(1) Four of these are numerous (retinula axons symapsing onto thick ocellar nerve fibres or onto thin ocellar fibres; thin ocellar nerve fibres synapsing onto thick ocellar nerve fibres or onto other thin ocellar fibres).
(2) Direct interactions between the ocelli and compound eyes are suggested by the projections of small ocellar interneurons into the proximal lobula.
(3) The central projections of the ocellar nerves from the intracranial ocelli also exhibit histamine-like immunoreactivity.
(4) The overall synaptic configurations are discussed in terms of the varied response characteristics of units in the ocellar nerve.
(5) The projections of ocellar fibres within the brain and thorax of the honey bee, Apis mellifera, were established using a modified cobalt sulphide technique, supplemented by serial sectioning of the brain for the light microscope.
(6) Electrophysiological recordings confirm the hyperpolarizing and localized action of histamine onto dendrites of second-order neurons in the ocellar cup.
(7) In addition to duplications of cuticular epithelia, extra glial cells, muscle fibers, and ocellar interneurons are sometimes found in extra-eye bearing flies.
(8) These results suggest that locust ocellar photoreceptors contain histamine and release it upon depolarization.
(9) Ocellar-mediated postsynaptic potentials influenced the firing of thoracic interneurons only if they arrived during the proper phase of rhythmic drive.
(10) There are 17 large 1st-order ocellar interneurons (Figs.
(11) rdgBKS222 and rgdAPC47 mutants are essentially normal with respect to structure and survival of ocellar receptors and synapses.
(12) The ocellar potential (OP) of planaria was recorded using microelectrode techniques.
(13) The small lateral ocellar neurons associated with these arborizations have cell bodies adjacent to the lateral ocellar tracts.
(14) It is present at high levels only in photoreceptor cell terminations, glomerulae of the antennal lobes, and the ocellar retina.
(15) All deltex alleles behave as recessive viables affecting wing, ocellar and eye morphology.
(16) Immunoreactivity of different intensity is found in the non-glomerular neuropil around the mushroom bodies, in the lateral protocerebrum, the central body, the optic tubercles, the lobula and medulla of optic lobe, the ocellar neuropil, in multiglomerular elements of the antennal lobes and in the dorsal deuterocerebrum.
(17) This collateral arborizes almost immediately in a region receiving input from arborizations of a number of small ocellar neurons (those less than 5 micrometer in diameter) from the ipsilateral ocellar nerve, together with small neurons from the median ocellar nerve, forming a region in each half of the brain which receives input from all three ocelli.
(18) No ocellar processes appear to be given off to the corpora pedunculata, central body, nervi corporis cardiaci, antennal lobes, or circumesophageal connectives; it is uncertain whether ocellar collaterals extend into the protocerebral bridge or optic lobes.
(19) Within each half of the posterior neuropil, two spatially separated regions of ocellar input have been identified.
(20) Anatomically, the sensory cells of the dorsal ocellus of Tenodera were determined histologically to be grouped into two distinct regions, each group making its own separate contribution to the ocellar nerve.
Ocellus
Definition:
(n.) A little eye; a minute simple eye found in many invertebrates.
(n.) An eyelike spot of color, as those on the tail of the peacock.
Example Sentences:
(1) Each ocellus has a cuticular lens located on the distal end of a cuticular cone which encapsulates the receptor cells.
(2) It appears, therefore, that the graded receptor potential, which survives the application of tetrodotoxin, is responsible for mediating synaptic transmission in the ocellus.
(3) The receptory area of the ocellus terminates in a tapetum which contains granules, soluble in alcohol.
(4) A third type comes from the median ocellus and can be traced into the cervical connectives.
(5) This idea and alternatives have been tested on the barnacle lateral ocellus, a simple eye with only three photoreceptors, each with its own axon about 1 cm long.2.
(6) Membrane potential changes following illumination of a photoreceptor cell in the lateral ocellus of a barnacle (Balanus eburneus) were studied by means of intracellular recording and polarization techniques.
(7) The decay of the depolarizing and hyperpolarizing components of the visual signal was studied by recording intracellularly from single receptor axons of the median ocellus of the giant barnacle.2.
(8) Each ocellus has about 80 retinula cells whose axons project to corresponding ganglia from which 4 giant afferent interneurons (per ganglion) project to the brain.
(9) The visual pigment of each ocellus of mosquitoes reared in darkness was characterized by microspectrophotometry, and found to be the same.
(10) However, the two bilaterally positioned cells destined to become the pigment cells in the first step are still equipotent at this stage in that they can give rise to either the ocellus or otolith.
(11) Anatomically, the sensory cells of the dorsal ocellus of Tenodera were determined histologically to be grouped into two distinct regions, each group making its own separate contribution to the ocellar nerve.
(12) In the absence of this interaction, melanocyte specification proceeds along the dominant pathway that results in the differentiation of an ocellus.
(13) Five cells are accessory cells of the sensory structures: three lens cells and a pigment-cup cell in the ocellus, and a single pigment cell in the otolith.
(14) Of the remaining 79 cells, 36 are sensory, 17 receptors in the ocellus and 19 presumed hydrostatic pressure receptors; these lie on the right and left sides of the sensory vesicle, respectively.
(15) The light-evoked slow potential responses of the postsynaptic units are not altered by the application of tetrodotoxin to the ocellus.
(16) A small number of cells in the supraesophageal ganglion hyperpolarize when the median ocellus is illuminated and depolarize when it is shadowed.
(17) The spectral sensitivities of single Limulus median ocellus photoreceptors have been determined from records of receptor potentials obtained using intracellular microelectrodes.
(18) The spectral sensitivity curve for the repolarizing responses peaks at 480 nm; it is the only spectral sensitivity curve for a median ocellus electrical response known to peak at 480 nm.
(19) Our main conclusions are that: 1) the photoreceptors (retinular cells) of the lateral eye project only to the lamina; 2) the photoreceptors of the lateral rudimentary eye project to both the lamina and medulla; 3) the photoreceptors of the median ocellus project only to the ocellar ganglion; and 4) the photoreceptors of the rudimentary median (endoparietal) eye project to the ocellar ganglion and also into the optic tract.
(20) The view that the ocellus of the cockroach represents a degenerated structure can no longer be supported.