1,720,967 research outputs found
I contratti a distanza in AA VV, La tutela del consumatore, in Trattato di diritto privato diretto da M. Bessone, a cura di A. Musio, P. Stanzione
No full textI contratti a distanza in AA VV, La tutela del consumatore, in Trattato di diritto privato diretto da M. Bessone, a cura di A. Musio, P. Stanzion
Accumbal shell and core dopamine responsiveness during operant responding for sucrose
No full textExperimental evidence indicates that accumbal dopamine (DA) is critically involved in the reward properties of food and drugs of abuse, that preferentially stimulate DA transmission in the nucleus accumbens (NAc) shell compare to the core. The involvement of the two NAc compartments in the responsiveness to conditioned stimuli (CS), linked with rewards (food, sex, drugs of abuse) (US), is debated. Much discrepancies exist about the impact of food CSs on mesolimbic DA transmission. In particular it has been reported that after classical conditioning paradigm NAc shell DA shows responsiveness to food US, but it is unresponsive to food CS, while NAc core and prefrontal cortex DA are both affected by food-CS and US.
Here we examined the changes of mesolimbic DA in the responsiveness to food CS and US.
Using microdialysis technique coupled with self administration paradigm, we have monitored DA transmission in NAc shell and core during: 1) sucrose pellets seeking behavior, 2) presentation of visual and auditory cues associated with primary stimulus and 3) non-contingent administration of sucrose pellets.
During our study we found that NAc shell DA has been activated not only by the conditioned cues but also by food after the instrumental conditioning, and that when both stimuli are presented in the same moment the increase of DA is strengthened and prolonged.
These results provide that DA in the NAc shell plays an important role on the acquisition and expression of motivated behavior in food consumption
Mesolimbic dopamine responsiveness to food conditioned stimuli after instrumental conditioning paradigm
No full textDopamine (DA) is regarded to play an important role in the reward properties of natural and pharmacological primary stimuli. It is well known that conditioned stimuli (CS), linked with rewards (food, sex, drugs of abuse) (US), are essential to support a motivated behavior. Much discrepancies exist about the impact of food CSs on mesolimbic DA transmission. In particular it has been reported that after classical conditioning paradigm, nucleus accumbens (NAc) shell DA shows responsiveness to food US, but it is unresponsive to food CS, while NAc core and prefrontal cortex (PFCX) DA are both affected by food-CS and US.
The aim of our study was to clarify the role of mesolimbic DA in the responsiveness to CS and to US.
Using microdialysis technique coupled with self administration paradigm, we have studied DA transmission in NAc shell and core during: 1) sucrose pellets seeking behavior, 2) extinction phase and 3) non-contingent presentation of sucrose pellets.
The main finding of our study was that NAc shell DA has been activated not only by the conditioned cues but also by food after the instrumental conditioning, and that when both stimuli are presented in the same moment the increase of DA is strengthened and prolonged.
We can conclude that DA in the NAc shell plays an important role on the acquisition and expression of motivated behavior in food consumption
Nucleus Accumbens Shell and Core Dopamine modifications during operant responding for sucrose
No full textNucleus Accumbens and Prefrontal Cortex Dopamine modifications during operant responding for sucrose
No full textMesolimbic dopamine (DA) plays a key role in the responsiveness to rewarding properties of natural and pharmacological stimuli. These stimuli are able to give rise to motivated behavior, and it is well known that conditioned stimuli (CS), linked with rewards (food, sex, drugs of abuse) (US), are essential to support it.
The purpose of this investigation was to clarify the role of mesolimbic and mesocortical DA in the responsiveness to food and food-CS using an instrumental conditioning paradigm with fixed-ratio (FR) 1 (1 nose poke corresponds to 1 sucrose pellet) or 5 (5 nose pokes correspond to 1 sucrose pellet).
We have coupled a self administration paradigm with microdialysis technique to study DA transmission in the NAc shell and core and in the prefrontal cortex during: 1) sucrose pellets seeking behavior, 2) extinction phase and 3) non-contingent presentation of sucrose pellets.
The main finding of our study was that NAc shell DA has been activated not only by the conditioned cues but also by food after the instrumental conditioning, and that when both stimuli are presented in the same moment the increase of DA is strengthened and prolonged.
We can conclude that DA in the NAc shell plays an important role on the acquisition and expression of motivated behavior in food consumption
Operant behavior for sucrose differentially affects nucleus accumbens shell and core dopamine transmission
No full text
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Reciprocal responsiveness of nucleus accumbens shell and core dopamine to food- and drug-conditioned stimuli
No full textRationale Drugs of abuse and palatable food share the ability
to stimulate dopamine (DA) transmission in the nucleus
accumbens shell. However, while the stimulation of shell DA
by food undergoes habituation, that by drugs of abuse does not.
Objective This study aims to directly compare the changes
of extracellular DA, by microdialysis, in shell and core and
prefrontal cortex (PFCX) in response to food- and drugconditioned
stimuli (CSs).
Methods Rats were trace-conditioned by Fonzies box (FB) or
vanilla box (VB; CS), followed by food: Fonzies, intraoral
chocolate solution (food-unconditioned stimulus (US)) and
morphine (1.0 mg/Kg sc; drug US). Control (unconditioned)
rats received standard food instead of Fonzies, tap water
instead of chocolate, saline instead of morphine.
Results Food–CSs increased core but not shell DA, while
drug–CSs did the opposite. Food and drug–CSs both
increased PFCX DA. Exposure to food–CSs potentiated core
and PFCX DA response to food while shell responsiveness
was dependent upon the relative CS and US nature. If the CS
was intrinsic to the food US (CS=FB/US=Fonzies) the
response of shell DA to the US was abolished. If the CS was
extrinsic to the food US (CS=FB/US=chocolate; CS=VB/
US=Fonzies), shell DA increased in response to the US.
Exposure to the drug–CS potentiated the DA response to the
drug–US in the shell and in the PFCX, but not in the core.
Conclusion Drug–CSs differentially activate DA as compared
to food–CSs in shell and core and differentially affect
DA response to the US in these areas. These differences
might be relevant for the role of DA in the mechanism of
drug addiction
- …
