Conditioning of skin conductance levels through a combined instrumental-classical conditioning procedure

A paucity of studies and inconsistent results characterize attempts to instrumentally condition tonic electrodermal activity. The present study was conducted to further explore the classical and instrumental conditioning of skin conductance levels (SCLs) through auditory analogue feedback. Fifty undergraduates were randomly assigned to one of five groups of equal size: instrumental conditioning alone, classical conditioning alone, instrumental and classical conditioning combined, and two control groups. The combined training group achieved significantly higher SCLs relative to the group receiving instrumental conditioning alone.     

Effects of Enriched Physical and Social Environments on Motor Performance,Associative Learning,and Hippocampal Neurogenesis in Mice

We have studied the motor abilities and associative learning capabilities of adult mice placed in different enriched environments. Three-month-old animals were maintained for a month alone (AL), alone in a physically enriched environment (PHY), and, finally, in groups in the absence (SO) or presence (SOPHY) of an enriched environment. The animals'' capabilities were subsequently checked in the rotarod test, and for classical and instrumental learning. The PHY and SOPHY groups presented better performances in the rotarod test and in the acquisition of the instrumental learning task. In contrast, no significant differences between groups were observed for classical eyeblink conditioning. The four groups presented similar increases in the strength of field EPSPs (fEPSPs) evoked at the hippocampal CA3-CA1 synapse across classical conditioning sessions, with no significant differences between groups. These trained animals were pulse-injected with bromodeoxyuridine (BrdU) to determine hippocampal neurogenesis. No significant differences were found in the number of NeuN/BrdU double-labeled neurons. We repeated the same BrdU study in one-month-old mice raised for an additional month in the above-mentioned four different environments. These animals were not submitted to rotarod or conditioned tests. Non-trained PHY and SOPHY groups presented more neurogenesis than the other two groups. Thus, neurogenesis seems to be related to physical enrichment at early ages, but not to learning acquisition in adult mice.     

The Pavlovian analysis of instrumental conditioning.

An account was given of the development within the Russian literature of a uniprocess formulation of classical and instrumental conditioning, known as the bidirectional conditioning hypothesis. The hypothesis purports to offer a single set of Pavlovian principles to account for both paradigms, based upon a neural model which assumes that bidirectional (forward and backward) connections are formed in both calssical and instrumental conditioning situations. In instrumental conditioning, the bidirectional connections are hypothesized to be simply more complex than those in classical conditioning, and any differences in empirical functions are presumed to lie not in difference in mechanism, but in the strength of the forward and backward connections. Although bidirectional connections are assumed to develop in instrumental conditioning, the experimental investigation of the bidirectional conditioning hypothesis has been essentially restricted to the classical conditioning operations of pairing two CSs (sensory preconditioning training), a US followed by a CS (backward conditioning training) and two USs. However, the paradigm involving the pairing of two USs, because of theoretical and analytical considerations, is the one most commonly employed by Russian investigators. The results of an initial experiment involving the pairing of two USs, and reference to the results of a more extensive investigation, leads us to tentatively question the validity of the bidirectional conditioning account of instrumental conditioning.     

A comparison of the effects of vicariously instigated classical conditioning and direct classical conditioning procedures.

Two groups of Ss received either two or 16 paired classical conditioning trails beyond the peak CR. A third group received the same stimuli as the 16 postpeak condition but in an unpaired and random order. The stimuli in all three groups were delivered directly to S. Subsequently, all three groups, including a fourth which was not given any prior direct classical conditioning, were exposed to vicariously instigated classical conditioning. This consisted of having S observe someone (model) employed by E who received the same CS as was delivered during direct conditioning. The CS was paired with the feigned arm movement of the model, simulating a reaction to shock. This vicarious classical conditioning procedure when compared to direct classical conditioning resulted in smaller GSR magnitudes for both the CRs and UCRs. Previous experience with direct classical conditional seems to have had an attenuating effect on GSR magnitude during the vicarious situation. A postexperimental questionnaire tended to support the results, and the relationship between the present study and current classical conditioning theory is discussed.     

Corticosterone responses, hurdle-jump acquisition, and the effects of dexamethasone using classical conditioning of fear

Male hooded rats were habituated, classically conditioned with 30 CS-UCS (light-footshock) pairings, and subsequently tested for corticosterone response or instrumental hurdle-jump acquisition. In Experiment 1, corticosterone levels were lowest during chamber placement alone (during habituation), higher during presentations of the CS after conditioning with a low shock intensity, even higher during classical conditioning with the low shock intensity, and highest during classical conditioning or CS presentations involving a high shock intensity. Injections of the synthetic glucocorticoid dexamethasone before both conditioning and hurdle-jump acquisition sessions (Experiment 2) did not affect acquisition occurring during early trials, but produced slow hurdle-jump speeds late in the session. This agrees with previous findings of glucocorticoid facilitation of fear extinction, but does not indicate a simple suppression of fear by dexamethasone. When dexamethasone was given only prior to the classical conditioning session (Experiment 3) hurdle-jump acquisition was poor only on the early trials, and corticosterone levels after 60 min of CS presentations were higher than control values. These results agree with the proposal of a state-dependent effect of dexamethasone on memory retrieval.     

