Distribution of GABAergic neurons and axon terminals in the macaque striate cortex

1987 ◽  
Vol 264 (1) ◽  
pp. 73-91 ◽  
Author(s):  
D. Fitzpatrick ◽  
J. S. Lund ◽  
D. E. Schmechel ◽  
A. C. Towles
Keyword(s):  
Striate Cortex ◽  
Gabaergic Neurons ◽  
Axon Terminals

Effect of retinal impulse blockage on cytochrome oxidase-rich zones in the macaque striate cortex: II. Quantitative electron-microscopic (EM) analysis of neuropil

1989 ◽  
Vol 2 (5) ◽  
pp. 499-514 ◽  
Author(s):  
Margaret T. T. Wong-Riley ◽  
Thomas C. Trusk ◽  
Satish C. Tripathi ◽  
Daniel A. Hoppe
Keyword(s):  
Cytochrome Oxidase ◽  
Metabolic Activity ◽  
Striate Cortex ◽  
Unmyelinated Axon ◽  
Neuronal Structure ◽  
Electron Microscopic ◽  
Axon Terminals ◽  
Mitochondrial Population ◽  
Low Levels ◽  
Activity Dependent

AbstractUnilateral retinal impulse blockage with tetrodotoxin (TTX) induces reversible shrinkage and decreased cytochrome oxidase (CO) activity in alternate rows of supragranular, CO-rich puffs in the adult macaque striate cortex (Wong-Riley & Carroll, 1984b: Carroll & Wong-Riley, 1987). The present study extended the findings to the electron-microscopic (EM) level to determine if various neuropil profiles in control puffs exhibit heterogeneous levels of CO activity, and whether specific processes were more susceptible to intravitreal TTX than others.Within the neuropil of control puffs, 60% of the total mitochondrial population resided in dendrites, and the majority of dendritic mitochondria were highly reactive for CO. Axon terminals forming symmetrical synapses also contained darkly reactive mitochondria, whereas those forming asymmetrical synapses possessed very few and mainly lightly reactive mitochondria. Unmyelinated axon trunks, myelinated axons, and glia all exhibited low levels of CO activity. Synaptic count revealed a 3:1 ratio of asymmetrical to symmetrical synapses.Intravitreal TTX for 2–4 weeks adversely affects dendrites and symmetrical terminals much more so than other neuropil processes. There was a general decrease in darkly and moderately reactive mitochondria and an increase in lightly reactive mitochondria throughout the puffs, especially in dendrites. This indicates that afferent blockade is more detrimental to processes of higher metabolic activity. Changes also differed between central and peripheral regions of puffs, and indications of axonal and synaptic reorganization were more evident in the latter. Thus, stabilization of neuronal structure and synapses appears to be activity-dependent even in the adult. A working model of these metabolic and morphological responses to chronic TTX is proposed.

scholarly journals A description of the GABAergic neurons and axon terminals in the motor nuclei of the cat thalamus

1985 ◽  
Vol 5 (5) ◽  
pp. 1346-1369 ◽  
Author(s):  
K Kultas-Ilinsky ◽  
CE Ribak ◽  
GM Peterson ◽  
WH Oertel
Keyword(s):  
Gabaergic Neurons ◽  
Axon Terminals ◽  
Motor Nuclei

scholarly journals Dopaminergic neurons establish a distinctive axonal arbor with a majority of non-synaptic terminals

2020 ◽  
Author(s):  
Charles Ducrot ◽  
Marie-Josée Bourque ◽  
Constantin V. L. Delmas ◽  
Anne-Sophie Racine ◽  
Dainelys Guadarrama Bello ◽  
...  
Keyword(s):  
Dopaminergic Neurons ◽  
Synapse Formation ◽  
Critical Role ◽  
Gabaergic Neurons ◽  
Dopamine Neurons ◽  
Target Cells ◽  
Axon Terminals ◽  
Synaptic Terminals ◽  
Axonal Arbor ◽  
The Brain

ABSTRACTChemical neurotransmission in the brain typically occurs through synapses, which are structurally and functionally defined as sites of close apposition between an axon terminal and a postsynaptic domain. Ultrastructural examinations of axon terminals established by monoamine neurons in the brain often failed to identify a similar tight pre- and postsynaptic coupling, giving rise to the concept of “diffuse” or “volume” transmission. Whether this results from intrinsic properties of such modulatory neurons remains undefined. Using an efficient co-culture model, we find that dopaminergic neurons establish an axonal arbor that is distinctive compared to glutamatergic or GABAergic neurons in both size and propensity of terminals to avoid direct contact with target neurons. Furthermore, while most dopaminergic varicosities express key proteins involved in exocytosis such as synaptotagmin 1, only ~20% of these are synaptic. The active zone protein bassoon was found to be enriched in a subset of dopaminergic terminals that are in proximity to a target cell. Irrespective of their structure, a majority of dopaminergic terminals were found to be active. Finally, we found that the presynaptic protein Nrxn-1αSS4- and the postsynaptic protein NL-1AB, two major components involved in excitatory synapse formation, play a critical role in the formation of synapses by dopamine neurons. Taken together, our findings support the idea that dopamine neurons in the brain are endowed with a distinctive developmental program that leads them to adopt a fundamentally different mode of connectivity, compared to glutamatergic and GABAergic neurons involved in fast point-to-point signaling.SIGNIFICANCE STATEMENTMidbrain dopamine (DA) neurons regulate circuits controlling movement, motivation, and learning. The axonal connectivity of DA neurons is intriguing due to its hyperdense nature, with a particularly large number of release sites, most of which not adopting a classical synaptic structure. In this study, we provide new evidence highlighting the unique ability of DA neurons to establish a large and heterogeneous axonal arbor with terminals that, in striking contrast with glutamate and GABA neurons, actively avoid contact with the target cells. The majority of synaptic and non-synaptic terminals express proteins for exocytosis and are active. Finally, our finding suggests that, NL-1A+B and Nrxn-1αSS4-, play a critical role in the formation of synapses by DA neurons.

