SRCD 2019: fNIRS decoding

Here is our poster for SRCD 2019.

Verbal prediction is claimed to be an important mechanism supporting language development (Elman, 1990; Dell & Chang, 2014). In line with this view, prior findings indicate that infants can predict upcoming words during language processing (Reuter et al., under revision) and that prediction and vocabulary size are positively correlated (e.g., Mani & Huettig, 2012). However, previous research investigating verbal prediction has relied on behavioral methods and it’s unclear whether infants use top-down connections to pre-activate lexical representations. In two ongoing experiments, we extend prior fNIRS decoding methods (Emberson, Zinszer, et al., 2017) to decode infants’ lexical representations and to investigate whether infants are able to pre-activate (i.e., predict) lexical representations. These experiments make both methodological and theoretical contributions: First, it is possible to decode infants’ lexical representations using fNIRS decoding methods. Second, these methods provide a promising means of evaluating verbal prediction in infancy and determining to what extent infants pre-activate lexical representations. Future work will use fNIRS decoding to investigate verbal prediction among infants at-risk for language impairment in order to uncover the cognitive and neural origins of language delays.

We thank all participant families. We also thank Carolyn Mazzei and Jean Bellamy for their assistance with stimuli, and Princeton Baby Lab research assistants for their help recruiting and scheduling participants.

rochester fNIRS workshop

It’s been a long time since my last post (tisk tisk!) so here I am, catching up.

Last week one of my advisors, Lauren Emberson, hosted an fNIRS workshop at the University of Rochester. fNIRS (functional near-infrared spectroscopy) is a non-invasive imaging technique used to measure the metabolic activity in the cortex. (For a great review, see Aslin, 2012.) Basically, when areas of the cortex are more active, this requires additional metabolic support, so more oxygenated hemoglobin is transferred to the location of activation. Light is absorbed differentially for oxygenated hemoglobin and deoxygenated hemoglobin, so our measure is essentially how much light the cortex in an approximate area is absorbing during x measurement time. (Note: I say “approximate” because one of the downsides of current fNIRS systems is low spatial resolution, as compared to fMRI, so we can’t make super exact claims about cortical areas.) fNIRS is an excellent method to use with infants, because the imaging doesn’t require rigid head stabilization. Infants wear a cap (similar to EEG) and can sit on their parent’s lap while watching+/listening to audio+/visual stimuli.

This was a great opportunity – both to learn more about the fNIRS methodology and recent literature, but also to bond with my future labmates. Here are a few pictures from the trip:

IMG_6900  IMG_6935