Contextual ambiguity resolution during discourse comprehension
Our understanding of the meaning being portrayed within a conversation or discourse changes to each instance of a new semantic item. However, when the topic of a conversation is ambiguous, we must actively search for and identify the meaning/purpose that interlocultors or narrators are attempting to portray. This ambiguity extends beyond single words but rather encompasses the broader discourse context. We are using ERPs to study how the brain resolves this contextual ambiguity. Furthermore, is this process distinct from that which involves the change/update of an existing context?
Preliminary results from this study suggest that the Late Anterior Positivity ("Frontal post-N400 positivity") fluctuates to coherent words that partially resolve contextual ambiguity. In contrast, greater P600 amplitudes are recorded to coherent, but unexpected words within a known, existing context.
How distracting is your iPhone?
The literature is rich in its demonstrations of the distracting properties of your cell-phone when used while driving. It turns out that humans are not as good at multi-tasking as we think. In fact, the term "multi-tasking" is a misnomer, as we instead switch between tasks with the performance on each task decreasing as a function of the number of tasks being performed.
The social aspects of smartphones (e.g., texting, notifications) have the capacity to provide us with potentially limitless positive reinforcement. The Motivated Cognition Model (Lang, 2006) demonstrates that we allocate greater attentional resources to stimuli we are motivated to engage in, such as those which provide positive reinforcement (e.g., cell phones). And as long our phones are turned on, there is always the opportunity to receive this gratification. This study is the first to examine if and how the mere presence of a smartphones alters ERP markers of attention.
Effects of sports-related concussion on the neurocognitive-linguistic system
The short- and long-term effects of sports-related concussions remain a growing concern. Although the majority of college athletes' symptoms and cognitive deficits typically recover within 1-2 weeks post-concussion, findings from our lab (and others) used ERPs to demonstrate persistent changes to the functional neural networks underlying attention (Ledwidge & Molfese, 2016) and working memory (Hudac, Cortesa, Ledwidge & Molfese, 2017) years following injury. However, a lack of difference in neuropsychological abilities between athletes with and without a history of concussion begs the question: What is the clinical utility of ERPs if behavioral markers of cognition are not affected?
Recently, we suggested that investigations studying the association between sports-related concussion and language abilities are warranted (Ledwidge, in press). Sparse research has considered this avenue, which is surprising given the number of studies demonstrating persistent language deficits following non-sports-related concussion. Efficient and accurate language comprehension involves the interaction between both lexical, cognitive, (and often social) mechanisms. Consequently, it is possible that behavioral and electrophysiological assessments of language comprehension provide naturalistic tools to examine recovery from sports-related concussion
We are collaborating with the BW Department of Communication Disorders to study changes to the cognitive-linguistic system during concussion recovery in college athletes. We are collecting both functional measures as well as recording ERPs during both comprehension and cognitive inhibition. Our goal is to successfully chart the time course of recovery of cognition and language in this population to better inform clinical best practices for concussion management and intervention.