scholarly journals Computational modeling of medium spiny projection neurons in nucleus accumbens: toward the cellular mechanisms of afferent stream integration

2001 ◽  
Vol 89 (7) ◽  
pp. 1083-1092 ◽  
Author(s):  
J.A. Wolf ◽  
L.F. Schroeder ◽  
L.H. Finkel
Keyword(s):  
Nucleus Accumbens ◽  
Computational Modeling ◽  
Projection Neurons ◽  
Cellular Mechanisms

scholarly journals Robust information routing by dorsal subiculum neurons

2021 ◽  
Vol 7 (11) ◽  
pp. eabf1913
Author(s):  
Takuma Kitanishi ◽  
Ryoko Umaba ◽  
Kenji Mizuseki
Keyword(s):  
Nucleus Accumbens ◽  
Large Scale ◽  
Dorsal Hippocampus ◽  
Retrosplenial Cortex ◽  
Projection Neurons ◽  
Target Region ◽  
Ca1 Neurons ◽  
Axonal Projections ◽  
Output Structure ◽  
Hippocampal Ca1

The dorsal hippocampus conveys various information associated with spatial navigation; however, how the information is distributed to multiple downstream areas remains unknown. We investigated this by identifying axonal projections using optogenetics during large-scale recordings from the rat subiculum, the major hippocampal output structure. Subicular neurons demonstrated a noise-resistant representation of place, speed, and trajectory, which was as accurate as or even more accurate than that of hippocampal CA1 neurons. Speed- and trajectory-dependent firings were most prominent in neurons projecting to the retrosplenial cortex and nucleus accumbens, respectively. Place-related firing was uniformly observed in neurons targeting the retrosplenial cortex, nucleus accumbens, anteroventral thalamus, and medial mammillary body. Theta oscillations and sharp-wave/ripples tightly controlled the firing of projection neurons in a target region–specific manner. In conclusion, the dorsal subiculum robustly routes diverse navigation-associated information to downstream areas.

Postnatal Development of Electrophysiological Properties of Nucleus Accumbens Neurons

2000 ◽  
Vol 84 (5) ◽  
pp. 2204-2216 ◽  
Author(s):  
Marc L. Belleau ◽  
Richard A. Warren
Keyword(s):  
Nucleus Accumbens ◽  
Postnatal Development ◽  
Action Potentials ◽  
Membrane Resistance ◽  
Inward Rectification ◽  
Resting Membrane Potential ◽  
Projection Neurons ◽  
Patch Clamp Technique ◽  
Whole Cell ◽  
Wide Range

We have studied the postnatal development of the physiological characteristics of nucleus accumbens (nAcb) neurons in slices from postnatal day 1 ( P1) to P49 rats using the whole cell patch-clamp technique. The majority of neurons (102/108) were physiologically identified as medium spiny (MS) projection neurons, and only these were subjected to detailed analysis. The remaining neurons displayed characteristics suggesting that they were not MS neurons. Around the time of birth and during the first postnatal weeks, the membrane and firing characteristics of MS neurons were quite different from those observed later. These characteristics changed rapidly during the first 3 postnatal weeks, at which point they began to resemble those found in adults. Both whole cell membrane resistance and membrane time constant decreased more than fourfold during the period studied. The resting membrane potential (RMP) also changed significantly from an average of −50 mV around birth to less than −80 mV by the end of the third postnatal week. During the first postnatal week, the current-voltage relationship of all encountered MS neurons was linear over a wide range of membrane potentials above and below RMP. Through the second postnatal week, the proportion of neurons displaying inward rectification in the hyperpolarized range increased steadily and after P15, all recorded MS neurons displayed significant inward rectification. At all ages, inward rectification was blocked by extracellular cesium and tetra-ethyl ammonium and was not changed by 4-aminopyridine; this shows that inward rectification was mediated by the same currents in young and mature MS neurons. MS neurons fired single and repetitive Na+/K+ action potentials as early as P1. Spike threshold and amplitude remained constant throughout development in contrast to spike duration, which decreased significantly over the same period. Depolarizing current pulses from rest showed that immature MS neurons fired action potentials more easily than their older counterparts. Taken together, the results from the present study suggest that young and adult nAcb MS neurons integrate excitatory synaptic inputs differently because of differences in their membrane and firing properties. These findings provide important insights into signal processing within nAcb during this critical period of development.

scholarly journals Enhanced food motivation in obese mice is controlled by D1R expressing spiny projection neurons in the nucleus accumbens.

