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- P-ISSN1226-9654
- E-ISSN2733-466X
- KCI
ISSN : 1226-9654
Vol.11 No.1
Abstract
The image of an object in central visual field is projected to both eyes. According to the way two retinal image were projected to the brain, binocular visual field can be classified into two regions:unilaterally projected visual field(UPVF) and bilaterally projected visual field(BPVF). Considering the fact that it is necessary to compare two retinal images for computing the binocular disparity, disparity processing of the objects in BPVF may differ from that of the objects in UPVF. We investigated the solution of correspondence problem of objects and measured stereoscopic depth of an object in UPVF and in BPVF, respectively. Unlike an object in UPVF, object in BPVF was always perceived as double images at the depth corresponding to its half disparity, not its disparity. These results imply that at the stage of disparity processing bilaterally projected binocular images are not combined through corpus callosum, instead those might be processed as two monocular stimuli in each hemisphere separately.
Abstract
The present study reviewed the current models with their merits and limitations, based on which prevalent neuropsychological tests have been developed. Main variables influencing the composition of the tests and the interpretation of the results(e.g., patients' histories, causes of brain injury, types of deficit, etc.) were examined in clinical fields where neuropsychological tests were ubiquitously used. Recently, screening batteries tend to be flexibly developed according to the purposes of various deficits in psychological functions caused by brain injury. Finally, within a short history of neuropsychological assessment in Korea, recently imported neuropsychological assessment and its research have been reviewed. Possibility of development and practice of some neuropsychological screening battery was also suggested based on these reviews.
Abstract
The hypothesis that activation of phonological representation is obligatory in visual access of word meaning was tested. In a series of five experiments which differed only in stimulus onset asynchronies (SOA; 51ms, 85ms, 119ms, 153ms, and 255ms, respectively) and subjects, a target word was named following an semantic associate of the target or a word homophonic with the associate. Semantic associates produced reliable priming regardless of the length of SOA, whereas homophones produced marginally significant priming at SOA 153 ms only. The results suggest that visual access of word meaning is primarily accomplished via activation of orthogrphic codes, and that the phonological constraint hypothesis is not tenable.
Abstract
Motor evoked potentials(MEPs) have been used widely both experimentally and clinically to study the function of the motor nervous system. However, the origins and the waveforms of MEPs in small animals like rats may be different from those of potentials evoked by intracortical microstimulation in carnivore like cats because of current spread. The patterns and characteristics of MEPs also could be affected by recording techinques and methods of stimulation. In the present study, we used a specially designed electrode to stimulate localized cortical area. The pointed tip of a special stimulating electrode was inserted into the cerebral cortex perpendicular to the cortical surface so that the round area gently contacted with the cortical surface. We investigated the characteristics of pyramidal motor evoked potentials (PMEPs) and extrapyramidal motor evoked potentials (EPMEPs) evoked by the electrical stimulation of the mortex cortex and the gigantocellular reticular nucleus. Using this technique, we could constantly obtain the PMEP and EPMEP. The results of the present study showed that the PMEP and the EPMEP were different in their latencies and waveforms.
Abstract
In a lexical decision task with two primes and a target, some studies have shown that reaction times were faster when there are two related words in the prime display when there is only one. This has been regarded as evidence that priming is additive. However, the experimental conditions for these studies varied, and converging evidence for additivity is needed. In this context, the present study examines the two following issues: (i) whether the additivity is obtained by word repetition, and (ii) whether priming occurs with the complex prime which has one related word and one unrelated word in the prime. Results from two experiments revealed that additivity is not observed in case of word repetition and complex primes do not produce the priming effect. Implications of the present study have been discussed.
Abstract
This study investigated the role of anterior cingulate cortex (Acc: Brodman area 24) in the fear conditioning in rats using Pavlovian conditioning paradigm. Conditioned fear (freezing responses) was measured during both the acquisition and the extinction phases of the task. Conditioned fear was measured both at the conditioned stimulus (CS) and at contextual stimuli during both phases. Acc lesions attenuated conditioned fear to contextual stimuli but not to CS during acquisition. Acc lesions prompted extinction to both contextual stimuli and CS. These results show that Acc lesions facilitate extinction of conditioned fear to context and CS and decrease conditioned fear of context and suggest that Acc may be involved in the acquisition of conditioned fear to contextual stimuli, and in the inhibition of extinction of conditioned fear both to contextual stimuli and to CS.
