ISSN : 1226-9654
According to Hierarchical editor, or HED model, choice reaction time depends on structure of motor program, position of uncertain response, and length of movement sequence. The present study investigated the assignement processing of hand and finger parameters under the condition in which subjects performed one of two memorized finger sequence. The position of uncertain response affected on response initiating time(T1). However Rosenbaum, Inhoff, and Gordon (1984) claimed that the number of feature to be edited does not affect on chossing time, but in the present study, T1 was shorter when hand parameter had been set and finger parameter rad been uncertain than when hand and finger parameter had been uncertain. But T1 was not shorter when finger parameter had been set and hand parameter had been uncertain than when hand arid finger parameter had been uncertain. This result is consistent with Rosenbaum et. al. (1984)'s result. These results suggest that hand parameter is independently edited with finger parameter and is determined before finger parameter is. In other words, hand parameter decision is occured on higher element than finger parameter decision. On the one hand, to-be-edited feature did not affect on interresponse time. This result derived from the face to-be-edited feature did net change the number of element for subprogram.
Previous studies have reported that a novel environment renders animals hypoalgesic and this novelty-induced hypoalgesia(NIHA) is not reversed by naloxone-pretreatment; in fact, the NIHA seems to be mediated through the monoaminergic system such as serotoninergic- and noradrenergic substrate, according to the studies on the effects of i.p. injection of those receptor ligands on the NIHA. The present study is conducted to investigate not only whether the central amygdaloid nucleus(ACe), which is known as mediating anti-nociceptive response as well as emotional/cognitive ones including fear/anxiety response, is responsible for the NE-mediated NIHA, but also whether the opiate system modulates this kind of NE mediation. In the present experiment, all rats were first given bilateral cannulae-implantations into the ACe. 7 days later, after these rats were randomly assigned into two groups named 'exposure group(EXP)' and 'non-exposure group(NON)', only the EXP started to be exposed to the non-functional floor of the Hot-Plate Apparatus (at the temperature of 23℃) 5 minutes every day for 7 consecutive days. On the 8th day, after being divided into two subgroups such as yohimbine group and saline group and being supplied with bilaterally-microinjected yohimbine or saline equivalent to its condition into the ACe, each group received a hot-plate(49℃) test. The latency to lick a hind-paw was manually recorded. As soon as picked out of the Apparatus all the rats were re-provided with naloxone, one of opiate receptor antagonists, and were re-tested under the same conditions mentioned. The result is that the novelty rats produced more hypoalgesia than the adapted rats in the hindpaw-licking latency, and that the bilateral micro-injection of yohimbine, an a<sub>2</sub>-NE receptor antagonist increaing NE release in the brain-neuron synaptic cleft by blocking the presynaptic autoreceptors, potentiated the hypoalgesia, only in the novelty rats; which indicates that the novelty-induced hypoalgesia appears to be carried through the NE substrate and that the ACe is the chief forebrain site conducting the NE-potentiated novety-induced hypoalgesia. As far as the effect of naloxone injection under the influence of the preinjected yohimbine and saline is concerned, the hypoalgesia was reduced only under the condition of novelty yohimbine, neither under that of novelty saline nor under that of non-novelty yohimbine and saline; which implicates the opiate substrast may participate in the hypoalgesia necessarily as the NE-substrate-dependant pattern rather than by itself. Thus, the NE system may play more important role than opiate system in mediating the novelty-induced hypoalgesia.
The aspects of relative motion and the 2nd-order long-range motion were examined to investigate the interdependency between the two different processes of short-range and long-range apparent motion. Random-dot cinematograms and contoured stimuli were used to help classifying an observed motion into the two different categories of apparent motion following the Braddick's criterion, In the relative mention, the tendency of perceiving the motion direction of a target stimulus relative to that of the frame was greater when the processes involved in the target and frame motion were in the same category than when they were in different categories. This result was interpreted as an indication of the independence of the short-range and the long-range processes, In the 2nd-order long-range motion which was defined as the long-range apparent motion of a stimulus patch dipicted by a pair of random-dot cinematograms, no evidence was found that the output of the short-range process is hierachically fed into the long-range process as an input stimulus for the further processing. In conclusion, the results of the current study suggest that there be neither processing dependency nor hierachical relationship between the mechanisms of short-range and long-range apparnet motion.
