We have discussed what intelligence means and how it is inherited, I would like the readers to follow me thru a small digression where we will have a “zoom-in” on the exact ways by which genes work in the brain.
The technical details might be indigestible to the general reader hence an oversimplified version of the story is presented in the posts below. I should make clear at the outset that this is indeed a digression and skipping these few posts wont break the continuity of the whole thread…heh he Scientists…especially geneticists, have strange ways of naming genes and proteins that discover. Most genes are named based on the “effect” they produce in the body if they start malfunctioning. For example the now famous gene that helps in memory functions is named Amnesiac, (!??)because its mutation or absence can result severe “forgetfulness” in the carrier ! Genes like comatose and mini brain are of this kind. Another popular way of naming genes and proteins is giving the names-names of comic or epic characters or names of individuals, breeds, and even objects resembling the proteins for that matter; examples of this kind being leonardo, homer, Miranda, dachshund, slipper, sickle etc. Some scientists are fond of names from classical languages other than the “done-to death” Latin. A protein (an amide to be exact) called anandamide called so because anandam– pronounced “aanaanthom”- is the Sanskrit word for bliss or euphoria. So my readers can now speculate on the effects of this protein in brain..
Biological systems are built in order to respond to environmental stimulus. Learning takes this ability to extremes. Memory involves increasing the efficiency of how brain cells “communicate” with one another, otherwise called synaptic function.
Memories are thought to be due to lasting synaptic modifications in the brain. Repeatedly used information is processed in the brain by what is called Long term Potentiation. This mainly includes tuning the nerve cells to make them ready for repeated firing of the synapse. (a Synapse is the fancy term for the point of contact of two connected nervecells).
What is the role of genes and their protein products in these synaptic changes?
Coincidence of information from two or more modalities (for example: a baby inadvertently touching a hot iron rod) results in increased neural activity, that is, an influx of Calcium ions. Elevated amounts of Calcium ions in nerve cells cause Ca2+ to bind to a protein called Calmodulin. The Calcium-Calmodulin complex joins hands with another molecule called Adenylate Cyclase. The final combination of all three increases the cellular manufacture of a molecule known as Cyclic AMP or c-AMP for short. This molecule is called a second messenger. The job of a second messenger is to wake up genes in a cell; cAMP does just that. Thru a series of reactions subsequently, it stimulates a number of genes like CREB, Dunce, Rutagaba, Amnesiac and so on. These “activated” genes start making a lot of proteins that enhance the nerve-to-nerve connection, making the route clear for easy passage of ionic signals. The connexions thus made form the secret behind learning & memory.
Here’s a short list of some weird (!) genes and their functions in brain, to amaze your friends at the next party…
Homer : required for brain cells to control movement of limbs and body parts, and also behavioural plasticity.
Rutagaba : required for changing synaptic connexions for modifying learned things.
Dunce : destroys cAMP. And regulates amount of info stored.
Amnesiac : Needed for associating various stimuli to learned concepts.
Leonardo : Strongly associated with learning and smell, especially in fruit flies.
BALB : Makes you introverted but good at tracking back old ways.
NCS-I : Determines flexibility of learning.
BDNF : Encourages growth of nerve cells.
…you can extend this list to any number of pages…so complex is the simple task of learning..!