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- P-ISSN1226-9654
- E-ISSN2733-466X
- KCI
ISSN : 1226-9654
Vol.9 No.1
Abstract
The function of attention has been characterized in terms of target selection. As a mechanism of target selection, inhibition of the non-targets or distractors in a display has been proposed. The negative priming (NP) effect has been regarded as evidence for the attentional inhibition. Park & Kanwisher(1994), however, have shown that NP for spatial locations is independent of prime target selection. The same results were obtained for a non-spatial task modeled after Fox(1994) : NP resulted without the prime target selection (Experiment 1) ; when subjects arbitrarily selected one of two candidate targets, the unselected target caused facilitation, rather than NP (Experiment 2) ; NP was observed even when there was no response requirement to the prime display (Experiment 3). These results, together with those of Patk & Kanwisher(1994), cast doubt on the distractor inhibition hypothesis. The proponents for the distractor inhibition hypothesis, must propose a better explanation specifying what is inhibited and why it is inhibited.
Abstract
This paper reviews contemporary research findings concerning factors which are known to affect P3 variability. Based on the review, this paper also develops a set of recommendations which could properly handle such noisy factors and thus accurately measure the P3 component especially in clinical populations. The P3 event-related brain potential (ERP) provides an easily obtained, noninvasive neuroelectric measure of cognitive function. This component is sensitive to the cognitive changes resulting from normal aging and the mental decline associated with dementia and other cognitive disorders. The relationship between the P3 ERP and the cognitive dysfunction found in dementing illness is reviewed to provide the context for discussion of the theoretical meaning, appropriate methods, and measurement of the P3 component in clinical populations. However, successful clinical application of the P3 component requires that (1) it be recorded with correct technical parameters; and (2) sufficient control over extraneous factors be also exercised for more accurate amplitude and latency measures. The paper concludes that the P3 ERP can provide useful information about cognitive function in a clinical settings only under the conditions that acceptable P3 data are guaranteed through careful consideration of the methodological, biological factors and that the clinical capabilities of this cognitive brain potential are evaluated properly
Abstract
A new animal model is proposed of neuropathic pain in rats. In this model, damage to the tibial and sural nerves produces behavioral and electrophysiological signs of profound pain. In the experiment, under pentobarbital anesthesia, male Sprague-Dawley rats were subjected to surgical injuries to the tibial and sural nerves by tightly ligating and then sectioning out 10mm-long part of each nerve. The rats showed apparent signs of spontaneous pain. They also showed mechanical allodynia in responding to von Frey filament stimulation and cold allodynia to aceton treatment when these treatments were given to the paws of the injured side. The neuronal responses in the L4 or L5 spinal cord were further recorded with sympathetic manipulations, intravenous injection of phentolamine, an alpha-antagonist, or electrical stimulation of the preganglionic nerve fibers in order to determine whether the neuropathic pain in this model is a sympathetically maintained (SMP) or sympathetically independent pain (SIP). Neither manipulation resulted in any significant change in the neuronal response, which suggests that the sympathetic nervous system is not involved in the development of neuropathic pain in this model. In conclusion the new animal model has been consistant in producing neuropathic behaviors and seems useful for the investigation of sympathetically independent pain.
Abstract
According to the localization hypothesis(Tsal, 1989), attention merely facilitates feature localization porcesses, not the feature integration. In two visual conjunctive-target search tasks, subjects were previewed with the display containing half of features(color or form) of each item before presenting the full conjunction display. The hypothesis predicts that search slope in the preview condition would be reduced in half. However, the results failed to confirm the prediction, suggesting that feature localization alone may not be sufficient for conjunctive search.
Abstract
We recorded multiple-unit activities (MU As) in the cerebellar interpositus nucleus(INT) and the dorsal accessory inferior olive(DAO) simultaneously to investigate dynamic functional cooperation of cerebellum and brain stem structures. MU As were monitored during delay conditioning(ISI=300msec) following trace conditioning(ISI=700msec). Behavioral and neuronal data were divided into four categories based on the stimuli presented and the response performed in each trials :CS(Conditioned Stimulus)-only trials, US(unconditioned stimulus)-only trials, CR(conditioned response)-paired trials, and noCR-paired trials. We made the smoothing curve by Savitzky-Golay method and the fitting curve by multiple Gaussian functions from 4 msec time bin histogram of neuronal activities to compare and analyze time correlation. In both sites, conditioning-related activities were developed in CR-trials but not in noCR-trials. These activities are preceding behavioral CR with different time lead. Rather than an increase, CS period-activities of INT in noCR trials are reduced after CR acquisition. INT may participate directly in motor command for CR. DAO showed large US-evoked activity, which remained unchanged during training. The presence of CR-related DAO activity suggests that DAO may receive CR-related feedback information from cerebellum and provide CR-related information to cerebellum. Conditioning-related neuronal activities established m DAO were lasting continuously. These activities suggest that lower level of brain structures involve actively in producing CR.
