brains-and-bodies

brains-and-bodies:

My eyes burn, why do we use this stuff?

If you’ve ever been in a biology lab, you’ve probably been in this situation before. You marvel at jars of organs, animals and parasites but the moment you open that lid, you start exercising your tear ducts.

Yesterday I was asked by a colleague how we preserve human tissues and I explained that formaldehyde is a standard fixative. Upon further discussion, I realized that I did not know the mechanism behind tissue fixation, merely the need for gloves and a good face mask (a little perfume on the upper lip doesn’t hurt either).

As it turns out, formaldehyde is a fixation favorite for its ability to increase the rigidity of cells, prevent bacterial growth and disable proteolytic enzymes that would otherwise digest the cells.

As an aldehyde, formaldehyde does a great job of cross linking proteins, as illustrated in the second figure. The resulting covalent bonds make for some serious cell stability.

It also has the added bonus of making those in its presence extremely hungry for reasons I’m still investigating.

Stay curious my friends

Sources:

  1. http://synapses.clm.utexas.edu/lab/howto/cross-linking%20fixatives.pdf
  2. http://en.wikipedia.org/wiki/Fixation_(histology)
  3. http://images.nationalgeographic.com/wpf/media-live/photos/000/010/cache/human-brain_1001_600x450.jpg
  4. http://publish.uwo.ca/~jkiernan/formfix.gif
colorful-history

colorful-history:

Henry Ossawa Tanner (1859-1937) was the first African American painter to gain international renown. His desire to paint developed in his teen years as he grew up around the Philadelphia art scene. At the age of 21 he enrolled in the prestigious Pennsylvania Academy of the Fine Arts and learned under the guidance of the visionary Thomas Eakins. In 1888 Tanner began teaching at Clark College, but desperately wanted to go abroad due to the racism he felt at home. He would gain enough funds to do so when a bishop and his wife purchased his entire collection. He would settle in Paris and learn under many famous artists and eventually came to reside in the Etaples art colony in Normandy. His paintings would depict African American and Peasant life with respect and care, but he would eventually transition into Biblical pieces. His art was very well received and he even had pieces exhibited in the Paris Salon, one of which was purchased by the French government and now resides in the Louvre’s collections. During WWI he would paint from the front lines of war, which earned him a knighthood in the Legion of Honor. He became a member of many art societies and the first African American full academician at the National Academy of Design. He would continue to paint the rest of his life and would be awarded many medals for his art internationally.

metacogs

metacogs:

NPR just ran this fun piece about James Pennebaker’s work on pronouns and filler words, and how they signal status and romantic interest. Turns out we can learn a lot from the words we never think about: pronouns like I or you, fillers like “uh” and “um,” and “verbal ticks” like “like.” Word nerds, if you want to read up on the topic, check out these papers:

Clark, H. H. & Fox Tree, Jean E. (2002). Using uh and um in spontaneous speaking. Cognition, 84, 73-111. — “Uh” signals a minor delay in your sentence, whereas “um” signals a more major delay.

Arnold, J. E., Tanenhaus, M. K., Altman, R. J., & Fagnano, M. (2004). The old and thee, uh, new. Psychological Science, 15(9), 578-582. — “Uh” signals that the speaker will probably be referencing something new in their sentence that hasn’t yet been mentioned in that conversation.

Fox Tree, J. E. (2006). Placing like in telling stories. Discourse Studies, 8(6), 749-770. — Using ‘like’ isn’t always vapid! An overview of the different ways ‘like’ is used in speech and what it signals.

Kidd, C., White, K.S., & Aslin, R.N. (2011). Toddlers use speech disfluencies to predict speakers’ referential intentions. Developmental Science, 14(4), 925–934. — Kids use people’s “um”s and “uh”s to learn new words.

anthrocentric
neurosciencestuff:

How studying damage to the prefrontal lobe has helped unlock the brain’s mysteries
Until the last few decades, the frontal lobes of the brain were shrouded in mystery and erroneously thought of as nonessential for normal function—hence the frequent use of lobotomies in the early 20th century to treat psychiatric disorders. Now a review publishing August 28 in the Cell Press journal Neuron highlights groundbreaking studies of patients with brain damage that reveal how distinct areas of the frontal lobes are critical for a person’s ability to learn, multitask, control their emotions, socialize, and make real-life decisions. The findings have helped experts rehabilitate patients experiencing damage to this region of the brain.
Although fairly common, damage to the prefrontal lobes (also called the prefrontal cortex) is often overlooked and undiagnosed because patients do not manifest obvious deficits. For example, patients with prefrontal brain damage do not lose any of their senses and often have preserved motor and language abilities, but they may manifest social abnormalities or difficulties with high-level planning in everyday life situations.
"In this review, we aimed to highlight a blend of new studies using cutting edge research techniques to investigate brain damage, but also to relate these new studies to original studies, some of which were published more than a century ago," said lead author Dr. Sara Szczepanski, of the University of California, Berkeley. "There is currently a large push to better understand the functions of the prefrontal cortex, and we believe that our review will make an important contribution to this understanding."
In addition to revealing the functions of different areas within the prefrontal cortex, studies have also demonstrated the flexibility of the region, which has helped experts optimize cognitive therapy techniques to enable patients with brain damage to learn new skills and compensate for their impairments.
The review indicates that by studying patients with damage to the prefrontal cortex, investigators can gain insights into this still-mysterious region of the brain that is critical for complex human skills and behavior.

neurosciencestuff:

How studying damage to the prefrontal lobe has helped unlock the brain’s mysteries

Until the last few decades, the frontal lobes of the brain were shrouded in mystery and erroneously thought of as nonessential for normal function—hence the frequent use of lobotomies in the early 20th century to treat psychiatric disorders. Now a review publishing August 28 in the Cell Press journal Neuron highlights groundbreaking studies of patients with brain damage that reveal how distinct areas of the frontal lobes are critical for a person’s ability to learn, multitask, control their emotions, socialize, and make real-life decisions. The findings have helped experts rehabilitate patients experiencing damage to this region of the brain.

Although fairly common, damage to the prefrontal lobes (also called the prefrontal cortex) is often overlooked and undiagnosed because patients do not manifest obvious deficits. For example, patients with prefrontal brain damage do not lose any of their senses and often have preserved motor and language abilities, but they may manifest social abnormalities or difficulties with high-level planning in everyday life situations.

"In this review, we aimed to highlight a blend of new studies using cutting edge research techniques to investigate brain damage, but also to relate these new studies to original studies, some of which were published more than a century ago," said lead author Dr. Sara Szczepanski, of the University of California, Berkeley. "There is currently a large push to better understand the functions of the prefrontal cortex, and we believe that our review will make an important contribution to this understanding."

In addition to revealing the functions of different areas within the prefrontal cortex, studies have also demonstrated the flexibility of the region, which has helped experts optimize cognitive therapy techniques to enable patients with brain damage to learn new skills and compensate for their impairments.

The review indicates that by studying patients with damage to the prefrontal cortex, investigators can gain insights into this still-mysterious region of the brain that is critical for complex human skills and behavior.