scholarly journals Populations of striatal medium spiny neurons encode vibrotactile frequency in rats: modulation by slow wave oscillations

2013 ◽  
Vol 109 (2) ◽  
pp. 315-320 ◽  
Author(s):  
Thomas G. Hawking ◽  
Todor V. Gerdjikov

Dorsolateral striatum (DLS) is implicated in tactile perception and receives strong projections from somatosensory cortex. However, the sensory representations encoded by striatal projection neurons are not well understood. Here we characterized the contribution of DLS to the encoding of vibrotactile information in rats by assessing striatal responses to precise frequency stimuli delivered to a single vibrissa. We applied stimuli in a frequency range (45–90 Hz) that evokes discriminable percepts and carries most of the power of vibrissa vibration elicited by a range of complex fine textures. Both medium spiny neurons and evoked potentials showed tactile responses that were modulated by slow wave oscillations. Furthermore, medium spiny neuron population responses represented stimulus frequency on par with previously reported behavioral benchmarks. Our results suggest that striatum encodes frequency information of vibrotactile stimuli which is dynamically modulated by ongoing brain state.

2020 ◽  
Author(s):  
Adrienne C. Loewke ◽  
Adelaide R. Minerva ◽  
Alexandra B. Nelson ◽  
Anatol C. Kreitzer ◽  
Lisa A. Gunaydin

ABSTRACTThe dorsomedial prefrontal cortex (dmPFC) has been linked to approach-avoidance behavior and decision-making under conflict, key neural computations thought to be altered in anxiety disorders. However, the heterogeneity of efferent prefrontal projections has obscured identification of the specific top-down neural pathways regulating these anxiety-related behaviors. While the dmPFC-amygdala circuit has long been implicated in controlling reflexive fear responses, recent work suggests that this circuit is less important for avoidance behavior. We hypothesized that dmPFC neurons projecting to the dorsomedial striatum (DMS) represent a subset of prefrontal neurons that robustly encode and drive approach-avoidance behavior. Using fiber photometry recording during the elevated zero maze (EZM) task, we show heightened neural activity in prefrontal and fronto-striatal projection neurons, but not fronto-amydalar projection neurons, during exploration of the anxiogenic open arms of the maze. Additionally, through pathway-specific optogenetics we demonstrate that this fronto-striatal projection preferentially excites postsynaptic D1 receptor-expressing medium spiny neurons in the DMS and bidirectionally controls avoidance behavior. We conclude that this striatal-projecting subpopulation of prefrontal neurons regulates approach-avoidance conflict, supporting a model for prefrontal control of defensive behavior in which the dmPFC-amygdala projection controls reflexive fear behavior and the dmPFC-striatum projection controls anxious avoidance behavior. Our findings identify this fronto-striatal circuit as a valuable therapeutic target for developing interventions to alleviate excessive avoidance behavior in anxiety disorders.


Author(s):  
K. Semba ◽  
H.C. Fibiger ◽  
S.R. Vincent

ABSTRACT:The major input and output pathways of the mammalian striatum have been well established. Recent studies have identified a number of neurotransmitters used by these pathways as well as by striatal interneurons, and have begun to unravel their synaptic connections. The major output neurons have been identified as medium spiny neurons which contain ɣ-aminobutyric acid (GABA), endogeneous opioids, and substance P. These neurons project to the pallidum and substantia nigra in a topographic and probably chemically organized manner. The major striatal afferents from the cerebral cortex, thalamus, and substantia nigra terminate, at least in part, on these striatal projection neurons. Striatal interneurons contain acetylcholine, GABA, and somatostatin plus neuropeptide Y, and appear to synapse on striatal projection neurons. In recent years, much activity has been directed to the neurochemical and hodological heterogeneities which occur at a macroscopic level in the striatum. This has led to the concept of a patch-matrix organization in the striatum.


