Related Experiment Video
Updated: Aug 9, 2026
Habituation and Prepulse Inhibition of Acoustic Startle in Rodents
Published on: September 1, 2011
Development and habituation of the heart rate orienting response to auditory and visual stimuli in the rat
Insights
Young rat pups initially show accelerated heart rates (HR) to sounds and light, indicating a defensive response. As they mature, this response shifts to deceleration, suggesting an orienting response to sensory stimuli.
Area of Science:
- Developmental Neuroscience
- Sensory Physiology
- Behavioral Biology
Background:
- Understanding the ontogeny of sensory processing is crucial for comprehending early life development.
- Heart rate (HR) changes serve as a reliable indicator of autonomic nervous system responses to stimuli in developing mammals.
Purpose of the Study:
- To investigate the developmental trajectory of responsiveness to auditory and visual stimuli in young rats.
- To characterize the habituation and nature of heart rate (HR) responses to sensory input during early postnatal development.
Main Methods:
- Utilized changes in heart rate (HR) as the primary measure of response to auditory (white noise) and visual (light) stimuli.
- Studied pups aged 8-19 days, examining responses across different stimulus intensities (60, 70, 90 dB) in older pups.
Main Results:
- Responsiveness to sound emerged around 14-15 days, initially as HR acceleration, shifting to bradycardia within 3 days.
- HR response to light also transitioned from tachycardia in younger pups (14 days) to bradycardia in older pups (16+ days).
- Auditory stimulus intensity affected the magnitude but not the direction of HR response in 19-day-old pups.
Conclusions:
- Early sensory stimuli elicit a defensive reaction (HR acceleration) shortly after sensory system maturation.
- With further development, the same stimuli evoke an orienting response (cardiac deceleration), indicating adaptive changes in sensory processing.
Abstract:
Development and habituation of responsitivity to sound and visual stimuli were studied in 8-19 day-old pups by using a change in heart rate (HR) as the indicant response. A change in HR to sound (white noise) first occurred around 14-15 days of age and was acceleratory in nature. Within 3 days the direction of the HR response shifted to bradycardia. The HR response to light was also characterized by tachycardia in young pups (14 days) which shifted to bradycardia as the pups matured (16 days and older). Experiment 2, the HR response to 15- and 19-day-old rats was studied at three auditory stimulus intensities (60, 70, and 90 dB, B scale). Stimulus intensity did not alter the direction of the HR response, but it did influence the magnitude of the cardiac response in the 19-day-old pups. These data suggest that even weak sensory stimuli elicit a defensive reaction (HR acceleration) during the first few days that follow onset of function in each sensory system. Later in development the same stimulus elicit an orienting response (cardiac deceleration).
More Related Videos
10:50Behavioral Determination of Stimulus Pair Discrimination of Auditory Acoustic and Electrical Stimuli Using a Classical Conditioning and Heart-rate Approach
Published on: June 6, 2012
09:13A Fully Automated and Highly Versatile System for Testing Multi-cognitive Functions and Recording Neuronal Activities in Rodents
Published on: May 3, 2012