Gap Detection in Auditory Cortex
Datum
2016-06
Autor:innen
Duckler, Ulysses
Zeitschriftentitel
ISSN der Zeitschrift
Bandtitel
Verlag
University of Oregon
Zusammenfassung
Strong evidence supports that for older adults, hearing loss and difficulty with
speech comprehension in noisy environments is the result of temporal processing
deficits in central auditory structures such as the auditory cortex. There is a general
canonical circuit model of layer by layer serial information flow through the auditory
cortex from the thalamus, before information is projected back into inferior colliculus
neurons. However the specific cortical circuits and cell types which regulate temporal
processing through the auditory cortex are still unknown and not linked to behavior.
The auditory cortex contributes to temporal acuity in receiving auditory stimuli.
Temporal acuity is used, for example, for brief noise gap detection and discriminating
between similar phonemes. Impairments to temporal activity can cause speech
perception deficits. In this study, I tested gap detection behavior in mice. To do this, I
measured how their startle responses were modulated by gaps in continuous background
noise. The presence of the gap attenuates the startle response to the stimulus, so that
measuring the startle response gives a measure of temporal acuity by assessing gap
detection behavior. I used a technology called optogenetics to manipulate brain activity
during this behavior. Optogenetics allows for the gaps to be paired with a laser pulse that silences auditory cortex neurons and allowed me to see how gap detection is
impaired by temporally precise suppression of auditory cortex. By probing cortex
circuit mechanisms through layer-specific optogenetic silencing before and after gap, I
found that layer-specific silencing of auditory cortex neuron populations in layers four
and five suggests behavior in accordance with the canonical model.
Beschreibung
33 pages. A thesis presented to the Department of Chemistry and Biochemistry and the Clark Honors College of the University of Oregon in partial fulfillment of the requirements for degree of Bachelor of Science, Spring 2016.
Schlagwörter
Neurosciences, Auditory cortex, Gap detection, Optogenetics, Hearing loss, Mice