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Published on: April 1, 2022
Ultrasound exposure of the foetal chick brain: effects on learning and memory
Michal E Schneider-Kolsky1, Zohel Ayobi, Paul Lombardo
1Department of Medical Imaging & Radiation Sciences, Faculty of Medicine, Nursing and Health Sciences, School of Biomedical Science, Monash University, Clayton, 3800 Victoria, Australia. michal.schneider-kolsky@med.monash.edu.au
Insights
Pulsed Doppler ultrasound exposure in ovo can impair learning and memory in newly hatched chicks. This cognitive dysfunction occurred after 4-5 minutes of exposure, suggesting potential risks from this imaging technique near hatching.
Area of Science:
- Neuroscience
- Developmental Biology
- Medical Imaging
Background:
- Cerebral ultrasound imaging is vital for monitoring brain development in premature infants.
- Animal studies indicate potential for ultrasound to harm developing fetal and neonatal tissues.
Purpose of the Study:
- To investigate the impact of in ovo ultrasound exposure on learning and memory in chicks post-hatch.
- To determine if specific ultrasound modes (B-mode, pulsed Doppler) and durations affect cognitive function.
Main Methods:
- Chicks were exposed to B-mode or pulsed Doppler ultrasound on day 19 of incubation.
- Learning and memory were assessed at day 2 post-hatch using behavioral tests.
- Exposure durations varied from 1 to 10 minutes depending on the ultrasound mode.
Main Results:
- B-mode ultrasound exposure did not impair memory function.
- Pulsed Doppler ultrasound exposure for 4-5 minutes resulted in significant memory impairment 2 hours after training.
- Impairment affected short-, intermediate-, and long-term memory, indicating a learning deficit.
Conclusions:
- Extended exposure to pulsed Doppler ultrasound near hatching can adversely affect cognitive function in chicks.
- The findings suggest a potential risk of learning and memory impairment from specific ultrasound applications in neonatal development.
Abstract:
Ultrasound imaging of the brain is routinely used to monitor the development and resolution of brain lesions among premature and compromised newborn human babies. However, animal studies have shown that ultrasound can cause damage to developing foetal and neonatal tissues. In this study we investigated if ultrasound of the chick brain can lead to learning and memory impairment after hatch. We exposed the brains of chicks on day 19 of a 21 day incubation period to 5 or 10 min of B-mode, or to 1, 2, 3, 4 or 5 min of pulsed Doppler ultrasound in ovo. Learning and memory function were assessed at day 2 post-hatch. Our results show that B-mode exposure at E19 does not affect memory function. On the other hand, 2h after training, significant memory impairment occurred following 4 and 5 min of pulsed Doppler exposure at E19. In separate groups of chicks, short-, intermediate- and long-term memory was equally impaired suggesting an inability to learn. Further, the chicks were still unable to learn with a second training session 5 min after completion of the initial testing. These results demonstrate that extended exposure to pulsed Doppler ultrasound can adversely affect cognitive function in the chick when exposure occurs close to the time of hatch.
