Passive avoidance learning in psychopathic and nonpsychopathic offenders.

Research on passive avoidance learning has demonstrated reliable differences between psychopaths and controls when avoidance errors result in electric shock but not in loss of money. Using monetary punishments, J. P. Newman et al (see record 1985-22847-001) found that psychopathic delinquents performed more poorly than controls in an experimental paradigm employing monetary reward as well as the avoidance contingency. The present study was conducted to replicate and extend these findings using adult psychopaths and a computer controlled task. 60 White male prisoners (mean age approximately 25 yrs) were assigned to psychopathic or nonpsychopathic groups using R. D. Hare's psychopathy checklist and the Diagnostic and Statistical Manual of Mental Disorders (DSM-III). Ss were administered a "go/no-go" discrimination task involving monetary incentives. One condition entailed competing reward and punishment contingencies; the other, 2 punishment contingencies. As predicted, psychopaths made significantly more passive avoidance errors than nonpsychopaths when the task contained competing goals but performed as well as controls when the Ss' only goal was avoiding punishment. Results corroborate earlier findings that psychopaths are relatively poor at learning to inhibit reward-seeking behavior that results in monetary punishment. (22 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Changes in rat brain muscarinic receptors after inhibitory avoidance learning

It is widely accepted that cerebral acetylcholine is necessary for learning and memory, but little is known about the type of muscarinic receptors involved in these functions. To investigate this problem, [3H]-N-methyl-scopolamine which binds to different types of muscarinic receptors, [3H]-Pirenzepine an M1 receptor antagonist, and [3H]-Oxotremorine-M which binds mainly to M2 receptors, were used as ligands to look for possible changes in muscarinic receptor density in neostriatum (NEO), hippocampus (HIP), amygdala (AMY), and temporo-parietal neocortex (CTX), after testing for retention of inhibitory avoidance, trained with high or low footshock intensities. After low reinforcement there was an M1 postsynaptic receptor up-regulation in NEO, HIP, and CTX, and an M2 presynaptic receptor down-regulation in HIP, which suggests a concerted pre- and postsynaptic cholinergic activation in this area. An up-regulation of both M1 and M2 receptors was detected in CTX of low and high footshocked animals, which indicates the presence of a cortical postsynaptic M2 receptor.     

Effects of intrathecal alpha1- and alpha2-noradrenergic agonists and norepinephrine on locomotion in chronic spinal cats

Noradrenergic drugs, acting on alpha adrenoceptors, have been found to play an important role in the initiation and modulation of locomotor pattern in adult cats after spinal cord transection. There are at least two subtypes of alpha adrenoceptors, alpha1 and alpha2 adrenoceptors. The aim of this study was to investigate the effects of selective alpha1 and alpha2 agonists in the initiation and modulation of locomotion in adult chronic cats in the early and late stages after complete transection at T13. Five cats, chronically implanted with an intrathecal cannula and electromyographic (EMG) electrodes were used in this study. Noradrenergic drugs including alpha2 agonists (clonidine, tizanidine, and oxymetazoline) and an antagonist, yohimbine, one alpha1 agonist (methoxamine), and a blocker, prazosin, as well as norepinephrine were injected intrathecally. EMG activity synchronized to video images of the hindlimbs were recorded before and after each drug injection. The results show differential effects of alpha1 and alpha2 agonists in the initiation of locomotion in early spinal cats (i.e., in the first week or so when there is no spontaneous locomotion) and in the modulation of locomotion and cutaneous reflexes in the late-spinal cats (i.e., when cats have recovered spontaneous locomotion). In early spinal cats, all three alpha2 agonists were found to initiate locomotion, although their action had a different time course. The alpha1 agonist methoxamine induced bouts of nice locomotor activity in three spinal cats some hours after injection but only induced sustained locomotion in one cat in which the effects were blocked by the alpha1 antagonist prazosin. In late spinal cats, although alpha2 agonists markedly increased the cycle duration and flexor muscle burst duration and decreased the weight support or extensor activity (effects blocked by an alpha2 antagonist, yohimbine), alpha1 agonist increased the weight support and primarily the extensor activity of the hindlimbs without markedly changing the timing of the step cycle. Although alpha2 agonists, especially clonidine, markedly reduced the cutaneous excitability and augmented the foot drag, the alpha1 agonist was found to increase the cutaneous reflex excitability. This is in line with previously reported differential effects of activation of the two receptors on motoneuron excitability and reflex transmission. Noradrenaline, the neurotransmitter itself, increased the cycle duration and at the same time retained the cutaneous excitability, thus exerting both alpha1 and alpha2 effects. This work therefore suggests that different subclasses of noradrenergic drugs could be used to more specifically target aspects of locomotor deficits in patients after spinal injury or diseases.     