2005 ◽  
Vol 93 (2) ◽  
pp. 1119-1126 ◽  
Author(s):  
Fatuel Tecuapetla ◽  
Luis Carrillo-Reid ◽  
Jaime N. Guzmán ◽  
Elvira Galarraga ◽  
José Bargas

This work investigated if diverse properties could be ascribed to evoked inhibitory postsynaptic currents (IPSCs) recorded on rat neostriatal neurons when field stimulation was delivered at two different locations: the globus pallidus (GP) and the neostriatum (NS). Previous work stated that stimulation in the GP could antidromically excite projection axons from medium spiny neurons. This maneuver would predominantly activate the inhibitory synapses that interconnect spiny cells. In contrast, intrastriatal stimulation would preferentially activate inhibitory synapses provided by interneurons. This study shows that, in fact, intensity-amplitude experiments are able to reveal different properties for IPSCs evoked from these two locations (GP and NS). In addition, while all IPSCs evoked from the GP were always sensitive to ω-conotoxin GVIA (CaV2.22.2 or N-channel blocker), one-half of the inhibition evoked from the NS exhibited little sensitivity to ω-conotoxin GVIA. Characteristically, all ω-conotoxin GVIA–insensitive IPSCs exhibited strong paired pulse depression, whereas ω-conotoxin GVIA–sensitive IPSCs evoked from either the GP or the NS could exhibit short-time depression or facilitation. ω-Agatoxin TK (CaV2.12.1+ or P/Q-channel blocker) blocked IPSCs evoked from both locations. Therefore 1) distinct inhibitory inputs onto projection neostriatal cells can be differentially stimulated with field electrodes; 2) N-type Ca2+ channels are not equally expressed in inhibitory terminals activated in the NS; and 3) synapses that interconnect spiny neurons use both N- and P/Q-type Ca2+ channels.


2016 ◽  
Vol 2016 ◽  
pp. 1-5 ◽  
Author(s):  
Svetlana A. Ivanova ◽  
Anton J. M. Loonen

A serendipitous pharmacogenetic finding links the vulnerability to developing levodopa-induced dyskinesia to the age of onset of Huntington’s disease. Huntington’s disease is caused by a polyglutamate expansion of the protein huntingtin. Aberrant huntingtin is less capable of binding to a member of membrane-associated guanylate kinase family (MAGUKs): postsynaptic density- (PSD-) 95. This leaves more PSD-95 available to stabilize NR2B subunit carrying NMDA receptors in the synaptic membrane. This results in increased excitotoxicity for which particularly striatal medium spiny neurons from the indirect extrapyramidal pathway are sensitive. In Parkinson’s disease the sensitivity for excitotoxicity is related to increased oxidative stress due to genetically determined abnormal metabolism of dopamine or related products. This probably also increases the sensitivity of medium spiny neurons for exogenous levodopa. Particularly the combination of increased oxidative stress due to aberrant dopamine metabolism, increased vulnerability to NMDA induced excitotoxicity, and the particular sensitivity of indirect pathway medium spiny neurons for this excitotoxicity may explain the observed increased prevalence of levodopa-induced dyskinesia.


2012 ◽  
Vol 108 (6) ◽  
pp. 1739-1751 ◽  
Author(s):  
Luis A. Tellez ◽  
Isaac O. Perez ◽  
Sidney A. Simon ◽  
Ranier Gutierrez

Neurons in the nucleus accumbens (NAc) have been shown to participate in several behavioral states, including feeding and sleep. However, it is not known if the same neuron participates in both states and, if so, how similar are the responses. In addition, since the NAc contains several cell types, it is not known if each type participates in the transitions associated with feeding and sleep. Such knowledge is important for understanding the interaction between two different neural networks. For these reasons we recorded ensembles of NAc neurons while individual rats volitionally transitioned between the following states: awake and goal directed, feeding, quiet-awake, and sleeping. We found that during both feeding and sleep states, the same neurons could increase their activity (be activated) or decrease their activity (be inactivated) by feeding and/or during sleep, thus indicating that the vast majority of NAc neurons integrate sleep and feeding signals arising from spatially distinct neural networks. In contrast, a smaller population was modulated by only one of the states. For the majority of neurons in either state, we found that when one population was excited, the other was inhibited, suggesting that they act as a local circuit. Classification of neurons into putative interneurons [fast-spiking interneurons (pFSI) and choline acetyltransferase interneurons (pChAT)] and projection medium spiny neurons (pMSN) showed that all three types are modulated by transitions to and from feeding and sleep states. These results show, for the first time, that in the NAc, those putative inhibitory interneurons respond similarly to pMSN projection neurons and demonstrate interactions between NAc networks involved in sleep and feeding.


2022 ◽  
Author(s):  
Mackenzie A. Catron ◽  
Rachel K. Howe ◽  
Gai-Linn K. Besing ◽  
Emily K. St. John ◽  
Cobie Victoria Potesta ◽  
...  

