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Results for “Proactive Inhibition”

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At least 199 records · Page 11Linked to original sources
PubMed1996

Improving text memory by organizing interfering text at retrieval.

We provide evidence that information that organizes interfering text after learning improves recall of original text to which the organizing information does not pertain. Subjects learned two text passages. The second passage was difficult to understand without the aid of a picture that provided the necessary clarifying context. Using the picture as an organizing cue for the second passage (just before retrieval of the first passage) improved recall of the first passage. We address and rule out an alternate explanation that is based on the difficulty of the task immediately preceding recall. These results contradict several traditional hypotheses about interference, and they are difficult to explain with several current models of memory. Implications for learning are discussed.

Adult↗
PubMedDate not supplied

[The effects of proactive interference in the task of spatial choice in a Y maze by rats].

The influence of the preceding conditioned reaction on the current conditioned performance was studied. Rats were trained to perform delayed and non-delayed spatial tasks in Y-maze. Two types of errors were analyzed: 1) the rats ran to the same maze arm as in the previous trial (errors of repetition), 2) the animals ran to the other arm (errors of alternation). It was shown that the alternation errors were more frequent under conditions of short intertrial interval and non-delayed choice. The repetition errors occurred more frequently under conditions of long intertrial interval and delayed choice. The obtained evidence supports the idea that not only cue presentation and delay periods are important for successful performance but the whole structure of the task influences the complex organization of the behavioural acts.

Animals↗
PubMedDate not supplied

[Strengthening interhemispheric interferential inhibition in man with diazepam].

The influence of oral diazepam administration (10 mg) on interhemispheric proactive and retroactive interferential inhibition during detection of test verbal signals was tachistoscopally studied in eight healthy right-handed subjects, in conditions of forward and backward contralateral masking according to the scheme of double blind investigations. Strengthening of effects of forward and backward contralateral masking was revealed which is considered as a testimony to participation of GABA-ergic inhibitory systems in the mechanisms of interhemispheric proactive and retroactive interferential inhibition.

Adult↗
PubMed2005

Can the location negative priming process operate in a proactive manner?

The location negative priming (NP) effect refers to the fact that the processing of a current target stimulus (probe trial) is delayed when it appears at a location that has recently contained a distractor event (prime trial), relative to when it occurs at a previously unoccupied position. One view is that the process causing the NP effect involves the inhibition of the internal representation of the prime-distractor event, and that the future processing of target stimuli that involve this event are prolonged because this distractor inhibition is persistent. In this study, we examined the possibility that the NP process (inhibition) could act proactively; specifically asking whether inhibition could be allocated to a location merely predicted to hold a future distractor event. To do this, we cued the probe distractor's location using an otherwise traditional location NP paradigm. No evidence of a proactive NP process was obtained. Probe-trial target latency was the same whether it appeared at the cued distractor location or at a new location, but was delayed when it occupied the prime-distractor location (NP effect). The location NP process is seemingly a reactive one, applying inhibition only when an actual distractor is present, much as past theories have implied.

Attention↗
PubMed1997

Effects of triazolam and ethanol on proactive interference: evidence for an impairment in retrieval inhibition.

The effects of two memory-impairing drugs, ethanol and triazolam, on proactive interference (PI) in memory were studied. Following ingestion of either one of these drugs or a placebo, subjects studied an A-B list (e.g., BEE-WASP) of paired associates, followed by an A-C list (e.g., BEE-HONEY) on the interference trial, and a D-E list (e.g., KING-QUEEN) followed by an A-C list on the control trial. A PI effect was found in the data, such that subjects produced fewer correct second list targets on the interference trial than on the control trial. Neither ethanol nor triazolam was found to influence the size of the PI effect. However, both drugs were found to increase B intrusions on the test of the A-C list, to impair subjects' ability to produce more than one studied response for each cue word, and to impair the subjective experience of retrieved memory information. These data suggest that ethanol and triazolam impair an inhibitory process that normally operates as one component of intentional retrieval, playing an important role in the suppression of unwanted information during a memory task.

