Associative learning changes intrinsic to Hermissenda Type A photoreceptors.

The eyes of the nudibranch mollusc Hermissenda contain 2 classes of photoreceptors. Type B photoreceptors exhibit increased light responses (LRs) and membrane excitability after repeated pairings of light and rotation and play an important role in the mediation of associatively produced reductions in phototactic behavior. Type A photoreceptors (TAPs) have also been shown to change with associative training. In previous research it was not possible to determine whether the effects of associative training reflected changes in synaptic input to TAPs or intrinsic changes in somatic conductances. In the present study, intracellular recordings from synaptically isolated TAPs were obtained on retention days after training, and pairing-specific decreases in light-induced generator potentials and decreases in resting input resistance were observed. Current- and voltage-clamp analysis of TAPs from untrained animals revealed that an important determinant of the steady-state LR was a calcium-activated K+ current (IK–Ca). Thus, TAPs also appear to be a primary site for associative information storage in Hermissenda. It is suggested that enhancement of IK–Ca by associative training may contribute to the diminished LR of TAPs. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Trial-spacing effects in Hermissenda suggest contributions of associative and nonassociative cellular mechanisms.

In behaving Hermissenda, a preparatory conditioned response developed across repeated pairings of light (conditioned stimulus; CS) and rotation (unconditioned stimulus; US) with intertrial intervals (ITIs) of 60 and 120 s, but not 30 s. Likewise, contiguous in vitro stimulation of the visual and vestibular receptors, an analog of behavioral conditioning, resulted in an increase in the input resistance (i.e., excitability, a correlate of conditioning) of the B photoreceptors of the Hermissenda's eye, but only with ITIs greater than 60 s. Calcium signaling in the B cell, critical to the induction of this neuronal plasticity, was attenuated with shorter ITIs owing to (a) a reduction of the light-induced generator potential and hence voltage-dependent Ca2+ influx during the light CS, (b) a depression of the Ca2+ current that persisted throughout shorter ITIs, and (c) a steady-state inactivation of the Ca2+ current as a result of a sustained depolarization persisting from the previous trial. These results are consistent with a 2-process theory of associative learning in which a primary process (Ca2+ influx) may be opposed by a secondary process (depression of the Ca2+ current) during short ITIs. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Contingency learning and causal detection in Hermissenda: I. Behavior.

The addition of extra light-alone or rotation-alone presentations to sequences of light-rotation pairings reduced the associative suppression of phototaxic behavior for the nudibranch Hermissenda. Training-induced changes in Type B photoreceptor light responses were found to parallel the training-induced behavioral changes in the intact animal. The decremental effects of the degraded contingency treatments upon neural and behavioral changes normally occasioned by light-rotation pairings reflected two processes. One factor was the increased stimulation frequency entailed by degraded contingency training. The second factor reflected the specifically unpaired character of the added light-alone or rotation-alone presentations, independent of frequency changes. The attenuation of phototaxic suppression was not because of a general habituation process or adaptation to the effects of either visual or vestibular stimulation. Instead, attenuation seemed to reflect a local interference effect of interspersed unpaired stimuli. The present experiments demonstrate a sensitivity to stimulus contingencies for Hermissenda similar to that of many vertebrates and indicate that contiguity and contingency relations are both encoded and stored in the Type B photoreceptors. The results indicate that similar neurophysiological mechanisms are involved. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Contingency learning and causal detection in Hermissenda: II. Cellular mechanisms.

Neural correlates of contingency-sensitive behavioral changes in the nudibranch Hermissenda were studied by in vitro conditioning of the isolated nervous system. The additions of unpaired light-alone or hair cell-alone stimulation presentations to sequences of light-hair cell stimulation pairings were found to attenuate the cumulative depolarization of Type B photoreceptors that normally result from pairings. Unpaired light presentations produced a transitory depression of the light-induced depolarizing generator potential of the B cell. Unpaired hair cell stimulation synaptically hyperpolarized the B photoreceptor and thus acted in a retroactive manner to partially reverse the cumulative depolarization owing to prior pairings. Behavioral experiments revealed a striking temporal specificity for the decremental effects of added light and rotational stimulation. The present experiments indicate that contiguity and contingency relations are both encoded and stored in the Type B photoreceptors, and to a first approximation reflect similar biophysical mechanisms. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Potentiation of phototactic suppression in Hermissenda by a chemosensory stimulus during compound conditioning.

