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)     

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)     

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)     

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)     

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)     

Interactive contributions of intracellular calcium and protein phosphatases to massed-trials learning deficits in Hermissenda.

Using Hermissenda as subjects, massed-trials training deficits were examined. Associative pairings of light and rotation induced a progressively greater conditioned foot contraction in response to light as the intertrial interval (ITI) was extended (up to 8 min). In contrast, a short ITI (30 s) produced no evidence of learning. In a corresponding in vitro conditioning experiment that mimicked training of the intact animal, facilitation of neuronal excitability in the animal's B photoreceptors paralleled the results obtained in vivo. Imaging of intracellular Ca2+ using Fura-2 indicated that Ca2+ levels remained elevated during short ITIs. This Ca2+ accumulation appears to induce activation of protein phosphatases because normal facilitation of the B photoreceptors was induced with a short ITI if training occurred in the presence of a phosphatase inhibitor. These results suggest that intracellular Ca2+ and protein phosphatases contribute interactively to the kinetics of memory formation and provide evidence that an accumulation of intracellular Ca2+ across training trials may impede memory formation. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Differential conditioning to a compound stimulus and its components in the terrestrial mollusc Limax maximus..

The neuronal mechanism of associative learning and memory storage operating in the central nervous system of the terrestrial mollusc Limax maximus has been modeled as a computer simulation called LIMAX (A. Gelperin et al [1985]). One test of the LIMAX model is to determine whether Limax can learn to avoid a compound stimulus composed of the mixture of two innately attractive odors without simultaneously learning an aversion to the individual odors comprising the mixture. We found that Limax can learn a strong aversion to odor A?+?B while odor A and odor B remain strongly attractive when presented individually. This result led us to reexamine the sensory coding scheme used in the LIMAX model to represent stimulus mixtures, and it suggests neurophysiological experiments to examine the actual chemosensory coding scheme used by Limax. (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)     

Conditioned suppression of proboscis extension in Drosophila melanogaster..

Conducted a modified replication of J. Médioni and G. Vaysse's (1975) observations on conditioned inhibition of proboscis extension in the fruit fly. Médioni and Vaysse reported that the inhibition of the proboscis-extension response can be conditioned over trials if such proboscis extensions are punished by applying an aversive stimulus to the foreleg tarsi. In the present study, quinine was used as the aversive stimulus, and Ss were adult virgin female D. melanogaster of the Berlin wild-type strain. Ss in the experimental group showed a consistent decrement (62%) in the number of proboscis extensions over trials relative to the random control group, thus replicating Médioni and Vaysse's basic observations of conditioning, using a different strain of flies and a modified conditioning apparatus. (21 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Genetic architecture of olfactory discriminative avoidance conditioning in Drosophila melanogaster..

Recent claims to have demonstrated associative learning ability in fruitflies raise questions about the adaptive significance of behavioral modifiability of this species. In a strain survey and a 9?×?9 half diallel cross study of olfactory discriminative avoidance conditioning, a low narrow heritability and strong directional dominance or heterosis controlling nonrandom phenotypic variation were found. Furthermore, the predicted inbreeding depression and asymmetrical response to bidirectional genetic selection were both observed. The genetic architecture revealed in these 3 experiments is consistent with a close association between this conditioning phenotype and evolutionary fitness. Predictions from this interpretation to the nature of new mutations have been confirmed, and a possible role for conditioning in courtship behavior has been identified. (33 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Specific and nonspecific changes in visual evoked potentials during eyelid conditioning in the rabbit (Oryctolagus cuniculus).

