Changing synaptic connections on cell bodies of growing identified spinal motoneurons of the eel, Anguilla

2001 ◽  
Vol 203 (2) ◽  
pp. 129-136 ◽  
Author(s):  
W. A. Smit ◽  
E. H. Velzing ◽  
P. C. Diegenbach ◽  
B. L. Roberts
PEDIATRICS ◽  
1976 ◽  
Vol 57 (1) ◽  
pp. 142-147
Author(s):  
M. Gabriel ◽  
M. Albani ◽  
F. J. Schulte

The incidence of apneic spells during different sleep states, active sleep, quiet sleep, and undifferentiated sleep was determined in eight preterm infants of 30 to 35 weeks' conceptional age, by means of a polygraphic recording technique. They were free of perinatal and postnatal complications other than apnea. During their active or rapid eye movement (REM) sleep they showed significantly more apneic episodes which were also longer lasting and they were accompanied by bradycardia of a greater severity. The organization of the immature nervous system with a preponderance of inhibitory synaptic connections and the additional inhibition of spinal motoneurons during REM sleep are likely to be the cause of apneic spells in otherwise "normal" preterm infants.


2015 ◽  
Vol 594 (1) ◽  
pp. 189-205 ◽  
Author(s):  
Hitoshi Maeda ◽  
Satoshi Fukuda ◽  
Hiroshi Kameda ◽  
Naoyuki Murabe ◽  
Noriko Isoo ◽  
...  

2021 ◽  
Author(s):  
Eiji Takasawa ◽  
Mitsunari Abe ◽  
Kenji Takagishi ◽  
Hirotaka Chikuda ◽  
Takashi Hanakawa

Abstract Evolution of the direct connection from primary motor cortex to motoneurons in the spinal cord parallels acquisition of hand dexterity and lateralization of hand preference. Recent studies indicated that the phylogenetically older pathway consisting of multi-synaptic connections from primary motor cortex to spinal motoneurons also participate in controlling dexterous hand movement. However, it remains unknown how the two corticospinal pathways work in concert to control unilateral hand movement with lateralized preference. Using corticospinal functional magnetic resonance imaging, we discovered the asymmetric organization of the two corticospinal networks that modelled monosynaptic or polysynaptic control from primary motor cortices over spinal motoneurons. Moreover, the degree of the involvement of the two corticospinal networks paralleled the lateralization of hand preference. The present results pointed to the functionally lateralized motor nervous system that underlies the behavioural asymmetry of handedness, a uniquely human trait which could have phylogenetically differentiated humans from other primates.


Author(s):  
Peter Sterling

The synaptic connections in cat retina that link photoreceptors to ganglion cells have been analyzed quantitatively. Our approach has been to prepare serial, ultrathin sections and photograph en montage at low magnification (˜2000X) in the electron microscope. Six series, 100-300 sections long, have been prepared over the last decade. They derive from different cats but always from the same region of retina, about one degree from the center of the visual axis. The material has been analyzed by reconstructing adjacent neurons in each array and then identifying systematically the synaptic connections between arrays. Most reconstructions were done manually by tracing the outlines of processes in successive sections onto acetate sheets aligned on a cartoonist's jig. The tracings were then digitized, stacked by computer, and printed with the hidden lines removed. The results have provided rather than the usual one-dimensional account of pathways, a three-dimensional account of circuits. From this has emerged insight into the functional architecture.


2015 ◽  
Vol 223 (3) ◽  
pp. 157-164 ◽  
Author(s):  
Georg Juckel

Abstract. Inflammational-immunological processes within the pathophysiology of schizophrenia seem to play an important role. Early signals of neurobiological changes in the embryonal phase of brain in later patients with schizophrenia might lead to activation of the immunological system, for example, of cytokines and microglial cells. Microglia then induces – via the neurotoxic activities of these cells as an overreaction – a rarification of synaptic connections in frontal and temporal brain regions, that is, reduction of the neuropil. Promising inflammational animal models for schizophrenia with high validity can be used today to mimic behavioral as well as neurobiological findings in patients, for example, the well-known neurochemical alterations of dopaminergic, glutamatergic, serotonergic, and other neurotransmitter systems. Also the microglial activation can be modeled well within one of this models, that is, the inflammational PolyI:C animal model of schizophrenia, showing a time peak in late adolescence/early adulthood. The exact mechanism, by which activated microglia cells then triggers further neurodegeneration, must now be investigated in broader detail. Thus, these animal models can be used to understand the pathophysiology of schizophrenia better especially concerning the interaction of immune activation, inflammation, and neurodegeneration. This could also lead to the development of anti-inflammational treatment options and of preventive interventions.


2014 ◽  
Vol 1 ◽  
pp. 644-647 ◽  
Author(s):  
Toshiyuki Hamada ◽  
Jousuke Kuroiwa ◽  
Hisakazu Ogura ◽  
Tomohiro Odaka ◽  
Izumi Suwa ◽  
...  
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