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- P-ISSN1226-9654
- E-ISSN2733-466X
- KCI
ISSN : 1226-9654
Vol.12 No.1
Abstract
We examined the possibility that attention could modulate the early visual motion processing. We used multi-aperture patterns, in which a center aperture is surrounded by 8 apertures. The apertures contained 3 c/deg cosine gratings moving in different directions (center: 45 deg; surround: 0 or 90 deg). In Expt. 1, all 9 apertures including the center were presented and subjects indicated the perceived motion direction of the center grating by adjusting pointer. In Expt. 2, four circles at the surround and one at the center indicating locations subjects should attend to were shown for 1.5 sec and then 9 gratings moving in different apertures were presented. The four gratings shown in the cued locations have identical or different motion directions. To control subjects attention to the cued locations, we had them press an appropriate key showing the correct motion direction of the grating in the cued locations after they indicated the perceived direction of the center grating motion. In Expt. 1, when all the surrounding motion direction was different from that of the center in 90 deg, the perceived direction of the center motion deviates from its physical motion direction as large as 30 deg. In Expt. 2, selective attention to the gratings moving in the identical direction caused perceived motion repulsion of the center grating as large as 12 deg but attention to the gratings moving in two different directions did not. Present results show that selective attention to the motion at specific areas could affect the perceive direction of the motion in different area. To explain the attentional effect on motion integration over space, inhibitory interactions among motion networks responding to different areas were discussed.
Abstract
Yun et al.(1999) 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 testing phase separated by a delay period(5 min. in the 1st task, and 30min. 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 test phase. In this study subjects were also overtrained by using the same delayed SWS tasks and then they were trained in a new visual cueing task for 8 sessions. In the new task, PL-lesioned animals showed impairment in the 3rd session but it lasted transiently. ACC-lesioned animals showed impairment at the 3th, 4th, 5th, 6th session. These results were interpreted that PL is involved in attention control or strategy shift, and ACC involved in the reorganization of information in a new and challenging situation.
Abstract
How does the visual system encode and select the locations of visual objects? To examine the question, we used a symbolic spatial probe technique and observed the relationship between the peripheral location of search elements and the symbolic orientation of a central arrow-probe. In two experiments, probe responses were faster when the arrow pointed to the target location than when it pointed to one of the distractor locations, indicating that discriminating the arrow was sensitive to the location of the target and the spatial relationship between the target and distractors. It is possible that some more abstract type of spatial coding occurred during search, and that visual selection occurred based not (or not only) on a physical or absolute location per se, but on symbolic or relative spatial relation. Based on the evidence, implications for cognitive theories of spatial attention will be discussed.
Abstract
This study is concerned with the question whether the prelimbic area and anterior cingulate cortex of the rat is important subtrates in the attentional control or strategy shift and in the spatial localization learning with Morris water maze. In the 1st task, rats with either prelimbic area or anterior cingulate cortex lesions were subjected to the visually-cued task with the visible platform. And then they were subjected to spatial reference memory task, transfer test and then spatial working task. In the visually-cued task, animals with prelimbic lesions showed a transient impairment and animals with anterior cingulate cortex lesions showed impairment that lasted than the prelimbic lesion animals`. In the spatial localization task with the invisible platform, animals with prelimbic area lesions learned and remembered the platform equally well as their controls. However animals with anterior cingulater cortex showed impairment in the spatial reference task but no impairment in the spatial working task. The results were interpreted that prelimbic area may be involved in the attentional control and anterior cingulater cortex in the learning of rules and response reorganization in a new and challenging situation.
Abstract
Many previous studies of auditory distance have involved manipulation of the obvious physical characteristics of the target stimuli (e.g., sound level, spectral content) or the environment (e.g., conditions of reverberation). The present research examined the contribution of familarity (long-term experience) to the perception of auditory distance, while attempting to control/evaluate the influences of unavoidable physical differences among stimuli. Spectral digital recordings of different vocal "styles" were presented from a stationary loudspeaker to blindfolded male and female listeners in an acoustically absorbent (but not anechoic) space. Voices included shouts, whispers and a normal conversational style. Playback levels were adjusted to avoid extraneous sound level cues. The shouting voice was reported as appearing farthest, the whispering voice closest. The conversational voice was intermediate. In a control experiment, non-speech stimuli with spectral content similar to the most extreme differences of the whispering and shouting voices were presented to new groups of listeners. Reports of perceived distance varied for the actual voices but not for the corresponding control stimuli. The results are interpreted to suggest that the perception of auditory distance may be affected by past experience. Also, unlike many previous auditory manipulations, the use of speech sounds was capable of producing a clear over-perception of the distance to the source.
