Postsynaptic neuronal geometry and synaptic effectiveness

1987 ◽  
Vol 45 ◽  
pp. 690-697
Author(s):  
C.J. Wilson
Keyword(s):  
Central Nervous System ◽  
Nervous System ◽  
Synaptic Function ◽  
Postsynaptic Neuron ◽  
Synaptic Inputs ◽  
Partial Analysis ◽  
Postsynaptic Cell ◽  
Neuronal Geometry ◽  
The Relationship ◽  
Complex Scale

Most central nervous system neurons receive synaptic input from hundreds or thousands of other neurons, and the computational function of such neurons results from the interactions of inputs on a large and complex scale. In most situations that have yielded to a partial analysis, the synaptic inputs to a neuron are not alike in function, but rather belong to distinct categories that differ qualitatively in the nature of their effect on the postsynaptic cell, and quantitatively in the strength of their influence. Many factors have been demonstrated to contribute to synaptic function, but one of the simplest and best known of these is the geometry of the postsynaptic neuron. The fundamental nature of the relationship between neuronal shape and synaptic effectiveness was established on theoretical grounds prior to its experimental verification.

New concepts on the structure of the neuronal networks: The miniaturization and hierarchical organization of the central nervous system*

1984 ◽  
Vol 4 (2) ◽  
pp. 93-98 ◽  
Author(s):  
Luigi F. Agnati ◽  
Kjell Fuxe
Keyword(s):  
Central Nervous System ◽  
Nervous System ◽  
Neuronal Networks ◽  
Hierarchical Organization ◽  
Memory Storage ◽  
Information Handling ◽  
New Concepts ◽  
The Central Nervous System ◽  
Local Circuits ◽  
The Relationship

The hypothesis is introduced that miniaturization of neuronal circuits in the central nervous system and the hierarchical organization of the various levels, where information handling can take place, may be the key to understand the enormous capability of the human brain to store engrams as well as its astonishing capacity to reconstruct and organize engrams and thus to perform highly sophisticated integrations. The concept is also proposed that in order to understand the relationship between the structural and functional plasticity of the central nervous system it is necessary to postulate the existence of memory storage at the network level, at the local circuit level, at the synaptic level, at the membrane level, and finally at the molecular level. Thus, memory organization is similar to the hierarchical organization of the various levels, where information handling takes place in the nervous system. In addition, each higher level plays a role in the reconstruction and organization of the engrams stored at lower levels. Thus, the trace of the functionally stored memory (i.e. its reconstruction and organization at various levels of storage) will depend not only on the chemicophysical changes in the membranes of the local circuits but also on the organization of the local circuits themselves and their associated neuronal networks.

On humoral factors in nervous activity

1935 ◽  
Vol 31 (6) ◽  
pp. 777-787
Author(s):  
D. S. Vorontsov
Keyword(s):  
Central Nervous System ◽  
Nervous System ◽  
Nervous Activity ◽  
Active Part ◽  
Humoral Factors ◽  
The Central Nervous System ◽  
Relationship Of ◽  
The Relationship

Not only in the peripheral working organs, irritating substances are formed, which, as we can see, take an active part in their regulation, but also in the central nervous system, in the relationship of its individual elements, such substances apparently play an important role.

Patterned activation of unpaired median neurons during fictive crawling in manduca sexta larvae

1999 ◽  
Vol 202 (2) ◽  
pp. 103-113 ◽  
Author(s):  
R.M. Johnston ◽  
C. Consoulas ◽  
H. Pflüger ◽  
R.B. Levine
Keyword(s):  
Central Nervous System ◽  
Nervous System ◽  
Manduca Sexta ◽  
Motor Pattern ◽  
Intracellular Recordings ◽  
Subesophageal Ganglion ◽  
Synaptic Inputs ◽  
Functional Consequences ◽  
Manduca Sexta Larvae ◽  
Synaptic Drive

The unpaired median neurons are common to the segmental ganglia of many insects. Although some of the functional consequences of their activation, among them the release of octopamine to modulate muscle contraction, have been described, less is understood about how and when these neurons are recruited during movement. The present study demonstrates that peripherally projecting unpaired median neurons in the abdominal and thoracic ganglia of the larval tobacco hornworm Manduca sexta are recruited rhythmically during the fictive crawling motor activity that is produced by the isolated central nervous system in response to pilocarpine. Regardless of the muscles to which they project, the efferent unpaired median neurons in all segmental ganglia are depolarized together during the phase of the crawling cycle when the thoracic leg levator motoneurons are active. During fictive crawling, therefore, the unpaired median neurons are not necessarily active in synchrony with the muscles to which they project. The rhythmical synaptic drive of the efferent unpaired median neurons is derived, at least in part, from a source within the subesophageal ganglion, even when the motor pattern is evoked by exposing only the more posterior ganglia to pilocarpine. In pairwise intracellular recordings from unpaired median neurons in different ganglia, prominent excitatory postsynaptic potentials, which occur with an anterior-to-posterior delay in both neurons, are seen to underlie the rhythmic depolarizations. One model consistent with these findings is that one or more neurons within the subesophageal ganglion, which project posteriorly to the segmental ganglia and ordinarily provide unpatterned synaptic inputs to all efferent unpaired median neurons, become rhythmically active during fictive crawling in response to ascending information from the segmental pattern-generating network.

