The Novelty Effect in Recovered Hemineglect

Abstract

Left neglect patients, patients who had recovered from left neglect and control subjects performed a task of simple motor reaction times (RTs) to lateralised visual stimuli. Neglect and recovered patients were slower than controls on left-sided targets. To explore the time course of the allocation of attention across space, an analysis of responses as a function of the serial order of the trials was performed. While neglect patients' performance did not substantially change over time, recovered patients showed a stereotyped ‘novelty effect’, consisting of larger left/right RT differences at the beginning of the task than at the end of it. To explain this practice-related change, a trade-off is hypothesised between the process of learning the motor task and the mechanisms involved in recovery from neglect, such as the reorienting of attention toward the contralesional side following the initial ipsilesional orienting. A possible role is proposed for the prefrontal cortex as the crucial neural structure that mediates both processes