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Pituitary surgery
Published in Michael Y. Wang, Andrea L. Strayer, Odette A. Harris, Cathy M. Rosenberg, Praveen V. Mummaneni, Handbook of Neurosurgery, Neurology, and Spinal Medicine for Nurses and Advanced Practice Health Professionals, 2017
Valentina Pennacchietti, Nelson M. Oyesiku
The suprasellar area is the region above the sella turcica. It extends from the ventral surface of the midbrain, around the optic chiasm, to the subcallosal area. The cerebral peduncles form its posterior wall. The infundibulum of the pituitary gland passes through this region to go in the diaphragma sellae. The suprasellar region also hosts the optic nerves and chiasm. Above the optic chiasm lie the anterior cerebral and anterior communicating arteries, the lamina terminalis, and the third ventricle (Rhoton, 2002).
Profiling intermittent tinnitus: a retrospective review
Published in International Journal of Audiology, 2019
Elouise A Koops, Fatima T Husain, Pim van Dijk
Rauschecker et al. (2010) alluded to this subject in their paper on limbic-auditory interactions in tinnitus. They proposed that in the event of a cochlear lesion, due to noise exposure or ageing, plastic reorganisation occurs. This reorganisation is involved in the generation of hyperactivity in the ascending auditory pathways. In a normal functioning limbic system, the hyperactivity is identified and a noise cancellation mechanism is employed to cancel it out. This cancelling out is hypothesised to occur by subtraction of the hyperactivity (i.e. the tinnitus signal) from the afferent signal via feedback to the inhibitory thalamic reticular nucleus. In an earlier paper, Jastreboff (2000) had theorised that the deviating activity in the limbic system of tinnitus patients reflects the emotional reaction to tinnitus and is an indicator of the consequences of having tinnitus. In contrast, Rauschecker et al. argued that the role of the limbic system in tinnitus is an active one opposed to a reactive one. In their proposed circuit, the limbic and para-limbic structures around subcallosal areas act as a self-regulating gating mechanism that prevents the tinnitus signal from reaching the cortex. When a break-down of this gating system occurs, the tinnitus signal is perceived. Chronic tinnitus is explained by the constant depletion of serotonin, which causes excitotoxicity due to the constant firing of serotonergic neurons that have to signal that the tinnitus sound needs to be filtered out (Rauschecker, Leaver, and Mühlau 2010). Intermittent tinnitus can then be explained by hypothesising that serotonin levels fluctuate rather than being depleted.
A different view on the link between tinnitus and cognition; is there a reciprocal link?
Published in International Journal of Neuroscience, 2018
Elham Tavanai, Ghassem Mohammadkhani
Recently, structural alterations in the central nervous system have been detected in tinnitus patients by voxel-based morphometry (VBM). Significant gray matter decreases in the left hippocampus right and in the inferior colliculus was observed in the tinnitus patients [53]. In contrast, Mühlau et al. (2006) found gray-matter increases only at the thalamic level. gray-matter decrease was also observed outside the auditory system, in the subcallosal area including the nucleus accumbens. The results of such studies indicate that the reciprocal involvement of both sensory and emotional areas are essential in tinnitus generation [54]