2022 ◽  
Author(s):  
Bridget A Matikainen-Ankney ◽  
Alex A Legaria ◽  
Yvan M Vachez ◽  
Caitlin A Murphy ◽  
Yiyan A Pan ◽  
...  
Keyword(s):  
Nucleus Accumbens ◽  
Food Reward ◽  
Ex Vivo ◽  
D1 Receptor ◽  
Physical Work ◽  
Projection Neurons ◽  
Food Motivation ◽  
Obese Mice ◽  
Food Seeking

Obesity is a chronic relapsing disorder that is caused by an excess of caloric intake relative to energy expenditure. In addition to homeostatic feeding mechanisms, there is growing recognition of the involvement of food reward and motivation in the development of obesity. However, it remains unclear how brain circuits that control food reward and motivation are altered in obese animals. Here, we tested the hypothesis that signaling through pro-motivational circuits in the core of the nucleus accumbens (NAc) is enhanced in the obese state, leading to invigoration of food seeking. Using a novel behavioral assay that quantifies physical work during food seeking, we confirmed that obese mice work harder than lean mice to obtain food, consistent with an increase in the relative reinforcing value of food in the obese state. To explain this behavioral finding, we recorded neural activity in the NAc core with both in vivo electrophysiology and cell-type specific calcium fiber photometry. Here we observed greater activation of D1-receptor expressing NAc spiny projection neurons (NAc D1SPNs) during food seeking in obese mice relative to lean mice. With ex vivo slice physiology we identified both pre- and post-synaptic mechanisms that contribute to this enhancement in NAc D1SPN activity in obese mice. Finally, blocking synaptic transmission from D1SPNs decreased physical work during food seeking and attenuated high-fat diet-induced weight gain. These experiments demonstrate that obesity is associated with a selective increase in the activity of D1SPNs during food seeking, which enhances the vigor of food seeking. This work also establishes the necessity of D1SPNs in the development of diet-induced obesity, identifying a novel potential therapeutic target.

scholarly journals Growth dynamics of the Arabidopsis fruit is mediated by cell expansion

2019 ◽  
Vol 116 (50) ◽  
pp. 25333-25342 ◽  
Author(s):  
Juan-José Ripoll ◽  
Mingyuan Zhu ◽  
Stephanie Brocke ◽  
Cindy T. Hon ◽  
Martin F. Yanofsky ◽  
...  
Keyword(s):  
Computational Modeling ◽  
Cell Expansion ◽  
Growth Dynamics ◽  
Spatial Separation ◽  
Cellular Level ◽  
Fruit Growth ◽  
Signaling Cascades ◽  
Comprehensive Understanding ◽  
Cellular Mechanisms ◽  
Plant Reproductive Success

Fruit have evolved a sophisticated tissue and cellular architecture to secure plant reproductive success. Postfertilization growth is perhaps the most dramatic event during fruit morphogenesis. Several studies have proposed that fertilized ovules and developing seeds initiate signaling cascades to coordinate and promote the growth of the accompanying fruit tissues. This dynamic process allows the fruit to conspicuously increase its size and acquire its final shape and means for seed dispersal. All these features are key for plant survival and crop yield. Despite its importance, we lack a high-resolution spatiotemporal map of how postfertilization fruit growth proceeds at the cellular level. In this study, we have combined live imaging, mutant backgrounds in which fertilization can be controlled, and computational modeling to monitor and predict postfertilization fruit growth in Arabidopsis. We have uncovered that, unlike leaves, sepals, or roots, fruit do not exhibit a spatial separation of cell division and expansion domains; instead, there is a separation into temporal stages with fertilization as the trigger for transitioning to cell expansion, which drives postfertilization fruit growth. We quantified the coordination between fertilization and fruit growth by imaging no transmitting tract (ntt) mutants, in which fertilization fails in the bottom half of the fruit. By combining our experimental data with computational modeling, we delineated the mobility properties of the seed-derived signaling cascades promoting growth in the fruit. Our study provides the basis for generating a comprehensive understanding of the molecular and cellular mechanisms governing fruit growth and shape.

scholarly journals Three-dimensional organization of dendrites and local axon collaterals of shell and core medium-sized spiny projection neurons of the rat nucleus accumbens

2008 ◽  
Vol 213 (1-2) ◽  
pp. 129-147 ◽  
Author(s):  
Yvette C. van Dongen ◽  
Philippe Mailly ◽  
Anne-Marie Thierry ◽  
Henk J. Groenewegen ◽  
Jean-Michel Deniau
Keyword(s):  
Nucleus Accumbens ◽  
Three Dimensional ◽  
Projection Neurons ◽  
Axon Collaterals ◽  
Rat Nucleus Accumbens

Complex Response to Afferent Excitatory Bursts by Nucleus Accumbens Medium Spiny Projection Neurons

2004 ◽  
Vol 92 (3) ◽  
pp. 1276-1284 ◽  
Author(s):  
Remigijus Lape ◽  
John A. Dani
Keyword(s):  
Nucleus Accumbens ◽  
Pyramidal Neurons ◽  
Glutamate Release ◽  
Neuronal Population ◽  
Synaptic Activity ◽  
Projection Neurons ◽  
Striatal Slices ◽  
Hippocampal Pyramidal Neurons ◽  
Stimulus Train

