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L M Schultz

Publications and source records attributed to L M Schultz.

6 recordsLinked to original sources
PubMed1998

Synaptic depression at type B to A photoreceptor connections in Hermissenda.

We quantified synaptic depression at the type B to A photoreceptor connections of Hermissenda. Type B cell action potentials were evoked at interstimulus intervals (ISIs) of 0.3, 3 or 30 s and the resulting inhibitory postsynaptic potentials (IPSPs) were recorded in a type A cell. A progressive decline in IPSP amplitude occurred at all three ISIs. Synaptic depression was greater at shorter ISIs, as was the level of recovery 2 min after the stimulus series. The profound level of synaptic depression observed (79.0+/-3.2% at the 0.3 s ISI) implies that synaptic depression is an important control process in the neuronal circuitry that drives phototactic behavior.

Action Potentials↗
PubMed1997

GABA-induced synaptic facilitation at type B to A photoreceptor connections in Hermissenda.

Gamma-aminobutyric acid (GABA) is a prevalent neurotransmitter in both vertebrate and invertebrate systems. Here we report that, in addition to its usual inhibitory actions, GABA induced synaptic facilitation at type B to A photoreceptor connections of the marine mollusk Hermissenda when applied transiently to the isolated nervous system. Synaptic facilitation also occurred in response to mechanical stimulation of the GABAergic hair cells, which are normally activated by rotational unconditioned stimuli during behavioral training of the intact animal. This synaptic facilitation represents a novel form of GABA-induced neuromodulation which may contribute to learning-dependent suppression of phototaxis in Hermissenda.

Action Potentials↗
PubMed1994

Visual-haptic relations in a two-dimensional size-matching task.

Visual and haptic perceptions of the two-dimensional size of square stimuli were compared using cross-modal, intramodal, and bimodal matching tasks. In a repeated-measures factorial design, 12 women participated in five matching tasks involving various combinations of vision and haptic touch; five sizes of standard squares were matched with a comparison range of 10 squares during each task. Analysis showed that, for stimuli with side lengths of .75 in. and smaller, matching accuracy was superior when vision was used during the matching task regardless of the modality used during inspection. When haptic touch was used in the matching task, accuracy was better when vision had been used during inspection than when it had not. These results were consistent with those of previous studies comparing size perception by vision and other forms of touch. The over-all relationship between matched size and inspected size was best accounted for by a third-order polynomial function.

Adolescent↗
PubMed1993

An HPLC method for the detection of ergot in ground and pelleted feeds.

A high performance liquid chromatography (HPLC) method is described for detecting ergot in ground or pelleted forages and grains. Samples were extracted with alkaline chloroform, filtered, and applied to silica gel/organic binder cleanup columns. Following elution of pigments with acetone: chloroform, ergopeptine alkaloids were eluted with methanol and analyzed by HPLC with fluorescence detection. Average recovery of ergotamine, the major ergopeptine alkaloid produced by Claviceps, was 93%, with a relative standard deviation of 4.9%. The detection limit of ergotamine was approximately 50 ppb in all feedstuffs. Confirmation of ergopeptine alkaloids was accomplished by treating the parent ergopeptine alkaloids with 0.2% acetic acid to produce their -inine isomers and reexamining by HPLC with fluorescence detection or silica gel/organic binder column cleanup in combination with tandem mass spectroscopy. The method described is a valid alternative to microscopic inspection for detecting ergot contamination in ground or pelleted feedstuffs.

Animal Feed↗