The Smart Gene essays

The Smart Gene essays The human brain has approximately 100 billion nerve cells, or neurons that are linked in networks to give rise to a variety of mental and cognitive attributes, such as memory, intelligence, and personality. These networks include the nerve cells. At the synapse, information in the form of chemicals called neurotransmitters flows from the so-called presynaptic cell to the postsynaptic cell. These nerve cells become more tightly linked when stimulated by a series of high-frequency electrical pulses. This increase in synaptic strength is know as long-term potentiation (LTP) just as the decrease in strength is known as long-term depression (LTD). LTP is found in the hippocampus, which is a crucial brain structure for memory formation. Research has indicated that the induction of the major forms of LTP and LTD requires the activation of NMDA (N-methyl-D-asparate) receptors, which sit on the cell membranes of postsynaptic neurons (see Fig 3) (Tsien 2000). The NMDA receptor, a syna ptic coincidence detector, acts as a switch for memory formation, enhancing the signal detection by NMDA receptors should enhance learning and memory. Protein subunits called NR2B are part of the complex of proteins that form the NMDA receptor. Research indicates that when the NMDA receptor channel is open, triggered by a stimulus from two neurons, it begins a biochemical cascade that results in memory retention and learning (Bassand 1999). In simpler terms, the extra copy of the NR2B gene controls the brains ability to link one event to another and remember the link. This double whammy of the gene quickened the way the mice learn and remember by speeding up the reactions between neurons, or brain cells (Guynup 2000). Tsien accomplished this task by taking a copy of the gene that directs the production of NR2B and linking it to a special piece of DNA. This DNA contained a special on switch to inc...