Text Box: Abstract: The cortex is thought to be the primary site of sensory plasticity, particularly during development. Here, we report that large-scale reorganization of the mouse auditory midbrain tonotopic map is induced by a specific sound-rearing environment consisting of paired low- (16 kHz) and high-frequency (40 kHz) tones. To determine the potential for plasticity in the mouse auditory midbrain, we used manganese-enhanced MRI to analyze the midbrain tonotopic maps of control mice during normal development and mice reared in the two-tone (16 40 kHz) environment. We found that the tonotopic map emerged during the third postnatal week in normal mice. Before 3 weeks, a larger percentage of auditory midbrain responded to each of the suprathreshold test frequencies, despite the fact that the primary afferent projections are in place even before hearing onset. By 3 weeks, the midbrain tonotopic map of control mice was established, and manganese-enhanced MRI showed a clear separation between the 16- and 40-kHz responses. Two-tone rearing dramatically altered the appearance of these discrete frequency-specific responses. A significant volume of the auditory midbrain became responsive to both rearing frequencies, resulting in a large-scale reorganization of the tonotopic map. These results indicate that developmental plasticity occurs on a much greater scale than previously appreciated in the mammalian auditory midbrain.  

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Text Box: July  21 2007

Text Box: Otorhinolaryngology News

Text Box: Inside This Issue · LigSubcortical Auditory Pathway & Plasticity..? · IMPer Nasal Approach to Petrous Apex...? · TinNew Thinking on 'Micrometastasis'...? *     Case of the Week

Case Review Clinical Photograph of The Week

A 39 year old female presented with 3 years history of painless mass within the right external auditory canal, associated with hearing loss. She also gave history of attempted 'excision' of the mass some years ago with little effect. Otoscopy was not possible because of a bony hard mass almost completely filling the right EAC with surrounding otorrhoea. Post auricular exposure revealed the finding shown here, with erosion of superior EAC wall >>>>

 

What is the Diagnosis ?

 
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1.    16th Annual general meeting and scientific conference of otorhinolaryngological society of Nigeria (ORLSON), November 21 - 24, 2007. See Here For details.

2. . Further Conference Announcement? Click Reed our Feed or Check the Conference Announcement Page

 

 

 

 
 

Text Box: Per Nasal Approach to Petrous Apex...?

The controversy surrounding precise definition of 'micrometastasis' led to this thought provoking short communication from Italy (Devaney, Rinaldo & Ferlito, Am. J. Otolaryngol Jul-Aug 2007 28(4): 271-274) that suggests among others uniform and consistent upper and lower size limits be set and further proposed that metastasis 0.2mm or less be designated 'isolated tumor cells', among others


Abstract:

Objective  Techniques are now being developed, which allow ever smaller metastatic deposits in regional lymph nodes to be detected; the question is, should they be sought, or does their presence convey no additional information for treatment of head and neck carcinoma patients at this time? Preliminary findings have suggested that the presence of micrometastases may carry with it some prognostic information, and as a consequence, the search for micrometastases would, for the foreseeable future, appear to be a fertile ground for investigation. To bring some uniformity to this project, it is suggested that these definitions be adopted: a micrometastasis measures greater than 0.2 mm but less than 2.0 mm in diameter, and smaller deposits should be designated as isolated tumor cells, which, in turn, are subdivided into those isolated tumor cells detected by light microscopy, immunohistochemistry, or molecular methods. At this juncture, the import of such micrometastases remains in the realm of the clinical investigator—it remains an open question whether the identification of micrometastases (however they may ultimately come to be defined) will prove to have an impact on the care of head and neck cancer patients.

     Journal Watch :Screening patients with sensorineural hearing loss for vestibular schwannoma using a Bayesian classifier, Nouraei, S.A.R et al, 2007..
 

 1.   The otolaryngologyinafrica.net resident's page has been re-designed. The current forum page is now separated from the archive page. FEEL FREE  to view the new design and recommend to your residents

 2.  From  http://www.otolaryngologyinafrica.net/grandround/  is a new addition - a recent conference poster presentation. This presentation is available at http://www.otolaryngologyinafrica.net/grandround/archive.htm .

 3.   DODA has been redesigned. Take time to view the new look of this program at the DODA Images Page... You may also download DODA Video, mobile devices edition, which can be installed on your cell phone (Note:  a multimedia cell phone is required).

 4.  Otolaryngologyinafrica.net is experimenting with use of SMS notification of newsletter release. Feel free to air your view on this issue by emailing orl-mailer@otolaryngologyinafrica.net .

 Till Next Week, Welcome to 2007!

 Biodun

 
 

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