Endoscopic transthoracic sympathectomy: an efficient and safe method for the treatment of hyperhidrosis

Rats learned serial patterns composed of either "run" chunks (e.g., 123 234 ...) or "trill" chunks (e.g., 121 232 ...). For each type of pattern, 1 group of rats encountered an element at the end of the pattern that violated the run or trill structure. In both run and trill patterns, violations were unusually difficult for rats to learn, whereas corresponding elements in "perfect" patterns that did not violate pattern structure were easy. Additionally, rats' errors on violation elements conformed to the structure of the patterns in which they were embedded. Thus, rats were sensitive to the run or trill organization of their patterns and mastered the rules governing the pattern before learning "exceptions to the rule."     

Rule abstraction, item memory, and chunking in rat serial-pattern tracking.

Two studies used a stimulus tracking paradigm to test whether rats are sensitive to the rule-based formal properties of structured serial patterns. Hooded rats tracked 16-element patterns of flashing lights by pressing levers under an array of 6 indicator lights. In Experiment 1, rats tracked a pattern similar to one previously used with human subjects and yielded remarkably similar results. More errors and response omissions occurred at boundaries of structural "chunks" than within chunks, and errors often reflected anticipation of the next chunk or extrapolation of the preceding chunk. In Experiment 2, temporal "phrasing" cues encouraged different groups to encode a pattern as a series of either "runs" or "trills." Differential placement of pauses induced rats to encode different rule-based representations of the pattern. Results indicate that under appropriate conditions rats may encode a representation of formal structure when they learn organized response patterns. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Sensitivity to violations of "run" and "trill" structures in rat serial-pattern learning.

Rats learned serial patterns composed of either "run" chunks (e.g., 123 234…) or "trill" chunks (e.g., 121 232…). For each type of pattern, 1 group of rats encountered an element at the end of the pattern that violated the run or trill structure. In both run and trill patterns violations were unusually difficult for rats to learn, whereas corresponding elements in "perfect" patterns that did not violate pattern structure were easy. Additionally, rats' errors on violation elements conformed to the structure of the patterns in which they were embedded. Thus, rats were sensitive to the run or trill organization of their patterns and mastered the rules governing the pattern before learning "exceptions to the rule." (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Phrasing cues and hierarchical organization in serial pattern learning by rats.

In Exp I, 42 female albino Sprague-Dawley rats received food quantities in a T-maze in a serial pattern. Ss learned under either no cue, temporal cue, place cue, and/or combined temporal-place cue conditions. In Exp II, 45 female albino Sprague-Dawley rats in the T-maze were trained in complex subpatterns with place cues or no cues. Exp I showed that phrasing facilitated pattern learning as long as phrasing cues were available but that Ss learned different things when different kinds of phrasing cues were used. Exp II showed that phrasing a pattern into formally complex rather than formally simple chunks produced poor learning. Overall findings demonstrate the rat's capacity to abstract and use higher-order rules in hierarchical serial patterns, especially when phrasing cues are available to facilitate the process. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

What is learned in sequential learning? An associative model of reward magnitude serial-pattern learning.

A computational model of sequence learning is described that is based on pairwise associations and generalization. Simulations by the model predicted that rats should learn a long monotonic pattern of food quantities better than a nonmonotonic pattern, as predicted by rule-learning theory, and that they should learn a short nonmonotonic pattern with highly discriminable elements better than 1 with less discriminable elements, as predicted by interitem association theory. In 2 other studies, the model also simulated behavioral "rule generalization", "extrapolation", and associative transfer data motivated by both rule-learning and associative perspectives. Although these simulations do not rule out the possibility that rats can use rule induction to learn serial patterns, they show that a simple associative model can account for the classical behavioral studies implicating rule learning in reward magnitude serial-pattern learning. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

The organization of exhaustive searches in a patchy space by capuchin monkeys (Cebus apella).

Search is a serial exploration of alternatives. Efficient search involves the ability to minimize costs (i.e., time/energy) and to keep track of alternatives already explored. The search abilities of 4 capuchin monkeys (Cebus apella) were evaluated by means of an apparatus featuring a set of suspended baited containers. The experiment featured conditions with different spatial configurations of the search space. Results show that the monkeys were able to search exhaustively 9 containers spatially distributed either as a 3?×?3 matrix or as 3 "patches" of 3 containers each. Search efficiency was higher in a search space suitable to organization in clusters or spatial chunks. In this condition, evidence for principled organization of search trajectories, as opposed to a random walk through the search space, emerges clearly and parallels search efficiency. This suggests that monkeys impose a structure over the search space and, by doing so, reduce the memory demands of the task. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Learning artificial grammars with competitive chunking.

