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H W Borchers

Publications and source records attributed to H W Borchers.

6 recordsLinked to original sources
PubMed1987

Miniature three-function transmitting system for single neuron recording, wireless brain stimulation and marking.

A telemetric micro-transmitting system has been developed for extracellular single unit recording, electrical brain stimulation and marking of the recording and stimulation site in small freely moving animals. The action potentials are transmitted by using frequency modulation for distances up to 10 m. Electrical brain stimulation through the recording electrodes is performed by means of an inductively powered circuit which is combined with the transmitter (mass of the system 2.38 g). Biphasic current pulses can be applied. Pulse frequency and duration are wireless remotely controlled. The recording and stimulation site in the brain can be marked by means of iron deposits.

Animals↗
PubMed1984

Visual unit, EEG and sustained potential shift responses in the brains of toads (Bufo bufo) during alert and defensive behavior.

Cranially mounted differential preamplifiers allowed visual unit activity, EEGs and sustained potential shifts to be monitored from the tectum of freely moving toads (Bufo bufo). Alert behavior was elicited by a moving visual stimulus. Movement of the stimulus in the receptive field of a unit elicited its activity and increased the amplitude of the high frequency component of the local EEG, accompanied by a sustained potential shift. When an animal received a "prod" with a perspex rod, defensive behavior ensued accompanied by slight activity of the visual unit, a large increase in the amplitude of the lower frequency component of the EEG and a large, sustained, potential shift. The results are discussed in relation to the specific neuronal unit responses of the animal and to possible sensitising functions of the non-specific EEG and sustained potential shift responses.

Animals↗
PubMed1984

Effects of telencephalic ablation on visual unit, sustained potential shift, and EEGs recorded from the toad tectum in response to a visual stimulus.

Extracellular recordings were made of visual unit activity, sustained potential shifts (SPSs), and electroencephalographic activity (EEGs) from the optic tectum and of EEGs from the telencephalon of immobilized toads (Bufo bufo). Moving visual stimuli were presented, and the bioelectric responses were monitored both before and after ligature of the telencephalon. The operation reduced the neuronal spike frequency and the amplitude of the tectal SPS and EEG responses. EEGs were still recorded from the tectum and even the isolated telencephalon. The results are discussed in relation to possible adaptive functions of SPS and EEG changes, the genesis of the EEG, and the role of the telencephalon in visually guided prey-catching behavior.

Animals↗
PubMed1979

Invariants in configurational prey selection by Bufo bufo (L.).

Toads (Bufo bufo) are able to distinguish small stripes with axis orientation in the direction of motion (worm-like stripes) from those with axis orientation perpendicular to the direction of motion (anti-worm-like stripes). The configurational discrimination ability of the toad is, thus far investigated, largely invariant for (1) movement direction in the x-y plane, (2) direction of contrast--stripe against background--and (3) velocity of stripe motion.

Animals↗