1.+ Tay Sachs Disease By: Sharmin Shanur Student of Understanding the Brain: The Neurobiology of Everyday Life

2. + Tay- Sachs Disease (The video from which my inspiration to explore Tay-Sachs Disease came from) http://www.youtube.com/watch?v=RzEpkBU-ITA 3. + What is Tay- Sachs Disease? Tay-Sachs is an inherited disorder that destroys neurons in both the brain and the spinal chord. Tay- Sachs occurs due to a mutation in the HEXA gene, which carries instructions for making a portion of an enzyme called beta-hexosaminidase A. Beta-hexosaminidase A plays a critical role in the brain and spinal chord because it helps break down GM2 ganglioside and acts as a recycling material. Mutations in HEXA disrupt beta-hexosaminidase A from breaking down GM2 gangliosides. This can have deleterious repercussions because the substance (GM2 gangliosides) will build up to toxic levels and cause the destruction on neurons. 4. + What is Tay-Sachs Disease? Cont. The most common form of Tay-Sachs is in the infantile form, where kids appear to mentally and physically develop at a normal rate but begin to slow down around the age of 3-6 months Initial symptoms begin with muscle atrophy and a lack of motor movements However, as the disease progresses, children suffer seizures, vision and hearing loss, intellectual disabilities, and eye abnormalities. Most cases of Tay-Sachs are in the infantile form, however it can occur in adolescents and adults. Symptoms for adolescents and adults are less severe, but include ataxia, problems with movements, speech impediments, and mental illness. 5. + Tay- Sachs Disease 6. + What Parts of the Nervous Systems are Active? Throughout the progression of Tay-Sachs all parts of the nervous system deactivate and are destroyed by the GM2 gangliosides. Basically in patients with Tay-Sachs, at the end of their lives, no part of the nervous system is active. Based on the video on the first slide, one aspect of the brain that seems to be active are the ocular motor verve, trochlear nerve, and the abducens nerve (however in time these nerves will slowly degenerate) The CNS (Central Nervous System) is destroyed by the gangliosides Due to the atrophy of all parts of the nervous system, Tay-Sachs patients will slowly lose motor control, voluntary muscle control, suffer seizure, mental deficits, blindness, and paralysis of the limbs. Based on the symptoms aforementioned, it can be surmised that the motor cortex is heavily affected by the build up of GM2 Gangliosides. 7. + Which Parts of the Nervous System Are Impaired As stated by the previous slide, the CNS is partially, if not completely destroyed. Many Tay-Sachs victims suffer blindness therefore their occipital lobe(dorsal and ventral streams) are heavily affected The cerebellum, which helps control motor behavior, is as rendered for the worse. The cerebellum is also associated with learning and considering that after the first few months of living, Tay-Sachs victims fail to learn new motor behaviors. Tay-Sachs victims cannot make fine movements and therefore their motor cortex is impaired. 8. + How This Course Has Helped Me Analyze the Events Around Me Quite frankly, upon entering this course, I was a complete novice to the subject matter of neurobiology. I had absolutely no spatial recognition of different parts of the brain and never knew that there are different pathways in our brain that control different aspects of our lives. Now whenever I see a person with Ataxia or Huntingtons disease, I realize that their motor pathways have been blocked or their cerebellum in having a few technical problems. Also, even if I see a completely normal person, I can analyze what controls their bodies, moods, memory, etc. However, I will say, neurobiology is still a subjects I lack a great amount of knowledge of; but I do know that the lessons taught here will help me exceed in the subject and understand far more complex problems. 9. + Bibliography (Websites Used) http://www.btbuddies.org.uk/about-high-grade-brain- tumours/areas-of-the-brain-and-their-functions.html http://en.wikipedia.org/wiki/Eye_movement http://www.ninds.nih.gov/disorders/taysachs/taysachs.htm http://ghr.nlm.nih.gov/condition/tay-sachs-disease http://www.ntsad.org/ http://www.genome.gov/10001220 http://www.mayoclinic.org/diseases-conditions/tay-sachs- disease/basics/definition/CON-20036799 http://www.tay-sachs.org/taysachs_disease.php