Sleep is the brain state when cortical activity decreases and memory consolidates. However, in human epileptic patients, including genetic epileptic seizures such as Dravet syndrome, sleep is the preferential period when epileptic spike-wave discharges (SWDs) appear, with more severe epileptic symptoms in female patients than male patients, which influencing patient sleep quality and memory. Currently, seizure onset mechanisms during sleep period still remain unknown. Our previous work has shown that the sleep-like state-dependent synaptic potentiation mechanism can trigger epileptic SWDs (Zhang et al., 2021). In this study, using one heterozygous (het) knock-in (KI) transgenic mice (GABAA receptor γ2 subunit Gabrg2Q390X mutation) and an optogenetic method, we hypothesized that slow-wave oscillations (SWOs) themselves in vivo could trigger epileptic seizures. We found that epileptic SWDs in het Gabrg2+/Q390X KI mice exhibited preferential incidence during NREM sleep period, accompanied by motor immobility/ facial myoclonus/vibrissal twitching, with more frequent incidence in female het KI mice than male het KI mice. Optogenetic induced SWOs in vivo significantly increased epileptic seizure incidence in het Gabrg2+/Q390X KI mice with increased duration of NREM sleep or quiet-wakeful states. Furthermore, suppression of SWO-related homeostatic synaptic potentiation by 4-(diethylamino)-benzaldehyde (DEAB) injection (i.p.) greatly decreased seizure incidence in het KI mice, suggesting that SWOs did trigger seizure activity in het KI mice. In addition, EEG delta-frequency (0.1-4 Hz) power spectral density during NREM sleep was significantly larger in female het Gabrg2+/Q390X KI mice than male het Gabrg2+/Q390X KI mice, which likely contributes to the gender difference in seizure incidence during NREM sleep/quiet-wake as that in human patients.


1997 ◽  
Vol 78 (3) ◽  
pp. 1248-1255 ◽  
Author(s):  
Masashi Umemiya ◽  
Lynn A. Raymond

Umemiya, Masashi and Lynn A. Raymond. Dopaminergic modulation of excitatory postsynaptic currents in rat neostriatal neurons. J. Neurophysiol. 78: 1248–1255, 1997. γ-aminobutyric acid (GABA)-containing medium spiny neurons constitute ∼90% of the neuronal population in the neostriatum (caudate and putamen) and play an important role in motor programming. Cortical glutamatergic afferents provide the main excitatory drive for these neurons, whereas nigral dopaminergic neurons play a crucial role in regulating their activity. To further investigate the mechanisms underlying the dopaminergic modulation of medium spiny neuronal activity, we tested the effect of dopamine receptor agonists on excitatory synaptic transmission recorded from these neurons. Excitatory postsynaptic currents (EPSCs) were evoked by local stimulation and recorded from medium spiny neurons in postnatal rat striatal thin brain slices. Recordings were made using the whole cell patch-clamp technique under voltage clamp and conditions that selected for the α-amino-3-hydroxy-5-methyl-4-isoxazole propionate- and kainate-type glutamate receptor-mediated components of the EPSC. Incubation of slices in 10 μM dopamine resulted in a 33 ± 11% (mean ± SE) decrease in the amplitude of evoked EPSCs, an effect that developed during seconds. The relative variability in amplitude of dopamine's effects on medium spiny neuron EPSCs may reflect activation of different receptor subtypes with opposing effects. In contrast to the results with dopamine, incubation of slices in SKF 38393, a D1-type dopamine receptor selective agonist, resulted in dose-dependent potentiation of the medium spiny neuron EPSC that developed during several minutes. At a concentration of 5 μM, SKF 38393 resulted in a 29 ± 4.5% increase in EPSC amplitude, an effect that was blocked by preincubation with the D1-selective antagonist, SCH 23390 (10 μM). On the other hand, 5 μM SKF 38393 had no apparent effect on medium spiny neuron currents activated by exogenous application of glutamate or kainate. However, because of the inherent limitations of rapid agonist perfusion in the brain slice preparation (caused by slow agonist diffusion and rapid glutamate receptor desensitization) and because of anatomic evidence that colocalizes D1 and glutamate receptors to medium spiny neuron dendrites, our results leave open the possibility that the effect of D1 receptor activation on the EPSC is mediated via modulation of postsynaptic glutamate receptor responsiveness. The significant potentiation by D1 receptor agonists of EPSC amplitude at the cortico-striatal medium spiny synapse that we observed, in part, may underlie the role of D1 receptors in facilitating medium spiny neuronal firing, with implications for understanding regulation of movement.