Eye blinks in 18 female New Zealand white rabbits were conditioned to either the visual or nonvisual element of a compound CS. The visual element consisted of a series of electrical pulses to the optic chiasma, and the averaged evoked potentials (AEPs) produced by this stimulus were recorded in the dorsal lateral geniculate nucleus and the visual cortex. Findings indicate that the initial surface positive component of the cortical AEP was enhanced only when the eye blinks were conditioned to the visual stimulus, an effect that cannot be attributed to nonspecific mechanisms. The "postsynaptic" component of the geniculate AEP was also enhanced, but this occurred regardless of whether the eye blinks were conditioned to the visual or nonvisual stimulus, an effect that appears to be entirely nonspecific. Data from recovery cycles indicate that this enhancement effect cannot be attributed to an inhibition of inhibitory interneurons in the lateral geniculate nucleus. (16 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Differential modulation of changes in hippocampal-septal synaptic excitability by the amygdala as a function of either elemental or contextual fear conditioning in mice

Recent data obtained using a classic fear conditioning paradigm showed a dissociation between the retention of associations relative to contextual information (dependent on the hippocampal formation) and the retention of elemental associations (dependent on the amygdala). Furthermore, it was reported that conditioned emotional responses (CERs) could be dissociated from the recollection of the learning experience (declarative memory) in humans and from modifications of the hippocampal-septal excitability in animals. Our aim was to determine whether these two systems ("behavioral expression" system and "factual memory" system) interact by examining the consequences of amygdalar lesions (1) on the modifications of hippocampal-septal excitability and (2) on the behavioral expression of fear (freezing) resulting from an aversive conditioning during reexposure to conditional stimuli (CSs). During conditioning, to modulate the predictive nature of the context and of a discrete stimulus (tone) on the unconditional stimulus (US) occurrence, the phasic discrete CS was paired with the US or randomly distributed with regard to the US. After the lesion, the CER was dramatically reduced during reexposure to the CSs, whatever the type of acquisition. However, the changes in hippocampal-septal excitability persisted but were altered. For controls, a decrease in septal excitability was observed during reexposure to the conditioning context only for the "unpaired group" (predictive context case). Conversely, among lesioned subjects this decrease was observed in the "paired group" (predictive discrete CS case), whereas this decrease was significantly reduced in the unpaired group with respect to the matched control group. The amplitude and the direction of these modifications suggest a differential modulation of hippocampal-septal excitability by the amygdala to amplify the contribution of the more predictive association signaling the occurrence of the aversive event.     

Evidence for the Type in Type A behavior: A taxometric analysis.

Four taxometric procedures were applied to the self-report responses of 1,239 Ss who completed the Jenkins Activity Survey (JAS). All 4 procedures provided clear evidence for a latent class variable. A continuous model simulation that mimicked the item characteristics of the JAS correctly rejected the presence of a latent class variable. Using an external validation procedure, I reexamined 5 previously published studies to determine if the simple Type A–B dichotomy was as predictive of outcome measures as the use of continuous JAS scores. The presence of a latent class variable predicts no gain in predictive power in moving from a simple dichotomy to continuous scores. Across 5 studies, there was a slight decrease in the size of the relation between Type A-B and outcome for the continuous JAS scores relative to the simple Type A-B dichotomy. Taken together, these results suggest that the Type A-B distinction is based on a latent typology. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Physical symptom reporting in Type A and Type B children.

The study examines the developmental origins of one coronary-prone component of the Type A pattern, the tendency to suppress attention to physical symptoms. The symptom-reporting behavior of 85 male and female children from 5 to 14 years of age was studied in both a laboratory and a clinical context along with associated illness behaviors. The results indicate that Type A children underreport a wide variety of symptoms and that this phenomenon is independent of sex and age. On some types of symptoms, Type A underreporting may increase with age. In addition, there is evidence that Type A children (boys in particular) miss less school following surgery. Interestingly, Type A children tend to be underrepresented in elective surgery populations. The apparent continuities in symptom reporting and illness behaviors among Type A children and coronary adults is discussed. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Immediate self-image confrontation and changes in self-concept: Erratum.

