation and hypercapnia on tracheal smooth muscle in humans

1990 ◽  
Vol 69 (2) ◽  
pp. 419-423 ◽  
Author(s):  
T. Nishino ◽  
K. Sugimori ◽  
K. Hiraga ◽  
Y. Honda
Keyword(s):  
Smooth Muscle ◽  
Endotracheal Tube ◽  
Tracheal Smooth Muscle ◽  
Interindividual Differences ◽  
Effective Stimulus ◽  
Intravenous Atropine

Both hypercapnia and tracheal irritation are known to constrict the airways in animals. To see whether similar responses occur in humans, we investigated tracheal smooth muscle (TSM) responses to hypercapnia and tracheal irritation with water in 14 paralyzed and anesthetized humans. TSM tone was monitored by measuring the pressure in the saline-filled cuff of the endotracheal tube. Although, tracheal irritation caused TSM constriction in 10 of 14 patients, 4 patients showed no TSM response. Administration of intravenous atropine attenuated the TSM constriction response. Hypercapnia did not cause any change in TSM tone in any of the 14 patients. These results indicate that in paralyzed and anesthetized humans, there exist interindividual differences in the TSM responses to tracheal irritation and that hypercapnia cannot be an effective stimulus for the TSM constriction.

Inhibition of development of Ostertagia ostertagi – effect of temperature on the infective larval stage

Parasitology ◽  
1982 ◽  
Vol 85 (1) ◽  
pp. 27-32 ◽  
Author(s):  
M. G. Smeal ◽  
A. D. Donald
Keyword(s):  
Low Temperature ◽  
Larval Stage ◽  
Effect Of Temperature ◽  
Ostertagia Ostertagi ◽  
Effective Stimulus ◽  
Low Temperature Storage ◽  
Temperature Storage

SUMMARYPopulations of Ostertagia ostertagi established from fresh larvae and from larvae stored at 4 °C for up to 12 weeks contained about 10% inhibited early 4th-stage larvae. This value rose to 21% after 16 weeks, due to an increase in numbers of inhibited larvae while adult numbers remained unchanged. Storage at 15 °C had no effect. In the case of larvae stored at 4 °C for 8 weeks, increasing the larval dose to 90000 had no significant effect on the proportion of the dose which was inhibited. The response to low temperature storage was much weaker than in previously reported studies on British populations, which accords with our earlier conclusion that low temperature cannot be the effective stimulus for inhibition in Australia.

Investment Tax Credit Effects On The United States And Canada, 1968-1985.

2011 ◽  
Vol 7 (4) ◽  
pp. 56 ◽  
Author(s):  
Paul A. Shoemaker
Keyword(s):  
United States ◽  
Capital Investment ◽  
The United States ◽  
Matched Pairs ◽  
Tax Credit ◽  
Effective Stimulus ◽  
Investment Tax Credit ◽  
Investment Rates

A micro approach of matched pairs (U.S. and Canadian firms) was utilized to ascertain investment tax credit impacts, differentiating between tax credit and non-tax credit firms. Univariate tests were used to measure the significance of the investment rates between the matched pairs over the period 1968-1985. This research found little evidence that the investment tax credit was an effective stimulus for capital investment.

Effects of Name Learning on Serial Learning, Position Learning, and Recognition Learning with Random Shapes

1963 ◽  
Vol 13 (3) ◽  
pp. 663-678 ◽  
Author(s):  
Howard B. Ranken
Keyword(s):  
Serial Position ◽  
Serial Learning ◽  
Spatial Arrangement ◽  
Temporal Sequence ◽  
Effective Stimulus ◽  
Subsequent Learning ◽  
Position Learning ◽  
The Difference ◽  
Recognition Learning

The effects of learning relevant names for random shapes on subsequent serial, position, and recognition learning were investigated in a series of four experiments. Name learning facilitated all three kinds of subsequent learning. The effect of naming was greater when an ordering of the shapes was learned as a temporal sequence (serial learning) than when it was learned as a spatial arrangement (position learning). Position learning was more rapid than serial learning, and the difference was greater for unnamed than for named shapes. Serial learning was as rapid with named shapes as with the names alone. Naming facilitated position learning even after Named and Unnamed groups had met the same criterion in recognition learning. Implications for various hypotheses concerning the mechanisms underlying the effects of naming are discussed. The results are interpreted as suggesting separate effects of naming on discriminability and on ease of association. The bearing of the findings on the question of the effective stimulus in serial learning is also considered.

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