Adult↗
PubMed2005

Neural mechanism in anterior prefrontal cortex for inhibition of prolonged set interference.

Once one cognitive set dominates our behavior, it continues to influence subsequent behavior for a while even after a task to be performed is changed to another. Despite abundant knowledge of the inhibitory mechanisms that are recruited at the first trial after the change (the first inhibition trial), little is known about the inhibition of prolonged proactive interference from a previous set that lingers for several trials after the first inhibition trial. The present functional MRI study explored the neural mechanisms for inhibition of a previous set that were recruited after the first inhibition trial. A modified Wisconsin Card Sorting Test was used where "dual-match stimuli" were intermittently presented and allowed subjects to perform correctly based on previously appropriate, now inappropriate, responses. In response to the dual-match stimulus at "release" trials presented after the first inhibition trials, the subjects were transiently exempted from inhibiting the prolonged previous set. As expected from the exempted inhibitory demands, significant reaction time decrease was revealed in the release trials. Consistent with the behavioral results, transient signal decrease time-locked to the release trials was revealed in the left anterior part of the superior frontal sulcus. Moreover, the anterior prefrontal region was not sensitive to the task change, which exhibited a marked contrast to the left posterior inferior prefrontal region that showed significant signal changes in both events. These results revealed multiple inhibitory mechanisms in the lateral prefrontal cortex that are recruited in different temporal contexts of the interference from a previous cognitive set.

Adult↗
PubMedDate not supplied

Frontal cortex as the central executive of working memory: time to revise our view.

For historical reasons (Bianchi, 1895; Harlow, 1968; Luria, 1966; Shallice, 1982), a specific link between the central executive of working memory and the frontal cortex was originally suggested by Baddeley (1986). This review discusses the evidence against such a univocal link. Two executive processes investigated in neuropsychology are discussed: inhibition (WCST, Stroop, proactive interference, go-no go, Stop signal and the Hayling test) and dual-task management. The evidence reviewed demonstrates (i) that executive processes involve links between different brain areas, not exclusively with the frontal cortex, (ii) that patients with no evidence of frontal damage present with executive deficits, and (iii) that patients with frontal lesions do not always show executive deficits. In conclusion, this review suggests that it is time for a more dynamic and flexible view of the neural substrate of executive processes to be considered. It also confirms, as recently suggested by Baddeley (1996, 1998a, 1998b), that the study of frontal patients cannot be used as a primary source of evidence to understand CE functions.

Attention↗
PubMed1987

Effect on gait of motor task learning acquired in a sitting position.

The purpose of this study was to ascertain the importance of learning a motor task in a sitting position and its influence on gait. Thirty-one healthy subjects, divided into three groups, were asked to learn a synchronous heel-up-heel-down rhythm task in a sitting position and to reproduce the rhythm during their gait cycle on three separate occasions over a three-day period. This study provided evidence that training of a subject in a sitting position produced a nonspecific influence during ambulation. The inability to obtain an exact transfer of learning from a sitting position to gait and its implication to the specificity principle of learning are discussed. Some subjects had difficulty maintaining their performance over the three-day period. This finding was attributed in part to the influence of proactive and retroactive inhibition. Mat activities, therefore, seem to have a very limited impact on modifying gait. The clinical implications of these findings are presented.

Adult↗
PubMed1990

The history of memory arts.

Ancient humans, lacking devices to store large amounts of information, invented and developed a system of mnemonics which evolved and passed to modern times. The mnemonics, collectively known as the Ancient Art of Memory, were discovered in 447 BC by a Greek poet, Simonides, and were adequately described by Cicero, Quintilian, and Pliny. These arts fell into neglect after Alaric sacked Rome in 410 AD, but were subsequently revived in 1323 by Saint Thomas Aquinas, who transferred them from a division of rhetoric to ethics and used them to recall Catholic doctrine and versions of biblical history. In 1540 Saint Ignatius Loyola used mnemonic images to affirm the faith with his newly formed Society of Jesus and tried to convert the Ming dynasty in China by teaching these memory skills to Chinese nobles. Today, the ancient memory arts have applications in pilot training, gambling, mentalism and telepathy demonstrations, and may have a role in the rehabilitation of brain-damaged patients. Objective testing confirms that with the use of these memory skills, recall is increased, at least 10-fold, and the memory deficits of proactive and retroactive inhibition do not exist.