Abstract
As a hybrid view rule and similarity between exemplars both have an influence on categorization has been prevalent, studies to find out factors deciding on categorization strategies have been increasing. This study planned to investigate whether attention to attributes decide on categorization strategies. In Experiment 1, attention to attributes was manipulated by presenting stimulus as a whole(high cohesiveness condition) or as attributes separated(low cohesiveness condition). Results showed that linear separable categories were learned more rapidly than linear nonseparable categories in low cohesiveness condition but the reverse was true in high cohesiveness condition. In Experiment 2, subject's attention to attributes was manipulated by two instruction conditions. We found that error rates of negative transfer condition and differences between two cohesiveness conditions were greater in the rule instruction condition than in the simple categorization instruction condition. These results implies that factors having an influence on attention to attributes decide on categorization strategies.
Abstract
The present experiment examined whether the amount of conditioned fear acquired in active avoidance learning varies with the degree of avoidance training. Fear-potentiated startle paradigm was used to measure the amount of conditioned fear. Rats were given 30 active avoidance training trials per day for 1, 2, 4, or 8 days using a light CS arid footshock US. After the training, fear-potentiated startle test was conducted for 3 days. The animals learned active avoidance rapidly, reaching an asymptote by the second day of training. In the Hist potentiated startle test, the conditioned fear to the CS was significant for all the training groups except for the 1-day training group. The conditioned fear extinguished gradually across the three tests. In each test, the amount of conditioned fear was not uniform, but gradually increased (test 1) or decreased (test 2) as the test proceeded. The main purpose of this study was to examine if overtraining of an active avoidance response eliminates or reduces conditioned fear to the CS used in the training, but the results indicated that there was no difference among the 2, 4, and 8-day training groups.
Abstract
This study investigated the effects of diazepam and ethanol on the conditioned freezing in Sparague-Dawley male rats, using 2-trial conditioned fear test. On the training day, each rat was placed in the observation chamber and 3 min later received shock eight times(1s, 0.6mA) at a VI-3.75 min. schedule. Behavior was observed two times for 10 min immediately after the eight shocks and in the retention test of the next day, according to a time-sampling procedure. During the first observation period, diazepam 5.0mg/kg, ethanol 0.6g/kg or ethanol 1.2g/kg decreased freezing response immediately following the shocks. Animals injected with diazepam 2.0mg/kg, diazepam 5.0mg/kg or ethanol 1.2g/kg on the training day showed a significant decrease in freezing response in retention test under the same drug or saline. This finding that both diazepam and ethanol attenuated the conditioned freezing response suggested that the anxiolytic effect of both diazepam and ethanol is mediated by a common underlying process.
Abstract
Two experiments used recognition and copy tests in order to explore the roles of attention in explicit and implicit memory of irrelevant forms that were ignored on the previous same-different matching task. Relative brightness between the relevant and the irrelevant forms that were overlapped was manipulated in two experiments. The relative brightness selectively influenced the presence or absence of priming effects in the implicit copy test. Our results indicate bottom-up attention capture might be responsible for implicit form memory, whereas top-down attention allocation might be responsible for explicit form memory.
Abstract
While most neurological models of schizophrenia have focused on cerebral functions, cerebellar atropy, especially in vermis has been repeatedly reported in schizophrenic patients from brain imaging and lesion studies. Cerebellar vermis has been implicated for adaptive control of saccadic eye movements, which has not been studied in schizophrenics to our knowlege. We investigated saccadic adaptation using double-step paradigm in 5 schizophrenic patients and 5 normal control. Gaze and head movements were recorded v/ith scleral search coil method in head-free condition. Time course of adaptation in schizoprenics was similar to that of control, but it never reached to the complete level of adaptation seen in control, and accordingly gaze gain (gaze amplitude/target amplitude) was low even after 600 adaptative trials. Head contribution to gaze saccade was relatively low and time to peak head velocity was longer in schizophrenics suggesting a different strategy of gaze control. Variability across patients iii adaptation parameters need to be further investigated in combination with cerebellar volumetry.
Abstract
Two<sup>***</sup>Present study was intended to explore the boundary condition of the list-strength effect, that is repeated items in a list inhibit recall of nonrepeated items. The results of seven experiments showed that mere presence of repeated items in a list is not necessary condition of the list-strength effect. List-strength effects were found when intralist repetition with relatively large set size occurred in a block and close to test. Repeated items were recalled significantly earlier than nonrepeated items in output positions of recall curve. Thus, temporal cue should be considered as a constraint of the list-strength effect in recall. No current memory model seem to explain such boundary conditions of the effect.
