Delay discounting and affective priming in individuals with negative schizotypy.

Previous studies have demonstrated that patients with schizophrenia and individuals with schizotypy experience decreased anticipatory pleasure. However, it is unclear whether this decrease is contributed by altered reward processing at the proximal or distal future. In order to investigate the preference for receiving rewards in the proximal or distal future for individuals with schizophrenia spectrum disorders, individuals with either high or low levels of negative schizotypy performed a delay discounting task under positive, neutral and negative affective priming conditions. Compared with individuals with low levels of negative schizotypy, individuals with high levels of schizotypy exhibited increased delay discounting, preferring to choose immediate but smaller rewards instead of delayed but larger rewards across all three affective priming conditions. Negative affective priming elevated discounting for both groups compared with both the positive and neutral affective conditions. After dividing delayed temporal distance into the proximal and distal future, the results showed that individuals with high levels of negative schizotypy exhibited more preference for immediate but smaller rewards in the distal instead of proximal future compared with controls. Our results suggest that individuals with high levels of negative schizotypy have altered anticipatory reward processing, which is mainly attributed to alterations in representing rewards in the distal future. These findings extend the alterations in representing reward values from schizophrenia patients to schizotypal individuals, and suggest that diminished anticipatory pleasure in schizophrenia spectrum disorders may be due to changes in processing anticipatory rewards in the distal future.

Retrieval intention modulates the effects of directed forgetting instructions on recollection.

The neurocognitive basis of memory retrieval is often examined by investigating brain potential old/new effects, which are differences in brain activity between successfully remembered repeated stimuli and correctly rejected new stimuli in a recognition test. In this study, we combined analyses of old/new effects for words with an item-method directed-forgetting manipulation in order to isolate differences between the retrieval processes elicited by words that participants were initially instructed to commit to memory and those that participants were initially instructed to forget. We compared old/new effects elicited by to-be-forgotten (TBF) words with those elicited by to-be-remembered (TBR) words in both an explicit-memory test (a recognition test) and an implicit-memory test (a lexical-decision test). Behavioral results showed clear directed forgetting effects in the recognition test, but not in the lexical decision test. Mirroring the behavioral findings, analyses of brain potentials showed evidence of directed forgetting only in the recognition test. In this test, potentials from 450-650 ms (P600 old/new effects) were more positive for TBR relative to TBF words. By contrast, P600 effects evident during the lexical-decision test did not differ in magnitude between TBR and TBF items. When taken in the context of prior studies that have linked similar parietal old/new effects to the recollection of episodic information, these data suggest that directed-forgetting effects manifest primarily in greater episodic retrieval by TBR than TBF items, and that retrieval intention may be important for these directed-forgetting effects to occur.

Concreteness effects in the processing of Chinese words.

The present study examined the relationship between word concreteness and word frequency using event-related potential (ERP) measurements during a lexical decision task. Potential effects of concreteness in the processing of verbs were also examined. ERPs were recorded from 119 scalp electrodes in 23 right-handed participants. The results showed that concrete nouns were associated with a more negative ERP than abstract nouns at 200-300 and 300-500 ms after stimulus onset, regardless of word frequency. Between 300 and 500 ms, concrete nouns and abstract nouns produced differentiated scalp distributions, respectively. In terms of verbs, concreteness only produced small difference in ERP primarily in the central-parietal sites of the left hemisphere.