The morphology of collicular and retinal axons ending on small relay (W-like) cells of the primate lateral geniculate nucleus

1993 ◽  
Vol 10 (3) ◽  
pp. 403-418 ◽  
Author(s):  
E. A. Lachica ◽  
V. A. Casagrande
Keyword(s):  
Lateral Geniculate Nucleus ◽  
Striate Cortex ◽  
Optic Tract ◽  
Small Cells ◽  
Retinal Projection ◽  
Axon Terminals ◽  
Retinal Axons ◽  
Bush Baby ◽  
Lateral Geniculate ◽  
Cell Class

AbstractThe lateral geniculate nucleus (LGN) of every primate examined contains a set of small relay cells in addition to separate sets of magnocellular and parvocellular relay cells. These small cells receive a direct retinal projection, and an indirect retinal projection via the superior colliculus (SC). Receptive-field analyses of the small LGN cells in the bush baby, a lorisiform primate, indicate that this cell class is composed of subclasses, similar in physiology to cat W cells. In an effort to identify some of these subclasses, we have examined the morphological features of retinal and collicular axonal arbors that end on small W-like cells in the LGN of the bush baby, Galago crassicaudatus. Small cells in this species are found in a prominent pair of koniocellular (K) layers as well as the interlaminar zones (ILZs).Retinal arbors were examined by bulk iontophoretic injection of horseradish peroxidase into the optic tract. Collicular arbors were filled via iontophoretic injection of biocytin into the superficial layers of the SC. Forty-eight axon arbors were completely reconstructed and quantitatively evaluated. Our findings show that retinal and collicular axon terminals differ in morphology on the basis of a number of criteria. Our analyses also suggest that retinal axons may have a stronger influence on K cells and collicular axons have a stronger influence on ILZ cells. The ramifications of these findings are provocative since these small LGN cells are known to project directly to the cytochrome-oxidase (CO) blobs within striate cortex. This relationship suggests that CO blob cells receive complex visual input not only from magnocellular and parvocellular LGN cells, but also from small cell pathways that are differentially influenced by retinal and collicular cells.

Three dimensional morphometric analyses of axon terminals early changes induced by methylmercury intoxication in the adult cat striate cortex

2008 ◽  
Vol 1244 ◽  
pp. 155-163 ◽  
Author(s):  
Ricardo Bezerra de Oliveira ◽  
Wallace Gomes Leal ◽  
Domingos Luis Wanderley Picanço-Diniz ◽  
João Bento Torres Neto ◽  
Nara Lins ◽  
...  
Keyword(s):  
Striate Cortex ◽  
Three Dimensional ◽  
Axon Terminals ◽  
Morphometric Analyses ◽  
Adult Cat ◽  
Methylmercury Intoxication ◽  
Cat Striate Cortex

GABAergic neurons and axon terminals in the brainstem auditory nuclei of the gerbil

1987 ◽  
Vol 258 (2) ◽  
pp. 267-280 ◽  
Author(s):  
Rosalinda C. Roberts ◽  
Charles E. Ribak
Keyword(s):  
Gabaergic Neurons ◽  
Axon Terminals

Computer-assisted morphometric analysis of intrinsic axon terminals in the supragranular layers of cat striate cortex

2002 ◽  
Vol 205 (4) ◽  
pp. 291-300 ◽  
Author(s):  
Walace Gomes-Leal ◽  
Seleno Silva ◽  
Ricardo Oliveira ◽  
Cristovam Picanço-Diniz
Keyword(s):  
Morphometric Analysis ◽  
Striate Cortex ◽  
Computer Assisted ◽  
Axon Terminals ◽  
Cat Striate Cortex

GABAergic neurons with AMPA GluR1 and GluR2/3 immunoraactivity in the rat striate cortex

Neuroreport ◽  
1997 ◽  
Vol 8 (11) ◽  
pp. 2495-2499 ◽  
Author(s):  
Iñaki Gutiérrez-Ibarluzea ◽  
Juan L. Mendizabal-Zubiaga ◽  
Concepción Roblet ◽  
José L. Bueno-López
Keyword(s):  
Striate Cortex ◽  
Gabaergic Neurons
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