Vestibular, cochlear and trigeminal projections to the cortex in the anterior suprasylvian sulcus of the cat

Abstract

SUMMARY1. Cats anaesthetized with chloralose were used. Potentials evoked by electrical stimulation of the vestibular, cochlear, facial, trigeminal and chorda tympani nerves were recorded with micro-electrodes in the cortex in the anterior syprasylvian sulcus.2. Negative focal potentials with a latency of 3 msec were evoked by stimulation of the contralateral and ipsilateral vestibular nerves. These potentials were located in the lower and upper banks of the sulcus at a level just caudal to the projection of the Group I muscle afferents to the lower bank.3. The cochlear projections were located mainly in the lower bank partially overlapping the vestibular and the Group I fields.4. Trigeminal responses were recorded in both banks of the sulcus but were of largest amplitude and shortest latency rostrally in the upper bank. The potentials evoked by the chorda tympani had a similar distribution but were of low amplitude.5. The hypothesis is suggested, that the cortex in the anterior suprasylvian sulcus plays a role in the orientation of the body and head towards auditory stimuli.

Somato‐sensory paths to the second cortical projection area of the group I muscle afferents

“…8, vertical hatching). Vestibular and cochlear projections were also found most caudally in the investigated part of the fold, as described in a following report by Landgren et al (1967 The cortex of the fold is, however, not a mere extension of the adjacent SII fields but differs in important details. No responses to Group I muscle afferents were found either in the anterior ectosylvian or suprasylvian gyri, but a projection area of these afferents was demonstrated in the lower bank of the fold.…”

“…One of them should be located in the hindlimb locus of the upper bank where responses to skin afferents from the hindlimb were evoked with a latency as short as that found in SI and SI. The vestibular and cochlear responses of short latency described by Landgren, et al (1967) indicated the existence of two other primary colonies.…”

Cervico‐lumbar reflex interactions involving a proprioceptive receiving area of the cerebral cortex

“…ABRAHAMS 52 known concerning the functional significance of the ASSG, but it does receive extensive connexions from major sensory systems. In addition to the proprioceptive connexions previously mentioned, the ASSG has input from the vestibular system (Walzl & Mountcastle, 1949;Kempinsky, 1951;Mickle & Ades, 1952;Andersson & Gernandt, 1954;Landgren, Silfvenius & Wolsk, 1967b), from skin (Landgren et al 1967a;Landgren et al 1968) and from visual and auditory systems (Landgren et al 1967b;Landgren & Silfvenius, 1968).…”

The projection of the vestibular nerve to the cerebral cortex in the cat

“…The vestibular nerve was dissected by the method given by Anderson & Gernandt (1954) and modified by Landgren et al (1967). The stereotaxic frame used in these experiments could be inverted to facilitate the dissection.…”

“…Search for such units in the areas reported by Anderson & Gernandt (1954) and by Landgren, Silfvenius & Wolsk (1967) was not successful and it was thought desirable to re-investigate the areas reported to receive contralateral vestibular projections, by electrical stimulation of the vestibular nerve.…”