It has been known that the amygadala is the neural substrate for conditioned fear as well as unconditioned fear. Among the substructures of amygdala, the basolateral nucleus where CS and US inputs converge and LTP occurs, contains high densities of NMDA receptors and so seems to have a critical role in synaptiplasticity. NMDA antagonist, AP5 prevent induction of Long-term potentiation, but not expression of LTP. LTP is an activity dependent enhancement of synaptic efficacy and is regarded the psysiological mechanisms that might underlie learning and memory. So this experiment was done to investigate what effect AP5 injection to the basolateral amygdala on the acquisition and expression of the fear conditioning, using the fear potentiated Startle paradigm. Animals were allocated to AP5-AP5, AP5-saline, saline-AP5, saline-saline groups. AP5 or saline was injected just before conditioning and testing. The re sult is that AP5-AP5, AP5-saline group didn`t show the potentiated startle, comparative to the saline-AP5, saline-saline group, and AP5-AP5 group is not significantly different from AP5-saline. So we conclude that AP5 blocked the acquisition but not expression of conditio-ned fear-potentiated startle and convince that the blocking is not due to state-dependent retrieval failure.
Three experiments were conducted to find some factors which influence the processing of Kulca, the Hangul orthographic unit which corresponds to Korean syllable. In Experiment 1 and 2 pronunciation task was used. In Experiment 1, subjects took longer to pronounce the high frequency Kulcas than the low frequency Kulcas, whereas equivalent pronunciation latencies were obtained for Kulcas with Patchim (final consonant letter) and Kulcas without it. In Experiment 2, although the significant frequency effect of Kulca was replicated, the Kulcas containing very frequent nuclei (initial. consonant letter plus vowel letter) were pronounced faster than the Kulcas containing rarer nucle, This result .shows that Kulca nucleus plus Patchim units are used in pronouncing kulcas. In experiment 3 using same-different matching task, the psychological reality of the six types of Kulcas in their combination of consonant letters and a vowel letter was tested. The result suggests that both the presence of Patchim and the type of vowel letter are significant variables in the processing of Kulca type. Implications for possible models of Kulca processing are discussed.
This study was conducted to examine the effects of medial septal lesions on the spatial learning in rats. A standard Morris water maze task was used in both Experiment 1 and 2. In Experiment 3, a modified spatial working memory version of the Morris water maze task was used. In Experiment 1, colchicine or kainic acid(KA) lesions of the medial septal area were made in rats. Both colchicine and KA rats learned to find the hidden platform as quickly as sham-operated rats in the water maze, but KA rats spent somewhat less time in the training quadrant than did sham-operated rats in a probe trial. In Experiment 2, rats with pretraining infusion of lidocaine into medial septum showed impairment on acquision of the water maze, but they could retain place information as much as sham-operated rats in a probe trial. In Experiment 3, Animals were trained to swim directly to a visible platform in one of four quadrant and subsequently probed a hidden platform in the same location. Each day the platform was placed in a different quadrant. In the task, rats with colchicine-induced lesions to medial septum were significantly impaired relative to control animals. In summary, medial septal lesions did not consistently interfered with the acquisition of the standard Morris water maze task, but impaired the performance in a spatial working memory version of the water maze task. These results indicate that damage to the medial septum disrupts spatial working memory more than it disrupts cognitive mapping ability.
Two experiments were conducted to determine the roles of phonological and orthographic codes involved in Hangul word recognition. Experiment 1 examined naming latencies for words and nonword as a function of the number of charaters (syllables) in the visually presented stimulus items, Words were named faster than nonwords. Latencies increased with the number of characters for both words and nonwords, However, the increasing rate for nonwords was much higher that that, for words, These findings suggest that words and nonwords are named through different processes, Experiment 2 measured lexical decision times for the same items used in Experiment 1, Mean response time (RT) for words was shorter than that for nonwords. Mean RT for nonwords with mare than two characters increased with the number of charaters in the items; however, mean RT for words did not, suggesting that words arid nonwords were differentially processed. It was concluded that, enven though Hangul is a phonologically shallow orthography, phonological code does not assume critical roles in Hangul ward recognition.
