1,721,007 research outputs found
Effects of intra-amygdala R(+) 7-OH-DPAT on intra-accumbens d- amphetamine-associated learning I. Pavlovian conditionin
No full textWe have previously obtained evidence that the mesoamygdaloid dopamine projection modulates the acquisition of a conditioned response (CR) elicited by presentation of a conditioned stimulus (CS) predicting the availability of a natural (sucrose) reward. This property was found to be dependent upon D3, but not D1 or D2, dopamine receptor activation. The aim of the present study was to determine whether the mesoamygdaloid dopamine projection is similarly involved in the acquisition of a drug-associated CR. Thus, two groups of rats with guide cannulae aimed at the nucleus accumbens and amygdala were trained using a Pavlovian conditioning procedure in which an initially neutral CS was paired with a computer-controlled, bilateral intraaccumbens infusion of d-amphetamine (the unconditioned stimulus; US). Conditioning sessions were conducted in standard operant chambers, with each session consisting of a single CS-US trial. For one group of rats, CS presentation was positively correlated with the drug US (Paired group), while for the second group CS and US presentations were negatively correlated (Unpaired group). During training, locomotor activity was recorded and was utilised as the measure both of the unconditioned (UR) and conditioned response (CR). A within-subjects design was utilised to investigate the effect of post-session bilateral intraamygdala administration of R(+) 7-OH- DPAT on the development of the drug-associated CR. Hence, both Paired and Unpaired groups were exposed to two different CSs which were presented on alternate sessions. Post-session bilateral intra-amygdala administration of R(+) 7-OH-DPAT (10 nmol) followed sessions in which one CS was presented, while intra-amygdala vehicle followed sessions in which the alternate CS was presented. The development of a CR occurred only in the presence of a CS that had been positively correlated with presentation of the drug US. Post- session, intra-amygdala administration of R(+) 7-OH-DPAT enhanced the acquisition of this CR. However, R(+) 7-OH-DPAT was without effect upon the unconditioned response to intra-accumbens d-amphetamine. Our previous data indicate a comparable effect of R(+) 7-OH-DPAT on conditioning to a CS associated with a non-drug, natural reward. Therefore, taken together, these findings suggest that D3 dopamine receptors within the amygdala modulate specifically the acquisition of Pavlovian conditioned responses, regardless of whether drug or natural rewards constitute the US
Double dissociation of the behavioural effects of R(+) 7-OH-DPAT infusions in the central and basolateral amygdala nuclei upon Pavlovian and instrumental conditioned appetitive behaviours
No full textDopaminergic cell bodies located within the ventral mesencephalon innervate the amygdaloid complex, a region critically involved in the attribution of affective significance to environmental stimuli. Recently, we have shown that post-session intra-amygdala administration of a D3 dopamine receptor agonist enhances selectively the acquisition of an appetitive conditioned response. In the present study, we have investigated the potential involvement of the central nucleus and the basolateral nuclei of the amygdala in mediating this effect. Thus, rats were trained to associate an arbitrary stimulus (CS+) with the availability of 10% sucrose reward. Post-session infusions of the D3 receptor-preferring agonist, R(+) 7-OH- DPAT, were made into either the central nucleus or basolateral nuclei. Acquisition of a conditioned approach response was enhanced by R(+) 7-OH- DPAT infusions within the central nucleus, but not within the basolateral nuclei. Drug infusions into either region failed to affect approach behaviour elicited by presentation of a control stimulus (CS-), explicitly unpaired with sucrose reward. The effects of pre-test infusions of R(+) 7-OHDPAT on the instrumental properties of the stimuli were then determined. Rats were presented with two novel levers, depression of one lever resulted in presentation of the CS+, while presentation of the CS- was contingent upon depression of the other lever. Rates of response upon each lever as well as the ability of the conditioned stimuli subsequently to elicit conditioned approach behaviour were recorded. Data revealed a double dissociation of the effects of R(+) 7-OH-DPAT on the expression of the Pavlovian and instrumental properties of the reward-related stimulus. Thus, within the central nucleus R(+) 7-OH-DPAT dose-dependently attenuated expression of the conditioned approach response, but had no effect upon instrumental responding maintained by the conditioned reward. In contrast, within the basolateral nuclei, R(+) 7-OH-DPAT had no effect upon expression of conditioned approach behaviour, but abolished selectively the ability of the reward-associated stimulus to support the acquisition of a novel instrumental response. Hence, these data indicate that distinct regions of the amygdaloid complex process distinct aspects of conditioned appetitive behaviours
