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J Boeckh

Publications and source records attributed to J Boeckh.

23 records · Page 2Linked to original sources
PubMed1986

CO2 sensitive receptors on labial palps of Rhodogastria moths (Lepidoptera: Arctiidae): physiology, fine structure and central projection.

The tips of the labial palps of Rhodogastria possess a pit housing uniform sensilla, histologically characterized by wall-pores and receptor cells with lamellated outer dendrites. The receptor cell axons project to glomeruli in the deutocerebrum which are not innervated by antennal receptors. From their histology as well as from their central projection these sense organs are identical with palpal pit organs of other Lepidoptera (Lee et al. 1985; Kent et al. 1986; Lee and Altner 1986). Physiologically, the palp-pit receptors respond uniformly; they are most excitable by stimulation with carbon dioxide while they exhibit relatively moderate responses to various odorants. The responses to CO2 show a steep dose-response characteristic. In ambient atmosphere (i.e., ca. 0.03% CO2) the cells are in an excited condition already; the seeming 'spontaneous activity' exhibited in air is decreased if the preparation is kept under N2 or O2 or CO2-free air. There is hardly any adaptation of the responses to continuous or repeated stimulation. Perhaps CO2 sensitivity is correlated with sensilla characterized by both wall-pores and lamellated dendrites. Pilot tests indicate that CO2 perception might be widespread in the Lepidoptera, but the biological significance remains obscure.

Animals↗
PubMed1983

A neuroanatomical study on the organization of the central antennal pathways in insects. III. Neuroanatomical characterization of physiologically defined response types of deutocerebral neurons in Periplaneta americana.

1. Single unimodal (olfactory) or multimodal (olfactory and mechanosensory) neurons in the antennal lobe of the deutocerebrum of the American cockroach were characterized functionally by microelectrode recording, and their morphological types and positions in the brain were established by dye injection. Thus individual, physiologically identified neurons of known shape could be mapped in reference to the areas of soma groups, glomeruli, tracts and their projection regions in the brain. 2. All of these neurons send processes to deutocerebral glomeruli, i.e., the regions in which the axons of antennal sensory cells terminate. Output neurons have axons that leave the deutocerebrum whereas local interneurons are anaxonic. 3. An output neuron innervates only one glomerulus, sending its axon into the calyces of the corpora pedunculata (CP) in the protocerebrum, where by multiple branching they reach many CP neurons. The same axons send collaterals into the lateral lobe of the protocerebrum. Because of this arrangement, each deutocerebral glomerulus is represented individually and separately in the two projection regions. The fine structure of the endings of the deutocerebral axons in the protocerebrum is described. In the CP calyces they form microglomeruli with typical divergent connectivity. 4. A local interneuron innervates many glomeruli without sending processes to other parts of the brain. 5. Unimodal olfactory and multimodal neurons can be either output neurons or local interneurons; multimodal information is sent to the protocerebrum directly, in parallel with the unimodal information. 6. At least one glomerulus--the macroglomerulus of the male deutocerebrum--is specialized so as to provide an exclusive topographic representation of certain olfactory stimuli not represented elsewhere (female sexual pheromone).

Animals↗
PubMed1977

A neuroanatomical study on the organization of the central antennal pathways in insects.

Receptor cell axons from the antennal flagellum terminate in the glomeruli of the ipsilateral deutocerebrum in Periplaneta americana and Locusta migratoria. Processes from several groups of deutocerebral neurons also enter the glomeruli and terminate in characteristic branching patterns. There, they contact the antennal axons. Connections are both convergent and divergent. Not only do single central neurons collect the inputs from many receptor cells, but receptor axons were often observed to branch and terminate at more than one deutocerebral neuron. The axons from a portion of the neurons go to form the deutocerebral bundle of the tractus olfactorio-globularis. These axons of the bundle terminate in the ipsilateral calyx of the corpus pedunculatum and in the lateral lobus protocerebri. The processes of the majority of the deutocerebral neurons stay within the deutocerebrum itself and may serve as local interneurons. Part of some antennal fibers terminate in the lobus dorsalis. The lobus glomeratus receives inputs from the maxillary palps and also from processess of deutocerebral neurons. Electron microscopy of synaptic connections and anatomical experiments reveal a complicated pattern of connections between receptor axons and higher order neurons as well as between higher order neurons themselves within the glomeruli. The ratio of the number of antennal fibers to that of relay fibers could easily lead to the interpretation, that the deutocerebrum merely serves as a device for reducing the number of transmission channels. However, coupled with physiological data, anatomical details such as con- and divergence of input and interconnections between input channels suggest rather a filtering system and a highly complicated integrative network.

Afferent Pathways↗