Related Experiment Videos
Changes in the auditory-evoked potentials induced by fear-evoking stimulations
M L Brandão1, N C Coimbra, M Y Osaki
1Laboratório de Psicobiologia, FFCLRP, Campus University of São Paulo, Avenida Bandeirantes 3900, 14049-901 Ribeirão Prêto, São Paulo, Brazil. mbrandao@usp.br
Physiology & Behavior
|March 29, 2001
Summary
Microinjections of glutamate into the inferior colliculus increase auditory-evoked potentials. Fear-inducing stimuli also enhance these responses, suggesting a role for excitatory amino acid receptors in auditory processing and fear responses.
Area of Science:
- Neuroscience
- Auditory Neuroscience
- Neurophysiology
Background:
- The inferior colliculus is crucial for processing auditory information and relaying it to higher brain centers.
- Electrical stimulation of the inferior colliculus can elicit aversive responses, including freezing and escape behaviors.
- Excitatory amino acids, such as glutamate, have been shown to mimic these aversive effects when microinjected into the inferior colliculus.
Purpose of the Study:
- To investigate the effect of glutamate microinjections into the inferior colliculus on collicular-evoked potentials.
- To examine how fear-evoking stimuli modulate neuronal activity in the inferior colliculus.
- To further elucidate the role of excitatory amino acid receptors in auditory processing and fear responses within the inferior colliculus.
Main Methods:
- Unilateral microinjections of glutamate (5 nmol) into the inferior colliculus of rats.
- Bilateral recording electrodes placed in the inferior colliculus to measure collicular-evoked potentials.
- Application of fear-evoking stimuli: light as a conditioned stimulus (CS) and 22 kHz ultrasound signals.
Main Results:
- Glutamate microinjections into the inferior colliculus significantly increased the magnitude of ipsilateral collicular-evoked potentials compared to saline controls.
- Fear-evoking stimuli (light-CS and ultrasound) also led to an increased amplitude of evoked potentials in the inferior colliculus.
- These findings indicate that fear-eliciting stimuli enhance acoustically evoked neuronal firing in the central nucleus of the inferior colliculus.
Conclusions:
- Fast-acting excitatory amino acid receptors in the inferior colliculus are involved in processing auditory information.
- Fear-eliciting stimuli modulate neuronal activity in the inferior colliculus, potentially through excitatory amino acid pathways.
- The inferior colliculus plays a significant role in the neural processing of auditory fear responses.