They were aimed at building a national citizenship based on “the equal protection of the laws,” and they prohibited the states from denying that protection to any American. Other key sections come from what are known as the Reconstruction amendments (the 13th, 14th and 15th) that emerged from the blood and ashes of the Civil War.
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history - the full name for the Social Security Act of 1935, for example, was “an act to provide for the general welfare by establishing a system of federal old-age benefits.” This idea anchors many of the landmarks of U.S. Constitution begin in the preamble, which says that one of its core purposes is to “promote the general welfare” as opposed to private interests. This is why we hear so much about the second phrase of the Second Amendment - “ … the right of the people to keep and bear Arms, shall not be infringed.”īut for all its limitations, the constitution remains the supreme law of the land in America, the one document that can guarantee the rights and liberties that Democrats correctly see as under threat from Republican extremism.Īs such, they need to rediscover its pro-democratic dimensions so they can work with the document - and make it work for them. (National Archives Museum)įrustrated by the document’s anti-majoritarian elements, including the Electoral College and the Senate, American progressives tend to cede the constitutional ground to their opponents, who eagerly turn the lines they like into holy writ. Constitution as displayed at the National Archives Museum in Washington, D.C. (Provided by: Webvision: The Organization of the Retina and Visual System.The U.S. A simple neuron from a light microscope capture. Fluorescently Tagged Primary Visual Cortex Neuron. Neurons within a minicolumn (microcolumn) encode similar features, whereas a hypercolumn “denotes a unit containing a full set of values for any given set of receptive field parameters.” Fig.9.10.1. Color-selective neurons live in blobs (regions of cortex that stain dark when you stain for cytochrome oxidase, because they’re metabolically rich) there’s a blob for each pinwheel.Ī cortical column is a group of neurons in the cortex of the brain that can be successively penetrated by a probe inserted perpendicularly to the cortical surface, and which have nearly identical receptive fields. Some V1 neurons are color-blind some are color-selective.
A cluster of orientation columns is called a pinwheel-there’s an orientation pinwheel for each eye. This segregation is strongest in the input layer (4), so when we look for ODCs, we look in the middle of the cortex. Left and right eye inputs are segregated into ocular dominance columns. For V1, this means that as you move across the cortex, you find neurons with different orientation preferences. If you sample neural responses as you move across the surface, they change.This means that as you move down through cortex, you find neurons with the same orientation preferences. If you sample neural responses as you move through the depth, they stay approximately the same.The gray matter has 2 important directions: across the surface and through the depth. No modifications.)Ĭolumnar organization is an important property of primary sensory and motor cortices.
(Credit: McGill: The Brain from Top to Bottom, Figure of hypercolumns, Copyleft. Blobs are color selective and for every pinwheel there is a blob. Orientation columns are neurons that get excited at different orientations and a cluster of these is called a pinwheel. Ocular dominance columns are segregated into left and right eye inputs. Know how the V1 neurons are organized according to their orientation preferences (depth vs surface).įigure 9.2. Know how the V1 neurons are organized according to eye of origin.
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