Age-dependent improvement in passive avoidance learning of the young chick: Cholinergic mediation?

Studied cholinergic mediation of the age-dependent improvement in response suppression of the young chick by determining the performance of 144 Vantress?×?Arbor Acre 4-day-old chicks, pretreated with scopolamine (SCO), during passive avoidance (PA) and extinction testing. In Exp I, Ss were trained to keypeck for heat reward (prepunishment training), and then tested for PA learning under immediate, 2-sec-delayed, or no shock condition. Half of the Ss in each condition received saline injections before prepunishment training and .5 mg/kg SCO injections after training. The rest received .5 mg/kg SCO injections both before and after training. For Ss in both SCO groups, delaying shock onset resulted in significantly less response suppression than immediate response-contingent shock. In Exp II, 4-day-old Ss injected with saline or SCO were trained to keypeck for heat reward and then tested for resistance to extinction under response-contingent shock or nonshock conditions. Punishment decreased the number of extinction responses for both saline and SCO groups. Results indicte that the age-dependent improvement in response suppression of the young chick cannot be explained solely by a significant increase in central cholinergic functioning. (24 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Observation learning in day-old chicks using a one-trial passive avoidance learning paradigm

The ATP-binding cassette (ABC) transporters belong to a large superfamily of proteins which share a common function and a common nucleotide-binding domain. The CvaB protein from Escherichia coli is a member of the bacterial ABC exporter subfamily and is essential for the export of the peptide antibiotic colicin V. Here we report that, surprisingly, the CvaB carboxyl-terminal nucleotide-binding domain (BCTD) can be preferentially cross-linked to GTP but not to ATP at low temperatures. The cross-linking is Mg2+ and Mn2+ dependent. However, BCTD possesses similar GTPase and ATPase activities at 37 degrees C, with the same kinetic parameters and with similar responses to inhibitors. Moreover, a point mutation (D654H) in CvaB that completely abolishes colicin V secretion severely impairs both GTPase and ATPase activities in the corresponding BCTD, indicating that the two activities are from the same enzyme. Interestingly, hydrolysis activity of ATP is much more cold sensitive than that of GTP: BCTD possesses mainly GTP hydrolysis activity at 10 degrees C, consistent with the cross-linking results. These findings suggest a novel mechanism for an ABC protein-mediated transport with specificity for GTP hydrolysis.     

Passive avoidance training and recall are associated with increased glutamate levels in the intermediate medial hyperstriatum ventrale of the day-old chick

