Response shaping at long interstimulus intervals in ratings of signaled shock aversiveness

1972 ◽  
Author(s):  
Tonnar G. Brace ◽  
Milton D. Suboski
Author(s):  
Sergio Morra ◽  
Valentina Epidendio

Abstract. Most of the evidence from previous studies on speeded probed recall supported primacy-gradient models of serial order representation. Two experiments investigated the effect of grouping on speeded probed recall. Six-word lists, followed by a number between 1 and 6, were presented for speeded recall of the word in the position indicated by the number. Grouping was manipulated through interstimulus intervals. In both experiments, a significant Position × Grouping interaction was found in RT. It is concluded that the results are not consistent with models of order representation only based on a primacy gradient. Possible alternative representations of serial order are also discussed; a case is made for a holistic order representation.


2021 ◽  
Vol 11 (5) ◽  
pp. 645
Author(s):  
Andrea Guerra ◽  
Edoardo Vicenzini ◽  
Ettore Cioffi ◽  
Donato Colella ◽  
Antonio Cannavacciuolo ◽  
...  

Recent evidence indicates that transcranial ultrasound stimulation (TUS) modulates sensorimotor cortex excitability. However, no study has assessed possible TUS effects on the excitability of deeper brain areas, such as the brainstem. In this study, we investigated whether TUS delivered on the substantia nigra, superior colliculus, and nucleus raphe magnus modulates the excitability of trigeminal blink reflex, a reliable neurophysiological technique to assess brainstem functions in humans. The recovery cycle of the trigeminal blink reflex (interstimulus intervals of 250 and 500 ms) was tested before (T0), and 3 (T1) and 30 min (T2) after TUS. The effects of substantia nigra-TUS, superior colliculus-TUS, nucleus raphe magnus-TUS and sham-TUS were assessed in separate and randomized sessions. In the superior colliculus-TUS session, the conditioned R2 area increased at T1 compared with T0, while T2 and T0 values did not differ. Results were independent of the interstimulus intervals tested and were not related to trigeminal blink reflex baseline (T0) excitability. Conversely, the conditioned R2 area was comparable at T0, T1, and T2 in the nucleus raphe magnus-TUS and substantia nigra-TUS sessions. Our findings demonstrate that the excitability of brainstem circuits, as evaluated by testing the recovery cycle of the trigeminal blink reflex, can be increased by TUS. This result may reflect the modulation of inhibitory interneurons within the superior colliculus.


1976 ◽  
Vol 42 (3) ◽  
pp. 919-928 ◽  
Author(s):  
Eleanor B. Simon

This 26 factorial experiment investigated the primacy effect in the orienting response. The type of stimuli (tone or “music”), stimulus intensities (loud or soft), length of adaptation period (same, 5 or 30 sec.; or different, 5 min.), interstimulus intervals (5 or 30 sec.), and sex were studied. College students, 32 males and 32 females were randomly assigned to each group. In the same condition, the tone (or music) was soft (or loud) for 5 sec. (or 30 sec.) in adaptation and was then changed alternately without interruption to loud, soft, etc. (or soft, loud, etc.) for 5 sec. (or 30 sec.). The different condition was identical except for the length of the adaptation period in which the stimuli sounded continuously for 5 min. Analyses of the GSR manifestation of the orienting responses indicated: (a) an over-all primacy effect with the auditory stimuli and (b) the primacy effect occurred in the 5-sec.-same but not in the 30-sec.-same condition as predicted.


2017 ◽  
Vol 123 (6) ◽  
pp. 1451-1460 ◽  
Author(s):  
Alessandro Messere ◽  
Gianluca Ceravolo ◽  
Walter Franco ◽  
Daniela Maffiodo ◽  
Carlo Ferraresi ◽  
...  

The rapid hyperemia evoked by muscle compression is short lived and was recently shown to undergo a rapid decrease even in spite of continuing mechanical stimulation. The present study aims at investigating the mechanisms underlying this attenuation, which include local metabolic mechanisms, desensitization of mechanosensitive pathways, and reduced efficacy of the muscle pump. In 10 healthy subjects, short sequences of mechanical compressions ( n = 3–6; 150 mmHg) of the lower leg were delivered at different interstimulus intervals (ranging from 20 to 160 s) through a customized pneumatic device. Hemodynamic monitoring included near-infrared spectroscopy, detecting tissue oxygenation and blood volume in calf muscles, and simultaneous echo-Doppler measurement of arterial (superficial femoral artery) and venous (femoral vein) blood flow. The results indicate that 1) a long-lasting (>100 s) increase in local tissue oxygenation follows compression-induced hyperemia, 2) compression-induced hyperemia exhibits different patterns of attenuation depending on the interstimulus interval, 3) the amplitude of the hyperemia is not correlated with the amount of blood volume displaced by the compression, and 4) the extent of attenuation negatively correlates with tissue oxygenation ( r = −0,78, P < 0.05). Increased tissue oxygenation appears to be the key factor for the attenuation of hyperemia upon repetitive compressive stimulation. Tissue oxygenation monitoring is suggested as a useful integration in medical treatments aimed at improving local circulation by repetitive tissue compression. NEW & NOTEWORTHY This study shows that 1) the hyperemia induced by muscle compression produces a long-lasting increase in tissue oxygenation, 2) the hyperemia produced by subsequent muscle compressions exhibits different patterns of attenuation at different interstimulus intervals, and 3) the extent of attenuation of the compression-induced hyperemia is proportional to the level of oxygenation achieved in the tissue. The results support the concept that tissue oxygenation is a key variable in blood flow regulation.


Perception ◽  
1981 ◽  
Vol 10 (6) ◽  
pp. 695-702 ◽  
Author(s):  
William Epstein

Judgments were obtained of the surface texture and rotation in depth of a briefly-exposed monocularly-viewed rectangular grid rotated in depth and a set of projective equivalents of the grid presented in the frontalparallel plane. The judgments were secured when the grids were presented alone and when they were followed by a masking textured surface after interstimulus intervals (ISIs) ranging from 0 to 120 ms. In the absence of the mask judged texture varied corresponding to the variations of optical texture both for the rotated rectangular grids and the frontalparallel projections. Judgements of orientation in the absence of the mask varied corresponding to the variations in objective orientation for the rectangular grid and corresponding to the projective equivalent rotations for the frontalparallel projections. Introduction of the mask at ISI = 0 led to disruption of discriminative gradient and orientation judgments. The degree of disruption decreased as ISI increased. These findings were interpreted as supporting a mediational hypothesis of the relationship between optical texture and perceived slant-in-depth. In contrast to the direct perception hypothesis advanced by Gibson, the mediational hypothesis assigns an important role to the perceptual representation of the optical gradient. When the formation of this representation is arrested by processing of the mask, the relationship between optical texture and perceived slant-in-depth is disrupted.


2003 ◽  
Vol 114 (8) ◽  
pp. 1513-1520 ◽  
Author(s):  
Toshiaki Onitsuka ◽  
Hideaki Ninomiya ◽  
Eigo Sato ◽  
Tomoya Yamamoto ◽  
Nobutada Tashiro

2011 ◽  
Vol 1411 ◽  
pp. 65-75 ◽  
Author(s):  
Linda V. Heinemann ◽  
Jochen Kaiser ◽  
Christian F. Altmann

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