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Striatal dopamine release is triggered by synchronized activity in cholinergic interneurons.

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Striatal dopamine plays key roles in our normal and pathological goal-directed actions. To understand dopamine function, much attention has focused on how midbrain dopamine neurons modulate their firing patterns. However, we identify a presynaptic mechanism that triggers dopamine release directly, bypassing activity in dopamine neurons. We paired electrophysiological recordings of striatal channelrhodopsin2-expressing cholinergic interneurons with simultaneous detection of dopamine release at carbon-fiber microelectrodes in striatal slices. We reveal that activation of cholinergic interneurons by light flashes that cause only single action potentials in neurons from a small population triggers dopamine release via activation of nicotinic receptors on dopamine axons. This event overrides ascending activity from dopamine neurons and, furthermore, is reproduced by activating ChR2-expressing thalamostriatal inputs, which synchronize cholinergic interneurons in vivo. These findings indicate that synchronized activity in cholinergic interneurons directly generates striatal dopamine signals whose functions will extend beyond those encoded by dopamine neuron activity.

A feud that wasn't: acetylcholine evokes dopamine release in the striatum.

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In this issue of Neuron, Threlfell et al. (2012) report that synchronous activation of cholinergic interneurons evokes striatal dopamine release by activating presynaptic nicotinic acetylcholine receptors. These findings call for a fundamental reevaluation of the long-standing view that dopamine and acetylcholine "feud" over control of striatal circuitry.

Responses of monkey dopamine neurons to reward and conditioned stimuli during successive steps of learning a delayed response task.

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The present investigation had two aims: (1) to study responses of dopamine neurons to stimuli with attentional and motivational significance during several steps of learning a behavioral task, and (2) to study the activity of dopamine neurons during the performance of cognitive tasks known to be impaired after lesions of these neurons. Monkeys that had previously learned a simple reaction time task were trained to perform a spatial delayed response task via two intermediate tasks. During the learning of each new task, a total of 25% of 76 dopamine neurons showed phasic responses to the delivery of primary liquid reward, whereas only 9% of 163 neurons responded to this event once task performance was established. This produced an average population response during but not after learning of each task. Reward responses during learning were significantly more numerous and pronounced in area A10, as compared to areas A8 and A9. Dopamine neurons also showed phasic responses to the two conditioned stimuli. These were the instruction cue, which was the first stimulus in each trial and indicated the target of the upcoming arm movement (58% of 76 neurons during and 44% of 163 neurons after learning), and the trigger stimulus, which was a conditioned incentive stimulus predicting reward and eliciting a saccadic eye movement and an arm reaching movement (38% of neurons during and 40% after learning). None of the dopamine neurons showed sustained activity in the delay between the instruction and trigger stimuli that would resemble the activity of neurons in dopamine terminal areas, such as the striatum and frontal cortex. Thus, dopamine neurons respond phasically to alerting external stimuli with behavioral significance whose detection is crucial for learning and performing delayed response tasks. The lack of sustained activity suggests that dopamine neurons do not encode representational processes, such as working memory, expectation of external stimuli or reward, or preparation of movement. Rather, dopamine neurons are involved with transient changes of impulse activity in basic attentional and motivational processes underlying learning and cognitive behavior.
Latest Updated Curations

Basal Ganglia Advances

 
 
Basal Ganglia Advances is a collection highlighting research on the structure, function, and disorders of the basal ganglia. It features studies spanning neuroscience, clinical insights, and computational models, serving as a hub for advances in movement, cognition, and behavior.

Progress in Voltage Imaging

 
 
Recent advances in the field of Voltage Imaging, with a special focus on new constructs and novel implementations.

Navigation & Localization

 
 
Work related to place tuning, spatial navigation, orientation and direction. Mainly includes articles on connectivity in the hippocampus, retrosplenial cortex, and related areas.
Most Popular Recent Articles

Co-occurring stigmas and associations with HIV testing, mental health, and substance use: a latent class analysis among youth in Kazakhstan.

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Co-occurring perceived community stigmas (HIV, sexual/gender minority status and substance use) impact health behaviors and access to healthcare services, particularly in low- and middle-income countries, but there is a paucity of research among adolescents and young adults). This paper explores the associations between co-occurring perceived community stigmas (HIV, sexual/gender minority status and substance use) and their relationship to mental health and substance use outcomes among youth in Kazakhstan.

Priorities to eliminate congenital syphilis in Australia: findings from a national roundtable.

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Congenital syphilis remains a significant public health threat in Australia, warranting national efforts to reduce syphilis incidence overall, focusing on women of reproductive age. To identify priority actions to eliminate congenital syphilis, ASHM convened a national multidisciplinary roundtable with attendance from organisations, colleges, and bodies across the healthcare sector with a focus on Aboriginal and Torres Strait Islander peoples' health, sexual and reproductive health, antenatal health, primary care, pathology, and pharmacy, as well as research institutes and community organisations. This position statement outlines the immediate, short-term and long-term actions identified by roundtable participants to eliminate congenital syphilis in Australia.

Australian GP experiences and perspectives of mental health care for adolescents: a qualitative study.

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General practitioners (GPs) play a crucial role in providing timely and appropriate adolescent mental health care in Australia, and this involves working within the Medicare Benefits Schedule (MBS), the national framework that sets rebates and rules for subsidised medical services. This study aimed to explore the experiences and perspectives of Australian GPs in delivering care for adolescents experiencing anxiety and depression in general practice, with a particular focus on how GPs navigate the MBS in this context.
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