Brain Development Cortex has six distinct layers of cell bodies called laminae There are six distinct laminae layers in the cortex the cell layers run parallel to the surface of the cortex These layers vary in thickness and prominence in different areas of the cortex or how much of the cortex area they take up Laminae 4 is important for sensory information it is absent from the motor areas of the cortex Each of these cell layers has a bunch of cells These cells are arranged in columns they re perpendicular to the layer These cells in a column respond to the same stimulus if one cell receives the stimulus all the cells respond There are about 50 distinct areas in the cortex but there are only 4 lobes Occipital lobe is in the back deals with sight visual cortex Main target for axons from the thalamus that receive input from visual pathways Very back most posterior portion of occipital lobe is primary visual cortex If primary visual cortex is damaged you will suffer cortical blindness People suffering from this cannot visualize anything they can t imagine how anything looks Parietal lobe is between the occipital lobe and the central sulcus Body information center An area of the parietal lobe called the post central gyrus is known as the primary somatosensory cortex It is the primary target for touch information muscle skin information It is important for knowing where you are in space The parietal lobe is important for relaying visual and spacial information Damage to the parietal lobe can have many different effects depending on location But damage to parietal in the left hemisphere isn t as severe in the right Temporal lobe is on the sides Target for information from ears and vestibular system which is responsible for sense of balance Important for understanding spoken language facial recognition some emotional and motivational behaviors and depending on where damage is seen very different effects Sometimes if someone has a tumor in the temporal lobe they may have visual hallucinations Damage to other parts of these lobes lead to syndrome known as Kluver Bucy which is loss of fear Frontal lobe which is in the front Contains motor cortex which is the pre central gyrus This specializes in fine motor movement Most anterior part of the frontal cortex is the pre frontal cortex Pre frontal cortex receives sensory information from all sensory systems It s important for working memory and may be responsible for object permanence Pre frontal cortex undergoes massive neurological development between 7 and 12 months Develops last and can continue developing through early adulthood Important for impulse control and predicting negative outcomes and possible consequences of actions The binding problem is one of the big mysteries of neuroscience How is the brain able to put together movement sound color etc to come up with anything to see like a squirrel The inferior parietal cortex and parts of the basal ganglia might be necessary for the brain to figure things out put things together People with damage in these areas cannot put shape motion and color together A lot of lesioning in animals is done using the stereotactic surgical apparatus Making a lesion involves making damage to the brain so it no longer works in a specific area Whenever performing a study involving lesioning of animals it is imperative you have a sham control group The only difference is the lack of lesions In order to double check that the exact area was lesioned it s important to do a necropsy which is an autopsy for animals Most people freeze the brain before slicing through it because it s spongy and will otherwise turn to mush Microtome is used to slice through brains and it s probably the sharpest object in the world so one needs to be trained to use it A lesion can have either a direct effect or an indirect effect It may be that lesioning the hypothalamus causes the effects one sees but it also might be that lesioning the hypothalamus prevents the neurons from firing the information to thalamus meaning it can t do what it needs to Several methods to measuring brain activity in animals one of which is microdialysis Another is autoradiography A third is immunohistochemistry People s brains can also be measured in activity and structure To measure structure in humans one can use CAT scans CAT scans allow you to construct a 180 degree image of the brain A CAT scan is a so called dirty method Any method that involves radioactive activity X ray or chemical is called dirty Another method for measuring structure is MRI The MRI uses atomic movement to give images of the brain It uses magnets PET scan is a way to look at brain activity this involves radioactive decay which produces gamma rays A cyclotron is needed to produce the chemicals required for a PET scan These aren t available everywhere but research institutions hospitals will have them fMRI functional magnetic resonance imaging Looks at both structure and activity of brain Resolution is very good Diagnostically the above methods are used pretty often One question is Does size matter Does brain size equal intelligence a bigger brain more smarts If one looks at total mass that notion can be tossed out the window Blue whale has the biggest brain in the world elephants have big brains as well Brain to body ratio is another way of looking at it Another issue with this is that a kind of fish and a squirrel monkey would have humans beat and if one looked at it like that a Chihuahua would be the smartest dog and they re not There is a modest correlation in humans regarding brain size equaling intelligence about 0 3 but correlation does not equal causation It is a fact that men have larger brains than women but women have more sulci and gyri than men It is impossible to separate out environment s influence Men and women have different brains Given hormonal differences they need to be Brain changes shape all the time Neurons are born neurons die and dendritic spines grow or go away