When exposed to a regular stimulus field, for instance, that generated by an artificial grammar, subjects unintentionally learn to respond efficiently to the underlying structure (G. A. Miller [1958]; A. S. Reber [see PA, Vol 42:8911]). We explored the hypothesis that the learning process is chunking and that grammatical knowledge is implicitly encoded in a hierarchical network of chunks. We trained subjects on exemplar sentences while inducing them to form specific chunks. Their knowledge was then assessed through judgments of grammaticality. We found that subjects were less sensitive to violations that preserved their chunks than to violations that did not. We derived the theory of competitive chunking (CC) and found that it successfully reproduces, via computer simulations, both Miller's experimental results and our own. In CC, chunks are hierarchical structures strengthened with use by a bottom-up perception process. Strength-mediated competitions determine which chunks are created and which are used by the perception process. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Automaticity and word perception: Evidence from Stroop and Stroop dilution effects.

The Stroop effect is cut in half by adding a neutral word to the display. D. Kahneman and D. Chajczyk's (see record 1984-05774-001) "attention capture" account of "Stroop dilution" holds word recognition to be involuntary but strictly serial. The authors compared attention capture to 3 alternatives involving parallel rather than serial processing: In the lexicon, activation is divided among multiple words; postlexically, multiple words race for access to response processes; or prelexically, feature processing is degraded by multiple patterns whether or not they are words. Results support the latter. Multiple patterns are processed in parallel. If any are color words, Stroop effects occur but are reduced because any color word's input to lexical memory is lower in quality than if a single color word were the only pattern. Thus, lexical encoding is involuntary but can operate on several input representations in parallel, with effectiveness determined by input quality. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Associative learning in neonatal rats revealed by cardiac response patterns.

Tested whether heart rate (HR) responses could measure learning in infant rats and assessed the effects of odor-temperature pairings on HR. In Exp I, the 15 infant rat pups (3-4 days of age) that received a single pairing of a novel odor (CS) with illness later responded to the CS with sustained accelerations in HR; a different novel odor evoked deceleratory HR responses. The 29 control pups responded to the CS and the 2nd novel odor with cardiac deceleration. In Exp II with 73 Ss, those that received 3 pairings of a novel odor with a cold (10°C) temperature reinforcement displayed a similar pattern of HR responses, i.e., acceleration to the CS and deceleration to the novel odor. The authors conclude that cardiac response patterns are a useful measure of learning in infant mammals. The directional modulations of HR found in the present experiments correspond to previous interpretations of "orienting" and "defensive" reactions derived from studies of HR responses in humans. (28 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Dorsal hippocampus, CA3, and CA1 lesions disrupt temporal sequence completion.

An experiment was designed to evaluate effects of dorsal hippocampus, dorsal CA3a,b, dorsal CA1, and control lesions on performance of a temporal sequence task. Rats were trained on a sequential learning task involving six spatial locations on a radial 8-arm maze. After initial training followed by surgery, it was found that all lesioned animals were able to remember the sequence. To test temporal sequence completion, rats were started at different positions in the sequence and expected to complete the remainder of the sequence. The results indicate that control rats had no difficulty completing the sequence, regardless of starting point. In contrast, rats with dorsal hippocampus and dorsal CA3a,b lesions made errors by always returning to the first position in the sequence, regardless of which start position was used, whereas rats with dorsal CA1 lesions made random errors in the process of completing the sequence and did not appear to remember the serial order of the spatial sequence. This suggests that the dorsal hippocampus, and specifically the dorsal CA3 in conjunction with CA1, may be involved in temporal pattern completion processes. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Theory of serial pattern production: Tree traversals.

Structural information about a serial pattern may be encoded in the form of a hierarchical memory code. Conversely, when the pattern is to be produced, the memory code should be decoded. In this article, a theory on serial pattern production is proposed that builds on F. Restle's (see record 1971-03427-001) theory of structural trees and, especially, on the process models for sequence production developed by J. G. Greeno and H. A. Simon (see record 1974-29157-001). According to the tree traversal interpreter presented in the present paper, a structural tree corresponds to the interpretive process that operates on a hierarchical memory code. A comparative analysis of computational properties and psychological relevance is substantiated by empirical test and extension to recent work on the internal representation of music. (27 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Hypochord, an enigmatic embryonic structure: study of the axolotl embryo