In the young chick, the intermediate medial hyperstriatum ventrale is involved in learning paradigms, including imprinting and passive avoidance learning. Biochemical changes in the intermediate medial hyperstriatum ventrale following learning include an up-regulation of amino-acid transmitter levels and receptor activity. To follow the changes of extracellular amino acid levels during passive avoidance training, we used an in vivo microdialysis technique. Probes were implanted in chicks before training the animals, either on a methylanthranylate- or water-coated bead. One hour later, recall was tested in both groups by presenting a similar bead. An increase of extracellular glutamate levels accompanied training and testing in both groups; during training, glutamate release was higher in methylanthranylate-trained than in water-trained chicks. When compared with the methylanthranylate-trained chicks during testing, the water-trained chicks showed enhanced extra-cellular glutamate levels. No other amino acid examined showed significant changes. After testing, the chicks were anesthetized and release-stimulated with an infusion of 50 mM potassium. Extracellular glutamate and taurine levels were significantly increased in both methylanthranylate- and water-trained chicks. The presentation of methylanthranylate as an olfactory stimulus significantly enhanced glutamate levels, especially in methylanthranylate-trained chicks. The results suggest that such changes in extracellular glutamate levels in the intermediate medial hyperstriatum ventrale accompany pecking at either the water- or the methylanthranylate-bead. The taste of the aversant may be responsible for the greater increases found in methylanthranylate-trained birds.     

The role of telencephalic NMDA receptors in avoidance learning in goldfish (Carassius auratus).

Studies with goldfish (Carassius auratus) have suggested that N-methyl-D-aspartate (NMDA) receptors are concentrated most densely in the telencephalon, a simple structure homologous to the limbic stricture of higher vertebrates. The present study investigated the amnestic effects of microinjections of the NMDA receptor antagonist D(-)-2-amino-5-phosphonopentanoic acid (D-AP5) to the goldfish telencephalon on avoidance conditioning. Results showed that microinjections of D-AP5 before training impaired avoidance learning at doses that did not impair performance processes. High-performance liquid chromatography measurements showed that D-AP5 was detected only in the telencephalon following microinjections. Thus, D-AP5 impaired avoidance learning through its interaction with telencephalic NMDA receptors in goldfish. Furthermore, microinjections of D-AP5 to the goldfish telencephalon immediately following training did not impair memory consolidation of avoidance conditioning. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Learning color words involves learning a system of mappings.

This research examines the difficulty children encounter when acquiring 2 specific sets of adjectives, color and size words, and suggests that children must acquire a system of mapping in learning these words. Children were assessed on 4 types of mappings (word–word maps, property–property maps, word–property maps, and word–word–property maps) by completing 3 color tasks. Children also participated in comparable tasks for size words. In Study 1, 13 two-year-olds were followed longitudinally at 3-week intervals. In Study 2, 56 two-year-olds participated in a cross-sectional replication. The results indicate that children acquire color maps in a characteristic order. Children demonstrated a different pattern of acquisition for size words. The results suggest that learning word associations may promote color word acquisition and that learning color words may promote selective attention to color. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Chloramphenicol-induced amnesia for passive avoidance training in the day-old chick

In all, 56 triads of same-sex 3rd-, 4th-, and 5th-grade children were observed during an intimate discussion, a cooperative puzzle task, a competitive game, and free play. Observers coded triadic interaction using a Q sort and individual process ratings. Of particular interest was how gender and the pattern of friendship ties among group members related to children's behavior. Triads of girls were more intimate, exchanged more information, and were less aggressive than were triads of boys. Analyses of within-gender variability revealed 2 prototypical types of triads among boys but only 1 among girls. Girls and boys expressed similar attitudes toward triadic interaction in postsession interviews. However, girls', but not boys', attitudes were closely linked to the quality of interactions during the session. For both sexes, interaction was not strongly influenced by the initial configuration of friendship ties among triad members.     

Isolation-stress-induced facilitation of passive avoidance memory in the day-old chick

