Current Research Projects

EEG Biomarkers of Temporal Selection in Episodic Encoding

Attention varies over time, and this affects episodic encoding. Recent work suggests behaviorally relevant moments are prioritized for encoding via mechanisms that briefly, but broadly, facilitate perception and memory (temporal selection). With the Attentional Boost Effect (ABE), responding to a target in a detection task (e.g., a red square) enhances the encoding of other concurrently presented, but unrelated items (e.g., the word it appeared with). If the ABE reflects temporal selection, then it should immediately affect neural processing and boost momentary context memory. In an EEG study, we asked participants to perform a target detection task as they memorized and then recalled lists of words. Relative to distractors, targets modulated EEG frequency bands associated with attention and successful encoding, particularly for words that were later recalled. An additional study demonstrated that temporal selection enhanced relational memory between a word and the stimuli it appeared with, but not its association with other words or its temporal context. The results suggest that target detection during encoding engages neural systems involved in attention and episodic memory, and may enhance momentary event representations.

Physical Fitness and Episodic Memory Function in the Aging Brain

Cognitive Aging results in well-characterized deficits to episodic memory performance. One proposed reason for decreasing memory performance with age is a reduced ability to associate items with temporal context memory. Many health-related factors such as cardiovascular fitness may mediate the effects of aging on memory, but it is unclear whether temporal context memory is sensitive to these mediators. In a collaboration with researchers from the Nathan Kline Institute, I leveraged data from an open-data neuroimaging and memory assessment sample (N > 1000) to investigate the influence of brain health and physical fitness on temporal context memory in free recall, and how this relationship changes with age. By applying a computational model of brain age to neuroimaging data and examining participants’ tendency to cluster free recall outputs by their presentation order, my colleagues and I demonstrated that temporal context memory is highly sensitive to brain health in adults over 40, and that the relationship between physical fitness and memory performance is not uniform across the lifespan (Broitman, Swallow, Colcombe, & MacKay-Brandt, In Prep).