Age-dependent alterations in behavioral and neuronal functioning were assessed in young (2-3 month), middle-aged (12 month), and aged (24 month) Fischer 344 rats treated with the indirect dopamine agonist amphetamine (2.25 or 5 mg/kg), the D1 agonist SKF 38393 (7.5, 15, 30 mg/kg), or the D2 agonist quinpirole (0.3, 1.0, 3.0 mg/kg). Drug-induced changes in activity and stereotypy were measured during a 90-min testing session, with Fos immunohistochemistry being used to assess the neuronal response to dopamine agonist treatment. As expected, aged rats given amphetamine (5 mg/kg) had fewer activity counts and higher stereotypy scores than young rats. Middle-aged rats also had fewer activity counts but were similar in stereotypy scores to young rats. Amphetamine also induced different patterns of Fos immunoreactivity in the neostriatum and nucleus accumbens of young and aged rats, as Fos expression in aged rats exhibited a distinctive dorsal to ventral pattern of decline. In general, SKF 38393 had few age-related actions, although aged rats did show a slight relative increase in stereotypy. In contrast, the D2 agonist quinpirole substantially enhanced the motor activity and Fos expression of young rats, while only modestly affecting aged rats. Hence, these results suggest that the D2 receptor is more vulnerable to the effects of aging than the D1 receptor.     

Short-term memory for serial order: the Start-End Model

Three solutions to the problem of serial order can be identified: chaining, ordinal and positional theories. Error patterns in serial recall from short-term memory fail to support chaining theories, yet provide unequivocal evidence for positional theories. In a new model of short-term memory, the Start-End Model (SEM), the positions of items in a sequence are coded relative to the start and end of that sequence. Simulations confirm SEM's ability to capture the main phenomena in serial recall, such as the effects of primacy, recency, list length, grouping, modality, redundant suffices, proactive interference, retention interval, and phonological similarity. Moreover, SEM is the first model to capture the complete pattern of errors, including transpositions, repetitions, omissions, intrusions, confusions, and, in particular, positional errors between groups and between trials. Unlike other positional models however, SEM predicts that positional errors will maintain relative rather than absolute position, in agreement with recent experiments (Henson, 1977).     

Alphabetic search: Comment on Klahr, Chase, and Lovelace (1983).

Response time (RT) curves were obtained from Ss who were instructed to search for following or preceding letters in the alphabet with respect to given stimulus letters. To describe the shape of these curves, D. Klahr et al (see record 1984-05777-001) proposed a search model. It was assumed that the alphabet was internally represented by a number of chunks of a few letters. Klahr et al assumed that serial searches occurred along 2 hierarchical levels: (1) a search for the correct chunk and (2) a search of the letters within the chunk. The Klahr et al model predicted an ascending sawtooth-shaped RT curve. However, according to the authors' analysis of the data, the RT curves did not show the expected sawtooth shapes. In order to find out whether the lack of empirical support for the model was an artifact of averaging the data, the experiment was replicated. It was found that individual RT curves did not show the shape characteristics that were predicted by the Klahr et al model either. The data supported the hypothesis that the access of letters was direct without any hierarchy, and that the retrieval of successive letters was determined by the variable associations between subsequent letters. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Evidence for a multistage model of practice in a sequential movement task.

This study explored the effects of practice when discrete keypress sequences were produced in response to a stimulus. Eighteen students practiced 3 sequences with consistent stimulus-sequence mappings and 2 sequences with varied mappings in a 2,500-trial practice phase. In 2 subsequent transfer phases, the performance effects were assessed of a preceding serial reaction time task and of reversal of 2 consistently practiced stimulus-sequence mappings. The results are explained by the development of 3 types of memory codes (stimulus-response associations, stimulus-response rules, and motor chunks) that are used at 2 independent stages in a serial information-processing stage architecture. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

A production system theory of serial memory.

A theory is described that provides a detailed model of how people recall serial lists of items. This theory is based on the Adaptive Character of Thought-Rational (ACT-R) production system (J. R. Anderson, 1993). It assumes that serial lists are represented as hierarchical structures consisting of groups and items within groups. Declarative knowledge units encode the position of items and of groups within larger groups. Production rules use this positional information to organize the serial recall of a list of items. In ACT-R, memory access depends on a limited-capacity activation process, and errors can occur in the contents of recall because of a partial matching process. These limitations conspire in a number of ways to produce the limitations in immediate memory span. As the span increases, activation must be divided among more elements, activation decays more with longer recall times, and there are more opportunities for positional and acoustic confusions. The theory is shown to be capable of predicting both latency and error patterns in serial recall. It addresses effects of serial position, list length, delay, word length, positional confusion, acoustic confusion, and articulatory suppression. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

"Recovery of sensorimotor function after frontal cortex damage in rats: Evidence that the serial lesion effect is due to serial recovery": Correction.

