Covariation of pupillary and auditory cortical activity in rats under isoflurane anesthesia.
Neuroscience
; 300: 29-38, 2015 Aug 06.
Article
em En
| MEDLINE
| ID: mdl-25967265
ABSTRACT
Very slow fluctuations of spontaneous activities significantly influence not only behavioral performance in a conscious state, but also neural activities in an unconscious state. Covariation of pupil and cortical activities may lend important insights into the state-dependent modulation of stimulus encoding, yet this phenomenon has received little attention, especially with regard to non-visual cortices. In the present study, we investigated co-fluctuation of pupil size and neural activity in the auditory cortex of rats under isoflurane anesthesia. Pupil fluctuation consisted of longitudinal irregular shifts, and 1-min cyclic modulations. Both spontaneous and auditory-evoked potentials (AEPs) covaried with the longitudinal fluctuation of pupil size, but not with the 1-min cycle. Pupil size exhibited a positive correlation with spontaneous activity and negative correlation with AEP amplitude, particularly when the pupil size was beyond the normal range. Stimulus-specific adaptation characterized using an oddball paradigm was less dependent on pupil size than AEP. In contrast to the cortical activity, heart rate covaried with pupil size with the 1-min oscillatory component, but not the non-oscillatory component. Furthermore, light exposure induced the pupil reflex through the autonomic system, but did not modify cortical activity, indicating that autonomic activity was not causing the cortical modulation. These results together suggest that cortical activities spontaneously covary with pupillary activity through central cholinergic modulation that triggers sympathetic nerve activation. Such a state-dependent property may be a confounding factor in cortical electrophysiology studies.
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Texto completo:
1
Coleções:
01-internacional
Base de dados:
MEDLINE
Assunto principal:
Córtex Auditivo
/
Pupila
/
Anestésicos Inalatórios
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Isoflurano
Limite:
Animals
Idioma:
En
Revista:
Neuroscience
Ano de publicação:
2015
Tipo de documento:
Article