Research in the lab proceeds
principally on four fronts:
• human auditory cortex physiology
• neural basis of speech perception
• auditory/speech psychophysics
• (mostly lexical level) psycholinguistics and neurolinguistics.
We use all the techniques we can get our hands on to study these areas,
depending on what method might provide the right type of answer given
a certain problem. That is, we are not ‘methodological imperialists’.
Beyond all kinds of behavioral paradigms, the majority of the physiological
work uses magnetoencephalography (MEG), although we also use electroencephalography
(EEG) and functional magnetic resonance imaging (fMRI). We have used
PET and TMS as well, although these are not techniques we commonly
employ.
Unifying themes in the lab include (i) what
is the 'parts list' for speech perception/lexical representation/processing,
both from the linguistic and from the neurobiological points of view,
i.e. what are the primitives and the elementary operations;
and (ii) how do temporal mechanisms encode or represent
information in the auditory cortex and form the basis
for speech perception and auditory cognition (latency-based
codes, oscillatory activity, phase, etc.)? Are here temporal
primitives? Our experiments use stimuli of varying complexity
and ecological relevance, ranging from pure tones to FMs to ripples
to syllables to words to connected speech.
One principle guiding some of the
work is based on the assumption that the problem in speech perception
is to execute the transformations from ‘vibration in
the ear to abstraction in the head.’ Speech perception
and successful lexical access means making contact with the internal
mental representations that have specific characteristics. Given this
perspective, two further topics that are increasingly investigated
in the lab concern multi-sensory (audio-visual) speech perception
as well as lexical processing. Questions regarding the nature and
processing of lexical representations are investigated using a combination
of behavioral and MEG studies.
Some of the topics on the brain basis
of speech & language that we worry about are discussed more or
less informally on a new blog:
Talking Brains
Lab
meetings