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  • Reduviidae  (3)
  • Cocaine  (2)
  • 1
    ISSN: 1432-2072
    Keywords: Key words Compulsion ; Addiction ; Cocaine ; Amphetamine ; Cannabis ; Phencyclidine ; Nucleus accumbens ; Amygdala ; Frontal cortex ; Limbic ; Stimulus-reward association ; Conditioned reward ; Sensitization ; Drug-seeking ; Inhibitory control ; Cognition ; Conditioned stimulus ; Incentive motivational ; Dopamine ; Rat ; Monkey
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract  Drug abuse and dependence define behavioral states involving increased allocation of behavior towards drug seeking and taking at the expense of more appropriate behavioral patterns. As such, addiction can be viewed as increased control of behavior by the desired drug (due to its unconditioned, rewarding properties). It is also clear that drug-associated (conditioned) stimuli acquire heightened abilities to control behaviors. These phenomena have been linked with dopamine function within the ventral striatum and amygdala and have been described specifically in terms of motivational and incentive learning processes. New data are emerging that suggest that regions of the frontal cortex involved in inhibitory response control are directly affected by long-term exposure to drugs of abuse. The result of chronic drug use may be frontal cortical cognitive dysfunction, resulting in an inability to inhibit inappropriate unconditioned or conditioned responses elicited by drugs, by related stimuli or by internal drive states. Drug-seeking behavior may thus be due to two related phenomena: (1) augmented incentive motivational qualities of the drug and associated stimuli (due to limbic/amygdalar dysfunction) and (2) impaired inhibitory control (due to frontal cortical dysfunction). In this review, we consider the neuro-anatomical and neurochemical substrates subserving inhibitory control and motivational processes in the rodent and primate brain and their putative impact on drug seeking. The evidence for cognitive impulsivity in drug abuse associated with dysfunction of the frontostriatal system will be discussed, and an integrative hypothesis for compulsive reward-seeking in drug abuse will be presented.
    Type of Medium: Electronic Resource
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  • 2
    ISSN: 1432-2072
    Keywords: Key words Locomotor activity ; Nucleus accumbens ; d-Amphetamine ; Cocaine ; Sensitization ; Conditioned reward
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract  The mesolimbic dopamine (DA) system has been implicated in conditioned reward (CR), locomotor sensitization, and the reinforcing properties of psychomotor stimulants. Stimuli with formerly motivationally neutral properties that gain incentive properties by their predictive association with primary reinforcers are termed conditioned, or secondary, reinforcers. In these experiments, we investigated whether cocaine sensitization could potentiate augmented responding for CR produced by intra-accumbens amphetamine. After subjects were trained on the CR paradigm for 14 days, they received a regimen of cocaine sensitization or saline injections. On 2 test days, 8–10 days later, subjects were given amphetamine (6 µg/0.5 µl) or saline infusions into the nucleus accumbens (NAc) and responding for CR was measured using the ”acquisition of a new response” paradigm. Responding on one novel lever resulted in the delivery of the conditioned stimulus (conditioned reinforcer, or CR lever), whereas responding on the other lever resulted in no CR stimulus presentation (NCR lever). Animals sensitized to cocaine showed increased responding on the CR lever after intra-NAc saline and potentiated CR lever responding after intra-NAc amphetamine. No differences in responding between the cocaine- and saline-treated groups on the NCR lever after the challenge were found. Locomotor sensitization under these conditions was confirmed in a separate group of subjects. These findings show that prior exposures to cocaine results in changes that potentiate the ability of intra-NAc amphetamine to enhance CR. Repeated stimulant drug use may induce long-term neuronal adaptations that result in increased sensitivity to the behavioral, or incentive motivational, effects of stimulant drugs.
    Type of Medium: Electronic Resource
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  • 3
    ISSN: 1572-8889
    Keywords: Reduviidae ; intraspecific interactions ; cannibalism ; predation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The behaviors exhibited by first-instarSinea diadema (F.) (Hemiptera: Reduviidae) during intraspecific interactions are described. Five distinct behaviors were characterized: posturing, striking, stalking, stridulating, and beaking. Distinct bouts of grappling were also noted. Interactions between unfed 2-day-old nymphs, unfed 3-day-old nymphs, and unfed 5-day-old nymphs were recorded and analyzed. The behavior of the nymphs changed with the duration of food deprivation. As the period of food deprivation increased from 2 to 5 days, the frequency of posturing decreased as the frequency of beaking increased. During noncannibalistic interactions, posturing or striking by one nymph was most frequently followed by posturing by the other nymph. In contrast, during cannibalistic interactions, posturing or striking was usually followed by beaking. The incidence of grappling increased with the duration of food deprivation. Moreover, grappling always preceded cannibalism. Although first instars were capable of capturing and killing conspecifics of the same age, cannibalism occurred only after 4 days of food deprivation. These results suggest that a decision-making process is involved. During interactions the nymphs can assess the vulnerability of the opponent. Whereas recently emerged nymphs usually forego the risk of attacking conspecifics, the attacks made by nymphs deprived of food are more persistent despite the danger of predation by their opponent.
    Type of Medium: Electronic Resource
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  • 4
    Electronic Resource
    Electronic Resource
    Springer
    Journal of insect behavior 9 (1996), S. 23-35 
    ISSN: 1572-8889
    Keywords: Reduviidae ; interspecific predation ; intraspecific predation ; nutrition ; kin recognition
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Selected nutritional and developmental factors regulating the predatory behavior of first-instar spined assassin bugsSinea diadema (Fabricius) (Hemiptera: Reduviidae) were investigated. The longevity of unfed nymphs provided with free water, bean pod sections, or glucose solutions was not significantly greater than that of unfed nymphs which were not provided with a source of water. First-instarS. diadema that were provided with larvae ofEphestia kuehniella Zeller (Lepidoptera: Pyralidae) as prey began feeding 1.9 (±0.9) days after hatching. In contrast, first-instarS. diadema that were provided with conspecifics of the same age did not begin feeding until they were 3.9 (±0.9) days old. These results suggest that the potential nutritional benefits to be gained from feeding equal or outweigh the risk of attacking prey capable of effective self-defense only when nymphs have not fed for 4 days after hatching. Providing the nymphs with water or glucose solutions significantly delayed the onset of conspecific predation. Additional data are presented which demonstrate that first-instarS. diadema are not restrained from preying on siblings by kin recognition.
    Type of Medium: Electronic Resource
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  • 5
    Electronic Resource
    Electronic Resource
    Springer
    Journal of insect behavior 9 (1996), S. 37-45 
    ISSN: 1572-8889
    Keywords: predator-prey interactions ; Reduviidae ; hunger ; cannibalism
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Fed and unfed first instars of the spined assassin bugSinea diadema were paired to evaluate the effects of food deprivation on their behaviour during encounters. Fed nymphs encountering starved 5-day-old nymphs retreated from 69% of the encounters after contacting the starved nymph. In contrast, starved nymphs initiated grappling during 30% of the encounters with fed nymphs and retreated significantly less often than the fed nymphs. When a single fed nymph was placed together with two unfed 3-day-old nymphs in a closed arena, the fed nymphs generally were not the first nymph cannibalized and were the final survivors in 67% of 24 replicates. These results are discussed in the context of the relative costs and benefits of escalating or retreating from encounters.
    Type of Medium: Electronic Resource
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