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Behavioral/Systems/Cognitive Vestibular Signals in Primate Thalamus: Properties and
 

Summary: Behavioral/Systems/Cognitive
Vestibular Signals in Primate Thalamus: Properties and
Origins
Hui Meng,1 Paul J. May,2 J. David Dickman,1 and Dora E. Angelaki1
1Department of Anatomy and Neurobiology, Washington University School of Medicine, St. Louis, Missouri 63110, and 2Departments of Anatomy,
Ophthalmology and Neurology, University of Mississippi Medical Center, Jackson, Mississippi 39216
Vestibular activation is found in diverse cortical areas. To characterize the pathways and types of signals supplied to cortex, we recorded
responses to rotational and/or translational stimuli in the macaque thalamus. Few cells responded to rotation alone, with most showing
convergence between semicircular canal and otolith signals. During sinusoidal rotation, thalamic responses lead head velocity by 30
on average at frequencies between 0.014 Hz. During translation, neurons encoded combinations of linear acceleration and velocity. In
general, thalamic responses were similar to those recorded in the vestibular and cerebellar nuclei using identical testing paradigms, but
differed from those of vestibular afferents. Thalamic responses represented a biased continuum: most cells more strongly encoded
translationandfewercellsmodulatedprimarilyinresponsetonetgravitoinertialacceleration.Responsiveneuronswerescatteredwithin
a large area that included regions of the ventral posterior and ventral lateral nuclei, and so were not restricted to the known vestibular
nuclei projection zones. To determine the origins of these responses, a retrograde tracer was injected into a dorsolateral thalamic site
where rotation/translation-sensitive cells were encountered. This injection labeled neurons in the rostral contralateral anterior inter-
posedandfastigialnuclei,butdidnotlabelcellswithinthevestibularnuclei.Examinationofthalamicterminationsaftertracerinjections
into the cerebellar and vestibular nuclei indicated that most vestibular responsive units fall within the thalamic terminal zones of these
nuclei. Thus, vestibular signals, which are supplied to the thalamus from both vestibular and cerebellar nuclei, are positioned for
distribution to widespread cortical areas.

  

Source: Angelaki, Dora - Department of Anatomy and Neurobiology, Washington University in St. Louis

 

Collections: Biology and Medicine