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Exploring how the brain is shaped and wired. http://www.greenspine.ca/media/neuron_culture_800px.jpg. Jonaki Sen BSBE Department, IIT Kanpur. http://www.cs4fn.org/biology/images/brainxray.jpg. Input received through dendrite. Cell body of neuron containing DNA. Output sent through axon.
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Exploring how the brain is shaped and wired http://www.greenspine.ca/media/neuron_culture_800px.jpg Jonaki Sen BSBE Department, IIT Kanpur http://www.cs4fn.org/biology/images/brainxray.jpg
Input received through dendrite Cell body of neuron containing DNA Output sent through axon Synapse: connection Between two neurons
Embryonic development Neural development http://www.greenspine.ca/media/neuron_culture_800px.jpg ? ? http://www.pieuvre.ca/2013/05/04/science-cellules-division/zygote/ http://www.hdwallpapers-3d.com/human-body-pictures/ http://www.cs4fn.org/biology/images/brainxray.jpg
Series of events that build the brain • Patterning and morphogenesis of the neural tube • Neurogenesis: production of neurons • Neuronal differentiation • Neuronal migration • Axon guidance and synaptogenesis
Patterning(organization) and morphogenesis (shape and size) of the neural tube Patterning and morphogenesis of the neural tube http://www.ib.cnea.gov.ar/~redneu/2013/BOOKS/Principles%20of%20Neural%20Science%20-%20Kandel/gateway.ut.ovid.com/gw2/ovidweb.cgisidnjhkoalgmeho00dbookimagebookdb_7c_2fc~61.htm http://www.mun.ca/biology/desmid/brian/BIOL3530/DEVO_05/ch05f32.jpg http://www.mun.ca/biology/desmid/brian/BIOL3530/DEVO_05/ch05f32.jpg
Neurogenesis (production of neurons) and Neuronal differentiation (acquiring the properties of a neuron) Neurogenesis: production of neurons http://journal.frontiersin.org/Journal/10.3389/fnmol.2012.00064/full http://www.ibmb.csic.es/index.php?pg=laboratorio&tab=186&idLaboratorio=18 http://mindsparke.com/brain-training-blog/wp-content/uploads/2010/03/neurogenesis.jpg http://www.ibmb.csic.es/index.php?pg=laboratorio&tab=186&idLaboratorio=18
Neuronal migration (move from birthplace to workplace) Radial route Tangential route Neuronal migration http://upload.wikimedia.org/wikipedia/commons/7/70/Interneuron-radial_glial_interactions_in_the_developing_cerebral_cortex.png http://www.brainfacts.org/~/media/Brainfacts/Article%20Multimedia/Brain%20Basics/Neuroanatomy/Neuron%20Migration.ashx
Axon guidance (connecting with the right partner) Primary neurulation • Formation of the neural plate • Shaping of the neural plate • Bending of the neural plate to form the groove • Closure of the neural groove to form the neural tube. http://www.mun.ca/biology/desmid/brian/BIOL3530/DEVO_12/ch12f19.jpg http://briebuzz.blogspot.in/ http://www.neuralimages.org/images/growth-cone.gif http://www.ibdm.univ-mrs.fr/equipe/axon-guidance-in-the-mammalian-brain/ http://www.mun.ca/biology/desmid/brian/BIOL3530/DEVO_12/ch12f19.jpg
Model system http://csatimes.co.in/wp-content/uploads/2014/02/baby-chick-and-an-egg.jpg
Morphogenesis (shape and size) of the forebrain Neural tube formation in the chick embryo
Patterning and morphogenesis of the neural tube Hippocampus M L D ChP X V Holoprocencephalic forebrain
The visual pathway in chicken Visual centers In the forebrain Thalamic nuclei Optic tectum Retina
Ganglion cells from specific locations in the chick retina project to specific locations in the optic tectum. This gives rise to the retinotectal map Dorsal Medial Lateral Ventral Retina Optic Tectum
Topographic guidance cues along the AP and DV axes EphA Ephrin-A Caudal temporal nasal Rostral Optic Tectum Retina Dorsal Ephrin-B Medial Ventral Lateral EphB
Strategy to identify new retino-tectal guidance molecules : Hypothesis Dorsal There are as yet unidentified guidance molecules that regulate retinotectal map-formation. Ventral Cy5 Total RNA Total RNA Cy3 Microarray
Candidate topographic guidance molecules expressed asymmetrically along the dorsal-ventral axis of the tectum D D D V V V Ten-M3 homolog Coiled coil domain containing 46 Wnt-5A D D V V Lactotransferrin Utrophin Genes expressed at higher levels in the dorsal tectum
In-vivo experiments to validate the candidate guidance molecules T T N DiI Injection site A A P P WT RNAi-mediated knockdown and misexpression of candidate retinotectal guidance molecules Termination zone in tectum
Summary Regulatory molecules ? Axon guidance Neurogenesis Patterning Migration