On the relation between metacontrast masking and suppression of visible persistence

Does the introduction of additional contours in a display sequence (an operation known to reduce the strength of suppression in metacontrast) also reduce suppression of visible persistence? In three experiments, duration of visible persistence was estimated by a method in which successful performance depends on the temporal integration of a pattern whose elements are displayed in two successive frames. In this procedure, the arrival of the trailing frame is known to exert a suppressive influence on the visible persistence of the leading frame. Embedding the elements of the leading frame within additional contours (a line grid) reduced the degree of suppression exerted by the trailing frame. This did not occur when the grid was part of the trailing display. We conclude that suppression of visible persistence and metacontrast masking belong to the same class of events.     

2-Deoxy-d-Galactose Effects on Passive Avoidance Memorization in the Rat

2-Deoxy-d-galactose (do-gal) hinders glycoprotein fucosylation. This compound was intracerebroventricularly administered to male adult Wistar rats in order to assess whether it could exert amnesic effects on a passive avoidance response (PAR) to be learned in the light–dark box apparatus. Three experiments were performed. In the first, do-gal was administered immediately after the acquisition trials at three dosages (2, 4, and 8 μmol). It was found that only the 4-μmol dosage was followed by PAR disruption. In the second, do-gal was administered at the adequate dosage (4 μmol) either 30 min before the acquisition trial or 30 min before retrieval testing. It was found that only the preretrieval administration was followed by PAR impairment. In the third, do-gal (4 μmol) was administered in postacquisition, at increasing postacquisition delays (0.25, 1.5, 4, and 6 h). It was found that there was PAR disruption only after do-gal administration at the shortest (0.25 h) delay. The results confirm that in the rat, glycoprotein fucosylation is involved in some of the phases of memory trace processing, and they are discussed in relation to other findings in the rat and the chick.     

Perfect MV-algebras are categorically equivalent to abelianl-groups

In this paper we prove that the category of abelianl-groups is equivalent to the category of perfect MV-algebras. Furthermore, we give a finite equational axiomatization of the variety generated by perfect MV-algebras.Presented byDaniele Mundici     

“打”出来的手机成瘾？父母粗暴养育对青少年智能手机成瘾的作用

对湖北省两所中学3219名初一至初三年级学生进行问卷调查,建立结构方程模型考察父母粗暴养育、核心自我评价、友谊质量和青少年智能手机成瘾的关系。结果发现：（1）核心自我评价在父母粗暴养育和青少年智能手机成瘾之间起部分中介作用,即父母粗暴养育既对青少年智能手机成瘾产生直接影响,也通过核心自我评价对青少年智能手机成瘾产生间接影响;（2）父母粗暴养育和核心自我评价的关系（中介作用的前半段路径）受到友谊质量的调节,即在高友谊质量和低友谊质量条件下,随着粗暴养育程度的增加,青少年核心自我评价均显著下降,但在高友谊质量的条件下,下降的程度更高。研究结果有助于揭示父母粗暴养育对青少年智能手机成瘾的影响及其作用机制,为预防和干预青少年智能手机成瘾带来一些重要的启示。     

One-trial conditioned suppression: effects of instructions on extinction

Two experimental groups of undergraduate volunteers received a single Pavlovian conditioning trial consisting of a paired presentation of a tone conditioned stimulus (CS) and a shock unconditioned stimulus (UCS). Control groups received either the CS alone or the UCS alone. Subjects from one experimental group were subsequently instructed that they would not receive further shocks, while the other experimental group received no such instructions. The CS alone was then presented once to all four groups while subjects were engaged in a button-pressing task maintained by slide reinforcement. During the latter phase, rate of button-pressing was measured. Classically conditioned suppression of button-pressing was obtained in the noninstructed experimental group but not in the instructed group. The results demonstrate that suppression can be a sensitive index of Pavlovian conditioning in humans but question the use of conditioned suppression as an adequate experimental analog of clinically observed anxiety-motivated behavior.     

Learning capacities during sleep: A preliminary study in a group of schizophrenic inpatients

The relationship between sleep and learning processes is analysed in a sample of schizophrenic patients, starting from more recent hypotheses about the function of REM sleep in learning and memory processes. This is done by means of two experiments: in the first AA. evaluate the possibility to elicit a simple motor conditional reflex acquired during daytime in different sleep stages. With the second experiment daytime learning performances are evaluated with and without a reinforcement administered during REM sleep. Results for the first experiment underline a qualitative difference between REM and nREM sleep in a reflexological perspective. In nREM sleep the conditional response is better maintained than in REM sleep. The second experiment confirms the possibility to improve daytime learning performances after an additional presentation of learning material in REM. The joint study of sleep abnormalities and learning and cognitive impairment in schizophrenic patients is finally suggested.     

Selective deficit of conceptual structures in aphasia: Class versus thematic relations

Conceptual structures in aphasia were investigated by means of a nonverbal test. The understanding of class and thematic relationships was demonstrated to be selectively impaired according to varieties of aphasic deficit. Broca's aphasics showed difficulty evaluating a thematic relationship and did not differ from normal controls as far as class relationships were concerned. The opposite happened for Wernicke's aphasics whose defect seems to be selectively restricted to class relationships.     

Hemispheric symmetry in duration of visible persistence

Nine right-handed subjects performed a visual task requiring perceptual integration of a pattern whose parts were displayed sequentially in time. Correct performance on the task depended critically on the simultaneous visibility of all parts of the pattern; duration of visible persistence could therefore be gauged by varying the duration of the temporal interval between successive portions of the display. The pattern was displayed either foveally or parafoveally in either visual field. Analysis of overall performance and of distribution of errors at each temporal interval revealed more accurate performance for foveal displays but no hemispheric asymmetries in duration of visible persistence. These and other results reported in the literature are interpreted in terms of Moscovitch’s (1979) information-processing model of hemispheric functioning.     

Duration of visible persistence in relation to range of spatial frequencies

Five experiments examined the relationship between range of spatial frequencies contained in a visual display and duration of visible persistence. The high spatial frequency contents of the display were reduced by defocusing the image at the retina. Duration of visible persistence was measured by a task that required perceptual integration of a pattern whose parts were displayed sequentially in time. Experiments 1 and 2 showed that progressive reductions in the high-frequency contents of the display produced corresponding decrements in the duration of visible persistence. Experiments 3, 4, 5 showed that decrements in the duration of visible persistence could not be attributed to changes in the apparent size or in the brightness of the display brought about by defocusing. The results were interpreted in terms of the temporal response properties of perceptual mechanisms attuned to separate ranges of spatial frequencies. Strong parallels were drawn with the multichannel theory of visual information processing proposed by Breitmeyer and Ganz.     

Selective semantic-lexical impairment of language comprehension in right-brain-damaged patients

Fifty right-brain-damaged patients and thirty-nine normal controls were given two tests of semantic-lexical discrimination (auditory language comprehension and reading comprehension) and a test of phoneme discrimination. The aims of the research consisted in checking: (A) if right-brain-damaged patients are significantly more impaired than normal controls on the tasks of semantic discrimination even when the influence of associated variables (such as unilateral spatial neglect or general mental impairment) is ruled out; and (B) if semantic-lexical disorders of right-brain-damaged patients are selective or if they are associated with disorders of phoneme discrimination. Results have shown that right hemispheric lesions consistently impair semantic-lexical discrimination but do not hamper phoneme discrimination. Some implications of these results are discussed.