Plasticity of the social behavior in Drosophila

Original data illustrate self-starting classical conditioning to environmental factors in Drosophila, the factors serving as signals of a possible threat from other individuals and blocking initiation of activity. Instrumental conditioning resulting in reduction of an initially high level of activity in the group situation, helps a fly to avoid aggression from other flies and to use the food resources more efficiently. Classical conditioning makes it unnecessary for a fly to learn this instrumental task again and again: being faced with an analogous situation the fly automatically decreases its activity following presentation of the conditioned stimuli or the specific environment.     

The evolutionary aspects of the dynamic acquisition of simple conditioned reflexes

The dynamics of elaboration of simple classical and instrumental conditioned reflexes in snails, rats, cars, dogs and humans was investigated. The dependence between the number of correct responses (in percentages) and the number of reinforcements was significantly approximated with exponential equation including the coefficient describing the initial level of conditioning. Regression analysis gave the opportunity to compare the dynamics of conditioning in different animal species.     

Avoidance conditioning in bamboo sharks (Chiloscyllium griseum and C. punctatum): behavioral and neuroanatomical aspects

Animals face different threats; to survive, they have to anticipate how to react or how to avoid these. It has already been shown in teleosts that selected regions in the telencephalon, i.e., the medial pallium, are involved in avoidance learning strategies. No such study exists for any chondrichthyan. In nature, an avoidance reaction may vary, ranging from a ‘freeze’ reaction to a startling response and quick escape. This study investigated whether elasmobranchs (Chiloscyllium griseum and C. punctatum) can be conditioned in an aversive classical conditioning paradigm. Upon successful conditioning, the dorsal, medial and lateral pallium were removed (group 1) and performance tested again. In a second group, the same operation was performed prior to training. While conditioning was successful in individuals of both groups, no escape responses were observed. Post-operative performance was assessed and compared between individual and groups to reveal if the neural substrates governing avoidance behavior or tasks learned in a classical conditioning paradigm are located within the telencephalon, as has been shown for teleosts such as goldfish.     

The role of visual stimuli in the acquisition of place preference with morphine reinforcement]

In experiments with rats was studied the role of visual stimuli in conditioning of place preference in a T-shaped chamber, certain stimuli being combined with morphine injection (5 mg/kg). Intensity of illumination of the chamber sections, colour of walls, and the orientation of dark stripes on the walls were varied. Testing the animals' behaviour began with determining the reward properties of certain visual stimuli on the basis of the total time of the animals' stay in a chamber. Procedure of combining the visual stimuli with morphine was repeated four times. Associative properties of the stimuli were revealed by comparing the learning efficiency in different experimental groups. Learning within the framework of the place preference model was concluded to depend upon the reward properties of the visual stimuli, whereas the behaviour itself to be based on the mechanism of the instrumental but not the classical conditioned response.     

Activity of neurons in the pedunculopontine nucleus in conditioned instrumental appetitive reflex

Activity of 91 neurons in the compact and diffuse parts of the pedunculopontine tegmental nucleus (PPTg) was recorded in freely moving rabbits during execution of instrumental appetitive conditioning. Of the recorded neurons, 37.4% changed their activity in response to a conditioned stimulus, which is the evidence for the PPTg involvement in instrumental conditioning. Excitatory conditioned neuronal responses to the conditioned stimulus and food reinforcement significantly prevailed over inhibitory reactions. Neuronal responses to the conditioned stimulus were classified in several basic patterns reflecting stimulus effects, structure of the behavioral act, and reinforcement properties. These reactions indicate the involvement of the PPTg in attention, motor learning, and reinforcement. The revealed differences in associative reactive properties of the compact and diffuse parts of the PPTg to the conditioned stimulus and reinforcement point to the functional heterogeneity of this structure and suggest the leading role of the cholinergic part of the PPTg in instrumental appetitive conditioning and reinforcement as well as the essential contribution of the diffuse part into classical appetitive conditioning.     

Reward,motivation, and reinforcement learning

There is substantial evidence that dopamine is involved in reward learning and appetitive conditioning. However, the major reinforcement learning-based theoretical models of classical conditioning (crudely, prediction learning) are actually based on rules designed to explain instrumental conditioning (action learning). Extensive anatomical, pharmacological, and psychological data, particularly concerning the impact of motivational manipulations, show that these models are unreasonable. We review the data and consider the involvement of a rich collection of different neural systems in various aspects of these forms of conditioning. Dopamine plays a pivotal, but complicated, role.     