History, 19th Century↗
PubMed1982

Fractionation of Limulus amebocyte lysate. Characterization of activation of the proclotting enzyme by an endotoxin-mediated activator.

Limulus amebocyte lysate was fractionated by heparin-Sepharose chromatography into four components (fractions A, B, C and D). Major coagulation factors, i.e., proclotting enzyme, coagulogen, and proclotting enzyme activating factor precursor (proactivator) in the lysate were eluted, respectively, in fraction A, fraction B and fraction C. Clotting enzyme activity was detected only following recombination of fraction A and fraction C in the presence of endotoxin. The conversion of proactivator to its active form (activator) was an endotoxin-dependent reaction and was inhibited by polymyxin B. Either proactivator is an endotoxin-sensitive factor or another endotoxin-sensitive factor, which activates proactivator, is present in fraction C. Optimal pH for proclotting enzyme activation by activator was broad and ranged from pH 6.0 to 8.0, while that for the endotoxin-mediated activation of proactivator was pH 7.0. No initial latent period was observed during activation of the proactivator or proenzyme. The activator was inhibited by benzamidine, leupeptin, soybean trypsin inhibitor and diisopropyl fluorophosphate, suggesting that the activator is a trypsin-type serine protease. Trypsin, but not thrombin, urokinase, plasmin, papain or alpha-chymotrypsin activated the proclotting enzyme. Therefore, limited proteolysis, i.e., of an arginyl- or lysyl-X bond(s), of the proenzyme molecule is probably involved in its activation.

Animals↗
PubMed1983

[Accelerated forgetting and increased proactive interference after long-term alcohol consumption in the mouse].

Male Mice of the BALB/c strain were given a solution of 15% ethanol as its only source of fluid for 8 months. 2 months after alcohols was omitted from the diet they were tested for memory and compared to two control groups which received either an isocaloric solution of sucrose or tap water. Memory was tested by using spontaneous alternation (S.A.) in a T maze as a learning paradigm involving two forced trials (acquisition) followed by a free trial (retention). The 1st experiment was aimed at studying the spontaneous alteration rate as a function of the acquisition-test interval. It was found that for a short interval (5 min) the S.A. rate did not differ between the experimental aid control subjects but that it decreases more rapidly over time (1 h and 24 h) in alcohol treated subjects. The second experiment was aimed at determining whether this accelerated forgetting might not be explained by an excess of proactive interference. Results showed that when experimental subjects remembered for 1 h informations associated with a first acquisition, they were no longer able to remember those associated with a second acquisition when the interval between the two acquisitions was 5 h. Such proactive interference was not found in control subjects. These results suggest that, as in humans, prolonged alcohol consumption results in accelerated forgetting and increased proactive interferences.

Alcoholism↗
PubMed2005

Latent inhibition is disrupted by nucleus accumbens shell lesion but is abnormally persistent following entire nucleus accumbens lesion: The neural site controlling the expression and disruption of the stimulus preexposure effect.

Latent inhibition (LI) is the proactive interference of repeated nonreinforced preexposure to a stimulus with subsequent performance on a learning task involving that stimulus. The present experiments investigated the role of the nucleus accumbens (NAC) in LI. LI was measured in a thirst motivated conditioned emotional response procedure with low or high number of conditioning trials, and in two-way active avoidance procedure with the stages of preexposure and conditioning taking place in the same or different contexts. Sham-lesioned rats showed LI with low but not high number of conditioning trials and if preexposure and conditioning took place in the same context but not if the context was changed between the stages. Lesion to the shell subregion of the NAC disrupted LI but LI was preserved in rats with a combined lesion to the NAC shell and core subregions. Moreover, rats with a combined shell-core lesion persisted in showing LI in spite of high number of conditioning trials and in spite of context change. These results show that the NAC is not essential for the acquisition of LI but rather plays a key role in regulating the expression of LI. Moreover, they suggest that the two subregions of the NAC contribute competitively and cooperatively to this process, selecting the response appropriate to the stimulus-no event or the stimulus-reinforcement association in conditioning.

