Aa. Palmer et Mp. Printz, ATTENUATION OF FOS EXPRESSION TO AIRPUFF STARTLE STIMULI FOLLOWING TYMPANIC MEMBRANE RUPTURE, Brain research, 787(1), 1998, pp. 91-98
The airpuff startle stimulus consists of two modalities, tactile and a
coustic. Tympanic membrane rupture (TMR) effectively deafens a rat, th
us preventing it from perceiving the acoustic component of the airpuff
and permitting study of the tactile component in isolation. Previous
studies have shown that the tactile modality is sufficient to drive th
e cardiovascular response to the airpuff, but cannot elicit the full b
ehavioral startle response. In the present study Fos protein was used
as a marker of neuronal activation to identify brain regions activated
by the airpuff in both intact and TMR rats. Results show an attenuati
on of Fos expression following TMR in the dorsal and ventral cochlear
nuclei, ventral nucleus of the lateral lemniscus and medial geniculate
nucleus. In contrast, Fos expression following TMR was unchanged in t
he locus coeruleus, the laterodorsal tegmental nucleus, the supramammi
lary nucleus, and the ventromedial hypothalamic nucleus. Analysis of b
ehavioral data confirmed that the startle response to the airpuff was
diminished following TMR. These data are the first of which we know to
employ an immediate early gene approach to discriminate between brain
regions activated by the tactile and acoustic startle stimulus modali
ties. The results are discussed in terms of the classical acoustic sta
rtle circuit, and the central autonomic pathways activated by the tact
ile component of the airpuff. (C) 1998 Elsevier Science B.V.