Left ventricular (LV) midwall shortening (MWS) is subnormal in relation to LV circumferential end-systolic stress (ESS) (ESS-corrected MWS) in many hypertensive patients with normal LV chamber function and predicts subsequent morbidity and mortality. However, little is known of the relations of LV midwall function to demographic and metabolic variables or to arterial geometry. Asymptomatic, unmedicated normotensive (n=366) or hypertensive (n=282) adults were assessed with echocardiography and carotid ultrasound. In normal adults, lower LV MWS and ESS-corrected MWS, an index of LV contractility, were related independently to high total peripheral resistance, high heart rate, and male gender (all P<.00001), lower serum HDL cholesterol (P=.001) and diastolic pressure (P=.003), and for ESS-corrected MWS only, arterial relative wall thickness (RWT, P=.03). Among hypertensive patients, lower values for both midwall function indices were associated independently with higher peripheral resistance (P<.00001), heart rate (P<.00005), body mass index (P<.01), and arterial RWT (P=.04), as well as male gender (P<.0002). In the entire population, lower LV MWS was independently related to higher peripheral resistance, heart rate (both P<.00001), body mass index (P=.0006) and arterial RWT (P=.009); male gender (P<.00001); and lower age (P=.004), diastolic pressure (P=.042), and systolic carotid artery expansion (P=.032). Lower ESS-corrected MWS in the entire population was independently associated with higher peripheral resistance and heart rate (both P<.00001), body mass index (P=.0006), arterial RWT (P=.004); male gender; and lower diastolic pressure (both P<.00001), age (P<.00005), arterial expansion in systole (P=.006), and serum HDL cholesterol levels (P=.04). Among a subset (n=60), ESS-corrected MWS was positively related to apolipoprotein A1 (P=.004) and negatively to hemoglobin A1c (P<.01). Thus, higher LV midwall function is associated with female gender and more favorable profiles of hemodynamics, metabolic pattern, and arterial structure and function.     

Passive avoidance in psychopathic offenders: A replication and extension.

A passive avoidance task was administered to 97 Caucasian and 110 African American offenders to (a) replicate prior research demonstrating poor passive avoidance in psychopathic individuals (Ps) with low anxiety, (b) compare the effects of anxiety, neuroticism, and fear in identifying subgroups of Ps and controls who differ in passive avoidance, and (c) reevaluate the generalizability of this finding to African American offenders. Replicating past research with Caucasian offenders, low-anxious Ps committed significantly more passive avoidance efforts than low-anxious controls. Although this difference was also found in Ps and controls with low neuroticism scores, the comparison involving low-fear offenders failed to reach significance. As in past research, comparable comparisons involving African American offenders were not statistically significant. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Passive avoidance in syndromes of disinhibition: Psychopathy and extraversion.

According to the physiological animal model proposed by E. E. Gorenstein and J. P. Newman (see record 1980-24372-001), psychopaths and extraverts may be characterized by a common psychological diathesis related to behavioral inhibition. One aspect of this diathesis involves deficient passive avoidance learning, which has been central to explanations of unsocialized and antisocial behavior. In 3 experiments, a passive avoidance task was completed by 90 14–18 yr old males, 40 male university students, and 40 18–50 yr old men and women. Ss were also assessed on measures including the Eysenck Personality Questionnaire and MMPI. Results support the prediction that psychopaths and extraverts would exhibit deficient passive avoidance relative to nonpsychopaths and introverts, respectively. The passive avoidance deficit was particularly evident in tasks that required Ss to inhibit a rewarded response to avoid punishment. The latter finding may be important for explaining the inconsistent results regarding passive avoidance learning in psychopaths. Discussion focuses on the importance of reward in mediating the passive avoidance deficit of disinhibited individuals and on the existence of an indirect relationship between psychopathy and extraversion—one that is consistent with the observed experimental parallels as well as with the more ambiguous evidence regarding a direct correlation between measures of the 2 syndromes. (39 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Hippocampal function in avoidance learning and punishment.

Discusses the effects of hippocampal lesions in avoidance and punishment situations. It is proposed that animals with such lesions cannot process information about places and therefore cannot employ place strategies in avoidance learning and punishment situations; they can only employ cue strategies that involve learning to approach or avoid a cue or to perform a response in the presence of a cue. Intact animals, on the other hand, can employ both place and cue strategies. The data are, to a large extent, consistent with this hypothesis. Implications for theories of learning in situations involving aversive reinforcers are discussed. (125 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Sensory responsiveness and avoidance learning in rats.