Blockade of the acquisition, but not expression, of associative learning by pre-session intra-amygdala R(+) 7-OH-DPAT
No full textRationale: Two issues were addressed regarding the effects of amygdala dopamine manipulations on associative learning: first, an apparent contradiction between the effects of post- vs. pre-session dopaminergic manipulations and second, the ability of dopaminergic infusions to affect association formation vs. its expression following extended training. Objectives: The ability of pre-session infusions of a dopamine receptor agonist (R(+) 7-OH-DPAT) to inhibit acquisition of a conditioned approach response was examined and compared with the same manipulation following overtraining. Further experiments extended these findings. Materials and methods: Experiment 1 infused pre-session intra-amygdala R(+) 7-OH-DPAT (0, 0.1, 1 nmol) during conditioned approach acquisition. Experiment 2 applied pre-session intra-amygdala R(+) 7-OH-DPAT (0, 0.01, 0.1, 1 nmol) during expression of the same response, once well learned. Experiment 3 required the inhibition of a conditioned approach response following unconditioned stimulus (US) removal. Experiment 4 examined the ability of animals with prior drug experience to acquire a conditioned response to a novel stimulus. Results: Experiments 1-3 showed that pre-session amygdala R(+) 7-OH-DPAT impaired acquisition of either excitatory or inhibitory conditioned responding, but was ineffective following overtraining. Drug-induced impairments in acquisition of a specific conditioned stimulus (CS)-US relationship continued well beyond the cessation of drug treatment, but were found not to transfer to an alternate CS in Experiment 4. Conclusions: Pre-session dopamine receptor activation within the amygdala may impair the acquisition, but not expression, of CS-US associations. Enhanced learning reported earlier following post-session dopamine receptor activation may occur indirectly through reduced interference with the consolidation of recent learning
Psychological factors contributing to active aging in Sardinia
No full textThe demands associated with rapid ageing populations are a significant concern in many countries. An aim central to many sociopolitical strategies is the promotion of successful ageing. Knowledge of the basis of successful ageing is advancing but many issues remain to be resolved not least because of a variety of challenges. One potentially important approach for enhancing successful ageing is through the study of people possessing exceptional longevity, health and happiness. One such population exists in the Ogliastra region of Sardinia. We have recently undertaken a series of studies examining links between various psychosocial factors and subjective well-being, the most common single criterion of successful ageing. In this presentation we will discuss some of the most salient findings from this investigatio
Do self-referent metacognition and residential context predict depressive symptoms across late-life span? A developmental study in an Italian sample
No full textThere is controversial evidence concerning the variables favoring depression in community-dwelling elderly individuals. This study mainly investigates the impact of lifestyle, residential environment, cognitive efficiency and social desirability in predicting self-assessed depressive signs in late adult span
Characterisation of the phenomenon of "one-trial tolerance" to the anxiolytic effect of chlordiazepoxide in the elevated plus-maze
No full textIn the elevated plus-maze test of anxiety the scores of control animals remain stable over repeated tests. However, a single prior exposure to the plus-maze renders an animal insensitive to the anxiolytic effects of chlordiazepoxide. This phenomenon of "one-trial tolerance" persisted even when the two trials were separated by as much as 2 weeks. It has previously been shown that the drug state of the animal on trial 1 is not important to the development of the phenomenon, but one-trial tolerance did not develop if a very high dose (75 mg/kg) of chlordiazepoxide was given on trial 1; it is suggested that this is due to the amnesic effects of the drug. The learning on trial 1 was not specific to a particular plus-maze and tolerance could be observed even when the maze on trial 1 was made from different material. The crucial experience on trial 1 was experience of an open arm of the maze. Whereas tolerance could be obtained as a result of a previous plus-maze experience, there was no evidence of an anxiogenic withdrawal response when rats were tested the following day undrugged. The phenomenon of one-trial tolerance is explained within our recently proposed two-factor theory of benzodiazepine dependence; it is suggested that one-trial tolerance provides a method for studying the mechanism underlying the development of tolerance to anxiolytic effects, independently from the mechanism underlying the development of withdrawal responses. © 1990 Springer-Verlag
Does education influence visuo-spatial and verbal immediate serial recall in healthy older adults?
