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Differentiation of motor neuron synapse with muscle. Parts (E) and (G) are depicted at a lower magnification than the others to give an overview of the region where axon meets muscle. (A) A growth cone approaches a developing muscle cell. (B) The axon stops and forms an unspecialized contact on the muscle surface. Agrin, released by the neural tube, causes the clustering of acetylcholine receptors near the axon. (C) Neurotransmitter vesicles enter the axon terminal, and an extracellular matrix connects the axon terminal to the muscle cell as the synapse widens. This matrix contains a nerve-specific laminin. (D) Other axons converge on the same synaptic site. (E) Overview of muscle innervation by several axons (seen in mammals at birth). (F) All axons but one are eliminated. The remaining axon can branch to form a complex junction with the muscle. Each axon terminal is sheathed by a Schwann cell process, and folds form in the muscle cell membrane. (G) Overview of the muscle innervation several weeks after birth. (After Hall and Sanes 1993; Purves 1994; Hall 1995.)

Cost-effectiveness planes under different scenarios. (a) Scenario 1; (b) scenario 2; (c) scenario 3; (d) scenario 4; (e) scenario 5; (f) scenario 6; (g) scenario 7; and (h) scenario 8.

(A) Ventral nerve cord fixed by classical method using osmium and glutaraldehyde. (B) Ventral nerve cord fixed by high-pressure freezing. Images in A and B are taken from (Rostaing et al., 2004) with permission. M, muscle; N, presynaptic terminal; Mit, mitochondria. Yellow arrows, SV; orange triangles, MT; *, space between nerve processes. Scale: 500nm. (C–E) Images of synapses by classical fixation method: neuron-neuron synapse in the ventral nerve cord (C), cholinergic neuromuscular junction (D), and GABAergic NMJ (E). M, muscle; N, presynaptic terminal; Mit, mitochondria. (F–G). Images of synapse by high-pressure fixation procedure. G shows an enlarged view of the presynaptic density (R. Weimer and J-L. Bessereau, personal communication). Yellow arrows, SV; light-blue arrows, dense core vesicles; dark-blue arrow, large core vesicle; green arrows, postsynaptic density-like structures; pink-purple arrow, presynaptic density; orange triangle, MT. (H). Image of longitudinal section of ventral nerve cord, showing the sharp transition of SV cluster and MT nearby. Black arrows, presynaptic density; orange triangles, MT; A, axon; M, muscle. Taken from Hedgecock and Hall (1991) with permission.

TRP, DEG/ENaC, and TMC channel proteins coexpressed in mechanosensory and thermosensory neurons in C. elegans nematodes. The gross morphology of identified mechanosensory and thermosensory neurons in C. elegans are diagrammed, and the ion channel subunits that are expressed in each cell are listed. Sources for C. elegans neuron expression are listed by numbers: (1) Driscoll, M. and M. Chalfie, Nature, 349, 6310, 588–593, 1991; (2) Huang, M. and M. Chalfie, Nature, 367, 6462, 467–470, 1994; (3) Chatzigeorgiou, M. et al., Nature Neurosci, 13, 7, 861–868, 2010; (4) Smith, C.J. et al., Dev Biol, 345, 1, 18–33, 2010; (5) Colbert, H.A. et al., J Neurosci, 17, 21, 8259–8269, 1997; (6) Kindt, K.S. et al., Nature Neurosci, 10, 5, 568–577, 2007; (7) Tavernarakis, N. et al., Neuron, 18, 107–119, 1997; (8) Hall, D.H. et al., J Neurosci, 17, 3, 1033–1045, 1997; (9) Tobin, D.M. et al., Neuron, 35, 307–318, 2002; (10) Voglis, G. and N. Tavernarakis, EMBO J, 27, 24, 3288–3299, 2008; (11) Walker, R.G. et al., Science, 287, 5461, 2229–2234, 2000; (12) Li, W. et al., Nature, 440, 7084, 684–687, 2006.

NM-MRI and QSM images. (A-C) represent the normal, possible abnormal and definitely abnormal SN on NM-MRI, respectively. Nigrosome-1 (N1) could be visualized in the dorsal part of the healthy SN on QSM images (D, arrow). D-F) represent that N1 was present, indecisively present and absent, respectively. (G-H), a control subject, female 65 years, neuromelanin was normal (G) and N1 was present (H, arrow) in bilateral SN. (I, J), an essential tremor (ET) patient, 59 years, female, neuromelanin was normal (I) and N1 was present (J, arrow) in bilateral SN. (K, L), a denovo PD patient, 75 years female, neuromelanin was definitely abnormal in unilateral SN (K, arrowhead) and N1 was absent in bilateral SN (L). Combined Visualization of Nigrosome-1 and neuromelanin in Substantia Nigra (SN) Using 3T MRI for the Differential Diagnosis of Essential Tremor and de novo Parkinson’s Disease.
Source: Front Neurol. 2019 Feb 12;10:100. Published with permission.

(a–c) “Love dust” particles on the hairs of the androconia of the male danaine butterflies Danaus formosa, Amauris tartarea, and Danaus sp. (Courtesy of M. Boppré.) (d–h) Olfactory hairs of a male moth of Antheraea polyphemus, electron-micrographic sections. (d, e) Sections treated with gold-labeled antibodies against SNMP. (Modified from Rogers M.E. et al. 2001a. Cell Tissue Res 303:433–446.) The gold particles (here intensified) are associated with the plasma membrane of the receptor neurons (D). Sl = sensillum lymph, Cut = cuticle. (f) Gold particles (here original) attached to antibodies against PBP. (Modified from Steinbrecht R.A. et al. 1995. Cell Tissue Res 282:203–217.) About 1% of the protein carries a gold label. (g, h) Cross section of hairs treated with cationic markers cationized ferritin (g), and ruthenium red (h). The markers indicate the presence of fixed negative charges. (Modified from Keil T.A. 1984. Tissue Cell 16:705–717.) (i) Antennal side branch of A. polyphemus. Sensillum lymph droplets ejected from cut hairs. Preparation under water-saturated paraffin oil. The size of the droplets corresponds to the volume of the basal lymph cavity (see Figure 4.1d). (Modified from Kaissling K.E. and Thorson J. 1980. Insect olfactory sensilla: Structural, chemical and electrical aspects of the functional organisation. In Receptors for Neurotransmitters, Hormones and Pheromones in Insects, D.B. Sattelle, L.M. Hall and J.G. Hilderbrand (eds.), 261–282. Amsterdam: Elsevier/North-Holland Biomedical Press.)