The role of contextual conditioning in the effect of reinforcer devaluation on instrumental performance by rats

Different groups of rats received different amounts of training to lever press for a food reinforcer before an aversion was conditioned to the food. This devaluation of the reinforcer reduced responding in both subsequent extinction and reinforced tests of responding to a degree that was independent of the amount of instrumental training. Moreover, interpolating context extinction between aversion conditioning and the extinction test reduced the magnitude of the devaluation effect, thereby indicating that Pavlovian contextual conditioning may play a role in the instrumental devaluation effect.     

Pavlov's cockroach: classical conditioning of salivation in an insect

Secretion of saliva to aid swallowing and digestion is an important physiological function found in many vertebrates and invertebrates. Pavlov reported classical conditioning of salivation in dogs a century ago. Conditioning of salivation, however, has been so far reported only in dogs and humans, and its underlying neural mechanisms remain elusive because of the complexity of the mammalian brain. We previously reported that, in cockroaches Periplaneta americana, salivary neurons that control salivation exhibited increased responses to an odor after conditioning trials in which the odor was paired with sucrose solution. However, no direct evidence of conditioning of salivation was obtained. In this study, we investigated the effects of conditioning trials on the level of salivation. Untrained cockroaches exhibited salivary responses to sucrose solution applied to the mouth but not to peppermint or vanilla odor applied to an antenna. After differential conditioning trials in which an odor was paired with sucrose solution and another odor was presented without pairing with sucrose solution, sucrose-associated odor induced an increase in the level of salivation, but the odor presented alone did not. The conditioning effect lasted for one day after conditioning trials. This study demonstrates, for the first time, classical conditioning of salivation in species other than dogs and humans, thereby providing the first evidence of sophisticated neural control of autonomic function in insects. The results provide a useful model system for studying cellular basis of conditioning of salivation in the simpler nervous system of insects.     

The Role of Matrix Metalloproteinase in the Intimal Sarcoma-Like Cells Derived from Endarterectomized Tissues from a Chronic Thromboembolic Pulmonary Hypertension Patient

Sarcoma-like cells (SCLs) were derived from endarterectomized tissue of a single chronic thromboembolic pulmonary hypertension (CTEPH) patient during incubation of those thrombi at second passage as described at our previous report. These cells had malignant potential, with an increased expression of matrix metalloproteinase-14 (MMP-14), leading to tumor emboli within pulmonary arteries in in vivo studies. The purpose of this study was to perform a more detailed evaluation of the characteristics of SCLs, and to elucidate the role of the increased expression of MMP-14 expression in the growth and death of these cells. In order to elucidate the characteristics of SCLs and to confirm the protein expression of MMP-14, three-dimentional culture, invasion assays, a Western blot analysis and immunohistochemical studies were performed. To examine the role of MMP-14 in tumorigenesis, the metalloproteinase inhibitor, batimastat, was administered to SCID mice which were subcutaneously injected with SCLs. Those mice were sacrificed on day 14 and the tumor volume was evaluated. A Western blot analysis showed the increased expression of MMP-14 in comparison to the expression in lung adenocarcinoma cells (A549). Immunohistochemistry showed that SCLs were positive for vimentin, MMP-14, MMP-2 and CD44. However, endothelial markers, such as CD31 and von Willebrand factor (vWF), were negative. The in vivo studies demonstrated that batimastat could suppress the growth of the subcutaneous tumors formed by the SCLs. This study suggested that MMPs had critical roles on the pathological activities of SCLs and that batimastat might have anti-proliferative and anti-invasive effects on these cells.     

A classical conditioning paradigm for the study of learning in a ganglion of the cockroach (Periplaneta Americana)

It has been demonstrated that a headless cockroach can be conditioned to hold up its leg if it receives a shock upon lowering it (Horridge 1962). This was demonstrated as a significant change in a large group of animals. The work here develops further the original preparation reducing the variability so that the change can be demonstrated in a single animal. A single leg can then be used as its own control. For electrophysiological study of conditioning a classical conditioning paradigm has advantages over an operant one and this is discussed. A method for applying the classical conditioning procedure is described.     

Olfactory conditioning of positive performance in humans

Olfactory conditioning effects have been widely demonstrated in the animal literature but more seldom in human populations and rarely of consciously controlled human behaviors. Building upon previous work on negative performance, we report the first experimental evidence that odors can be used effectively in a classical conditioning paradigm to positively influence human behavior. In the present study, underachieving schoolchildren experienced unexpected success at a paper-and-pencil task in the presence of an ambient odor. When they later experienced the same odor again, performance on other tasks was superior to that of relevant control groups. These data substantially extend previous results on human olfactory classical conditioning and show that odors potentially can be used to exert positive influences on human behavior.     

