Neural oscillations and a nascent corticohippocampal theory of reference
Nieuwland, M. S., & Martin, A. E.
Neural oscillations and a nascent corticohippocampal theory of reference. Journal of Cognitive Neuroscience, 29
(5), 896-910. doi:10.1162/jocn_a_01091.
The ability to use words to refer to the world is vital to the communicative power of human
language. In particular, the anaphoric use of words to refer to previously mentioned concepts
(antecedents) allows dialogue to be coherent and meaningful. Psycholinguistic theory posits
that anaphor comprehension involves reactivating a memory representation of the antecedent.
Whereas this implies the involvement of recognition memory, or the mnemonic sub-routines
by which people distinguish old from new, the neural processes for reference resolution are
largely unknown. Here, we report time-frequency analysis of four EEG experiments to reveal
the increased coupling of functional neural systems associated with referentially coherent
expressions compared to referentially problematic expressions. Despite varying in modality,
language, and type of referential expression, all experiments showed larger gamma-band
power for referentially coherent expressions compared to referentially problematic
expressions. Beamformer analysis in high-density Experiment 4 localised the gamma-band increase to posterior parietal cortex around 400-600 ms after anaphor-onset and to frontaltemporal
cortex around 500-1000 ms. We argue that the observed gamma-band power
increases reflect successful referential binding and resolution, which links incoming
information to antecedents through an interaction between the brain’s recognition memory networks and frontal-temporal language network. We integrate these findings with previous results from patient and neuroimaging studies, and we outline a nascent cortico-hippocampal
theory of reference.