Abstract
Two experiments were performed to investigate the psychological dimensions of pitches that compose of the octave in the Korean traditional music(KTM) and the effects of musical experience on the mental representation of KTM. KTM orchestra group, western music student group, and nanmusician group were participated. The royal traditional pitches('Jung-Ak' in Korean) were used in Experiment 1, and the folk traditional pitches('Minsok-Ak' in Korean) in Experiment 2. Both experiments used the probe-tone task Results showed that the three groups have their own mental structures of the two different kinds of KTM pitches(royal vs, folk pitches). Generally speaking, all the three groups have the similar dimensional structures. But they showed different relation among the pitches in their own structure according to the amount and contents of their musical experience. While two dimensions, 'octave vs. nonoctave scale tones' and 'pitch height', were found in the royal pitches, only one dimension, 'pitch height' was meaningful in the folk pitches. The results were discussed in the aspects of inappropriateness of the experimental paradigms used in the study of western tonal music for that of KTM and the differences between western tonal music and KTM.
Abstract
This study investigated the role of prelimbic area (PL) and anterior cingulate cortex (ACC) of medial prefrontal cortex using two delayed spatial win-shift (SWS) tasks and a single-phase random foraging task on an 8-arm radial maze. Delayed SWS task consisted of a training and a test phase separated by a delay period (5 min. in the 1st task and 30 min. in the 2nd task). PL-lesioned animals learned all the 3 tasks as well as the control animals. However ACC-lesioned animals revisited previously baited arms in the training and the test phase but they achieved performance criterion in the 1st task. ACC-lesioned animals showed no impairment in the 2nd or the 3rd task. These data suggest that PL is involved neither in working memory nor spatial learning and that ACC is important in memory demanding tasks. The effects of lesions of the ACC diminished as the training progressed. ACC appears to be of particular importance for a difficult task in a new and challenging situation.
Abstract
This study was conducted to investigate the effect of individual differences in working memory on goal inference processes in narrative comprehension. In correlational study, it was found that reading span score correlated word span score, but there was no significant relationship between Korean verbal SAT score and both types of span scores. In Experimental study, the interaction effect between reading span and text structure (goal-success vs goal-failure) was examined. It was found that there was no significant difference between high and low span readers when the distance between the goal and the and probe was near in Experiment 1. However, Experiment 2, which the probe was separated far from the goal, indicated that high span readers recognized the superordinate goal faster in the goal-failure structure than in the goal-success structure whereas low span readers did not differ in both types of text structure. The results suggest that high span readers construct integrative representation during reading whereas low span readers have some difficulties in constructing coherent representation, only when working memory loads are heavy.
Abstract
The red nucleus(RN) of the rabbits was destroyed with injection of kainic acid, and the conditioned nictitating membrane response was examined using a delayed paradigm with 450msec ISI, while the multiple neuronal activities were simultaneously recorded from both the cerebellar interpositus nucleus(INT) and the hippocampus(HIP). The RN lesion blocked the development of learning-related neuronal activities in the HIP as well as the aquisition of the conditioned response(CR). Animals with RN lesion also showed the retardation of development of learning-related neuronal activities in the INT compared to control animals, suggesting that the RN lesion affected the formation of memory trace in the INT. It is thought that, with a relatively long ISI, the information about the performance is required to establish successful learning. Similarly, according to a computational approach, CR information from the RN to the INT enables error-correction. Thus, based on results obtained in the current study we propose that RN is more than a simple relay station in the motor command pathway and it actively participates in establishment of the adaptive CR.