White Matter Changes Associated with Resting Sympathetic Tone in Frontotemporal Dementia vs. Alzheimer’s Disease

Background

Resting sympathetic tone, a measure of physiological arousal, is decreased in patients with apathy and inertia, such as those with behavioral variant frontotemporal dementia (bvFTD) and other frontally-predominant disorders.

Objective

To identify the neuroanatomical correlates of skin conductance levels (SCLs), an index of resting sympathetic tone and apathy, among patients with bvFTD, where SCLs is decreased, compared to those with Alzheimer’s disease (AD), where it is not.

Methods

This study analyzed bvFTD (n = 14) patients and a comparison group with early-onset AD (n = 19). We compared their resting SCLs with gray matter and white matter regions of interest and white matter measures of fiber integrity on magnetic resonance imaging and diffusion tensor imaging.

Results

As expected, bvFTD patients, compared to AD patients, had lower SCLs, which correlated with an apathy measure, and more gray matter loss and abnormalities of fiber integrity (fractional anisotropy and mean diffusivity) in frontal-anterior temporal regions. After controlling for group membership, the SCLs were significantly correlated with white matter volumes in the cingulum and inferior parietal region in the right hemisphere.

Conclusion

Among dementia patients, SCLs, and resting sympathetic tone, may correlate with quantity of white matter, rather than with gray matter or with white matter fiber integrity. Loss of white matter volumes, especially involving a right frontoparietal network, may reflect chronic loss of cortical axons that mediate frontal control of resting sympathetic tone, changes that could contribute to the apathy and inertia of bvFTD and related disorders.     

Fasting stress exacerbates classical conditioned histamine release in guinea pigs

To clarify the contribution of stress to classical conditioning-associated asthmatic responses, the effect of fasting stress on conditioned histamine release was investigated in a guinea pig model of asthma. The animals were randomly divided into 2 groups for Experiment 1 and 2, and received a conditioning procedure in which ovalbumin (OA) as an unconditioned stimulus (US) and dimethylsulfide (DMS, sulfur smelling) as a conditioned stimulus (CS) were simultaneously inhaled after fasting for 16 h. Then, one group was given food as a reward for respiratory distress, and the other group was denied it for more than 3 h, while being placed in front of the feeding group. After this procedure was repeated 5 times, the plasma histamine levels in response to the CS were measured in half of each group in Experiment 1, and the respiratory resistance (Rrs) was assessed similarly in the other half of each group in Experiment 2. The same experiments were again performed after exchanging assignments of feeding group or fasting group in both experiments. The control groups in both experiments received the CS and the US 10 times separately in a random order under 16 h fasting conditions and were provided food after the exposures. After these pseudo-conditioning presentations, the plasma histamine levels or the Rrs in response to the CS were measured. In Experiment 1, the plasma histamine levels in the fasting stress group after the first conditioning sessions were significantly higher than those of the other groups. This difference was not observed when the groups were exchanged. In Experiment 2, the fasting stress group showed higher values in the Rrs compared to the other groups, irrespective of the first or second conditionings; however, they were not significant. The present study indicates that fasting stress after the conditioning procedures exacerbates the following conditioned histamine release, although the stress effect on bronchoconstriction was not confirmed.     

Classical conditioning of ventilatory responses in humans

A classical conditioning experiment, in which an auditory stimulus was paired with a hypoxic stimulus, was carried out on 34 normal subjects assigned to two groups (experimental and control). Each subject took part in one session divided into two phases, acquisition and test. In the acquisition phase, eight hypoxic and eight auditory stimuli were paired in the experimental group and unpaired in the control group. In the test phase, which was identical for the two groups, the hypoxic stimuli were suppressed and three purely auditory stimuli were presented. Significant differences between the two groups in ventilatory response to these auditory stimuli provided evidence for conditioning. In the control group, no significant changes were elicited by the auditory stimuli, whereas a conditioned increase in total cycle duration was observed in the experimental group. The conditioned response closely resembled the first component of the hypoxic response. Analysis of the pattern of the conditioned response, along with postexperimental interviews, strongly suggests that this response was not mediated by volitional factors.     

A simple EMG—Reward system for biofeedback training of children

An automated reward system to be used with standard electromyographic (EMG) biofeedback instrumentation is described. The on-line reward system, when coupled with standard biofeedback instrumentation and procedures, constitutes instrumental conditioning. In addition to describing the EMG—reward interface circuity, a study demonstrating the efficacy of the instrumental conditioning approach with cerebral-palsied children is presented.This research was aided by a grant from the Easter Seal Research Foundation of the National Easter Seal Society for Crippled Children and Adults, and by a grant from the Tulsa Cerebral Palsy Association.