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The individual alpha peak frequency (IAPF) of the human electroencephalography (EEG) typically experiences slowing with increasing age. Despite this hallmark change, studies that investigate modulations of conventional EEG alpha power and connectivity by aging and age-related neuropathology neglect to account for intergroup differences in IAPF. To investigate the relationship of age-related IAPF slowing with EEG power and connectivity, we recorded eyes-closed resting-state EEG in 37 young adults and 32 older adults. We replicated the finding of a slowed IAPF in older adults. IAPF values were significantly correlated with the frequency of maximum global connectivity and the means of their distributions did not differ, suggesting that connectivity was highest at the IAPF. Older adults expressed reduced global EEG power and connectivity at the conventional upper alpha band (10-12 Hz) compared with young adults. By contrast, groups had equivalent power and connectivity at the IAPF. The results suggest that conventional spectral boundaries may be biased against older adults or any group with a slowed IAPF. We conclude that investigations of alpha activity in aging and age-related neuropathology should be adapted to the IAPF of the individual and that previous findings should be interpreted with caution. EEG in the dominant alpha range may be unsuitable for examining cortico-cortical connectivity due to its subcortical origins.

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Forgetting over the short-term has challenged researchers for more than a century, largely because of difficulty in controlling what goes on within the memory retention interval. But the Òrecent negative probesÓ procedure offers a valuable paradigm, by examining influences of (presumably) unattended memoranda from prior trials. Here we used a recent probes task to investigate forgetting for visual non-verbal short-term memory. Target stimuli (2 visually presented abstract shapes) on a trial were followed after a retention interval by a probe, and participants indicated whether the probe matched one of the target items. Proactive interference, and hence memory for old trial probes, was observed whereby participants were slowed in rejecting a nonmatching probe on the present trial that nevertheless matched a target item on the previous trial (a recent negative probe). The attraction of the paradigm is that, by uncovering proactive influences of past trial probe stimuli, it is argued that active maintenance in memory of those probes is unlikely. In two experiments we recorded such proactive interference of prior trial items over a range of interstimulus (ISI) and intertrial (ITI) intervals (between 1 and 6 seconds respectively). Consistent with a proposed t w o -process memory conception (the active-passive memory model or APM), actively maintained memories on current trials decayed but passively Òmaintained,Ó or unattended, visual memories of stimuli on past trials did not.(abstract 221 words)

Does the maintenance of feature bindings in visual short-term memory (VSTM) require sustained focused attention? This issue was investigated in three experiments, in which memory for single features (i.e., colors or shapes) was compared with memory for feature bindings (i.e., the link between the color and shape of an object). Attention was manipulated during the memory retention interval with a retro-cue, which allows attention to be directed and focused on a subset of memory items. The retro-cue was presented 700 ms after the offset of the memory display and 700 ms before the onset of the test display. If the maintenance of feature bindings - but not of individual features - in memory requires sustained focused attention, the retro-cue should not affect memory performance. Contrary to this prediction, we found that both memory for feature bindings and memory for individual features were equally improved by the retro-cue. Therefore, this finding does not support the view that the sustained focused attention is needed to properly maintain feature bindings in VSTM.

Humans have the ability to attentionally select the most relevant visual information from their extrapersonal world and to retain it in a temporary buffer, known as visual short-term memory (VSTM). Research suggests that at least two non-contiguous items can be selected simultaneously when they are distributed across the two visual hemifields. In two experiments, we show that attention can also be split between the left and right sides of internal representations held in VSTM.Participants were asked to remember several colors, while cues presented during the delay instructed them to orient their attention to a subset of memorized colors. Experiment 1 revealed that orienting attention to one or two colors strengthened equally partic colors, but only when they were from separate hemifields. Experiment 2 showed that in the absence of attentional cues the distribution of the items in the visual field per se had no effect on memory.These findings strongly suggest the existence of independent attentional resources in the two hemifields for selecting and/or consolidating information in VSTM. 3The ability to maintain visual information in an accessible state is a critical aspect of our cognitive capacities as it allows us to interact successfully in the visuo-spatial world. Because our visual short-term retention system (i.e., visual short-term memory -VSTM) is extremely limited in storage capacity (Luck & Vogel, 1997), only a subset of information from our extrapersonal world can be transferred into this limited memory space at any one time. The selection of this subset of information is made by attentional mechanisms that can be voluntarily or involuntarily oriented to particular locations or objects. For example, when spatial attention is cued to a particular location of the visual field, the object that occurs at that location will be more likely transferred into VSTM as compared to the other objects (Makovski & Jiang, 2007;Schmidt, Vogel, Woodman, & Luck, 2002).During the last 10 years, an increasing number of studies have revealed that once transferred into VSTM, the internal representations remain highly flexible and can be selectively accessed and , directing attention to one location previously occupied by an object helps solidify and/or retrieve that object from memory. However, this ability to attentionally select locations already held in VSTM appears to be more constrained than orienting attention in perception. In a recent study, Makovski and Jiang (2007) directly compared the effect of orienting attention to multiple locations before (pre-cuing) and after (retro-cuing) the appearance of a memory array. They found that while up to three attentional cues could be used effectively when presented before the memory array, 4 only a single cue was advantageous for memory performance when presented after the offset of the memory array. Although this, along with previous studies (Awh & Pashler, 2000;Kraft, Müller, Hagendorf, Schira, Dick, Fendrich, & Brandt, 2004; Kramer & Haln, 1995), indicates that spati...