Figure 3. Summary of the Present Study (IMAGE) Kanazawa University Caption The trace-like axonal fiber bundles are now considered to have become more robust during the evolution of ferrets or humans and, as a result, the second axonal fiber layer has been formed. The destinations of the two axonal fiber layers are also found to be different. Credit Kanazawa University Usage Restrictions Credit must be given to the creator. License CC BY Disclaimer: AAAS and EurekAlert! are not responsible for the accuracy of news releases posted to EurekAlert! by contributing institutions or for the use of any information through the EurekAlert system.