9 14 MIT Spring 2009 Classes 35 38 Questions on Nauta Feirtag ch 13 pp 220 227 235 238 Forebrain ch 16 pp 289 307 Neocortex 1 What is temporalization of the hemisphere See p 221 figs 88 94 Where would you look for the rodent equivalent of the primate inferotemporal cortex 2 The corona radiata the internal capsule the cerebral peduncle and the pyramidal tract are continuous from neocortical mantle outer layers of cells and fibers to the hindbrain and then to spinal cord Name one type of axon which is present in all of these named structures Then try and name some axons which are not present in all of them 3 What is the rhinal sulcus 4 Why did early anatomists mistakenly consider the olfactory peduncle in the human brain the most rostral cranial nerve The olfactory nerve itself is made up of the axons of the primary sensory neurons of the olfactory epithelium which course through the cribiform plate at the base of the skull to end in glomerular structures of the olfactory bulb where they synapse on mitral cells Thus they do not form a compact bundle of fibers 5 What is Nauta s definition of association cortex p 238 By this definition we would have to say that the posterior association cortex of primates has been shrinking in recent years A revised anatomical definition will be presented in class 6 What thalamic nuclei project to the frontal association cortex and to the posterior association cortex respectively 7 Contrast pyramidal cells and stellate cells of the neocortex 8 Layer four of the neocortex is most different in two areas the motor cortex and the primary visual cortex Summarize the differences 9 What are the radial fascicles of the neocortex p 293 295 What three major groups of cortical output axons are found in these fascicles 10 What is the line of Gennari see fig 112 Note you do not have to memorize the special names of other tangential fiber bands in the neocortex except for layer 1 plexiform layer with few cell bodies and the white matter below layer 6 11 How could an anatomist visualize the ocular dominance stripes in striate neocortex see fig 116 Compare Patricia Goldman Rakic s discovery with Nauta of 9 14 MIT Spring 2009 Classes 35 38 columns in the retrosplenial cortex posterior limbic system cortex near the posterior end or splenium of the corpus callosum see fig 117 12 What association fibers of the human cerebral hemisphere are prominent even in gross dissections of the brain fig 115 These are not evident in brains of small animals like rodents although some long association fibers do exist in these animals Additional questions covered in classes 14 What are the names of the two most commonly encountered classes of cortical cells 15 What is the major morphological characteristic of the neocortex How do different regions of cortex differ from each other 16 Describe the connections of the different cortical layers 17 What are the major types of neocortical areas What are Brodman s areas and what is the basis of their differentiation MIT OpenCourseWare http ocw mit edu 9 14 Brain Structure and Its Origins Spring 2009 For information about citing these materials or our Terms of Use visit http ocw mit edu terms