In the first study, the effect of intrathecal administration of substance P at T9/T2 on arterial blood pressure and heart rate was studied in acute spinal (T5/T1) transected rats. The results indicate that excitatory effects of substance P on sympathetic output can be elicited in spinal transected rats and that the neural substrate for the effects is intrinsic to the spinal cord. An opioid involvement in suppressing the response to substance P is also confirmed. / In the second study, the role of angiotensin (AII) receptors (AT$ sb1$ and AT$ sb2$) in mediating the effects of intrathecally administered AII on sympathetic output was investigated using DuP 753 and PD 123319, the AT$ sb1$ and AT$ sb2$ receptor antagonists, respectively. The results suggest that at the spinal level, AII expresses its effects on sympathetic output to the heart via the AT$ sb1$ receptor and to the vessels partly via AT$ sb1$ and perhaps also via AT$ sb2$ receptors.

The vestibular sensory apparatus and associated vestibular nuclei are generally thought to encode angular head velocity during our daily activities. However, in addition to direct inputs from vestibular afferents, the vestibular nuclei receive substantial projections from cortical, cerebellar, and other brainstem structures. Given this diversity of inputs we asked: how are the responses of vestibular nuclei neurons to head velocity modified by these additional inputs during naturally occurring behaviours? Here we have focused on three specific classes of neurons in the vestibular nuclei: (1) vestibular-only (VO) neurons which are thought to mediate, at least in part, the vestibulocollic reflex (VCR); (2) position-vestibular-pause (PVP) neurons which mediate the vestibuloocular reflex (VOR), and; (3) eye-head (EH) neurons, which are thought to mediate pursuit eye movements. / We first characterized neuronal responses to passive rotation in the head-restrained condition, and then released the head to record the discharges of the same neurons during self-generated head movements. VCR interneurons (VO neurons) faithfully transmitted head velocity signals during passive head motion, but their responses were greatly attenuated during all behaviours during which the monkey's behavioral goal was to move its head relative to the body. Moreover, the attenuation occurs only when neck proprioceptive inputs match those predicted by the neck motor command. We propose that the sensory-motor matching is meditated by interconnections with the cerebellum. Our findings indicate that the VCR is suppressed during active head movements, but remains responsive to unexpected head perturbations. In contrast, VOR interneurons (PVP neurons) faithfully transmitted head velocity signals when the animal stabilized its gaze, regardless of whether the head motion was actively or passively generated; their responses were attenuated only when the monkey's behavioral goal was to redirect its axis of gaze relative to space. We propose that efference copies of oculomotor/gaze commands are responsible for the behaviourally dependent modulation of PVP neurons (and by extension the VOR) during gaze redirection. Finally, the activity of EH neurons was recorded during head-restrained smooth pursuit and eye-head gaze pursuit. EH neurons were not influenced by error terms and their activity was best described by an eye movement-based model. In addition, during gaze pursuit EH neurons were found to encode gaze and head movement-related signals. Furthermore, neuron responses could be predicted by their head movement sensitivity during passive whole-body rotation in the dark and gaze movement sensitivity during smooth pursuit, regardless of the stimulation condition. We propose that EH neuron responses reflect the summation of head movement information fro

Thesis (Ph.D.)--Weill Medical College of Cornell University, 2007. / (UMI)AAI3251745. Source: Dissertation Abstracts International, Volume: 68-02, Section: B, page: 0830. Adviser: David Christini.

Thesis (Ph.D.)--University of California, San Francisco, 2005. / Source: Dissertation Abstracts International, Volume: 66-02, Section: B, page: 0742. Adviser: Allison Doupe.

Thèses (M.Sc.)--Université de Sherbrooke (Canada), 1998. / Titre de l'écran-titre (visionné le 20 juin 2006). Publié aussi en version papier.

Thesis (Ph.D.)--Indiana University, Dept. of Biology, 2008. / Title from PDF t.p. (viewed on Jul 22, 2009). Source: Dissertation Abstracts International, Volume: 69-10, Section: B, page: 5950. Adviser: Gregory E. Demas.

Thesis (Ph.D.)--Indiana University, Dept. of Biology, 2008. / Title from PDF t.p. (viewed on Jul 22, 2009). Source: Dissertation Abstracts International, Volume: 69-10, Section: B, page: 5873. Adviser: Rudolf A. Raff.

Thesis (Ph.D.)--The University of Memphis, 2007. / (UMI)AAI3293754. Source: Dissertation Abstracts International, Volume: 68-12, Section: B, page: 7739. Adviser: Stephan J. Schoech.

Thesis (Ph.D.)--University of Illinois at Urbana-Champaign, 2006. / Source: Dissertation Abstracts International, Volume: 67-11, Section: B, page: 6218. Adviser: Philip M. Best. Includes bibliographical references. Available on microfilm from Pro Quest Information and Learning.

Thesis (Ph.D.)--University of Illinois at Urbana-Champaign, 2006. / Source: Dissertation Abstracts International, Volume: 67-11, Section: B, page: 6222. Adviser: Joseph G. Malpeli. Includes bibliographical references (leaves 151-162) Available on microfilm from Pro Quest Information and Learning.