False recognition modality effects in short-term memory: Reversing the auditory advantage.

The auditory advantage in short-term false recognition - reduced false memories for auditory compared to visually presented words (Olszewska, Reuter-lorenz, Munier, & Bendler, 2015), has been attributed to greater item distinctiveness in auditory compared to visual memory traces. If so, varying auditory trace distinctiveness should influence false recognition rates. Phonologically and semantically related words were presented visually or aurally. The auditory advantage for semantic lists was replicated but a reversal was observed for phonological lists. Reducing modality-specific acoustic and phonological distinctiveness by increasing phonological similarity led to increased false memory. The findings are consistent with a framework positing the generation of input-dependent memory traces and the role of relative distinctiveness in influencing short-term memory.

Genetic analysis of the thermolabile methylenetetrahydrofolate reductase variant in schizophrenia and mood disorders.

OBJECTIVE: An elevated homocysteine level has been reported for patients with schizophrenia and depression. We investigated the frequency of the common C667 T variant of the enzyme methylenetetrahydrofolate reductase in controls and patients of Chinese descent. METHODS: Controls with no history of mental disorder and patients diagnosed with schizophrenia, bipolar and unipolar disorders were recruited. Genomic DNA from all were genotyped for the C667 T polymorphism by polymerase chain reaction-restriction fragment length polymorphism. RESULTS: There was no significant difference in genotype distributions or allele frequencies between controls and any of the diagnostic groups, although the frequency of the T allele was higher for all diagnostic groups and for both the male and female genders. When data was analyzed with the minor T allele as dominant, there was an excess of the T-containing genotypes in each of the patient groups compared with controls. For the difference between controls and all cases combined it almost reached statistical significance (P=0.077), with an odds ratio of 1.46 (95% confidence interval, 0.96-2.22). CONCLUSIONS: Although there was no significant association as measured by the P value, the odds ratio and confidence interval provided some evidence of increased risk for individuals with the T-containing genotypes. A minor role for this polymorphism in the pathogenesis of schizophrenia and depression could not be ruled out and would warrant further investigation.