Electrical Stimulation publications

Anticipating positive outcomes is a core cognitive function in the process of reward prediction. However, no neurophysiological method objectively assesses reward prediction in basic medical research. In the present study, we established a physiological paradigm using cortical direct current (DC) potential responses in rats to assess reward prediction. This paradigm consisted of five daily 1-h sessions with two tones, wherein the rewarded tone was followed by electrical stimulation of the medial forebrain bundle (MFB) scheduled at 1000 ms later, whereas the unrewarded tone was not. On day 1, both tones induced a negative DC shift immediately after auditory responses, persisting up to MFB stimulation. This negative shift progressively increased and peaked on day 4. Starting from day 3, the negative shift from 600 to 1000 ms was significantly larger following the rewarded tone than that following the unrewarded tone. This negative DC shift was particularly prominent in the frontal cortex, suggesting its crucial role in discriminative reward prediction. During the extinction sessions, the shift diminished significantly on extinction day 1. These findings suggest that cortical DC potential is related to reward prediction and could be a valuable tool for evaluating animal models of depression, providing a testing system for anhedonia.

This project investigated whether pediatric (5–14 years) and adult (30–60 years) cochlear implant (CI) users benefit from a target/masker sex-mismatch for speech-in-speech recognition. Speech recognition thresholds were estimated in a two-male-talker or a two-female-talker masker. Target and masker speech were either sex-matched or sex-mismatched. For both age groups, performance for sex-matched talkers was worse for male than female speech. Sex-mismatch benefit was observed for the two-male-talker masker, indicating CI users can benefit from a target/masker sex mismatch. No benefit was observed for the two-female-talker masker, suggesting this effect may depend on the relative contributions of energetic and informational masking.