Conducted an analysis of sensory responsiveness and avoidance learning in 3 experiments using 5 rat strains: MNR/Har/Lu, MR/Har/Lu, RCA/Lu, RHA/Lu, and RLA/Lu. Ss totaled 470. There were significant differences among the strains in response to electric footshock. Also, the strain-specific shock intensity as the UCS elicited significantly higher rates of avoidance learning as compared with the rates of avoidance learning under an equal but average level of shock intensity as the UCS. In general, discrete auditory and visual sensory modes as the CS produced almost the same rate of avoidance learning. The proportion of variation in avoidance learning attributable to strains was significant under all 6 experimental conditions except the no-discrete CS and strain-specific UCS conditions. (19 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

The role of nitric oxide in passive avoidance learning

The role of nitric oxide on passive avoidance learning was studied by administering L-arginine or D-arginine to male rats in a passive avoidance paradigm. L-Arginine administered into the lateral brain ventricle at a dose of 1.25 microg showed a tendency to increase the passive avoidance latency, and 2.5 microg exerted almost maximal action, but the action gradually increased still further up to 20 microg tested. D-Arginine had no action. Peripheral administration (intraperitoneal) of L-arginine facilitated the consolidation of passive avoidance learning in a dose-dependent manner. A significant increase in passive avoidance response was obtained following an injection of 100 mg/kg L-arginine. When L-arginine was given i.c.v. with a selected dose of 5 microg, 30 min prior to a learning trial, the latency of the passive avoidance response was likewise lengthened. However, when L-arginine was given 30 min before the 24-hr testing (retrieval), it was ineffective. It was also ineffective when given 6 hr after the training trial. However, when L-arginine was administered immediately following the training trial, the action in improving the consolidation could be detected 6 hr after the training trial. Nitro-L-arginine, which blocks nitric oxide synthase, can also block the facilitation of consolidation caused by the nitric oxide donor L-arginine. The nitric oxide synthase inhibitor per se in different doses had no action on the learning of a passive avoidance task. The results indicate that nitric oxide is able to facilitate the learning and consolidation of memory in a passive avoidance paradigm, but it is ineffective in retrieval processes. The results also suggest that, under the experimental circumstances used, nitric oxide is involved only in the facilitated learning and memory processes caused by pharmacological effect of L-arginine, and not involved in normal learning processes.     

Neuronal acetylcholine receptors with alpha7 subunits are concentrated on somatic spines for synaptic signaling in embryonic chick ciliary ganglia

Nicotinic acetylcholine receptors containing alpha7 subunits are widely distributed in the vertebrate nervous system. In the chick ciliary ganglion such receptors generate large synaptic currents but appear to be excluded from postsynaptic densities on the cells. We show here that alpha7-containing receptors are concentrated on somatic spines in close proximity to putative sites of presynaptic transmitter release. Intermediate voltage electron microscopy on thick sections, together with tomographic reconstruction, permitted three-dimensional analysis of finger-like projections emanating from cell bodies. The projections were identified as spines based on their morphology, cytoskeletal content, and proximity to presynaptic elements. Both in situ and after ganglionic dissociation, the spines were grouped on the cell surface and tightly folded into mats. Immunogold labeling of receptors containing alpha7 subunits showed them to be preferentially concentrated on the somatic spines. Postsynaptic densities were present in vivo both on the soma near spines and occasionally on the spines themselves. Synaptic vesicle-filled projections from the presynaptic calyx were interdigitated among the spines. Moreover, the synaptic vesicles often abutted the membrane and sometimes included Omega profiles as if caught in an exocytotic event, even when no postsynaptic densities were juxtaposed on the spine. The results suggest several mechanisms for delivering transmitter to alpha7-containing receptors, and they support new ideas about synaptic signaling via spines. They also indicate that neurons must have specific mechanisms for targeting alpha7-containing receptors to desired locations.     