Abstract
This study investigated the effects of preexposure to ethanol, diazepam, and context on conditioned fear and extinction in Sparague-Dawley male rats. Four drug-prexposure or saline-preexposure sessions were given in the experimental chamber before fear conditioning. Fear was conditioned by pairing an experimental chamber with footshocks and conditioned fear was assessed by observing freezing. During extinction session, rats were exposed to the chamber without shocks. Diazepam 5.0mg/kg and ethanol 1.2g/kg decreased freezing response immediately following the shocks. The preexposure to the context did not influence the conditioned freezing. In the saline-preexposure group, aminals that received extinction with either ethanol or diazepam showed significantly more freezing than the saline controls during undrugged test. These results indicated that both ethanol and diazepam produce state-dependent fear extinction even though the contextual preexposure. In the ethanol-preexposure or diazepam-preexposure groups, administration of the same drug during extinction did not interfere with fear extinction. These results showed that the contextual preexposure did not reduce conditioned freezing, but the preexposure to either ethanol or diazepam reduced the drugs' interference with fear extinction. These findings are discussed that the preexposure to drugs reduced the drugs' interference with fear extinction through both the drugs' sustained ability to weaken fear conditioning with all the repeated exposure and the tolerance effect due to drug preexposure. The practical implications for the interaction effects between drug therapy and extinction are noted.
Abstract
Four experiments were conducted to examine the effects of types of processing on priming for pictures and the time course of PRS (Perceptual Representation System). In Experiment 1 and 2, data-driven task was used whereas conceptually driven task was used in Experiment 3 and 4. The results indicated that the priming effects were found in the same condition regardless of types of processing and inter-stimulus interval, while the priming effects in the similar condition were found in conceptual processing regardless of inter-stimulus interval, but the effect disappeared in data-driven processing with 1-week delay. The priming effect in word condition was found only in conceptual processing with 1-week interval. The dissociation of priming effect between types of processing and inter-stimulus intervals was explained by the interaction between PRS and CRS (Conceptual Representation System).
Abstract
Latent Inhibition(LI) is a phenomenon in which the preexposure to a conditioned stimulus(CS) retards the subsequent association between the CS and unconditioned stimulus(US). In the present study, LI phenomenon was investigated with the eyeblink response conditioning of the rat. To record the electromyograph of the obicularis oculi muscle and to deliver US, 4 electrodes were implanted in eyelid muscle. The rats were classically conditioned in a Pavlovian delay paradigm with a 350msec tone CS (2.8kHz, 80dB, sine wave) and a 100msec periorbital electrical US shock (100Hz, 0.5~2.0mA, square wave). After 1200 CS preexposures, LI group were conditioned. The control group were conditioned without the preexposure to CS. The conditioning continued daily for a total 10 sessions (800 trials). LI was observed in LI group compared to the control group. The CR size, CR latency and other results were not significantly different between the both group. The study of LI with rat eyeblink conditioning has advantage since it can be compared with the LI results of the other behavioral tests. The present result verified that the eyeblink conditioning of rat can be applied to LI study.
Abstract
Keenan, Baillet, & Brown(1984) and Myers, Shinjo, & Duffy(1987) found that, when the degree of causal relatedness between a pair of sentences was varied, the probability of recall of a sentence, given the other sentence as a recall cue, was the highest at the intermediate level of causal relatedness. This inverted-U pattern of recall was interpreted as due to the elaboration which are assumed to occur during the reading of the sentences with the intermediate level of relatedness. On the other hand, Kim(1998) suggested that the predictability, that is, the degree of how easily the event of the first sentence predicts the event of the second sentence, affects the recallability. When the subjects were asked to recall the fast sentence given the second sentence as a recall cue, they could recall better in the low predictability, high causal relatedness condition. In this study, the subjects recalled the second sentence given the first sentence as a recall cue. The effect of predictability was reversed in the high causal relatedness condition: Higher recall rate in the high predictability than in the low predictability was found. It was concluded that there are no advantages in recall due to the elaboration. The effects of predictability were interpreted as due to the differences between forward and backward integration during the encoding.
Abstract
Peripheral nerve injury can lead to neuropathic pain which is a chronic pain state like hyperalgesia, spontaneous pain, mechanical allodynia, and thermal allodynia. Aging may affect the severity of neuropathic pain symptoms. In humans, there is difference between old and young persons in susceptibility of neuropathic pain. The present study was conducted to determine whether the behavioral signs of neuropathic pain following peripheral nerve injury depend on age at the time of the peripheral nerve injury. Under halothane anesthesia, the tibial and sural nerves were injured and the common peroneal nerve was left intact. Neuropathic pain behaviors were compared between young and old groups of rats. Rats with injury to the tibial and sural nerves showed the vigorous mechanical allodynia, cold allodynia, and spontaneous pain. Young rat group showed more profound mechanical allodynia, cold allodynia, and spontaneous pain compared to old rat group. The results suggested that all the behavioral signs of neuropathic pain may be manifested more robustly in young rat group rather than old rat group in our animal model of neuropathic pain which was produced by injury to the tibial and sural nerves, while leaving the common peroneal nerve intact. Aging appears to affect several factors related to the generation or maintenance of neuropathic pain.
