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Startle Response System
The acoustic startle reflex is a highly characteristic response to a sudden, intense stimulus. It has
been observed in many species (e.g. rats, mice and also humans). In rodents the startle response is
characterized by contractions of the major body muscles.
By performing acoustic startle response experiments general information about sensimotor processing can
be achieved. In "PPI" (prepulse inhibition) experiments a weak signal (the prepulse) is followed
immediately by a sudden intense stimulus (startle stimulus). Normally the weak signal attenuates the
response to the startle stimulus. Deficits in the PPI are related to deficits in sensimotoric gating
processes. Alternatively, "fear-potentiated startle" experiments can be performed: the response to a
startle-eliciting stimulus is increased when it has previously been paired with an aversive stimulus
like a foot shock. Fear-potentiated startle experiments have been widely used in studies of fear
conditioning.
Startle reflex in small rodents can be easily quantified with our new computerized startle response
measuring system. The whole setup is contained in sound-attenuating isolation cabinets. Up to 4 startle
boxes can be operated simultaneously with one computer.
Animals are tested restrained in small holders - restricting major movements and exploratory behavior -
that are mounted on species-specific load cell platforms. Intense auditory stimuli characterized by very
rapid rise times are generated by means of high-quality high-linearity speakers.
The auditory stimuli can be combined with tactile stimuli (air puffs) to form user-defined trial
sequences with variable inter-stimulus intervals. For assessment of fear-potentiated startle an
electrical stimulus (up to 3.1mA) can be applied using the integrated shock grid. The system also
provides a TTL signal (digital signal) that can be used to switch on a camera or a video tape recorder
or to control additional external devices such as user-specific signal generators. The flexible
profile editor allows all standard tests to be created including complex "pre-pulse" designs to
measure excitatory and inhibitory effects on startle.
After determination of baseline activity the startle reflex is triggered by exposure to stimuli.
Reaction time, i.e. response latency, and startle amplitude for each trial are presented in results
tables.
The results can be stored as CSV export files for import into statistical or spreadsheet packages (e.g.
MS Excel).
Copyright © 1995 - 2008 TSE Systems International Group - All rights reserved.
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