Linking performance with brain potentials: mental rotation-related negativity revisited

It has been suggested that the amplitude of parietal event-related potentials (ERPs) provides a neural signature of imaginary object rotation. Here, we evaluated the relationship between the so-called rotation-related negativity and individual performance in the mental rotation of alphanumeric characters. The signals were averaged with respect to two time events, stimulus onset (ERP(ONSET)) and response time (ERP(RT)) indexing, respectively, an early and a late phase of the mental rotation. The amplitude of a slow parietal negativity varied with the rotation angle in both ERP(ONSET) and ERP(RT). The amplitude of this potential correlated negatively with task performance, indexed by response time. This was the case in ERP(RT) but not in ERP(ONSET). We further show that variations of the ERP(ONSET) amplitude with the rotation angle might at least partially result from increased duration/latency jitter among single trials. These results suggest that late rather than early processing supports task solution in mental rotation.