Analysis of Variance↗
PubMed2006

Abnormally persistent latent inhibition induced by lesions to the nucleus accumbens core, basolateral amygdala and orbitofrontal cortex is reversed by clozapine but not by haloperidol.

Latent inhibition (LI) is the proactive interference of inconsequential preexposure to a stimulus with its ability to signal significant events, and disrupted LI is considered to model positive symptoms of schizophrenia. We have recently shown that lesions of the nucleus accumbens core (NACc), basolateral amygdala (BLA) and orbitofrontal cortex (OFC) produce abnormally persistent LI, and suggested that this phenomenon may model negative symptoms. Here we tested whether NACc, BLA and OFC lesion-induced persistent LI would be reversed by the atypical antipsychotic drug (APD) clozapine but not by the typical APD haloperidol. Because clozapine's action is likely reflecting its 5HT2A receptor antagonism, we also tested whether NACc lesion-induced persistent LI would be reversed by the selective 5HT2A antagonist M100907. LI was measured in a conditioned emotional response procedure by comparing suppression of drinking in response to a tone in rats receiving 0 (non-preexposed) or 40 tone presentations (preexposed) followed by five tone-shock pairings. Under these conditions, control rats did not show LI but all lesioned rats persisted in exhibiting LI, and this was reversed by clozapine but not by haloperidol. In addition, M100907 reversed NACc lesion-induced persistent LI. These two novel phenomena, abnormally persistent LI and its selective reversal by an atypical APD, suggest a novel index of schizophrenia relevant behavioral abnormality and of atypical antipsychotic activity in the LI model. The identification of brain regions whose damage leads to persistent LI in the rat may provide valuable cues on dysfunctional brain circuits involved in negative symptoms and in the action of atypical APDs.

Amygdala↗
PubMed1998

The ontogeny of glucocorticoid negative feedback: influence of maternal deprivation.

Glucocorticoid feedback can be viewed as having two modes of operation: proactive and reactive. "Proactive" feedback maintains basal activity of the hypothalamic-pituitary-adrenal axis, whereas the termination of stress-induced hypothalamic-pituitary-adrenal activity is facilitated by "reactive" feedback. In the present study we studied the ontogeny of both feedback modes and tested the hypothesis that the development of feedback depends on mother-pup interaction. On postnatal day 9 or 12, pups were deprived (DEP) of the dam for 24 h; nondeprived pups of the same age served as controls. The pups were adrenalectomized (ADX) at the end of deprivation and given corticosterone (CORT) replacement by either injection or pellet implants using the following two designs: first at the time of adrenalectomy (ADX) to test the role of CORT in the maintenance of basal ACTH levels, and then 3 h after ADX, to investigate CORT suppression of elevated ACTH levels induced by prior ADX. Regarding proactive feedback, the results showed that injection of CORT at the time of ADX was only partially effective in preventing ACTH elevations, whereas CORT pellets maintained basal levels of ACTH in all ADX pups. The reactive mode of negative feedback in nondeprived pups was resistant to CORT injection, whereas the CORT pellet resulted in a return to basal levels within 60 min. Maternal deprivation did not affect proactive feedback, but caused a more sustained increase in ACTH levels and a failure to return to basal levels 3 h after ADX despite significantly higher levels of circulating CORT in these DEP pups. It is concluded that 1) proactive and reactive modes of negative feedback are operative, provided the pups are maintained on chronic replacement with CORT; 2) DEP impairs the reactive, rather than the proactive, mode of feedback inhibition in the neonate.

Adrenalectomy↗