2019 ◽  
Vol 78 (8) ◽  
pp. 725-734 ◽  
Author(s):  
Blanca Paramo ◽  
Sean Wyatt ◽  
Alun M Davies

Abstract Medium spiny neurons (MSNs) comprise the vast majority of neurons in the striatum. Changes in the exuberant dendrites of these widely connected neurons are associated with a multitude of neurological conditions and are caused by a variety of recreational and medicinal drugs. However, we have a poor understanding of the physiological regulators of dendrite growth and elaboration of this clinically important population of neurons. Here, we show that MSN dendrites are markedly smaller and less branched in neonatal mice that possess a homozygous null mutation in the neuregulin-4 gene (Nrg4−/−) compared with wild type (Nrg4+/+) littermates. Nrg4−/− mice also had a highly significant reduction in MSN dendrite spine number in neonates and adults. The striking stunted dendrite arbor phenotype of MSNs observed in Nrg4−/− neonates was replicated in MSNs cultured from Nrg4−/− embryos and was completely rescued by soluble recombinant neuregulin-4. MSNs cultured from wild type mice coexpressed NRG4 and its receptor ErbB4. Our findings show that NRG4 is a major novel regulator of dendritic growth and arborization and spine formation in the striatum and suggest that it exerts its effects by an autocrine/paracrine mechanism.


2021 ◽  
Author(s):  
Weston Fleming ◽  
Junuk Lee ◽  
Brandy A Briones ◽  
Scott Bolkan ◽  
Ilana B Witten

Cholinergic interneurons (ChINs) in the nucleus accumbens (NAc) have been implicated in the acquisition and extinction of drug associations, as well as related plasticity in medium spiny neurons (MSNs). However, since most previous work has relied on artificial manipulations, if and how endogenous patterns of cholinergic signaling relate to drug associations is unknown. Moreover, despite great interest in the opposing effects of dopamine on MSN subtypes, whether ChIN-mediated effects are similar or different across MSN subtypes is also unknown. Here, we find that endogenous acetylcholine event frequency during extinction negatively correlates with the strength and persistence of cocaine-context associations across individuals, consistent with effects of artificial manipulation of ChIN activity during extinction. Moreover, ChIN activation during extinction produces a reduction in excitatory synaptic strength on both MSN subtypes, similar to the effect of multiple extinction sessions in the absence of ChIN manipulations. Together, our findings indicate that natural variation in NAc acetylcholine may contribute to individual differences in drug-context extinction by modulating glutamatergic presynaptic strength similarly at both D1R and D2R MSN subtypes.


Cells ◽  
2021 ◽  
Vol 10 (12) ◽  
pp. 3442
Author(s):  
Shannon L. Gourley ◽  
Kolluru D. Srikanth ◽  
Ellen P. Woon ◽  
Hava Gil-Henn

In day-to-day life, we often choose between pursuing familiar behaviors that have been rewarded in the past or adjusting behaviors when new strategies might be more fruitful. The dorsomedial striatum (DMS) is indispensable for flexibly arbitrating between old and new behavioral strategies. The way in which DMS neurons host stable connections necessary for sustained flexibility is still being defined. An entry point to addressing this question may be the structural scaffolds on DMS neurons that house synaptic connections. We find that the non-receptor tyrosine kinase Proline-rich tyrosine kinase 2 (Pyk2) stabilizes both dendrites and spines on striatal medium spiny neurons, such that Pyk2 loss causes dendrite arbor and spine loss. Viral-mediated Pyk2 silencing in the DMS obstructs the ability of mice to arbitrate between rewarded and non-rewarded behaviors. Meanwhile, the overexpression of Pyk2 or the closely related focal adhesion kinase (FAK) enhances this ability. Finally, experiments using combinatorial viral vector strategies suggest that flexible, Pyk2-dependent action involves inputs from the medial prefrontal cortex (mPFC), but not the ventrolateral orbitofrontal cortex (OFC). Thus, Pyk2 stabilizes the striatal medium spiny neuron structure, likely providing substrates for inputs, and supports the capacity of mice to arbitrate between novel and familiar behaviors, including via interactions with the medial-prefrontal cortex.


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