Reports an error in "Recovery of sensorimotor function after frontal cortex damage in rats: Evidence that the serial lesion effect is due to serial recovery" by John M. de Castro and Mark C. Zrull (Behavioral Neuroscience, 1988[Dec], Vol 102[6], 843-851). The plate for this article appears on page 996. The information should read, "Plate B. Photographs of the dorsal side of the brains showing the minimum (top) and maximum (bottom) extent of the lesion produced unilaterally in the sham group (left) and bilaterally in the single- and two-stage groups (right)." (The following abstract of the original article appeared in record 1989-28759-001.) Multiple-staged brain lesions produce fewer and smaller behavioral effects than single surgery (the serial lesion effect, SLE). Two hypotheses were tested: the reduced deficit hypothesis and the serial recovery hypothesis. Effects of lesions of the medial frontal cortex on sensorimotor behavior were investigated in 7 rats that received bilateral damage in single surgery, 16 in 2 unilateral stages separated by 3 wks, or 5 with unilateral damage followed 3 wks later by sham surgery. Unilateral damage produced deficits on the contralateral side in response to visual, tactile, and olfactory stimuli and impairments in roll-over and paw withdrawal responses. All impairments except visual placement recovered over the next 3 wks. A 2nd unilateral lesion on the contralateral side produced the same symptoms on the opposite side. Bilateral damage incurred in a single stage produced the same deficits on both sides. Because the effects of the 2nd unilateral lesion in the 2-stage group produced comparable contralateral effects to those produced in the single-stage group, but no reinstatement of ipsilateral deficits, the reduced deficit hypothesis was rejected. It was concluded that SLE occurred as a result of serial recovery of the deficits. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

"Artificial grammar learning depends on implicit acquisition of both abstract and exemplar-specific information": Correction.

Reports an error in the original article by B. J. Knowlton and L. R. Squire (Journal of Experimental Psychology: Learning, Memory, and Cognition, Vol 22[1], 169–181). The Appendix on page 181 contains several errors. The corrected Appendix is provided. (The following abstract of this article originally appeared in record 1996-02680-010). The contributions of exemplar-specific and abstract knowledge to artificial grammar learning were examined in amnesic patients and controls. In Experiment 1, grammatical rule adherence and chunk strength exerted separate effects in grammaticality judgments. Amnesic patients exhibited intact classification performance, demonstrating the same pattern of results as controls. In Experiment 2, amnesic patients exhibited impaired declarative memory for chunks. In Experiment 3, both amnesic patients and controls exhibited transfer when tested with a letter set different than the one used for training, although performance was better when the same letter sets were used at the training and test. The results suggest that individuals learn both abstract information about training items and exemplar-specific information about chunk strength and that both types of learning occur independently of declarative memory. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Levels of immunoglobulin E (IgE) in paired examinations of serum and synovial fluid in rheumatoid arthritis and reactive synovitis of local origin

Twenty-eight pregnant patients exhibiting subnormal fetal growth patterns by serial ultrasonic cephalometry were studied. Only 12 (43%) delivered small-for-gestational-age (SGA) infants indicating a poor correlation between the prenatal assessment of intrauterine growth retardation (IUGR) by ultrasonic cephalometry and the neonatal evaluation of the newborn as SGA. The most important factors in the evaluation of the fetus with subnormal serial ultrasonic cephalometry were: 1) the type of ultrasonic growth pattern ("late flattening" vs "low growth profile"), 2) the presence or absence of maternal high-risk factors, and 3) the gestational age of the fetus at the time of detection of the growth abnormality. A pregnancy showing a late flattening type of growth pattern by serial ultrasound in the presence of maternal high-risk factors and with the growth abnormality being detected before 35 weeks of gestation, almost certainly will terminate with the birth of a SGA infant. On the contrary, serial plasma free estriol determinations were not useful in predicting the fetal status at birth. All but 4 of these patients were delivered at term and there was neither perinatal mortality nor significant morbidity. It is suggested that the existence of an abnormal cephalometric pattern is not an indication for early delivery unless fetal distress is detected by means of an oxytocin challenge test.     

Avoidance learning in rats: Genetic evidence for two distinct behavioral processes in the shuttle box.

Used an 8 * 8 diallel cross of rats (Roman high, low, and control avoidance; Maudsley reactive and nonreactive; Tryon maze bright and dull; and Wistar albino) to analyze sequentially a conditioned avoidance response (CAR) within a session of 30 trials. On early conditioning trials, the F1 hybrids scored fewer avoidances than the parental strains, whereas on later trials the hybrids were superior to parents. This finding was confirmed within a session of 100 trials in a 3 * 3 diallel and interpreted to mean that 2 distinct adaptive behavior patterns underlie shuttle-box CAR acquisition in rats. There appears to be a tendency to develop an adaptive inactivity or "freezing" behavior pattern and later, as conditioning proceeds, to develop an equally adaptive but more active behavior pattern of "fleeing." Implications for 2-process theories of avoidance conditioning are considered briefly. (20 ref.) (PsycINFO Database Record (c) 2010 APA, all rights reserved)