Pharmacological modulation of the diazepam-insensitive recombinant gamma-aminobutyric acidA receptors alpha 4 beta 2 gamma 2 and alpha 6 beta 2 gamma 2

We characterized modulation of the gamma-aminobutyric acid (GABA)-evoked responses of the diazepam-insensitive alpha 4 beta 2 gamma2 and alpha 6 beta 2 gamma 2 recombinant GABAA receptors. The partial agonist bretazenil potentiated the responses of both receptors with similar dose dependence but with a higher maximal enhancement at the alpha 4 beta 2 gamma 2 receptor. The bretazenil-induced potentiation was reduced by the benzodiazepine antagonist flumazenil. At a high concentration (10 microM), flumazenil was a weak potentiator of the GABA response. The partial agonist imidazenil was inactive. The imidazobenzodiazepine inverse agonist Ro 15-4513, which is known to bind with high affinity to the alpha 6 beta 2 gamma 2 receptor, potentiated the GABA responses of the alpha 4 beta 2 gamma 2 and alpha 6 beta 2 gamma 2 receptor subtypes with similar dose dependence over the concentration range of 0.1-10 microM. Methyl-6, 7-dimethoxy-4-ethyl-beta-carboline, a beta-carboline inverse agonist, had a similar potentiating effect when tested at a concentration of 10 microM. The alpha 4 beta 2 gamma 2 and alpha 6 beta 2 gamma 2 receptor-mediated currents had equal sensitivities to furosemide and Zn2+ ions, both of which reduced the GABA-evoked responses. The alpha 6 beta 2 gamma 2 receptor but not the alpha 4 beta 2 gamma 2 receptor exhibited a low level of spontaneous activity in the absence of GABA; this resting current could be directly potentiated by Ro 15-4513, methyl-6,7-dimethoxy-4-ethyl-beta-carboline, bretazenil and flumazenil and was blocked by picrotoxin. Thus, although the alpha 4 beta 2 gamma 2 receptors are insensitive to benzodiazepine binding site full agonists, such as diazepam, they can be modulated by certain ligands acting as partial and inverse agonists at diazepam-sensitive receptors and thereby contribute to the respective pharmacological profiles.     

The modulation by neurosteroids of the scopolamine-induced learning impairment in mice involves an interaction with sigma1 (sigma1) receptors

Pulmonary tuberculosis: primary tuberculosis, usually asymptomatic, represents the first infection and is shown by a parenchymal mostly mid-pulmonary focus and satellite lymphadenopathy. Postprimary pulmonary tuberculosis, mostly located in the upper fields may be caused by endogenous reinfection for reactivation of a hematogenous focus formed during primary infection or from exogenous reinfection. Extrapulmonary tuberculosis: it includes numerous forms mostly from hematogenous spread. Miliary tuberculosis may involve a number of organs and apparatus besides the lung. Tuberculous meningitis predominantly involves the base of the skull, the fluid is clear with hypoglycorrhachia and lymphocyte pleocytosis. Lymph node tuberculosis is generally unilateral and cervical. Tuberculous pleuritis is exudative or dry. Other forms of tuberculous serositis are pericarditis and peritonitis. Renal tuberculosis involves the medullaris and intestinal tuberculosis the ileocecum; tuberculous spondilitis (Pott's disease) involves the last dorsal vertebrae. Other forms are osteoarthritis, genital tract tuberculosis, pancreatitis, laryngitis, otitis.     

Isolation–stress-induced facilitation of passive avoidance memory in the day-old chick.

This study showed that facilitation of recall of a weak version of the 1-trial passive avoidance learning task could be achieved by behavioral "stressing" of day-old chicks after training. Recall, usually retained for less than 9 hr, was extended by socially isolating the chicks for 1 hr immediately after training. There was a brief 3-fold increase in plasma corticosterone levels 10 min after isolation. Facilitated recall was not evident when chicks were isolated 2 hr after training, and it was blocked by intracerebral administration of 2-ng RU 38486, a specific glucocorticoid receptor antagonist, per chick. Male chicks responded more to isolation than did female chicks, presumably a consequence of the additional stress of the injection procedure. (PsycINFO Database Record (c) 2010 APA, all rights reserved)