Asystem for cutaneous electrical stimulation mimicking touch

An electrical system is described which produces pain-free touch sensations similar to those from mechanical stimulation. The apparatus is inexpensive, easily constructed, and can be used with human or animal Ss.     

Aversive properties of the negative stimulus during learning with and without errors

In a successive discrimination four groups of pigeons were trained to discriminate between red and green. The groups differed with respect to the procedure used to introduce S?: Early-Progressive, Early-Constant, Late-Progressive, and Late-Constant. The aversive properties of S? were measured by an escape response in which a single peck at a second key terminated S? for 10 sec and darkened the chamber. The correlation between the aversive and error-producing properties of extinction was zero. More errors occurred when S? was introduced abruptly at a constant intensity while more timeouts from S? occurred when S? was introduced late. The procedure for introducing S? rather than the number of responses to S? appears crucial in determining how aversive S? becomes.     

Aversive properties of the negative stimulus in a successive discrimination

Experiment I sought to determine if the stimulus correlated with extinction in a successive discrimination was an aversive stimulus. An escape response provided an index of aversive control. Two groups of pigeons were exposed to a multiple variable-interval 30-sec extinction schedule. For the experimental group, a single peck on a second key produced a timeout during which all lights in the chamber were dark. For the control group, pecks on the second key had no contingency. The rate of responding on the timeout key during extinction for the experimental group was higher than that of the control group during all sessions of discrimination training except the first. In Exp. II, green was correlated with variable interval 30-sec and red was correlated with variable-interval 5-min. Timeouts were obtained from variable-interval 5-min. There were more timeouts from extinction in Exp. I than from variable-interval 5-min in Exp. II. Experiment III showed that not presenting the positive stimulus reduced the number of timeouts from the negative stimulus for the two birds from Exp. I that had the highest rate of timeouts from extinction, but had little effect on the two birds that had the lowest rate of timeouts. These results suggest that in a multiple schedule, the stimulus correlated with extinction, or the lower response rate, functions as a conditioned aversive stimulus. Explanations of the timeout response in terms of extinction produced variability, displaced aggression, and stimulus change, were considered but found inadequate.     

Economic substitutability of electrical brain stimulation, food, and water.

Concurrent variable-ratio schedules of electrical brain stimulation, food, and water were paired in various combinations as reinforcement of rats' lever presses. Relative prices of the concurrent reinforcers were varied by changing the ratio of the response requirements on the two levers. Economic substitutability, measured by the sensitivity of response ratio to changes in relative price, was highest with brain stimulation reinforcement of presses on both levers and lowest with food reinforcement of presses on one lever and water reinforcement of presses on the other. Substitutability with brain stimulation reinforcement of presses on one lever and either food or water reinforcement for presses on the other was about as high as with brain stimulation for presses on both levers. Electrical brain stimulation for rats may thus serve as an economic substitute for two reinforcers, neither of which is substitutable for the other.     

经颅电刺激与视功能调控

经颅电刺激(Transcranial Electrical Stimulation, TES)通过电极将特定模式的低强度电流作用于大脑头皮以调控皮层活动, 是一种非侵入、无创的神经刺激方法。根据刺激电流的模式的不同, TES分为经颅直流电刺激(tDCS), 经颅交流电刺激(tACS)和经颅随机电刺激(tRNS)。TES能对视功能诸如光幻视阈值、视野、对比敏感度、视知觉运动等进行一定程度上的调控, 并且能够与传统的视觉知觉学习训练相结合以调控视觉功能。对于不同的视觉功能, 不同的TES参数和模式的调控效果有所不同。     

Influence of functional electrical stimulation training on premotor and motor reaction time.

This study was designed to investigate the influence of functional electrical stimulation on the improvement of reaction time and its fractionated components during learning an horizontal arm-sweep task. 62 subjects participated and were divided into control, stimulation, and trail/stimulation groups. Functional electrical stimulation was an effective method of improving total reaction time and its central component, premotor time.     

A study of the effects of cranial electrical stimulation on attention and concentration.

There have been several anecdotal accounts that cranial electrical stimulation (CES) enhances attention and the ability to learn new tasks in a normal population, but only one published investigation confirms that CES improves attention using the Alpha Stim CES (Madden and Kirsch, 1987). The purpose of this study was to corroborate the findings of Madden and Kirsch, using more precise measures of attention, such as a Continuous Performance Test (CPT). A pretest and posttest CPT was given to two groups using the LISS CES device. The control group consisted of twenty-one subjects who received the placebo treatment. The experimental group of thirty-one subjects received twenty minutes of CES. Four measures of the CPT show significant gains in attention: Number of Hits, p =.010 Hit RT ISI Change, p =.016, Risk Taking, p =.055; and Attentiveness, p =.054. Based on subjects who demonstrated improvement by one standard deviation on two different measures of the CPT, thirty-one percent of the experimental group improved versus four percent of the control group. The use of CES as a method of increasing attention is a promising area that requires further investigation.     

Spaced food but not electrical brain stimulation induces polydipsia and air licking.

An attempt was made to induce polydipsia in rats whose lever pressing was reinforced with food pellets or electrical brain stimulation. Nine food-deprived, water-sated rats drank water excessively during sessions in which food pellets were delivered. When brain stimulation was substituted for food, drinking immediately ceased. Delivering brain stimulation according to a variety of schedules, pairing brain stimulation with food reinforcement, and substituting an air stream for water, each failed to produce polydipsic licking. These results show that polydipsia is not induced by all reinforcers.     

Infant preferences for attractive faces: a cognitive explanation.

Research on infant face perception has shown that infants' preferences for attractive faces exist well before socialization from parents, peers, and the media can affect these preferences. Four studies assessed a cognitive explanation for the development of attractiveness preferences: cognitive averaging and infant preferences for mathematically averaged faces, or prototypes. Studies 1 and 2 demonstrated that both adults and 6-month-old infants prefer prototypical, mathematically averaged faces. Studies 3 and 4 demonstrated that 6-month-olds can abstract the central tendency from a group of naturalistic faces. Taken together, the studies suggest that infants' preferences for attractive faces can be explained by general information-processing mechanisms.     

Detection by the guinea pig of acoustic stimulation and of electrical stimulation of the brain

A threshold procedure using operant behavioral techniques with positive reinforcement was developed after initial efforts with avoidance behavioral procedures proved unsatisfactory. In the first of three experiments the operant threshold procedure was tested by determining masked auditory thresholds for trains of clicks. In a second experiment, similar techniques were used to measure thresholds for electrical stimulation of the brain. The last experiment, again an auditory problem, involved a determination of the absolute thresholds for trains of short noise bursts as a function of the time between bursts. Middle ear malfunction proved to be a more severe problem than had been anticipated on the basis of reports in the literature. The threshold procedure, however, seems to be adequate for determination of absolute or masked thresholds with auditory or electrical stimuli.