Dopamine: Difference between revisions

In popular culture and media, dopamine is often portrayed as the main chemical of pleasure, but the current opinion in pharmacology is that dopamine instead confers [[motivational salience]];<ref name="NAcc function" /><ref name="pmid24107968">{{cite journal |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 |language=en-US |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">{{cite journal | vauthors = Wenzel JM, Rauscher NA, Cheer JF, Oleson EB |date=January title2015 |title= A role for phasic dopamine release within the nucleus accumbens in encoding aversion: a review of the neurochemical literature | journal = ACS Chemical Neuroscience |language=en-US |volume = 6 | issue = 1 | pages = 16–26 | date = January 2015 | pmid = 25491156 | doi = 10.1021/cn500255p |quotepmc=5820768 |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.| pmc = 5820768 }}</ref> in other words, dopamine signals the perceived motivational prominence (i.e., the desirability or aversiveness) of an outcome, which in turn propels the organism's behavior toward or away from achieving that outcome.<ref name="Aversion neurons" /><ref name="Motivational salience">{{cite journal | vauthors = Puglisi-Allegra S, Ventura R | title = Prefrontal/accumbal catecholamine system processes high motivational salience | journal = Front. Behav. Neurosci. | volume = 6 | page = 31 | date = June 2012 | pmid = 22754514 | pmc = 3384081 | doi = 10.3389/fnbeh.2012.00031 | 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).-->| doi-access = free }}</ref> It is the [[Cannabinoid|endocannabinoid]], [[2-Arachidonoylglycerol]] (2-AG: [[Carbon|C]]₂₃[[Hydrogen|H]]₃₈[[Oxygen|O]]₄; 20:[[Double bond|4]], [[Omega-6 fatty acid|ω-6]]) that shape [[Nucleus accumbens|accumbal]] encoding of [[Sensory cue|cue]]-[[Motivation|motivated]] behavior via [[Cannabinoid receptor type 1|CB1 receptor]] activation in the [[Ventral tegmental area|ventral tegmentum]], and thereby modulates cue-evoked dopamine transients during the pursuit of [[Reward system|reward]].{{clarification needed|date=November 2023}}<ref>{{cite journal | vauthors = Oleson EB, Beckert MV, Morra JT, Lansink CS, Cachope R, Abdullah RA, Loriaux AL, Schetters D, Pattij T, Roitman MF, Lichtman AH, Cheer JF | display-authors = 6 | title = Endocannabinoids shape accumbal encoding of cue-motivated behavior via CB1 receptor activation in the ventral tegmentum | journal = Neuron | volume = 73 | issue = 2 | pages = 360–373 | date = January 2012 | pmid = 22284189 | pmc = 3269037 | doi = 10.1016/j.neuron.2011.11.018 }}</ref>