In the sentence extracted from biomedical literature, identify all the chemical entities. The required answer format is the same sentence with HTML <span> tags to mark up specific entities. 
### Entity Markup Guides:
Use <span class="chemical"> to denote a chemical.

### Input Text: To explore whether this benefit is linked to the restoration of sensorimotor plasticity of M1 , we conducted an additional study looking at changes in LIDs and PAS - induced plasticity after 10 sessions of either bilateral , real inhibitory cerebellar stimulation or sham stimulation .
### Output Text:
To explore whether this benefit is linked to the restoration of sensorimotor plasticity of M1 , we conducted an additional study looking at changes in LIDs and PAS - induced plasticity after 10 sessions of either bilateral , real inhibitory cerebellar stimulation or sham stimulation . 