This study was conducted to examine the role of hippocampus in nictitating membrane response in rabbits. Especially, the latent inhibition procedure was used to differenciate between the stage of stimulus(conditioned stimulus:CS) processing and that of association. As the pontine nuclei was the recording sites, it was possible to observe the effects of hippocampus on conditioned stimulus before the information of the CS enters cerebellum. The result was that the multi-unit neural activity in pontine necleus was influenced by hippocampal damage. That is, compared to the normal animals, the hippocampal lesion anmals consistently kept up more neural responses to the repeated CS. However, they showed no difference in the manner in which the multi-unit activity progresses during the course of time. These results indicate indirectly that hippocampus is related to processing and interpreting incoming stimuli. It is considered that hippocampal lesion animals show no retardation of learning in latent inhibition because they response redundantly to irrelavant stimuli. This study is insufficient to conclude that the computational procedure in hippocampus is concerned with attention. Yet, it is reasonable to attribute the cause which the hippocampal lesion animals differ from normal animals in latent inhibition to CS-related function of hippocampus. Therefore the role of hippocampus in classical conditioning is related to CS processing rather than association itself.
Seven experiments were designed to examine the role of attention in the development of mental codes regarding pattern-masked word inputs presented at various identification thresholds. Depending upon type of report required about pattern-masked prime words, either a positive repetition or an associative facilitation effect has been obtained in a lexical decision task. Most notably, associative inhibition effects were also obtained when either a prime or a probe word was slightly moved from its original position. The pattern of results indicates that visual and semantic codes are developed by focused attention to pattern-masked prime words and that these mental codes are locationally specific. Comparison of our results with Carr and Dagenbach's (1990) suggests that associative inhibition effects in our study are qualita-tively different from the effects they have found.
This study examined effects of lesions of the cerebellar cortical lobule VI (HVI) on the rabbit's conditioned nictitating membrane responses and the neural activity of the cerebellar interpositus nucleus (INT). Rabbits implanted with a recording electrode in INT were trained with a tone conditioned stimulus(CS) and an air puff unconditioned stimulus(US) for 4 days. They showed robust behavioral conditioned responses(CR) and time-amplitude neural model of learned responses in INT. Unilateral electrolytic lesions of lobule HVI were then made through 4 electrodes implanted before the training. The complete lesions of lobule HVI abolished not only the behavoiral CR but also the conditioned increase in neural activity of INT in the CS period that is considered as an essential neuronal plasiticity for the CR. Unconditioned responses(UR) and neural activities in the US period were not affected by the lesions. The results suggest that the input from HVI to INT plays an important role in the retention of the CR and the conditioned-related neural activity in INT. The INT thus seems not to be the only site that represents the learned response but to consist an element of the neural circuit that forms the memory trace for generating the CR. As the animals with lesions of HVI further retrained, they reacquisited the CR, though the CR amplitude and the learning rate were profoundly reduced. The neural modeling in INT was also slightly recovered. It indicates that HVI is ordinarily involved in the retention of the CR and the neural modeling in INT and that the classical conditioning is possible through the neural circuit even not including HVI.
Animals exposed to the naloxone-heat pairings reduced their sensitivity to the pain. Naloxone-induced analgesia may be, in nature, non-opioid in that was found in the rat pretreated with naloxone. The present study was conducted to examine the area which is the responsible for the analesia induced by naloxone-heat pairings. Hot-plate apparatus which was thermoregulated automatically at 53±0.5℃ was used for heat stimulus. The latencies for hind-paw lick was recorded as an index of pain sensitivity. The result of present experiment was as follows. Sham operated rats were maintained analgesia which developed in the training phase but, analgesia developed in the rats which belongs to the experimental group in the training phase was reduced to the baseline level after dorsal periaqueductal lesion. This result suggest that dorsal-periaqueductal gray is responsible for the analgesia induced by naloxone.
