Sensory information is
represented by the distributed activity of large numbers of neurons in a number
of distinct brain regions. To better
characterize how acoustic features are processed by the central auditory
system, we record how individual neurons and populations of neurons respond to
sounds ranging from simple clicks and tones to complex stimuli including animal
vocalizations and human speech.
Microelectrode mapping studies allow us to record from up to 160 sites
in a single animal. This approach allows
the highest density sampling of neurons possible today, but necessitates
recordings be made from anesthetized animals.
We have also developed techniques to record from 16 electrodes at once
from awake, freely moving animals using chronically implanted microwire arrays.
Since most recording of neural activity in humans take the form of
far-field evoked potentials, we also study similar potentials in awake rats by recording from epidural EEG electrodes.
To date, we have characterized in
detail the responses of rat auditory thalamus, primary auditory cortex,
posterior auditory field, and ventral auditory field to tone and noise burst
trains, FM sweeps, spectral gratings, spectrotemporal sequences, maromoset vocalizations, and human speech. These studies provide considerable insight
into the processing of sensory information.
These studies also provide baseline data for plasticity studies designed
to explore how these responses are altered by different forms of sensory