@misc{indiciae23a91746d248,
  title = {Task difficulty increases thresholds of rewarding brain stimulation.},
  author = {G Fouriezos and C Bielajew and W Pagotto},
  year = {1990},
  doi = {10.1016/0166-4328(90)90066-n},
  url = {https://pubmed.ncbi.nlm.nih.gov/2310490/},
  note = {Source identifier: 2310490}
}