By manipulating divided- and undivided-attention at retrieval stage, this study investigated the effects of conscious controlled processing and automatic processing upon retention of recognition test and word fragment completion test. Experiment 1 examined the retention of unattended words by selective attention procedure. Evidence for retention of unattended words was found when attention was divided at retrieval but was not found when undivided on both test. Experiment 2 examined the effects of processing capacity allocated to word learning. At both retrieval conditions, recognition judgement was dependent on processing capacity but word fragment completion was not. Experiment 3 examined level of processing(LOP) effects when attention was divided or undivided at retrieval. On recognition test, LOP effects were found and the effects were smaller at divided than undivided attention. But on word fragment completion test, LOP effects were not found both at divided and undivided attention. These findings support the notion that recogniton relies an both data- and conceptually-driven processing and word fragment completion relies primarily on data-driven processing.
This study investigated the effects of chronic injection of benzodiazepine agonist, diazepam(2mg/kg) and inverse agonist, β-CCM(1mg/kg) on the conditioned freezing in Sparague-Dawley male rats, using 2-trial conditioned fear test. Each animal in chronic treatment groups was injected twice a day for 5 days. Each animal in acute treatment groups was injected only once before training. On the first training day, each rat was placed in the observation chamber, and 3 min later it recieved three shock (0.75s, 1mA) at a 20-s intershock interval. During the second testing day, the animal's behavior was observed according to a time-sampling procedure in the same preshocked chamber. Results showed that the conditioned freezing was significantly reduced in animals treated with single injection of diazepam, administered before the 1st training trial, but not in those treated with repeated injections of diazepam(exp 1). In constrast, both single and repeated injections of β-CCM caused an increasing in the conditioned freezing response(exp 2). The finding that the acute treatment of diazepam given before training attenuate the conditioned freezing was consistent with our previous study. It was also founded that the repeated administrations of diazepam induced tolerance effect and the effects of agonist and inverse agonist ligands of benzodiazepine receptor on conditioned freezing were contrary to each other. It is suggested that benzodiazepine receptors are involved in the control of the rat's species-specific defensive response.
Behavioral Pharmachology has provided more refined animal models for investigating the effects of subcataleptic doses of neuroleptics on operant behavior since the early day of behavioral pharmachology. Based mainly on findings obtained from classical neuroleptics that are either D<sub>1</sub>/D<sub>2</sub> mixed antagonists or D<sub>2</sub> antagonists, some theories connected this neuroleptic-induced phenomena to anhedonia (incentive/motivational) changes, whereas others used motor impairments, and associative deficits as explanatory concepts. First, the anhedonia hypothesis assumes that reinforcers have hedonic value for the organism, and this hedonic impact is mediated through dopaminergic neurotransmission as case that mesolimbic DA system is the neuronal circuitry involved in reward/motivational processes. Second, the motor effects hypotheses focused on identification of motor side effects of neuroleptics drugs, in addition to the findings of the behavioral studies, likehood of neuroleptic-induced motor impairment is also suggested by the fact that among the anatomical regions where DA antagonists bind is the striatum which is a part of the extrapyramidal motor system and claimed to be involved in control of motor activity. Third, possible effects of neuroleptics on processes other than motor activities were suggested by the fact that antipsychotics target the mesolimbic and mesocortical DA system, which are believed to be important in memory and learning process. Taken together, re-evaluation of three major hypotheses may helpful to clarity some of the issues related to D<sub>1</sub> and D<sub>2</sub> antagonists and functional roles of respective receptors.
Two experiments investigated the possibility that memory for words is dependent on levels of attention of those words, In a study phase of Experiment 1, subjects first viewed pairs of words and were required to name one cued word and ignore other uncued word in each pair. The exposure duration of each pair was 250, 500, or I000msec. Recognition, perceptual contrast, or perceptual identification test was administered in a test phase, For cued words, irrespective of exposure duration, same amount of retention was observed in each of the memory tests. But for uncued words, the results were different among memory tests, Memory on recognition and perceptual identification was observed only at longer exposure duration, but memory on perceptual contrast was observed even at shorter exposure duration. In a study phase of Experiment 2, subjects first viewed one or two digits as a memory set and then four digits with a word. Subjecas were required to do digit-search only(non-attention condition) or see a word concurrently. More processing capacity was required when memory set size was two (high-difficulty condition) than one(tow-difficulty condition). Memory on recognition was observed only at low-difficulty condition and memory on perceptual identification was observed at low- and high-difficulty condition but not observed at non-attention condition. But Memory on perceptual contrast was observed even at non-attention condition, These findings, especially at perceptual contrast test, suggest that implicit memory is not dependent on levels of attention of words in the study phase.