No full textThere are conflicting findings concerning the effect of education on different cognitive measures in late adulthood. The primary aim of the current study was to determine if level of education predicted the efficiency of passive and active visuo-spatial and verbal immediate serial order functions in Italian cognitively healthy elders aged 60–99 years. In Experiment 1, participants were asked to immediately retrieve sequences of positions in forward
and backward order using the Corsi Block Tapping Task. In Experiment 2 a further sample of Italian elders was presented the Digit Span test, that is, the forward and backward immediate recall of strings of digits was requested. Our results suggest that level of education impacts significantly the efficiency of visuo-spatial and verbal immediate recall processes in late adulthood. Moreover, the assessment of passive and active working memory processes in older people can be partially biased by schooling effects
More to blue zones than long life: Positive psychological characteristics
No full textBlue Zones are defined as regions of exceptional longevity. Emerging evidence also indicates the presence of several positive psychological characteristics amongst older inhabitants. No synthesis of this information is currently available. The current article focuses on psychological characteristics of successful ageing, including perceived wellbeing and cognitive health. Relevant findings concerning the Sardinian Blue Zone are reviewed along with an evidence suggesting links to the distinctive sociocultural environment of this region. People aged 65+ living in the Sardinian Blue Zone have substantially lower levels of depressive symptomatology, higher levels of selfperceived well-being and better subjective and objective cognitive health relative to matched control samples. These differences are robust, reliable and persist throughout late adulthood. Important determinants of the positive traits include increased active engagement in community religious and leisure activities. Sparse evidence for other Blue Zones exists but reduced levels of depression may be a shared attribute. Older Blue Zone Sardinians possess positive psychological characteristics, which are associated with successful ageing and are known to promote longevity. Blue Zone populations appear to be a valuable, but overlooked, resource for the study of positive aspects of ageing
Does social desirability influence psychological well-being: perceived physical health and religiosity of Italian elders? A developmental approach
No full textObjective: This study was mainly aimed at exploring the relationship between psychological well-being and lifestyle, religion, perceived physical health and social desirability of Italian elders. Methods: Four hundred and six cognitively healthy 65–99 years old participants were recruited from the Italian isle of Sardinia, where a high prevalence of centenarians is registered. Participants were presented with several tools assessing psychological well-being, lifestyle, social desirability, religiosity and subjective physical health. Results: A hierarchical regression analysis revealed that the social desirability measure is the best predictor of general subjective well-being, whereas further predictors are age, perceived physical health and gardening. A significant but moderate relationship was also found between psychological well-being, subjective physical health and religiosity, while controlling for social desirability. Conclusions: Social desirability seems to contaminate the self-rating of psychological well-being in late adulthood. Moreover, from a developmental perspective, age-related factors, life style and perceived physical health are strictly related to and therefore influence the perception of life quality in the third and fourth age
Enhanced stimulus-reward learning by intra-amygdala administration of a D3 dopamine receptor agonist
No full textThe amygdala is considered to be a critical neural substrate underlying the formation of stimulus-reward associations, and is known to receive substantial innervation from dopaminergic neurons located within the ventral mesencephalon. However, relatively little is known about the function of the mesoamygdaloid dopamine projection in stimulus-reward learning. Recently, we have found post-session intraamygdala microinjections of d-amphetamine to enhance appetitive Pavlovian conditioning as assessed in a discriminative approach task. In the present study, we have examined the effects of dopamine receptor agonists possessing relative selectivity for the D1, D2 and D3 receptor subtypes in order to examine more fully the role of the mesoamygdaloid dopamine projection in stimulus-reward learning. Thus, subjects were trained to associate an initially neutral stimulus (CS+) with 10% sucrose reward (US). A second, control stimulus (CS-) was also presented but never paired with sucrose reward. In order to measure specifically the conditioned response to CS+/CS- presentation, responding during CS and US presentations was measured separately. Immediately following each training session, subjects received bilateral intra-amygdala infusion of 0.1, 1 or 10 nmol/side of SKF-38393, quinpirole or 7-OH-DPAT. Infusions of SKF-38393 or quinpirole were without effect on CS+ approach. However, post-session intra-amygdala infusions of 7-OH-DPAT enhanced selectively CS+ approach in a dose-dependent fashion. No dose of any drug affected CS-approach, US behaviours, or measures of extraneous behaviour. Subsequent acquisition of a novel conditioned instrumental response was also unaffected. Thus, the present data indicate a selective involvement of the D3 dopamine receptor subtype in the modulation of stimulus-reward learning by the mesoamygdaloid dopamine projection
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