scholarly journals Adiponectin and Cognitive Decline

2020 ◽  
Vol 21 (6) ◽  
pp. 2010 ◽  
Author(s):  
Maria Rosaria Rizzo ◽  
Renata Fasano ◽  
Giuseppe Paolisso
Keyword(s):  
Central Nervous System ◽  
Nervous System ◽  
Cognitive Decline ◽  
Neural Plasticity ◽  
Verbal Memory ◽  
Main Role ◽  
Menopausal Women ◽  
The Central Nervous System ◽  
The Relationship ◽  
The Brain

Adiponectin (ADPN) is a plasma protein secreted by adipose tissue showing pleiotropic effects with anti-diabetic, anti-atherogenic, and anti-inflammatory properties. Initially, it was thought that the main role was only the metabolism control. Later, ADPN receptors were also found in the central nervous system (CNS). In fact, the receptors AdipoR1 and AdipoR2 are expressed in various areas of the brain, including the hypothalamus, hippocampus, and cortex. While AdipoR1 regulates insulin sensitivity through the activation of the AMP-activated protein kinase (AMPK) pathway, AdipoR2 stimulates the neural plasticity through the activation of the peroxisome proliferator-activated receptor alpha (PPARα) pathway that inhibits inflammation and oxidative stress. Overall, based on its central and peripheral actions, ADPN appears to have neuroprotective effects by reducing inflammatory markers, such as C-reactive protein (PCR), interleukin 6 (IL6), and Tumor Necrosis Factor a (TNFa). Conversely, high levels of inflammatory cascade factors appear to inhibit the production of ADPN, suggesting bidirectional modulation. In addition, ADPN appears to have insulin-sensitizing action. It is known that a reduction in insulin signaling is associated with cognitive impairment. Based on this, it is of great interest to investigate the mechanism of restoration of the insulin signal in the brain as an action of ADPN, because it is useful for testing a possible pharmacological treatment for the improvement of cognitive decline. Anyway, if ADPN regulates neuronal functioning and cognitive performances by the glycemic metabolic system remains poorly explored. Moreover, although the mechanism is still unclear, women compared to men have a doubled risk of developing cognitive decline. Several studies have also supported that during the menopausal transition, the estrogen reduction can adversely affect the brain, in particular, verbal memory and verbal fluency. During the postmenopausal period, in obese and insulin-resistant individuals, ADPN serum levels are significantly reduced. Our recent study has evaluated the relationship between plasma ADPN levels and cognitive performances in menopausal women. Thus, the aim of this review is to summarize both the mechanisms and the effects of ADPN in the central nervous system and the relationship between plasma ADPN levels and cognitive performances, also in menopausal women.

scholarly journals General Management Strategies for Efavirenz Therapy and Associated Adverse Events

2006 ◽  
Vol 17 (suppl d) ◽  
pp. 10D-14D
Author(s):  
Jean-Guy Baril ◽  
Anita Rachlis
Keyword(s):  
Central Nervous System ◽  
Nervous System ◽  
Adverse Events ◽  
Sleep Disturbances ◽  
Neuropsychiatric Symptoms ◽  
Management Strategies ◽  
Plasma Concentrations ◽  
General Management ◽  
The Relationship ◽  
Contradictory Data

Efavirenz therapy-related central nervous system symptoms often occur shortly after initiation of treatment; therefore, the timing of therapy initiation must be carefully considered so that if side effects do occur, it is at a time when the patient is not mentally overburdened and when support is readily available. Current literature contains contradictory data on the relationship between plasma levels of efavirenz and the occurrence of neuropsychiatric adverse events; therefore, routine measurement of plasma concentrations is not recommended except under certain circumstances. Clinician management of general neuropsychiatric symptoms comprises four steps: preparation, education, reassurance and treatment. Among the specific central nervous system symptoms that are known to occur with efavirenz therapy are agitation, sleep disturbances, dreams, dizziness, impaired concentration and depression. There are recommended pharmacological and nonpharmacological protocols for managing these symptoms. Prompt, successful management of treatment-emergent neuropsychiatric symptoms is important so that the patient may receive the optimal longterm viral suppression that is possible with efavirenz therapy.

scholarly journals Death of developing neurons: New insights and implications for connectivity

2013 ◽  
Vol 203 (3) ◽  
pp. 385-393 ◽  
Author(s):  
Martijn P.J. Dekkers ◽  
Vassiliki Nikoletopoulou ◽  
Yves-Alain Barde
Keyword(s):  
Central Nervous System ◽  
Cell Death ◽  
Nervous System ◽  
Growth Factors ◽  
Axonal Degeneration ◽  
Neuronal Development ◽  
Critical Role ◽  
Synaptic Function ◽  
The Central Nervous System ◽  
Developing Neurons

The concept that target tissues determine the survival of neurons has inspired much of the thinking on neuronal development in vertebrates, not least because it is supported by decades of research on nerve growth factor (NGF) in the peripheral nervous system (PNS). Recent discoveries now help to understand why only some developing neurons selectively depend on NGF. They also indicate that the survival of most neurons in the central nervous system (CNS) is not simply regulated by single growth factors like in the PNS. Additionally, components of the cell death machinery have begun to be recognized as regulators of selective axonal degeneration and synaptic function, thus playing a critical role in wiring up the nervous system.

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