An amplifier was designed for extracellular recording of unit activity. It consists of a head stage amplifier and a postamplifier. The head stage amplifier and the postamplifier have differential input circuits. The amplifier had a high common mode rejection ratio(CMRR), well-defined gains, a low noise character, and a wide dynamic range. Multiple unit activity(MUA) and single unit activity(SUA) could be recorded satisfactorily in animals with the chronically implanted metal electrode and with the acute micropipette electrode in the brain.
The present research examined picture-word differences in attribute decision task. Experiment 1 and 2 tested the difference of activation between the attributes of high-frequency and low-frequency in pictures and words. It was found that the pictures were decided significantly faster than words on the low-frequency attributes. Experiment 2 was conducted to investigate the elaboration effect, It was found that the condition of word-plus-attributes was decideded significantly faster than that of words. Experiment 3 compared decision times among the conditions of ward, word-plus-low frequency attributes, word-plus-high frequency attributes, picture, picture-plus-low frequency attributes and picture-plus-high frequency attributes. There was significant difference between the condition of word-plus-high frequency attributes and word-plus-how frequency attributes, but not in others, In conclusion, the high-frequency attributes were activated both in pictures and words, but low-frequency attributes were activated in pictures, not in words, The picture-word differences were due to the difference of activation between pictures and words.
Schema theories are theories about the representation and use of knowledge for given information, The purposes of this study were to investigate scene comprehension and memory representation, and implication of schema theory to complex scene information, Therefore, Four experiments are conducted, In experiment 1, picture verification task was conducted by scene material, The result have shown that typical inventory was faster than atypical one, But there are no effects of organization and presence. In experiment 2, scene priming time was controlled and picture verification task was conducted by scene material. The result have shown that typical inventory was faster than atypical one, And there are no effects of organization and presence, But we gained interaction by typicality and organization, the source of interaction was atypical inventory in organization condition, In experiment 3, scene theme priming and picture naming task was conducted. The result was same as experiment 1, In experiment 4, scene naming was conducted. The result have shown that the effects of typicality and organization were significant, All these resluts support scene schema theory But spatial organization was complex and indirect effects on scene comprehension rather than typicality of inventory.
To investigate relationship between syntactic parsing processes and working memory processes, first, we reviewed various approaches on sentence processing and basic experimental results about Korean syntactic processing. Then, two experiments were performed to examine processing characteristics of conjoined coordinative sentence parsing in working memory. In Experiment I, four different types of the conjoined sentence were compared by using the speeded comprehension task. Especially, we tried to decide relative explanatory power of three hypotheses such as the accessibility hypothesis, the working memory hypothesis, and the recent filler strategy. The standard type of conjoined sentence that has a subject as a coreferent showed the fastest comprehension time, In Experiment II, to verify the validity of the working memory hypothesis, two kinds of ambiguous conjoined sentence were compared by asking an ambiguous coreferent word. It was found that the results of the two experiment could not be handled by any one hypothesis. They should be explained by considering all syntactic cues of the sentence and the processing characteristic of working memory, Different parsing processes between Korean arid English were also discussed.
The purpose of this study is to investigate on-line comprehension processsing in terms of the referential resolution of pronoun. The important question of on-line processing is the immediacy of processing. The immediacy of processing is conceptualized not funtion of time course, but the satisfaction of multiple constraints. These constraints include gender cue of pronoun, antecedent case and pronoun case, In experiment 1, using sentence reading task, The main effect of gender cue and case constancy, the interaction of pronoun case and case constancy were obtained, In experiment 2, The replication of Experiment 1 was conducted and the same results was obtained, In experiment 3, using phrase reading task, There are no readig time differences when the phrase of pronoun was reading. But the spill-over effect of pronoun reading time to gender cue and pronoun case was significant. All experimental results ware suggested gender cue was powerful constraints to resolution, but always sentence topic and case constancy were satisfied. The immediacy of referencial resolution processing is not all-or-none, but incremental characteristic.
