scholarly journals The Complement of Projection Neurons Activated Determines the Type of Feeding Motor Program in Aplysia

2021 ◽  
Vol 15 ◽  
Author(s):  
Colin G. Evans ◽  
Michael A. Barry ◽  
Jian Jing ◽  
Matthew H. Perkins ◽  
Klaudiusz R. Weiss ◽  
...  
Keyword(s):  
Repetition Priming ◽  
Functional Role ◽  
Motor Program ◽  
Projection Neuron ◽  
Seasonal Effect ◽  
Projection Neurons ◽  
Feeding System ◽  
Dynamic Changes ◽  
Trigger Activity

Multiple projection neurons are often activated to initiate behavior. A question that then arises is, what is the unique functional role of each neuron activated? We address this issue in the feeding system of Aplysia. Previous experiments identified a projection neuron [cerebral buccal interneuron 2 (CBI-2)] that can trigger ingestive motor programs but only after it is repeatedly stimulated, i.e., initial programs are poorly defined. As CBI-2 stimulation continues, programs become progressively more ingestive (repetition priming occurs). This priming results, at least in part, from persistent actions of peptide cotransmitters released from CBI-2. We now show that in some preparations repetition priming does not occur. There is no clear seasonal effect; priming and non-priming preparations are encountered throughout the year. CBI-2 is electrically coupled to a second projection neuron, cerebral buccal interneuron 3 (CBI-3). In preparations in which priming does not occur, we show that ingestive activity is generated when CBI-2 and CBI-3 are coactivated. Programs are immediately ingestive, i.e., priming is not necessary, and a persistent state is not induced. Our data suggest that dynamic changes in the configuration of activity can vary and be determined by the complement of projection neurons that trigger activity.

scholarly journals Use of the Aplysia feeding network to study repetition priming of an episodic behavior

2017 ◽  
Vol 118 (3) ◽  
pp. 1861-1870 ◽  
Author(s):  
Elizabeth C. Cropper ◽  
Jian Jing ◽  
Matthew H. Perkins ◽  
Klaudiusz R. Weiss
Keyword(s):  
Motor Activity ◽  
Repetition Priming ◽  
Molecular Mechanisms ◽  
Feeding Strategy ◽  
Pattern Generator ◽  
Feeding System ◽  
Dynamic Changes ◽  
Interesting Possibility ◽  
Study Repetition ◽  
The Neural Networks

Many central pattern generator (CPG)-mediated behaviors are episodic, meaning that they are not continuously ongoing; instead, there are pauses between bouts of activity. This raises an interesting possibility, that the neural networks that mediate these behaviors are not operating under “steady-state” conditions; i.e., there could be dynamic changes in motor activity as it stops and starts. Research in the feeding system of the mollusk Aplysia californica has demonstrated that this can be the case. After a pause, initial food grasping responses are relatively weak. With repetition, however, responses strengthen. In this review we describe experiments that have characterized cellular/molecular mechanisms that produce these changes in motor activity. In particular, we focus on cumulative effects of modulatory neuropeptides. Furthermore, we relate Aplysia research to work in other systems and species, and develop a hypothesis that postulates that changes in response magnitude are a reflection of an efficient feeding strategy.

scholarly journals Endocannabinoid signalling in stem cells and cerebral organoids drives differentiation to deep layer projection neurons via CB1 receptors

Development ◽  
2020 ◽  
Vol 147 (24) ◽  
pp. dev192161
Author(s):  
Juan Paraíso-Luna ◽  
José Aguareles ◽  
Ricardo Martín ◽  
Ane C. Ayo-Martín ◽  
Samuel Simón-Sánchez ◽  
...  
Keyword(s):  
Neuronal Differentiation ◽  
Deep Layer ◽  
Embryonic Stem ◽  
Projection Neuron ◽  
Projection Neurons ◽  
Neuron Development ◽  
Receptor Agonists ◽  
Pluripotent Embryonic Stem Cell

ABSTRACTThe endocannabinoid (eCB) system, via the cannabinoid CB1 receptor, regulates neurodevelopment by controlling neural progenitor proliferation and neurogenesis. CB1 receptor signalling in vivo drives corticofugal deep layer projection neuron development through the regulation of BCL11B and SATB2 transcription factors. Here, we investigated the role of eCB signalling in mouse pluripotent embryonic stem cell-derived neuronal differentiation. Characterization of the eCB system revealed increased expression of eCB-metabolizing enzymes, eCB ligands and CB1 receptors during neuronal differentiation. CB1 receptor knockdown inhibited neuronal differentiation of deep layer neurons and increased upper layer neuron generation, and this phenotype was rescued by CB1 re-expression. Pharmacological regulation with CB1 receptor agonists or elevation of eCB tone with a monoacylglycerol lipase inhibitor promoted neuronal differentiation of deep layer neurons at the expense of upper layer neurons. Patch-clamp analyses revealed that enhancing cannabinoid signalling facilitated neuronal differentiation and functionality. Noteworthy, incubation with CB1 receptor agonists during human iPSC-derived cerebral organoid formation also promoted the expansion of BCL11B+ neurons. These findings unveil a cell-autonomous role of eCB signalling that, via the CB1 receptor, promotes mouse and human deep layer cortical neuron development.

Expression and functional role of c-Kit and erbB2 in human hepatoblastoma.

2009 ◽  
Vol 221 (03) ◽  
Author(s):  
B Steiger ◽  
I Leuschner ◽  
D Denkhaus ◽  
D von Schweinitz ◽  
T Pietsch
Keyword(s):  
Functional Role

Can trust become a factor of economic growth? Dynamic changes in the level of trust of Russian youth

2020 ◽  
pp. 92-107 ◽  
Author(s):  
A. I. Bakhtigaraeva ◽  
A. A. Stavinskaya
Keyword(s):  
Institutional Environment ◽  
Negative Effects ◽  
Dynamic Changes ◽  
Generalized Trust ◽  
Level Of Education ◽  
Advantages And Disadvantages ◽  
The Future ◽  
Analysis Of Dynamics

The article considers the role of trust in the economy, the mechanisms of its accumulation and the possibility of using it as one of the growth factors in the future. The advantages and disadvantages of measuring the level of generalized trust using two alternative questions — about trusting people in general and trusting strangers — are analyzed. The results of the analysis of dynamics of the level of generalized trust among Russian youth, obtained within the study of the Institute for National Projects in 10 regions of Russia, are presented. It is shown that there are no significant changes in trust in people in general during the study at university. At the same time, the level of trust in strangers falls, which can negatively affect the level of trust in the country as a whole, and as a result have negative effects on the development of the economy in the future. Possible causes of the observed trends and the role of universities are discussed. Also the question about the connection between the level of education and generalized trust in countries with different quality of the institutional environment is raised.

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