Early-stage findings on long-term behavioral effects of Transcranial Magnetic Stimulation in cortical blindness in rats

Comprehensive Summary

In this study, blindness was induced in rats to create bilateral cortical lesions and to investigate transcranial magnetic stimulation. 20 Long-Evans male rats were split into 4 groups. Lesions of the primary visual cortex were made. Cortical blindness was verified using visual discrimination tests. Transcranial Magnetic Stimulation with a frequency of 60 Hz and 10 mT was given for 1 hour a day, 3 days a week, and for 4 weeks for Experimental Group 1 and 120 G for Experimental Group 2. After TMS was administered, evaluations were conducted 24 hours after each therapy session over a period of 4 weeks. Cortical blindness manifested in the Control Group and both Experimental Groups. After the evaluations, the Experimental Groups seemed to improve significantly when their performance in Week 1 and Week 4 after TMS use was compared.

Outcomes and Implications

Visual discrimination tests are very helpful in examining the functioning of the primary visual cortex. Transcranial Magnetic Stimulation was shown to improve recovery by at most 30 percent in the Experimental Groups. However, TMS could not fully recover primary visual cortex function after injury. More studies need to be performed on TMS to make it applicable in a clinical setting for human patients, but this early study shows promise in TMS as an instrument of recovery from cortical blindness.