Abstract
Most of the researches conducted in search of a coronary prone personality has focused on the TABP(Type A behavior pattern), a collection of behaviors that seems predictive of CHD(coronary heart disease). The two primary methods of assessing TABP are the SI(Structured Interview) and JAS(Jenkins Activity Survey). JAS is more convinient but has a weaker predictive value than SI. It is important to relate and compare Type A and other personalities to improve the prediction of CHD. Seventy two persons were divided by groups of type A with internal locus of control(IA), type A with external control(EA), type B with internal control(IB), and type B with external control(EB). This study has shown the IA group has low depression and trait anxiety and the EA group has high depression and trait anxiety. The differences of the two groups are significant. But the differences among B groups are not significant. That results arises from the interaction effect between Type A and locus of control. The similar trend was observed in FBV(finger blood volume). The IA group has shown the most decrease of FBV but the EA group has shown the least decrease. Much decrease of FBV can be interpreted as energy mobilization to cope with the environment. Booth-Kewley suggested that CHD-prone personality might be a personality with one or more negative emotions, in short, maladapted personality. It can be described that the IA group has hurried and impatient behavior type with positive emotions, and the EA group has hurried behaviors also but with negative emotions. Much FBV decrease of IA group can be interpreted of energy mobilization to cope the environment well, therefore IA group may be the well adapted group. Putting together these results, it was concluded the EA group might be coronary prone type A and the IA group might be the healthy type A. This study has found that the type A and the locus of control has interactive effects on predicting CHD. The results indicate that if JAS and the locus of control measurement are used together, the predictive value of JAS will be raised.
Abstract
In two experiments, the representation and processing of disyllabic Hanja words written in Hangul were studied. Hanja words are originated from China and Japan, but are in these days generally written in Hangul, the Korean script. Each syllable in Hanja words represents a bound morpheme and many Hanja morphemes are written as an identical Hangul syllable. Experiment 1 was a repetition priming experiment using the lexical decision task and the materials presented at long lags. The prime-target pairs were either identical("반항"-"반항"), morphologically related("반칙"-"반항"), orthographically related("반장"-"반항"), or unrelated("공개"-"반항"). Significant facilitation was obtained only for morphologically related prime-target pairs. Experiment 2 was a short-term priming experiment using the lexical decision task and the same materials. The morphological facilitation effect obtained in Experiment 1 disappeared, but significant inhibition effect was obtained for orthographically related pairs. The overall results were interpreted in terms of an interactive activation model, and the individual difference in morphological processing and the position effect of morphemes in Hanja words were discussed.
Abstract
Repeated intermittent administration of psychostimulants produces an enhancement of the subsequent behavioral effects of these drugs. This behavioral sensitization has been implicated in maintenance of and relapse to drug-taking, there has been great interest in elucidating the mechanisms underlying both the development and expression of behavioral sensitization. An accumulation of data from studies of stimulant-induced locomotor activity and stereotypy has implicated excitory amino acids and nitric oxide(NO) in the development and expression of behavioral sensitization. The present study examined the effects of non-competitive NMDA receptor antagonist, MK-801 and nitric oxide synthase inhibitor, N^(G)-nitro-L-arginine methyl ester(L-NAME) on behavioral sensitization induced by repeated administration of nicotine. Repeated administration of nicotine(0.4mg/kg, s.c.) twice daily for consecutive days result in an augmentation of the locomotor and stereotypy activating effect of nicotine(0.4mg/kg, s.c.) challenged 3 days after last injection. Administration of the NMDA receptor antagonist, MK-801(0.3mg/kg, i.p.) and nitric oxide inhibitor, L-NAME(75mg/kg, i.p.), before daily nicotine injections attenuated the development of behavioral sensitization to subsequent nicotine challenge. Whereas, administration of MK-801(0.3mg/kg, i.p.) and L-NAME (75mg/kg, i.p.) twice daily for withdrawal periods of 3 days ensuing after chronic nicotine treatment periods of 7 days results in different consequences. MK-801 attenuated the expression of behavioral sensitization to nicotine, but L-NAME did not significantly reduce activity scores. These results suggest that NMDA receptor is involved in the expression as well as development of behavioral sensitization to nicotine, and that nitric oxide synthesis is involved in the development of behavioral sensitization to nicotine but not critically involved in expression of behavioral sensitization to nicotine. However, nitric oxide synthesis may have a modulatory role in expression of behavioral sensitization to nicotine. In addition, behavioral sensitization is thought to be mediated by changes in central dopaminergic systems. Accordingly, NMDA receptor and nitric oxide may influence on these changes similar to proposed role of nitric oxide and NMDA receptor in cellular adaptation and learning.