Tri-2, Wk12, Day 114 - Deja vu

Kind of a long day today - headed out at 6 a.m. and got home at 7:30 p.m.

I stayed after for some neuro and biochem tutoring - the biochem tutoring was fantastic.

I was curious about some things in neuro - we were discussing the optic tract which is among the last part of the visual pathway. The ventral or lower part of the optic tract runs from the lateral geniculate nucleus which is located rather centrally in the brain and the ventral portion of that tract actually runs a bit forward before reversing directions and heading back to the visual cortex. Since it's the lower geniculate tract (aka Meyer loop) it would be going to the cuneus gyrus. I need to brush up on some of this but - the temporal lobe of the brain is what makes sense of what we see and I'm asking the teacher how this happens -

here's my conundrum - what's being said/taught is that the transmitting neurons kind of "drop off" information in the temporal lobe which is where we make sense of what we're seeing BUT - we dont' actually see ANYTHING until the nerve impulses reach the visual cortex of the brain - is it possible to make sense of something before we actually "see" it?!?

I was given the argument about everything happening so fast that we can't notice what's going on but that was kind of a unsatisfactory answer in my opinion.

I wondered if this visual construction may play a part in Deja vu? In case there is a time lag - say a millisecond between the temporal lobes which interpret and make sense of what we're seeing and the part of our brain that actually let's us see what's out there. If there ever is a time lag then it could/would be a plausible theory behind deja vu.

Small changes can make a huge difference. Even with the Flat Earth Society - if the curvature of the earth were zero then we would be on something flat but the actual curvature is about 6 inches every mile so while not zero, it's only off by about 6 inches.

Light is another thing like that - take the time it takes light to travel a meter - not zero seconds but, pretty darned close.

So too, the time to travel from the temporal portion of the ventral optic radiation to the visual cortex may be exceedingly fast but, it still requires a time greater than zero seconds.

Heck - I need to post some more notes on our Google Group website then get to bed.

Today's picture is a drawing of the visual pathway and includes the optic radiation I mentioned previously. :)