ABSTRACT
The impact of monetary reward on verbal working memory (vWM) and verbal long-term memory (vLTM) was evaluated in 50 patients with schizophrenia spectrum disorders and 52 matched healthy participants. This research was motivated by the observations that negative symptoms in schizophrenia are associated with reduced drive and that patients with these symptoms exhibit greater mnemonic impairments. Reward-related gains were evaluated across two levels of vWM load on the n-back task and across three aspects of vLTM derived from the California Verbal Learning Test-II (i.e., learning, total immediate recall, and retention). Although healthy individuals benefited from reward at a high vWM load level, schizophrenia patients exhibited no reward-related improvements in vWM. In contrast, improvement in vLTM retention was induced by reward for both patients and controls. Finally, symptomatic and pharmacology treatment factors were associated with reward-related gains in persons with schizophrenia. In conclusion, contingent monetary rewards delivered during vWM and vLTM enhanced specific aspects of memory. The influence was relatively small and dependent on the specific neurocognitive operation examined, the mental health status of the participants, and for patients, their particular symptoms and pharmacological treatments.
Subject(s)
Memory/physiology , Reward , Schizophrenia/physiopathology , Schizophrenic Psychology , Adult , Case-Control Studies , Cholinergic Antagonists/administration & dosage , Exploratory Behavior/physiology , Female , Humans , Male , Memory/radiation effects , Middle Aged , Neuropsychological Tests , Psychiatric Status Rating Scales , Reference Values , Regression Analysis , Schizophrenia/drug therapy , Verbal Learning/physiologyABSTRACT
To explore verbal memory impairments associated with multiple sclerosis (MS), we compared proactive and retroactive interference effects on the California Verbal Learning Test (CVLT; Delis et al., 1987) in a sample of 83 community-residing individuals with MS and 80 healthy participants. Individuals with MS demonstrated normal accumulation of proactive interference (PI), but attenuated release from PI relative to healthy individuals. Furthermore, accumulation of retroactive interference (RI) at short-delay free recall (SDFR) was intensified for those with MS as compared to healthy participants. Interestingly, accumulation of RI predicted long-term memory (LTM) only for participants with MS. These findings suggest that individuals with MS may experience particular difficulty when required to use semantic properties of information flexibly to facilitate verbal LTM.
Subject(s)
Memory Disorders/etiology , Memory/physiology , Multiple Sclerosis/complications , Adult , Case-Control Studies , Female , Humans , Male , Memory/classification , Middle Aged , Multivariate Analysis , Neuropsychological Tests/statistics & numerical data , Reaction Time/physiology , Verbal Learning/physiologyABSTRACT
Two experiments were conducted to investigate whether auditory and visual language laterality tasks test the same brain processes for verbal functions. In the first experiment, 48 undergraduate students (24 males, 24 females) completed both an auditory monitoring task and a visual monitoring task, with the Waterloo Handedness Questionnaire administered between the two tasks. The visual task was an analogue of the dichotic listening task used. It was hypothesized that a significant cross-modal correlation would be found, indicating that the dichotic listening task and the visual analogue task do, in fact, test the same brain processes for verbal functions. Results revealed a right ear advantage in the auditory task, a left visual field advantage (LVFA) in the visual task, and a cross-modal correlation of asymmetries of -.09. The LVFA observed in the visual task was replicated in Experiment 2, thus establishing its legitimacy. Results are discussed in relation with the type of processing that might produce such an unexpected finding on the visual task.