The nucleus accumbens (NAc) of the ventral striatum is involved in attention, motivation, movement, learning, reward, and addiction. GABAergic medium spiny projection neurons that make up ∼90% of the neuronal population are commonly driven by convergent bursts of afferent excitation. We monitored spiny projection neurons in mouse striatal slices while applying stimulus trains to mimic bursts of excitation. A stimulus train evoked a simple, short-lived postsynaptic response from CA1 hippocampal pyramidal neurons, but the train evoked a complex series of excitatory postsynaptic potentials (EPSPs) or currents (EPSCs) from the NAc spiny projection neurons. As is commonly seen with projection neurons, the EPSC amplitudes initially displayed facilitation followed by depression, and that pattern was sensitive to the extracellular calcium concentration. In addition, there were two other novel observations. The spiny projection neurons responded to the stimulus train with a prolonged depolarization that was accompanied by a posttrain increase of spontaneous glutamatergic synaptic activity. Blocking AMPA/kainate glutamate receptors strongly inhibited the evoked EPSP/EPSCs, the posttrain spontaneous synaptic activity, and the prolonged depolarization. A potassium channel inhibitor increased and extended the prolonged postsynaptic depolarization, causing a long-lasting depolarized plateau potential. Our results indicate that burst-like activity along ventral striatal afferents is extended in time by additional spontaneous glutamate release that is integrated by the postsynaptic spiny projection neurons into a prolonged depolarization. The results suggest that the posttrain quantal glutamate release helps to blend and maintain multiple afferent inputs. That convergent excitation is further integrated by the postsynaptic neuron into a prolonged depolarization that may contribute to the depolarized “up state” observed in vivo.

scholarly journals Network feedback regulates motor output across a range of modulatory neuron activity

2016 ◽  
Vol 115 (6) ◽  
pp. 3249-3263 ◽  
Author(s):  
Robert M. Spencer ◽  
Dawn M. Blitz
Keyword(s):  
Neuron Activity ◽  
Projection Neurons ◽  
Activity Levels ◽  
Cellular Mechanisms ◽  
Physiological Range ◽  
Network Activation ◽  
Network Output ◽  
The Impact

Modulatory projection neurons alter network neuron synaptic and intrinsic properties to elicit multiple different outputs. Sensory and other inputs elicit a range of modulatory neuron activity that is further shaped by network feedback, yet little is known regarding how the impact of network feedback on modulatory neurons regulates network output across a physiological range of modulatory neuron activity. Identified network neurons, a fully described connectome, and a well-characterized, identified modulatory projection neuron enabled us to address this issue in the crab ( Cancer borealis) stomatogastric nervous system. The modulatory neuron modulatory commissural neuron 1 (MCN1) activates and modulates two networks that generate rhythms via different cellular mechanisms and at distinct frequencies. MCN1 is activated at rates of 5–35 Hz in vivo and in vitro. Additionally, network feedback elicits MCN1 activity time-locked to motor activity. We asked how network activation, rhythm speed, and neuron activity levels are regulated by the presence or absence of network feedback across a physiological range of MCN1 activity rates. There were both similarities and differences in responses of the two networks to MCN1 activity. Many parameters in both networks were sensitive to network feedback effects on MCN1 activity. However, for most parameters, MCN1 activity rate did not determine the extent to which network output was altered by the addition of network feedback. These data demonstrate that the influence of network feedback on modulatory neuron activity is an important determinant of network output and feedback can be effective in shaping network output regardless of the extent of network modulation.

scholarly journals Angiotensin-converting enzyme governs endogenous opioid signaling and synaptic plasticity in nucleus accumbens

2021 ◽  
Author(s):  
Brian H. Trieu ◽  
Bailey C. Remmers ◽  
Carlee Toddes ◽  
Dieter D. Brandner ◽  
Wei Xie ◽  
...  
Keyword(s):  
Nucleus Accumbens ◽  
Angiotensin Converting Enzyme ◽  
Glutamate Release ◽  
Ace Inhibition ◽  
Receptor Activation ◽  
Projection Neurons ◽  
Converting Enzyme ◽  
Endogenous Opioid ◽  
Central Function ◽  
Opioid Signaling

AbstractAngiotensin-converting enzyme (ACE) regulates blood pressure by cleaving angiotensin I to produce angiotensin II. In the brain, ACE is expressed at uniquely high levels in the striatonigral pathway, but its central function remains poorly understood. We find that ACE degrades an unconventional enkephalin heptapeptide, Met-enkephalin-Arg-Phe, in the nucleus accumbens of mice. ACE inhibition enhanced mu opioid receptor activation by Met-enkephalin-Arg-Phe, causing a cell type-specific long-term depression of glutamate release onto medium spiny projection neurons expressing the Drd1 dopamine receptor. Systemic ACE inhibition was not intrinsically rewarding, but decreased the conditioned place preference caused by fentanyl administration, and enhanced reciprocal social interaction. Our results raise the enticing prospect that central ACE inhibition can boost endogenous opioid signaling for clinical benefit, while mitigating risk of addiction.

Sign in / Sign up

Export Citation Format

Share Document