The effects of target and distractor familiarity on visual search in de novo Parkinson's disease patients: Latent inhibition and novel pop-out

De novo Parkinson's disease (PD) patients identified presence or absence of a unique shape presented with homogeneous distracters. Response time (RT) was examined as a function of prior experience with target and/or distracte r assessing latent inhibition (LI; slower RTs to a target that was formerly a distracter against a background of distracters that were formerly target s as compared with a novel target with distracters that were formerly targe ts) and novel pop-out effects. PD patients were slower than controls in det ecting test-phase targets compared with preexposure-phase targets. Female P D patients with right-side motor symptoms had elevated LI compared with fem ale controls and female PD patients with left-side symptoms. Male PD patien ts with right-side symptoms did not exhibit LI. Results are discussed in te rms of the dopamine hypothesis and the reciprocal relationship between PD a nd schizophrenia.