Reports an error in the article "Immediate Self-Image Confrontation and Changes in Self-Concept" by Harry S. Boyd and Vernon V. Sisney (Journal of Consulting Psychology, 1967[Jun], 31[3], 291-294). On page 292, column 2, line 18, the sentence should read as follows: "The S was given a standardized interview which was designed to elicit a relatively high level of involvement and which lasted approximately 10 minutes." (The following abstract of this article originally appeared in record 1967-10493-001.) Changes in self-concept and concepts of interpersonal behavior of inpatients on a psychiatric ward were measured by Leary's interpersonal check list following self-image confrontation via video tape, and compared with a control group which was not given the self-image confrontation. Hypotheses regarding directions and kinds of change were developed and were supported. Interpersonal concept of the self, the ideal self, and the public self became less pathological and less discrepant with one another following the self-image confrontation, and differences between experimental and control groups remained significant 2 wk. later, with 1 exception. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Perceived control, Type A/B behavior, and quality of instruction.

Perceived control can impede achievement by interfering with instruction. College students who suffer temporary loss of control perform no better with an effective instructor than with an ineffective instructor. Type A students, however, may continue to benefit from effective instruction because of their intensified efforts to maintain control over academic outcomes when their control is threatened. Type A and B students received either contingent or noncontingent feedback on an aptitude test and then observed a half-hour lecture from either an unexpressive or expressive instructor. After the aptitude test they completed an attribution questionnaire, and after the lecture they took an achievement test and responded to a test-related questionnaire. Noncontingent feedback lowered both Type A and B students' perceived control and their internal attribution locus. It also reduced the effectiveness of instruction for Type B students but not for Type A students. Unlike those of Type B students, Type A students' self-perceptions were unaffected by instructional quality, which suggests a greater emphasis on self-directed, rather than other-directed, responsibility for achievement. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

The conditioning and generalization of changes in social perceptual dispositions.

This study examines hypotheses regarding the extent to which social perception may be effected by differential reinforcement and trait generalization. Ss are asked to judge photographs of faces as reflecting either one or the other of the following dimensions: safe-dangerous, good-bad, reliable-unreliable, and relaxed-tense. Selective response by E (saying "right" after the judgment "safe" was made," "wrong" after "dangerous") produced conditioning of the desired response and generalization to the other dimensions. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Overshadowing and summation in compound stimulus conditioning of the rabbit's nictitating membrane response.

Examined acquisition of the rabbit's nictitating membrane response to a light?+?tone simultaneous compound stimulus and its components as a function of the intensity of the tone. In Exp I, the tone intensity was varied across the values of 85, 89, and 93 db, and the CS–UCS interval was 400 msec. In Exp II, the tone intensities were 73, 85, and 93 db, and the CS–UCS interval was 800 msec. Exps III and IV further examined the effects of the 73-db CS–UCS tone at CS–UCS intervals of 400 and 800 msec. All experiments included control groups, which were trained with either a light or a tone CS. Overall results show repeated instances of overshadowing: the impairment of CR acquisition to one or both of the components of a compound. Two types of summation were obtained: within-Ss summation, in which Ss trained with a compound showed a higher level of responding to the compound than to either of its component CSs; and between-groups summation, in which a group trained with a compound showed faster CR acquisition than either of its corresponding control groups trained with a single CS. Results are discussed in terms of perceptual and distributive processing models of compound stimulus conditioning. (37 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Selective attention to negative feedback in Type A and Type B individuals.

In a study with 16 Type A (coronary prone) and 16 Type B (noncoronary prone) undergraduates, chosen by scores on the Jenkins Activity Survey, Ss were given a 4-min opportunity to gain feedback of their ostensible negative liabilities and positive assets. Specific asset and liability feedback was bogus and was held constant across all Ss. The amount of time spent in attending to negative information was the key dependent measure. Results show that Type A Ss selectively attended to significantly more negative information than did Type B Ss. It is suggested that selective attention to liability may exacerbate and/or maintain the Type A individual's belief of personal inadequacy and that this personal belief may in turn foster selective attention to liabilities. (8 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)