Abstract
The problem with typical antipsychotics have been that they induce motor side effects. Therefore, efforts have been focused on developing drugs without such side effects. The prepulse inhibition (PPI) of startle reflex is one of the paradigms used for screening antipsychotics, since PPI is reduced in schizophrenia patients and this PPI deficits can be induced in rats by injecting dopamine agonists. Until now, most studies with this paradigm have used only auditory prepulse stimuli. To ensure the generality of this paradigm, this study used a visual prepulse stimulus and showed that a dopamine agonist, apomorphine, dose-dependently blocks the PPI in rats (Experiment 1). This PPI deficits induced by apomorphine was blocked by typical antipsychotic, haloperidol (Experiment 2). Finally, the hypothesis that dopamine D<sub>4</sub> receptor is preferentially involved in mediating the antipsychotic effects of drugs was examined by using a selective D<sub>4</sub> receptor blocker, L-745,870. The results showed that L-745,870 did not block the effects of apomorphine (Experiment 3).
Abstract
Two experiments were performed to investigate the influence of relevance on the performance of Wason selection task In Experiment 1, the effects of negative consequents were observed and the inspecting order of the cards was correlated with the proportion of selection of the cards, which seemed to support relevance based processing of selection tasks. The effects of negative consequents and the content of the conditionals on the performance of Wason selection task were more systematically explored in Experiment 2. The effects of negative consequents and the effects of content seemed to be additive. That is, they work independently of each other, which suggested that the two work in different stages. In addition, effects of perspectives on the performance of Wason selection task were also observed in one of the two problems of Experiment 2.
Abstract
This study was performed to investigate the problems associated with word production in an anomic aphasic. The questions were as follows: 1) Are the structure of the semantic information system separated from the lexical system? 2) Does the semantic system have a modular structure? 3) What`s the difference and relationship between Korean and English in word production process? We examined a right-handed male patient who had been diagnosed as an anomic aphasia by Western Aphasia Battery (WAB) after cerebral infarction on the left hemisphere. Four tasks, such as picture naming, word naming, semantic categorization, and lexical decision task were performed. We used ninety eight pictures which were consisted of forty eight natural things and fifty artificials. After completion of four tasks with Korean, same tasks excluding the semantic categorization were performed through English. And the results were compared between two languages. In picture naming task, the patient named correctly in thirty (30.6%) out of the ninety eight pictures. After given verbal cues, the patient answered correctly in forty five more pictures (45.9%). Most effective cue was initial phonemes or syllables of the target name. In word naming task, the patient read all the names correctly. In case of semantic categorization and lexical decision task, the error rate was only 5.1% and 11.2%, respectively. And picture naming performance differed in the natural and artificial category members. Furthermore, some naming errors in English were overlapped with the naming errors in Korean, but the other naming errors in English occurred only in English naming. In conclusion, these results were suggestive of the possibility of disruption at the connection between lexical and semantic systems in anomic aphasia. And the semantic system may have modular structure, such as artificial versus natural things as shown in this study. The test results performed by English revealed that the word production system of the two languages had both the common and independent areas.
Abstract
This study examined whether analogical learning of scientific concepts can result in a better performance in inference problem solving. Donnelly and McDaniel's (1993) basic results regarding analogical learning effects were not replicated in Experiment 1. Analogical Teaming with pictures, however, was effective on inference in Experiment 2. The pattern of results in these experiments indicates that working memory affects analogical learning of new concepts via its mapping process.
Abstract
The purpose of this study was to test the influence of task complexity and information presentation format on information search pattern and the decision rule that a subject has employed. Previous research intended to test the traditional two-stage decision model has consistently shown that subjects switch to compensatory information search behavior when task complexity and difficulty decreases. Experiment 1 and 2 were intended to study whether or not the heuristic decision rules assumed in the dominance structure model were employed in various tasks. As a result, the use of the noncompensatory heuristic rules did not affect the task complexity. In experiment 1, The importance of dominant attributes in the selected alternative was bolstered more strongly in a post-decision than in a pre-decision, however, the importance of the dominant attributes in the competitive ones were de-emphasized much more low. In Experiment 2, the result on the attractiveness evaluation of attribute values showed that the evaluation of attractiveness of attribute values in the selected one was bolstered more strongly. But, the differences between a simple task and a complex task were not found in the pre- and post-rate of interalternatives search, the importance of attributes, and the attraction evaluation of attribute values. The result suggests that the decision even in a simple task can be also made via the stages assumed in the dominance search model. In Experiment 3, the effects of information presentation format on the way of combining information in the post-stage of decision making were investigated. The result showed that subjects used the noncompensatory heuristic rules even in the display condition that the compensatory rules can be employed easily. Thus, it seems that the compensatory normative rules are not used frequently in the decision making process, regardless of the task complexity and the information presentation format. Some possible limits and the future directions of the present research were discussed.