Abstract
ERP reflects activity originating within the brain. In the present study, we investigated the effects of task performance and 75dB noise on P200 as well as on behavioral performance during visuo-spatial detection tasks. The effects of conifer needle odor and soundguard on ERP and task were also investigated. The results showed that P200 mean amplitude evoked by target stimuli was larger than that by standstimuli on Fz, Cz and Pz. P200 amplitude recorded on Cz and Pz was larger than that on Fz. In no noise condition, ?200 amplitude by target stimuli on Fz, Cz was larger that by the standard stimuli in confer needle odor and soundgurard than in control condition. In noise condition, The results of P200 amplitude shows that target stimluli requires more initial information processing and attention than standard stimluli, The behavioral task performance in soundguard condition was more accurate than that in control condition. In soundguard condition, behavioral performance was increased. P200 evoked in conifer needles and soundguard were interpreted as early information processing or attention.
Abstract
The purpose of this study was to investigate the role of syllables on speech perception in Korean language. In Experiment 1 using syllable monitoring task, it was found that subjects detected CVC targets from CVC-CVC words more easily than CV targets while the response times for CV and CVC targets from CV-CVC or CVC-CV words did show very small difference. Experiment 2 was conducted to investigate the speech segmentation of irregular words. The types of irregular words used were syllable adjustment, apiration, nasalization, and liquidization. The results showed that monitoring times for irregular words was of the same pattern as those for regular words except in the condition of liquidization. It was suggested that deep syllables, or morphological syllables, can be used in speech segmentation and that speech segmentation processes in Korean language has many features that other languages do not have.
Abstract
This study compared the activation view with acquisition view of implicit memory by examining the priming of lexical and nonlexical components of Korean words. In Experiments 1-2, levels-of-processing(LOP) was manipulated at encoding stage and subjects performed a word fragment completion(WFC : implicit memory) and a recognition(explicit memory) task in which the targets were meaning- and orthographically-related components or only orthographically-related components of the primes. The targets were word fragments of first two letters(beginning component) (Experiment I) or those of last two letters(ending component) (Experiment 2) in three-letters primes. The results indicated that LOP had a large effect on recognition but no effect on WFC. Also, priming was obtained for orthographically-related beginning components even though it was smaller than that for meaning-related beginning components in Experiment 1, and priming was obtained only for meaning-related ending components in Experiment 2. These results were replicated in Experiment 3 using a perceptual identification(PI) task. In Experiment 4 using a PI task in which the targets were orthographically-related nonword components, priming was obtained for beginning components. Both acquisition of new representations of nonlexical(orthographic) components and activation of preexisting lexical(meaning) components appear to contribute to priming.
Abstract
The present study examined how the syntactic and pragmatic constraints, and working memory affected to the representation of sentence constituents. Relative sentences with 3 nouns and 2 verbs were used to see the effects of the three constraints together. The strengths of the effects were measured by the reaction time to recognize one of the three nouns. In experiment 1, center-embedded relative sentences(SOV/OO, OSV/SO) were used. The results were: First, syntactic and pragmatic constraints affected to the nouns with equal strength. Second, the effect of working memory was not observed. Third, the main clause was processed more because of the limit of the processing capacity. In experiment 2, to see the effect of working memory, left-branching relative sentences(SOV/SO, OSV/OO) was used. The results were: First, in the SOV/SO, the accessibility of the sentence nouns was not varied, because of the canonical(subject-object) order of the subordinate clause. Second, in the OSV/OO, the accessibility of the thee nouns was all different, and that pragmatic constraints affected the representation of the sentence constituents mote than the working memory. The results of experiment 1 and 2 provides that syntactic and pragmatic constraints affect the representation with the same intensity, and the working memory affects less than the two constraints. However, the accuracy of recognition shows the effects of working memory.
Abstract
This study was conducted to find out the integrative processing between pronoun resolution and script knowledge using time-course paradigm. In Experiment la (immediate condition) and Experiment lb (delay 250ms condition), the result was that the target words of reference resolution was faster than the target words of script knowledge in lexical decision response time. In Experiment 2 (delay 500ms condition), the result was that the target words of reference resolution was faster than the target words of script knowledge and interaction of processing type and word type in response time. In Experiment 3 (delay 1000ms condition), the result was that the antecedent words of reference resolution was faster than the non-antecedent words of reference resolution in response time. In Experiment 4, compared response time of knowledge and control word in immediate condition and delay 1000ms condition, the result was that the knowledge words was faster than the control words. The results of this study were explained by spreading-integrative elaboration framework.