Publications by authors named "Ernst-August Seyfarth"

The ability to maintain human brain explants in tissue culture was a critical step in the use of these cells for the study of central nervous system disorders. Ross G. Harrison (1870-1959) was the first to successfully maintain frog medullary tissue in culture in 1907, but it took another 38 years before successful culture of human brain tissue was accomplished.

View Article and Find Full Text PDF

The Marine Biological Laboratory (MBL) in Woods Hole, MA provided opportunities for women to conduct research in the late 19th and early 20th century at a time when many barriers existed to their pursuit of a scientific career. One woman who benefited from the welcoming environment at the MBL was Mary Jane Hogue. Her remarkable career as an experimental biologist spanned over 55 years.

View Article and Find Full Text PDF

Here we describe the neuronal organization of the arcuate body in the brain of the wandering spider Cupiennius salei. The internal anatomy of this major brain center is analyzed in detail based on allatostatin-, proctolin-, and crustacean cardioactive peptide (CCAP)-immunohistochemistry. Prominent neuronal features are demonstrated in graphic reconstructions.

View Article and Find Full Text PDF

The tympanal organ of the bushcricket Mecopoda elongata emits pronounced distortion-product otoacoustic emissions (DPOAEs). Their characteristics are comparable to those measured in other insects, such as locusts and moths, with the 2f1-f2 emission being the most prominent one. Yet the site of their generation is still unclear.

View Article and Find Full Text PDF

Johann H.L. Flögel (1834-1918) was an amateur scientist and self-taught microscopist in Germany who 130years ago pioneered comparative arthropod neuroanatomy.

View Article and Find Full Text PDF

Sensitive hearing organs often employ nonlinear mechanical sound processing which generates distortion-product otoacoustic emissions (DPOAE). Such emissions are also recordable from tympanal organs of insects. In vertebrates (including humans), otoacoustic emissions are considered by-products of active sound amplification through specialized sensory receptor cells in the inner ear.

View Article and Find Full Text PDF

We describe here for the first time the development of mechanosensory organs in a chelicerate, the spider Cupiennius salei. It has been shown previously that the number of external sense organs increases with each moult. While stage 1 larvae do not have any external sensory structures, stage 2 larvae show a stereotyped pattern of touch sensitive 'tactile hairs' on their legs.

View Article and Find Full Text PDF

Over the past 76 years Alberto Stefanelli has successfully used a comparative approach to study the nervous system. His main research focus during that time has been on identifiable reticulospinal neurons including Müller and Mauthner neurons found in anamniotic vertebrates. Born in Venice, Italy in 1908, Professor Stefanelli pursued most of his academic career at the University of Rome, where he retired as Chair of Comparative Anatomy in 1978.

View Article and Find Full Text PDF

Sensitive hearing organs often employ nonlinear mechanical sound processing which produces distortion-product otoacoustic emissions. Such emissions are also recorded from insect tympanal organs. Here we report high frequency distortion-product emissions, evoked by stimulus frequencies up to 95 kHz, from the tympanal organ of a notodontid moth, Ptilodon cucullina, which contains only a single auditory receptor neuron.

View Article and Find Full Text PDF

Tympanal organs of insects emit distortion-product otoacoustic emissions (DPOAEs) that are indicative of nonlinear ear mechanics. Our study sought (1) to define constraints of DPOAE generation in the ear of Locusta migratoria, and (2) to identify the sensory structures involved. We selectively destroyed the connection between the (peripheral) sensory ganglion and the tympanal attachment points of the "d-cell" dendrites; d-cells are most sensitive to sound frequencies above 12 kHz.

View Article and Find Full Text PDF

Julius Bernstein belonged to the Berlin school of "organic physicists" who played a prominent role in creating modern physiology and biophysics during the second half of the nineteenth century. He trained under du Bois-Reymond in Berlin, worked with von Helmholtz in Heidelberg, and finally became Professor of Physiology at the University of Halle. Nowadays his name is primarily associated with two discoveries: (1) The first accurate description of the action potential in 1868.

View Article and Find Full Text PDF

This review focuses on the structure and function of a single mechanoreceptor organ in the cuticle of spiders. Knowledge emerging from the study of this organ promises to yield general principles that can be applied to mechanosensation in a wide range of animal systems. The lyriform slit sense organ on the antero-lateral leg patella of the spider Cupiennius salei is unusual in possessing large sensory neurons, whose cell bodies are close to the sites of sensory transduction, and accessible to intracellular recording during mechanotransduction.

View Article and Find Full Text PDF

Two types of sensory organs in crustaceans and arachnids, the various mechanoreceptors of spiders and the crustacean muscle receptor organs (MRO), receive extensive efferent synaptic innervation in the periphery. Although the two sensory systems are quite different-the MRO is a muscle stretch receptor while most spider mechanoreceptors are cuticular sensilla-this innervation exhibits marked similarities. Detailed ultrastructural investigations of the synaptic contacts along the mechanosensitive neurons of a spider slit sense organ reveal four important features, all having remarkable resemblances to the synaptic innervation at the MRO: (1) The mechanosensory neurons are accompanied by several fine fibers of central origin, which are presynaptic upon the mechanoreceptors.

View Article and Find Full Text PDF

Spider mechanosensory neurons receive an extensive network of efferent synapses onto their sensory dendrites, somata and distal axonal regions. The function of these synapses is unknown. Peripheral synapses are also found on crustacean stretch-receptor neurons but not on mechanosensory afferents of other species, although inhibitory GABAergic synapses are a common feature of centrally located axon terminals.

View Article and Find Full Text PDF

Cupiennius salei (Ctenidae) is a tropical wandering spider which lives in close association with a particular type of plant (see companion paper). These plants are the channels through which the spiders receive and emit various types of vibrations. We measured the vibrations the spiders are typically exposed to when they sit on their dwelling plants (banana plant, bromeliad) in their natural biotope in Central America.

View Article and Find Full Text PDF

Cupiennius is a genus of hunting spiders with seven established species. One of these (C. salei) has been used in laboratory research for many years.

View Article and Find Full Text PDF