Modifications of Hermissenda's phototactic behavior by compound pairings of light, scallop extract, and rotation were assessed. In general, the scallop extract potentiated phototactic suppression. Potentiation was dependent on (a) conjunctive presentations of scallop and light, (b) number of conditioning trials, and (c) scallop extract concentration. In related experiments, no second-order conditioning or sensory preconditioning of phototactic suppression was observed, indicating that within-compound associations did not contribute appreciably to potentiation. These results represent the first detailed analysis of compound conditioning in a mollusk using discrete presentations of well-characterized conditioned stimuli from distinct sensory modalities. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Acquisition of conditioned associations in Hermissenda: Additive effects of contiguity and the forward interstimulus interval.

Examined conditioned suppression of photokinesis (CSPK) by the marine mollusc in 3 experiments. In each experiment, groups of Ss received light (conditioned stimulus, CS) paired with high-speed orbital rotation (unconditioned stimulus, UCS), light and rotation explicitly unpaired, or no exposure to these stimuli. 24 hrs after training, all Ss were tested for CSPK in the presence of the light. 50 CS–UCS pairings resulted in a marginal CSPK, whereas 100 and 150 pairings produced strong CSPK. In Exp 2, delay between CS onset and UCS onset was varied between 1 and 10 s. The 10-s interstimulus interval (ISI) did not support conditioning, whereas 1-s and 2-s ISIs were effective. In Exp 3, CS–UCS pairings in which the CS preceded the onset of the UCS and ended with the offset of the UCS evoked stronger CSPK than either a CS that preceded the UCS and ended with its onset or a CS that was paired in simultaneous compound with the UCS. CS–UCS contiguity and the forward ISI act additively to establish the CS–UCS association. No differences were observed between groups that were untreated and that received the CS and UCS unpaired. Similarities are noted in the temporal characteristics of associative learning in these Ss and vertebrate species. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Trends in institutional contributions to the Journal of Counseling Psychology..

Tabulated the institutional affiliation of each author for the major articles, brief reports, unsolicited comments, and contributions classified as research frontier or research methodology that appeared in Volumes 1–24 of the Journal of Counseling Psychology (JCP). Separate tabulations were made for most institutions, but the contributions of the following types of institutions were combined within type: community colleges, community mental health centers, correctional institutions, medical hospitals, public schools, religious organizations, and VA facilities. The data are summarized for the formative years of the journal (Volumes 1–8), the period of transition to an American Psychological Association journal (Volumes 9–26), the most recent 8-yr period (Volumes 17–24), and the 1st 24 yrs of publication. The data are also tabulated for the 4 latest volumes (21–24) to evaluate recent trends in institutional contributions. The 15 leading institutional contributors are rank ordered, and the number of contributions are reported within each time period. In addition, the impact of reassignment of credit for dissertation-related research on institutional productivity is studied. The relationship between institutional contributions to JCP and the perceived prestige of the institution is also investigated. (9 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Associative training results in persistent reductions in a calcium-activated potassium current in Hermissenda Type B photoreceptors.

Type B photoreceptors from the eyes of associatively trained Hermissenda had significantly greater light responses and net input resistances than Type B cells from control Ss on retention days following conditioning. Differences were still apparent when the contribution of a rapidly inactivating K+ current (IA) to the photoresponse was minimized by either depolarization-induced inactivation or block by 4-aminopyridine ions. Training-produced differences in Type B cell light responses were abolished by treatments that reduced the contribution of a calcium-activated K+ current (IK-Ca) to the light response. Under voltage-clamp conditions in which IK-Ca was isolated from other components of outward current, it was selectively reduced by associative training. The associative reduction of IK-Ca could not be attributed to training-produced reductions in the voltage-dependent calcium current of Type B cells. ICa was enhanced by associative training. A slower component of light-induced inward current was greater for Type B cells from associatively trained Ss. Previous results suggest that this slower component may be due to light-induced reduction of a calcium-activated K+ current. Training-produced reductions in a calcium-activated K+ may be responsible for enhanced photoresponses of Type B cells from conditioned Ss. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Hippocampal and nonhippocampal contributions to place learning in rats.

Brain structures thought to be critical for learning and memory were lesioned, and the effects on rats' ability to locate food on a radial maze in situations that provided different types of information was used to suggest general principles of information processing by hypothesized neural systems that include each of the lesioned structures. When animals were confined to food-containing and empty arms on different training trials, the learned discrimination between the arms was amygdala based. More training trials were required for ambiguous (adjacent arms) than for unambiguous (widely separated arms) discriminations. When rats moved around and entered both food and no-food arms on the same trial, the unambiguous discrimination was learned by both dorsal striatum- and hippocampus-based systems; however, the ambiguous discrimination was learned only by the hippocampus system. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Potentiation of phototactic suppression in Hermissenda by compound conditioning results in potentiated excitability changes in Type B and A photoreceptors.

