An electronic neural analog is described which contains variable absolute and relative refractory periods, two time constants, separate control of the ``accommodation'' to sub-threshold voltage changes ``adaptation'' produced by occurrence output pulses (spikes). The extensive use integrated-circuit operational amplifiers permits an accurate description input-output relationships over a wide range values for all parameters. This facilitates comparison results obtained both with data...

A new method is presented for the measurement of Wiener kernels a non-linear system. The uses complex exponential functions as set orthogonal with which to expand kernels. fast Fourier transform then employed in most efficient so far discovered.

With a growing world population and increasingly demanding consumers, the production of sufficient protein from livestock, poultry, fish represents serious challenge for future. Approximately 1,900 insect species are eaten worldwide, mainly in ...Read More

1. Photoreceptor cells in Calliphora stygia were stimulated with randomly fluctuating green light while the resulting fluctuations membrane potential recorded intracellular micro-electrodes. 2. Fourier analysis was used to obtain frequency response functions between intensity and at a range of different temperatures. 3. The results show that for small transducer function can be modelled by cascade five identical linear exponential filters whose time constants decrease as temperature cell is...

ABSTRACT Cell proliferation in the gastrulating chick embryo was assessed using two independent techniques which mark cells S phase of mitotic cycle: nuclear incorporation bromodeoxyuridine (BrdU) detected immunocytochemically and immunolocalization proliferating cell antigen (PCNA). Computer-reconstructed maps were produced showing distribution labelled nuclei primitive streak layers. These distributions also normalized to take into account regional differences density across embryo....

Our current understanding of insect phototransduction is based on a small number species, but insects occupy many different visual environments. We created the retinal transcriptome nocturnal insect, cockroach, Periplaneta americana to identify proteins involved in earliest stages compound eye phototransduction, and test hypothesis that environments are reflected molecular contributions function. assembled five novel mRNAs: two green opsins, one UV opsin, each TRP TRPL ion channel homologs....

1. We have developed an isolated mechanoreceptor-organ preparation in which the intact sensory structures are available for mechanical stimulation and electrical recording. The anterior lyriform slit sense organ on patella of spider, Cupiennius salei Keys., consists seven or eight cuticular slits, each innervated by a pair large bipolar neurons. neurons fusiform, largest somata < = 120 microns long. innervation was characterized light microscopy backfilled with neuronal tracers....

Octopamine is a chemical relative of noradrenaline providing analogous neurohumoral control diverse invertebrate physiological processes. There also evidence for direct octopaminergic innervation some insect peripheral tissues. Here, we show that spider mechanoreceptors are innervated by octopamine-containing efferents. The mechanosensory neurons have octopamine receptors colocalized with synapsin labeling in the efferent fibers. In addition, enhances electrical response sensory to...

Höger, Ulli, Päivi H. Torkkeli, Ernst-August Seyfarth, and Andrew S. French. Ionic selectivity of mechanically activated channels in spider mechanoreceptor neurons. J. Neurophysiol. 78: 2079–2085, 1997. The lyriform slit-sense organ on the patella spider, Cupiennius salei, consists seven or eight slits, with each slit innervated by a pair sensitive Mechanotransduction is believed to occur at tips dendrites, which are surrounded Na + -rich receptor lymph. We studied ionic basis sensory...

1. Intracellular microelectrodes recorded the receptor potential and current in neurons of spider slit sense organs during mechanical stimulation slits. 2. Mechanical produced two patterns action discharge, corresponding to groups described previously by electrical stimulation. 3. Tetrodotoxin eliminated potentials revealed a with both static adapting components. Voltage clamp gave an inward similar time course. 4. Replacement sodium ions bath reversibly current, indicating that it is...