Hemispheric asymmetries in the time course of recognition memory

Abstract

Hemispheric specialization has been studied extensively within subfields ranging from perception to language comprehension. However, the study of asymmetries for basic memory functions-an area that holds promise for bridging these low-and high-level cognitive domains-has been sporadic at best. We examined each hemisphere's tendency to retain verbal information over time, using a continuous recognition memory task with lateralized study items and central test probes. We found that the ubiquitous advantage of the left hemisphere for the processing and retention of verbal information is attenuated and perhaps even reversed over long retention intervals. This result is consistent with theories that propose differences in the degree to which the hemispheres maintain veridical versus semantically transformed representations of the input they receive.

The memory that's right and the memory that's left: Event-related potentials reveal hemispheric asymmetries in the encoding and retention of verbal information

“…The accuracy difference between the VFs increased between the short and medium lags (possibly reflecting the influence of a ceiling effect at the shortest lags), but decreased again at the longest lags. This same numerical pattern was present in the Federmeier and Benjamin (2005) data.…”

“…Of critical interest is whether the timecourse of these retrieval-related memory effects differs for words that were originally studied in the RVF/LH as compared with the LVF/RH. If the RT effects observed by Federmeier and Benjamin (2005) were driven by asymmetries in the strength of the memory signal, a similar pattern might be seen on the old/new effect, with hits to RVF/LH-studied words eliciting more positive ERP responses at short and medium lags, but hits to LVF/RH-studies items showing more positive responses at long lags. If, however, the RT difference reflects contributions from an implicit and perceptually based memory signal, then VF-based differences might be manifest instead on components such as the P2.…”

“…Given that many previous investigations of hemispheric asymmetries in verbal memory have used lateralized test words, it is particularly problematic that the observed RVF/LH speed and accuracy advantages are also consistent with the documented reading asymmetries that favor RVF/LH words. Federmeier and Benjamin (2005) tried to minimize the contributions of such biases by lateralizing only the study words, so that responses were instead measured to perceptually identical stimuli presented in central vision. In a continuous recognition paradigm, lateralized study words were interleaved with test words presented in central vision, spaced over a range of nine repetition lags (from immediate repetition, 'lag 1,' to 49 intervening words, 'lag 50').…”

“…There-fore, the present experiment uses ERP measures in conjunction with a VF design to examine memory asymmetries that arise due to encoding biases, and howthese asymmetries interact with repetition lag. Following Federmeier and Benjamin (2005), the experiment employs a continuous recognition task, with interleaved lateralized study words and central test words, spaced by a range of repetition lags. Three particular aspects of the ERP response are examined.…”

Time‐dependent hemispheric shift of the cortical control of volitional swallowing

“…Likely one of the best-known asymmetries is the lateralization of language function to the left hemisphere for the majority of right-handed subjects. Hemispheric differences were also found for other higher cognitive functions [Federmeier and Benjamin, 2005;Natale et al, 1983] and in the motor system [Yan et al, 2006]. Most of these studies described lateralization in terms of amplitude differences in electroencephalography (EEG) and magnetoencephalography (MEG) experiments or different extents of cortical activation using PET or functional MRI without discussing latency differences.…”