Homotopic callosal inhibition

Previous theories concerning the function of the corpus callosum have included a “topographic” column-to-column excitatory theory and a diffuse “regional” inhibitory theory. Here it is shown that a topographic inhibitory model, in conjunction with a postulate concerning surround inhibition among cortical columns, produces complementary patterns of cortical column firing which, although qualitatively different, do not imply quantitative metabolic asymmetries. The cognitive implications of such homotopic inhibition are discussed.     

Long-term proactive interference and novelty enhancement effect in monkey list memory

Serial-probe-recognition (SPR) performance by 2 monkeys deteriorated over several months of training. Three hundred and twenty different items were presented without repetition within a session (trial unique) but were repeated between sessions. The cause of the deterioration was identified as proactive interference (PI) due to repetitive use of items from day to day. Introduction of novel stimuli across days improved performance from 63% to 82% correct (Experiment 1). Tests with only probe items and no list items (Experiment 2) revealed that the monkeys were using a familiar/novel response strategy in combination with a relational strategy (relating the probe item to the list items) to further improve their SPR performance. Intermixing familiar baseline trials and novel transfer trials within a session (Experiment 3) encouraged the subjects to use a relational strategy, and it improved performance on baseline trials as well as on transfer trials. Possible qualitative similarity between the relational strategy and the familiar/novel response strategy is discussed along with theoretical implications of these findings for experiments which have used small number of repeating stimuli within a session.     

Expressed emotion and reciprocal affective relationships in families of disturbed adolescents

Relatives' expressed emotion (EE) is a known risk factor for relapse among recovering psychiatric patients. Recent research has focused on the behavioral correlates of EE, seeking better understanding of the family processes associated with this important variable. The present study used sequence analysis to explore interactions of high-EE and low-EE parent-child dyads in a sample of disturbed adolescents. High-EE mother-child interactions were characterized by bidirectional influence, and, in contrast to adolescents in low-EE dyads, adolescents in high-EE dyads had an oppositional style of responding. In Low-EE mother-child interactions, the adolescents showed more temporal consistency (stability) of affect than their high-EE counterparts. Overall, the results suggest that high-EE mother-child dyads constitute more tightly joined emotional systems than low-EE dyads. Consequently, interventions designed to reduce this connectedness might also reduce the risk of adolescent psychiatric problems.     

The effect of reading ‘List’ and ‘Overview’ summaries on the recall of two narrative texts

This paper reports an investigation of the mnemonic value of reading a summary before a text. Subjects (194 sixth-form students) read one of two folk-tales, either in isolation or preceded by a ‘List’ or an ‘Overview’ type of summary. Free recall of the story was then tested. Overall, both types of summary produced a significant increase in recall, although further analyses showed that their effects were located primarily in the recall of the latter parts of the stories. It is suggested that future work could usefully extend the analysis to a consideration of longer, and less well structured texts.