Ocular photoreceptor responses were recorded from Hermissenda exposed to compound conditioning, light conditioning, or one of several control treatments. Type A photoreceptors from light-conditioned animals responded with smaller generator potentials than those from untrained animals; type B photoreceptors from light-conditioned animals responded with greater generator potentials and action potential frequencies than cells from controls. These photoresponse changes were accompanied by increases and decreases in the input resistances of type B and A photoreceptors, respectively. The same photoresponse changes occurred in exaggerated form in cells from compound-conditioned animals, but no additional input resistance changes were observed. The results suggest that potentiation of phototactic suppression by compound conditioning involves a facilitation of the same photoreceptor excitability changes produced by mere pairings of light and rotation. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Associative learning in the marsupials Didelphis albiventris and Lutreolina crassicaudata..

A procedure to study associative learning in didelphid marsupials (Didelphis albiventris and Lutreolina crassicaudata) was developed, based on the use of an appetitive unconditioned stimulus, discrete conditioned stimuli, and multiple-behavior recordings of freely moving animals. In Experiments 1 and 2, three basic conditioning phenomena were reported: differential conditioning, stimulus reversal, and summation. A specific behavior developed during the excitatory signal, independently of the particular stimulus involved, consisting of rhythmic, goal-centered, sagittal head movements, highly similar across subjects and species. Unlike previous experiments on Pavlovian conditioning in marsupials, the use of differential conditioning in within-subjects designs, with appropriate counterbalance of stimuli, precludes interpretation of these results in terms of pseudoconditioning, sensitization, or sensory-perceptual effects. These results open the possiblity for systematic research on the comparative, developmental, and neuropsychological aspects of learning to which marsupials can contribute as models. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Hemispheric and attentional contributions to perceptual organization deficits on the global-local task in schizophrenia.

Right and left hemisphere hypotheses have been proposed to account for cognitive deficits in schizophrenia. To examine these hypotheses, perception of global-local patterns was studied in 22 patients with schizophrenia and 28 normal comparison participants. The patients with schizophrenia showed an abnormally exaggerated global processing advantage when attention was divided between global and local levels but not when participants were instructed to attend to either the local or global level. This finding suggested a local processing (left hemisphere) deficit, which was overcome through strategic attentional allocation (instructional set). When the stimulus visual angle was reduced from 9° to 3°, the normal participants showed a shift from a local to a global processing advantage, but the patients did not. This finding suggested a more subtle deficit in strategic attentional processes that develop through exposure to stimulus context. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Pavlov's contributions to behavior therapy: The obvious and the not so obvious.

The foundation, accomplishments, and proliferation of behavior therapy have been fueled largely by the movement's grounding in behavioral principles and theories. Ivan P. Pavlov's discovery of conditioning principles was essential to the founding of behavior therapy in the 1950s and continues to be central to modern behavior therapy. Pavlov's major legacy to behavior therapy was his discovery of "experimental neuroses," shown by his students M. N. Eroféeva and N. R. Shenger-Krestovnikova to be produced and eliminated through the principles of conditioning and counterconditioning. In this article, the Pavlovian origins of behavior therapy are assessed, and the relevance of conditioning principles to modern behavior therapy are analyzed. It is shown that Pavlovian conditioning represents far more than a systematic basic learning paradigm. It is also an essential theoretical foundation for the theory and practice of behavior therapy. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Review of Social learning and clinical psychology.

Reviews the book, Social learning and clinical psychology by Julian B. Rotter (1954). Social Learning and Clinical Psychology is in effect two books in one, a trenchant and forceful evaluation of just what clinicians are doing, and a formulation of a behavior theory which strives to provide a more secure groundwork upon which meaningful clinical practice may be based. The theory, admittedly tentative and incomplete, represents a genuine contribution to the clarification of thinking about clinical problems. The book falls rather naturally into three distinct sections. Chapters I through IV present a detailed survey of the current functions and problems faced by the working clinical psychologist from a theoretical and technical point of view. The middle section of the book comprises the author's unique contribution, a "social learning theory of personality." The third section of this book, while broadest in scope, is somewhat disappointing. Here Rotter attempts to relate his four classes of variables, the subject's behavior, expectation of reinforcement, the value of external reinforcements, and the psychological situation, to the vast panoply of theoretical approaches, clinical instruments, and psychotherapeutic techniques which are involved in the clinician's functioning. On the whole, then, this book is an impressive achievement. Despite a few shortcomings, there is much to be learned from this book by those who are willing to read it carefully and reflectively. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Same/different abstract-concept learning by pigeons.

