Old-new ERP effects and remote memories: the late parietal effect is absent as recollection fails whereas the early mid-frontal effect persists as familiarity is retained.

Understanding the electrophysiological correlates of recognition memory processes has been a focus of research in recent years. This study investigated the effects of retention interval on recognition memory by comparing memory for objects encoded four weeks (remote) or 5 min (recent) before testing. In Experiment 1, event related potentials (ERPs) were acquired while participants performed a yes-no recognition memory task involving remote, recent and novel objects. Relative to correctly rejected new items, remote and recent hits showed an attenuated frontal negativity from 300-500 ms post-stimulus. This effect, also known as the FN400, has been previously associated with familiarity memory. Recent and remote recognition ERPs did not differ from each other at this time-window. By contrast, recent but not remote recognition showed increased parietal positivity from around 500 ms post-stimulus. This late parietal effect (LPE), which is considered a correlate of recollection-related processes, also discriminated between recent and remote memories. A second, behavioral experiment confirmed that remote memories unlike recent memories were based almost exclusively on familiarity. These findings support the idea that the FN400 and LPE are indices of familiarity and recollection memory, respectively and show that remote and recent memories are functionally and anatomically distinct.

Broca's area supports enhanced visuospatial cognition in orchestral musicians.

We provide neurobehavioral evidence supporting the transferable benefit of music training to alter brain function and enhance cognitive performance in a nonmusical visuospatial task in professional orchestral musicians. In particular, orchestral musicians' performance on a three-dimensional mental rotation (3DMR) task exhibited the behavioral profile normally only attained after significant practice, supporting the suggestion that these musicians already possessed well developed neural circuits to support 3DMR. Furthermore, functional magnetic resonance imaging revealed that only orchestral musicians showed significantly increased activation in Broca's area, in addition to the well known visuospatial network, which was activated in both musicians and nonmusicians who were matched on age, sex, and verbal intelligence. We interpret these functional neuroimaging findings to reflect preferential recruitment of Broca's area, part of the neural substrate supporting sight reading and motor-sequence organization underpinning musical performance, to subserve 3DMR in musicians. Our data, therefore, provide convergent behavioral and neurofunctional evidence supporting the suggestion that development of the sight-reading skills of musical performance alters brain circuit organization which, in turn, confers a wider cognitive benefit, in particular, to nonmusical visuospatial cognition in professional orchestral musicians.

Temporal order memory in patients with Korsakoff's syndrome and medial temporal amnesia.

Two groups of patients with global amnesia resulting either from Korsakoff's syndrome (KS) or from medial temporal lobe (MTL) damage were compared with groups of matched healthy control subjects on a list discrimination paradigm. Item recognition memory was matched across the amnesic and control groups in order to determine whether KS, but not MTL amnesics are disproportionately impaired on list discrimination as predicted by Parkin's [Functional significance of etiological factors in human amnesia. In: Squire LR, Butters N, editors. Neuropsychology of memory, 2nd ed. New York: The Guilford Press, 1992] hypothesis. However, both patient groups were impaired disproportionately on the temporal order memory task, which is inconsistent with Parkin's hypothesis. It remains possible that the KS patients are more disproportionately impaired than those with MTL damage because both patient groups performed at floor on the list discrimination task. The results are consistent with theories that postulate a critical role for the hippocampus in the kind of associative memory which underlies memory for temporal order, but not in recognition of single items or arbitrary associations between items of similar kinds.

Intellectual, mnemonic, and frontal functions in dementia with Lewy bodies: A comparison with early and advanced Parkinson's disease.

Both Parkinson's disease (PD) and dementia with Lewy bodies (DLB) share a common neuropathological marker, the presence of Lewy bodies in brain stem and basal forebrain nuclei. DLB, in addition, is associated with Lewy bodies in the neocortex, and, in it's more common form, with Alzheimer-type pathological markers, particularly amyloid plaques. Published neuropsychological studies have focused on the differential profiles of DLB and Alzheimer's disease (AD). However, it is presently unclear whether DLB should be classified as a variant of AD or PD. In the present study we compare a healthy age-matched control group with three groups of patients, one with DLB, and two with PD. One of the PD groups was early in the course (PD-E) and the second, more advanced group (PD-A), was matched on severity of cognitive impairment with the DLB group. The results show that DLB was associated with a different pattern of neuropsychological impairment than the PD-A group, particularly in tests believed to be mediated by prefrontal cortical regions.