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	<title>ADDing Up &#187; prefrontal-cortex</title>
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	<link>http://addingup.org</link>
	<description>exploring NEW realities of adult ADD/ADHD</description>
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		<title>Is our brain still evolving?</title>
		<link>http://addingup.org/2009/05/19/human-brain-still-evolving/</link>
		<comments>http://addingup.org/2009/05/19/human-brain-still-evolving/#comments</comments>
		<pubDate>Tue, 19 May 2009 19:15:56 +0000</pubDate>
		<dc:creator>Roy</dc:creator>
				<category><![CDATA[Evolution]]></category>
		<category><![CDATA[Our brain]]></category>
		<category><![CDATA[evolution]]></category>
		<category><![CDATA[human-brain]]></category>
		<category><![CDATA[limbic-system]]></category>
		<category><![CDATA[personality]]></category>
		<category><![CDATA[prefrontal-cortex]]></category>

		<guid isPermaLink="false">http://www.addingup.org/?p=415</guid>
		<description><![CDATA[Our brain has gotten bigger in size over the last 3.5 million years of evolution. Is human brain still evolving?]]></description>
			<content:encoded><![CDATA[<p>We saw how our brain <a title="Evolution of human brain size" href="/2009/05/18/human-brain-size-evolution/" target="_self">got bigger in size</a> over the last 3.5 million years, as we <a title="A primer on Evolution" href="/2009/05/16/evolution-primer/" target="_self">evolved</a> from our earliest known human ancestor, the <a title="Hominid species" href="http://en.wikipedia.org/wiki/Hominidae" target="_blank">hominids</a><img title="(opens in a new window)" src="/images/newwindow.jpg" alt="new window" />. Is human brain evolving even <em>today</em>?<br />
<span id="more-415"></span></p>
<p>Absolutely. Why? Because,</p>
<h3 id="nstop">Evolution <em>never</em> stops.</h3>
<p id="cond">Our environment is always changing, and so our brain is also evolving, but <em>so slowly </em>(<a href="/2009/05/16/evolution-primer#take">take home message #1</a>) that we cannot see it unless several thousand generations have passed. And recent <a title="Evidence for human brain evolution" href="http://www.nytimes.com/2005/09/08/science/08cnd-brain.html?_r=1&amp;pagewanted=all" target="_blank">scientific evidence</a><img title="(opens in a new window)" src="/images/newwindow.jpg" alt="new window" /> suggests this too. Our ancestors had to adapt to the <a title="our early environments" href="/2009/05/18/human-brain-size-evolution#environ" target="_self">altered conditions</a> of ground-based threats, which triggered the brain size growth. How is the environment changing today?</p>
<p>After agriculture began about 12,000 years ago, and particularly the <a title="Know more about Industrial Revolution" href="http://en.wikipedia.org/wiki/Industrial_Revolution" target="_blank">industrial revolution</a><img title="(opens in a new window)" src="/images/newwindow.jpg" alt="new window" /><img class="alignright size-full wp-image-545" style="margin: 10px 0px 0px 10px; border: 0pt;" title="Progress" src="http://www.addingup.org/wp-content/uploads/2009/05/progress.jpg" alt="progress" width="350" height="179" /> of late 1800s and early 1900s, rapid advances in technology have considerably improved our life style, and made it <em>fast-paced</em>. Today a teenager&#8217;s brain processes more information in an hour than our forefathers did in their entire lifetime. Such increased demand on brain efficiency is likely to favor (<a title="A primer on Evolution" href="/2009/05/16/evolution-primer/" target="_self">Evolution point #2</a>) a <em>stronger brain</em> in the foreseeable future.</p>
<p>Does &#8220;stronger&#8221; mean &#8220;bigger&#8221;? Posed another way,</p>
<h3>Is our brain still getting <em>bigger</em>?</h3>
<p>The best answer that I, or anybody else, can give you today is: <em>Not necessarily</em>. Even though we know how our environment has changed in the last few thousands of years, we  still do not understand our brain well enough to know how exactly this change is driving its current evolutionary course.</p>
<p>We all agree, though, that modern human intelligence depends as much on the size of our brain as on its complex <em>internal structure</em>. And so, with each new generation getting smarter, it is possible that our brain is evolving <em>internally</em>, without getting bigger. Experts also seem to divide along these lines on their interpretation of the latest <a title="Evidence for human brain evolution" href="http://www.nytimes.com/2005/09/08/science/08cnd-brain.html?_r=2&amp;pagewanted=all" target="_blank">scientific evidence</a><img title="(opens in a new window)" src="/images/newwindow.jpg" alt="new window" />.</p>
<h3>A quick peek at our brain:</h3>
<p><a onclick="window.open('http://www.addingup.org/wp-content/uploads/2009/05/human_brain.jpg','popup','width=900,height=700,scrollbars=no,resizable=yes,toolbar=no,directories=no,location=no,menubar=no,status=yes,left=0,top=0');return false" href="http://www.addingup.org/wp-content/uploads/2009/05/human_brain.jpg"><img class="alignleft size-full wp-image-380" style="margin: 10px 10px 10px 0px; border: 0pt;" title="(click to enlarge)" src="http://www.addingup.org/wp-content/uploads/2009/05/human_brain2.jpg" alt="(click to enlarge)" width="350" height="242" /></a>If you cut open a human brain vertically in the middle, it looks like the picture here (click to enlarge). Our brain  is packed with many internal organs, each connected to the others in intricate arrangements, and each  performs a variety of complex tasks (much of which is still unknown).</p>
<p>For example, <a title="Read more about prefrontal cortex" href="http://en.wikipedia.org/wiki/Prefrontal_cortex" target="_blank">Prefrontal cortex</a><img title="(opens in a new window)" src="/images/newwindow.jpg" alt="new window" />(PFC) is the chief executive of our brain, because it is responsible for forethought, planning, impulse control, and decision making. Likewise, <a title="Read more about Limbic system" href="http://en.wikipedia.org/wiki/Limbic_system" target="_blank">Limbic system</a><img title="(opens in a new window)" src="/images/newwindow.jpg" alt="new window" />(LS) is made up of a number of component organs that together govern our emotion, memory and behavior. Not surprisingly, proper functioning of PFC and LS is vital to develop a <em>normal</em> personality. (People with ADD often differ from others in this aspect, as I will talk about in detail elsewhere.)</p>
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