Khác biệt giữa bản sửa đổi của “Dopamin”

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Trong văn hóa và truyền thông đại chúng, dopamine thường được xem là hóa chất chính của hạnh phúc, nhưng ý kiến hiện nay trong dược học là dopamine thay vào đó làm tăng động lực đạt tới kết quả <ref name="NAcc function">{{Chú thích sách|title=Molecular Neuropharmacology: A Foundation for Clinical Neuroscience|vauthors=Malenka RC, Nestler EJ, Hyman SE|publisher=McGraw-Hill Medical|year=2009|isbn=978-0-07-148127-4|veditors=Sydor A, Brown RY|edition=2nd|location=New York|pages=147–48, 366–67, 375–76|quote=<!-- VTA DA neurons play a critical role in motivation, reward-related behavior (Chapter 15), attention, and multiple forms of memory. This organization of the DA system, wide projection from a limited number of cell bodies, permits coordinated responses to potent new rewards. Thus, acting in diverse terminal fields, dopamine confers motivational salience (“wanting”) on the reward itself or associated cues (nucleus accumbens shell region), updates the value placed on different goals in light of this new experience (orbital prefrontal cortex), helps consolidate multiple forms of memory (amygdala and hippocampus), and encodes new motor programs that will facilitate obtaining this reward in the future (nucleus accumbens core region and dorsal striatum). In this example, dopamine modulates the processing of sensorimotor information in diverse neural circuits to maximize the ability of the organism to obtain future rewards.&nbsp;...<br />The brain reward circuitry that is targeted by addictive drugs normally mediates the pleasure and strengthening of behaviors associated with natural reinforcers, such as food, water, and sexual contact. Dopamine neurons in the VTA are activated by food and water, and dopamine release in the NAc is stimulated by the presence of natural reinforcers, such as food, water, or a sexual partner.&nbsp;...<br />The NAc and VTA are central components of the circuitry underlying reward and memory of reward. As previously mentioned, the activity of dopaminergic neurons in the VTA appears to be linked to reward prediction. The NAc is involved in learning associated with reinforcement and the modulation of motoric responses to stimuli that satisfy internal homeostatic needs. The shell of the NAc appears to be particularly important to initial drug actions within reward circuitry; addictive drugs appear to have a greater effect on dopamine release in the shell than in the core of the NAc.&nbsp;... If motivational drive is described in terms of wanting, and hedonic evaluation in terms of liking, it appears that wanting can be dissociated from liking and that dopamine may influence these phenomena differently. Differences between wanting and liking are confirmed in reports by human addicts, who state that their desire for drugs (wanting) increases with continued use even when pleasure (liking) decreases because of tolerance. --><!--&nbsp;... Addictive drugs are rewarding and reinforcing because they act in brain reward pathways to enhance either dopamine release or the effects of dopamine in the NAc or related structures, or because they produce effects similar to dopamine. -->}}</ref><ref name="pmid24107968">{{Chú thích tạp chí|vauthors=Baliki MN, Mansour A, Baria AT, Huang L, Berger SE, Fields HL, Apkarian AV|date=October 2013|title=Parceling human accumbens into putative core and shell dissociates encoding of values for reward and pain|journal=The Journal of Neuroscience|volume=33|issue=41|pages=16383–93|doi=10.1523/JNEUROSCI.1731-13.2013|pmc=3792469|pmid=24107968|quote=<!--Recent evidence indicates that inactivation of D2 receptors, in the indirect striatopallidal pathway in rodents, is necessary for both acquisition and expression of aversive behavior, and direct pathway D1 receptor activation controls reward-based learning (Hikida et al., 2010; Hikida et al., 2013). It seems we can conclude that direct and indirect pathways of the NAc, via D1 and D2 receptors, subserve distinct anticipation and valuation roles in the shell and core of NAc, which is consistent with observations regarding spatial segregation and diversity of responses of midbrain dopaminergic neurons for rewarding and aversive conditions, some encoding motivational value, others motivational salience, each connected with distinct brain networks and having distinct roles in motivational control (Bromberg-Martin et al., 2010; Cohen et al., 2012; Lammel et al., 2013).&nbsp;... Thus, the previous results, coupled with the current observations, imply that the NAc pshell response reflects a prediction/anticipation or salience signal, and the NAc pcore response is a valuation response (reward predictive signal) that signals the negative reinforcement value of cessation of pain (i.e., anticipated analgesia). -->}}</ref><ref name="Aversion neurons">{{Chú thích tạp chí|vauthors=Wenzel JM, Rauscher NA, Cheer JF, Oleson EB|date=January 2015|title=A role for phasic dopamine release within the nucleus accumbens in encoding aversion: a review of the neurochemical literature|journal=ACS Chemical Neuroscience|volume=6|issue=1|pages=16–26|doi=10.1021/cn500255p|pmid=25491156|quote=Thus, fear-evoking stimuli are capable of differentially altering phasic dopamine transmission across NAcc subregions. The authors propose that the observed enhancement in NAcc shell dopamine likely reflects general motivational salience, perhaps due to relief from a CS-induced fear state when the US (foot shock) is not delivered. This reasoning is supported by a report from Budygin and colleagues¹¹² showing that, in anesthetized rats, the termination of tail pinch results in augmented dopamine release in the shell.}}</ref> Nói cách khác, dopamine báo hiệu sự nổi bật động lực nhận thức (ví dụ, mức độ khao khát hoặc sự ác cảm) của một kết quả, do đó thúc đẩy hành vi của sinh vật hướng đến hoặc né tránh việc đạt được kết quả đó.<ref name="Aversion neurons" /><ref name="Motivational salience">{{Chú thích tạp chí|vauthors=Puglisi-Allegra S, Ventura R|date=June 2012|title=Prefrontal/accumbal catecholamine system processes high motivational salience|journal=Front. Behav. Neurosci.|volume=6|issue=|pages=31|doi=10.3389/fnbeh.2012.00031|pmc=3384081|pmid=22754514|quote=<!--Motivational salience regulates the strength of goal seeking, the amount of risk taken, and the energy invested from mild to extreme.&nbsp;... Motivation can be conceptually described as a continuum along which stimuli can either reinforce or punish responses to other stimuli. Behaviorally, stimuli that reinforce are called rewarding and those that punish aversive (Skinner, 1953). Reward and aversion describe the impact a stimulus has on behavior, and provided of motivational properties, thus able to induce attribution of motivational salience.&nbsp;... Attribution of motivational salience is related to the salience of an UCS (Dallman et al., 2003; Pecina et al., 2006). Thus, the more salient an UCS the more likely a neutral (to-be-conditioned) stimulus will be associated with it through motivational salience attribution. Prior experience is a major determinant of the motivational impact of any given stimulus (Borsook et al., 2007) and emotional arousal induced by motivational stimuli increases the attention given to stimuli influencing both the initial perceptual encoding and the consolidation process (Anderson et al., 2006; McGaugh, 2006).-->}}</ref>