Perhaps you should try some spelling variations:
reward processing » word processing (Expand search), onboard processing (Expand search), and processing (Expand search)
strain decreased » strain decrease (Expand search), strains decrease (Expand search), brain decreases (Expand search)
decrease reward » decrease awkward (Expand search), decrease towards (Expand search), increase rewards (Expand search)
decrease strain » increase strain (Expand search), decreases pain (Expand search), decreased brain (Expand search)
decreased sperm » decreased sleep (Expand search)
sperm decrease » term decrease (Expand search), speed decrease (Expand search), speed decreases (Expand search)

You may be able to get more results by adjusting your search query.

• The words AND, OR and NOT may confuse the search; try adding quotes: "(( decrease _ decrease reward processing ) OR ( decrease strain decreased sperm decrease ))~".
• Adding a wildcard symbol may retrieve word variants: (( decrease _ decrease reward processing ) OR ( decrease strain decreased sperm decrease ))*.