Sanford, Garrod & Bell(1979) varied the context biases prior to the anaphora sentences and compared the reading time for the general-term anaphora sentences with that for the instance-anaphora sentences. The hypothesis predicts a significant interaction between context biases and the types of anaphoras, but the results failed to confirm this prediction. The present study was conducted to test whether their results had been due to some insufficiences in producing relevant context biases. In this study it was predicted that with relevant and sufficient context biasing instantiation of general-term can be obtained. In experiment 1 and 2, using Lexical Decision Task, an interaction between context biases and types of anaphoras was obtained. This result suggests that Sanford et al's results were due to the difference in situation models generated by the context in the sentences prior to the target sentences with anaphoric subjects. In experiment 3, when the difference due to these situational models was controlled out, a significant interaction between contexts and the types of anaphora was obtained, which supports the instantiation hypotheses, In experiment 4, it was found that the consistency between the context bias prior to the anaphora sentences and in the anaphora sentences facilitates the processing of instantiation.
The present study examined the effects of preview sentences and paragraphing in expository text on subjects' recall of the text. College students who participated in this study were randomly assigned to one of four text version groups : the no preview sentences and no paragraphing group, the no preview sentences and paragraphing group, the preview sentences and no paragraphing group, and the preview sentences and paragraphing group. The result showed no significant effects of preview sentences and paragraphing. However, students' learning ability being considered, significant interaction effects were found. Although subjects with high teaming ability recalled well regardless of whether or not passage was paragraphed, subjects with low teaming ability recalled mare in paragraphing condition than no paragraphing condition. The implication of these results is discussed.
This study was planned to survey assumptions and problems of existing categorization models and to test the relative plausibility of an hybrid categorization approach based on mixed representation. Specially, we explored whether we could regard empirically defined prototypes as proper summary representations of a category and two-way interaction between exemplar frequencies and learning trials as a reasonable evidence for an hybrid categorization model. In experiment 1 and experiment 2, we distorted exemplars from category protptype and investigated change patterns of category judgment, accuracy with category size. Results showed that category learning strategies weren't fixed but adjusted by learning conditions ceaselessly, In experiment 3, we distorted exemplars from category prototypes and examined an existing hybrid model's assumption that, categorization depends on exemplar information primarily and summary information later, In consequence, we found same results as Homa, Dunbar, & Nohre (1991)'s study in the highly distorted category but couldn't find out two-way interaction between exemplar frequencies and leaning trials in low distorted category In conclusion, these result implicated that categorization processes are not prototype abstraction processes nor exemplar retrieval processes but dynamic learning processes optimizing performance according to learning conditions.
Two experiments were conducted to contrast quantitatively the MDS-based exemplar model (GCM) and the prototype abstraction model in predicting classification and old-new recognition performance of ill-defined category instances. Both models employed the typical learning-transfer phase paradigm to collect classification and recognition data. Experiment 1 used random dot patterns as instances and increased the category size. (up to 18 instances/ category) to extend the possibility of prototype abstraction. The MDS-based GCM and Prototype model were fitted to the data. The overall results of model-based theoretical analyses showed no indication of prototype abstraction. The results were interpreted that category size makes no contribution to prototype abstaction in the case of random dot patterns. Experiment 2 used Reed's(1972) schematic faces as category instances that are more meaningful compared to the random dot patterns. The results of theoretical analyses showed that abstracted prototype can contribute to the classification of schematic faces into categories. Category representation, the problem of similarity measurement, and alternative models for classification process were discussed.
S. Kim and Y. Lee (1991) demonstrated a significant transfer effect in solutions from a missionary-cannibal to a jealous husband-wife problem by presenting structurally mapped subgoals. Two experiments of the present study further examined which hypothesis is correct in explaining such a symmetric transfer effect, subgoal mapping, changes in processing strategies, or degree of constraints learning. The pattern of results supports the subgoal mapping hypothesis.
This study investigated the frequency of within-item attributes on forty pictures and words. The differences of within-item attributes between pictures and words were due to the concreteness of pictures. The present paper was to provide basic data for studying representation of concept and memory with pictures and words.