Eight pigeons were trained and tested in a simultaneous same/different task. After pecking an upper picture, they pecked a lower picture to indicate same or a white rectangle to indicate different. Increases in the training set size from 8 to 1,024 items produced improved transfer from 51.3% to 84.6%. This is the first evidence that pigeons can perform a two-item same/different task as accurately with novel items as training items and both above 80% correct. Fixed-set control groups ruled out training time or transfer testing as producing the high level of abstract-concept learning. Comparisons with similar experiments with rhesus and capuchin monkeys showed that the ability to learn the same/different abstract concept was similar but that pigeons require more training exemplars. (PsycINFO Database Record (c) 2011 APA, all rights reserved)     

Review of Social learning and systems approaches to marriage and the family.

Reviews the book, Social learning and systems approaches to marriage and the family by R. Dev. Peters and R. J. McMahon (see record 1988-97132-000). The volume aims specifically to address a variety of issues and to highlight areas where an integration of social learning and systems models seems to be occurring. In terms of variety, the editors have succeeded in their goal, with chapters on most of the key issues in the family field such as maternal depression, spouse abuse, divorce, sexual dysfunction, marital conflict and helping families deal with handicapped children. Most of the contributors are able to discuss theory and research pertaining to a particular family problem in an integrated and informative way and to relate these aspects to clinical intervention. This book is essentially a well written, easy to read volume which addresses a variety of family processes and problems and integrates theory, research and clinical practice. This broad scope should ensure that it will appeal to a wide audience in the helping professions. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Taste aversion learning in fyn mutant mice.

Conditioned taste aversion (CTA) learning is a robust form of classical conditioning in which animals rapidly associate a flavor with aversive internal symptoms. The present study assessed CTA learning in transgenic mice deficient in a specific nonreceptor tyrosine kinase (the fyn mutant). Fyn mutants show impaired long-term potentiation and marked deficits in acquisition of spatial learning tasks. To assess whether they are also impaired in CTA learning. fyn mutant and wild-type mice received 2 conditioning trials consisting of access to a flavored solution followed by administration of LiCl. Fyn mutant mice acquired significant CTAs following a single conditioning trial and these aversions were comparable to those seen in wild-type mice. These results indicate that the fyn mutation does not interfere with the acquisition of CTAs and hence that this mutation is not associated with a global learning deficit. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Induced variation of serotonin in Drosophila melanogaster and its relation to learning performance.

In insects the level of serotonin can be modified through the alimentary tract. Drosophila fed on chemically defined media to which has been added a synthesis inhibitor or an immediate precursor of this neurotransmitter have their serotonin level decreased or increased, respectively. (A 4- to 5-day treatment is optimal.) Such treated flies, if tested in a procedure of Pavlovian conditioning, have different learning performances. With the same duration of starvation, nearly the same threshold for sucrose solutions, but different amounts of serotonin, the flies (blindly trained) showed conditioned inhibition of the tarsal (or proboscis-extension) reflex according to the amount of serotonin. The highest level of this biogenic amine gave the best performance. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Interactive effects of age and familiarization in paired-associate learning.

Prior to learning a list of paired associates consisting of pictures of common objects, 40 preschool and 40 2nd graders were given 1 of 4 familiarization conditions: stimulus pretraining, response pretraining, irrelevant pretraining, and no pretraining. Results show that the 2nd graders exhibited positive transfer from familiarization to paired-associate learning due to nonspecific factors such as "warm-up." The preschoolers, however, displayed positive transfer due to more specific factors inherent in response and stimulus pretraining. These results suggest that the pretraining experience facilitated rehearsal by making available verbal labels. Results are consistent with (a) developmental hypotheses that emphasize growth in discriminative capacity and/or verbal mediation and (b) phase theories of paired-associate learning that emphasize stimulus and response learning stages. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Language-driven concept learning: Deciphering Jabberwocky.

Four experiments assessed (Whorfian) effects of language on acquiring event categories. During learning, English-like spoken language accompanied animated scenes in some conditions. Lexical (novel verbs) and/or syntactic cues (either argument structures or prepositions) covaried with event category. Other conditions provided no language. All participants' knowledge of event categories was tested without language. Participants learned the event categories better when some aspect of language covaried with them (Experiments 1, 2, & 3; but not with sounds, Experiment 4), and better still when two aspects of language covaried (Experiments 1 & 3). However, multiple (Experiments 2 & 3) and individual language cues (Experiment 4) did not always facilitate learning. The effect of language is more complicated than providing feedback, as in supervised learning, or increasing systematicity, as in unsupervised learning. Language form induced specific expectations, with effects on learning analogous to the effects of prior theories. (PsycINFO Database Record (c) 2010 APA, all rights reserved)