5,7-Dihydroxytryptamine injections into the prefrontal cortex and nucleus accumbens differently affect prepulse inhibition and baseline startle magnitude in rats

Mohr, Daniela; Ameln-Mayerhofer, Andreas von; Fendt, Markus

doi:10.1016/j.bbr.2009.03.014

Cited by 7 publications

(2 citation statements)

References 45 publications

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“…Alibiglou et al (2012) showcased that classic startle and startReact may utilize different neural pathways for expression. Since the cortex is known to modulate the amplitude of classic startle [23], we hypothesize that following a stroke the cortex loses ability to inhibit the classic startle response during startReact movements leading to simultaneous expression of both. This would be analogous to other instances of unsuppressed reflexes following stroke, like spasticity (hypermetric stretch reflex) [24], [25], [26], [27] and the resurgence of the typically dormant asymmetric tonic neck reflex [28], [29].…”

Section: Discussionmentioning

confidence: 99%

Planning of Ballistic Movement following Stroke: Insights from the Startle Reflex

Honeycutt

Perreault

2012

PLoS ONE

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Following stroke, reaching movements are slow, segmented, and variable. It is unclear if these deficits result from a poorly constructed movement plan or an inability to voluntarily execute an appropriate plan. The acoustic startle reflex provides a means to initiate a motor plan involuntarily. In the presence of a movement plan, startling acoustic stimulus triggers non-voluntary early execution of planned movement, a phenomenon known as the startReact response. In unimpaired individuals, the startReact response is identical to a voluntarily initiated movement, except that it is elicited 30–40 ms. As the startReact response is thought to be mediated by brainstem pathways, we hypothesized that the startReact response is intact in stroke subjects. If startReact is intact, it may be possible to elicit more task-appropriate patterns of muscle activation than can be elicited voluntarily. We found that startReact responses were intact following stroke. Responses were initiated as rapidly as those in unimpaired subjects, and with muscle coordination patterns resembling those seen during unimpaired volitional movements. Results were striking for elbow flexion movements, which demonstrated no significant differences between the startReact responses elicited in our stroke and unimpaired subject groups. The results during planned extension movements were less straightforward for stroke subjects, since the startReact response exhibited task inappropriate activity in the flexors. This inappropriate activity diminished over time. This adaptation suggests that the inappropriate activity was transient in nature and not related to the underlying movement plan. We hypothesize that the task-inappropriate flexor activity during extension results from an inability to suppress the classic startle reflex, which primarily influences flexor muscles and adapts rapidly with successive stimuli. These results indicate that stroke subjects are capable of planning ballistic elbow movements, and that when these planned movements are involuntarily executed they can be as rapid and appropriate as those in unimpaired individuals.

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Section: Discussionmentioning

confidence: 99%

Planning of Ballistic Movement following Stroke: Insights from the Startle Reflex

Honeycutt

Perreault

2012

PLoS ONE

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“…We and others have also found changes in mPFC DA levels after NAc 6-OHDA lesions (Nelson et al 2011 a ; Parkinson et al 2002). Similarly, other studies have shown comparable reductions in 5-HT levels in the mPFC following 5,7-DHT lesions to the NAc (Fletcher et al 2009; Ludwig & Schwarting, 2007; Mohr et al 2009). It is not clear why 5,7-DHT lesions to the NAc should produce 5-HT loss in distal regions but simple diffusion of the neurotoxin is a poor account of these effects as there were no significant changes in 5-HT content in the CPu which is dorsal to the infusion site.…”

Section: Discussionmentioning

confidence: 58%

Opposing effects of 5,7-DHT lesions to the core and shell of the nucleus accumbens on the processing of irrelevant stimuli

Nelson

Thur

Marsden

et al. 2011

Int. J. Neuropsychopharm.

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There is good evidence that forebrain serotonergic systems modulate cognitive flexibility. Latent inhibition (LI) is a cross-species phenomenon which manifests as poor conditioning to a stimulus that has previously been experienced without consequence and is widely considered an index of the ability to ignore irrelevant stimuli. While much research has focused on dopaminergic mechanisms underlying LI, there is also considerable evidence of serotonergic modulation. However, the neuroanatomical locus of these effects remains poorly understood. Previous work has identified the nucleus accumbens (NAc) as a key component of the neural circuit underpinning LI and furthermore, this work has shown that the core and shell subregions of the NAc contribute differentially to the expression of LI. To examine the role of the serotonergic input to NAc in LI, we tested animals with 5,7-dihydroxytryptamine (5,7-DHT) lesions to the core and shell subregions on LI assessed under experimental conditions that produce LI in shams and subsequently with weak stimulus pre-exposure designed to prevent the emergence of LI in shams. We found that serotonergic deafferentation of the core disrupted LI whereas 5,7-DHT lesions to the shell produced the opposite effect and potentiated LI.

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Does 5, 7-Dihydroxytryptamine injection into nucleus accumbens cause hyperacusis?

Farahani

Nasirinezhad

Danyali

et al. 2019

Neuroscience Letters

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5,7-Dihydroxytryptamine injections into the prefrontal cortex and nucleus accumbens differently affect prepulse inhibition and baseline startle magnitude in rats

Cited by 7 publications

References 45 publications

Planning of Ballistic Movement following Stroke: Insights from the Startle Reflex

Planning of Ballistic Movement following Stroke: Insights from the Startle Reflex

Opposing effects of 5,7-DHT lesions to the core and shell of the nucleus accumbens on the processing of irrelevant stimuli

Does 5, 7-Dihydroxytryptamine injection into nucleus accumbens cause hyperacusis?

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