one of the things that can happen when we don't get enough sleep is it changes
our thinking abilities, ability to be able to process information effectively
it can also impair your memory and there's a couple of reasons for both of these effects
as far as the thinking problems and the memory in fact insomnia
increases cortisol levels. Cortisol is the stress hormone we think of it it
also contributes to the fight-or-flight response
giving that surge of adrenaline. But and so it is very useful we do need cortisol
but what we don't need is elevated levels of cortisol just kind of sitting
there sitting around. Elevated levels of cortisol can cause memory problems or
trouble trouble retrieving information and this is the same kind of decline in
memory that we see with age-related changes that's that's one of the causes
of age-related or senile dementia we sometimes refer to it as.
So as far as memories go it's the slow-wave sleep that helps
consolidate declarative memories and it's REM sleep that helps
consolidate procedural memories. Now what are these two different types of
memories just for your information. Declarative memories is the ability to
remember facts and things that we've learned in the past such as say a to-do
list. I can at the beginning of my day have this to-do list of things that I
want to do today and then as the day progresses I file back and recall things
oh yeah grocery store pick up dry cleaning these
sorts of things that would be declarative memory procedural memory would be memory
for things like things tasks that you've learned procedures you can think of it
as like riding a bike or even something like learning
Photoshop which is a pretty complex program. But learning things that you
have learned and where there's several steps and after a while those things can
become very rote and it's not an effort to remember how to write a bicycle for
example. So the reason this is important is because when you get less sleep let's
say you only sleep four hours who knows how that's translates into how
much less slow-wave sleep you've gotten and how much less REM you've gotten
you've had less time in the laboratory
forming these memories and this can have really important implications for people
students who are studying staying up late let's pull an all-nighter to
remember these facts and things and perhaps you may
be able to stuff some of it down, but you're really compromising your ability
to really learn and remember when intuitively it seems that if you just
spend more time you'll be able to remember and it actually works against
you. So another quick analogy to illustrate the difference between
procedural memory and declarative memory for those of you who like technology
would be to compare it to the memory in your computer. The computer has two types
of memory the RAM which is random access memory and ROM which is typically what
we think of as the computer's hard drive where things are permanently stored.
So for us our declarative memory would be RAM that's our ability to quickly
remember things keep a lot of things in our head. If you have a computer that has
lots of RAM, gigabyte several gigabytes of RAM you're gonna be able to run a lot
of programs at the same time click here click there have the internet your email
something else going and hardly be slowed down at all if you don't have
enough RAM you're gonna click can have to wait see the hourglass and things
might even freeze on you. So where do we get this RAM well first of all so taking
it to the workplace if you have the kind of job where you really have to be on
your toes for most of the day you've got people asking you questions you've got
to recall things that came up in meetings yesterday and be able to act on
that information etc., you need a lot of RAM. So where do you get the RAM? The RAM
comes in the slow-wave sleep portion so it's that deep sleep
the restorative sleep as far as there's lots of things that happened during that
phase but also consolidating our declarative memory. Then our REM sleep
would be responsible for consolidating the ROM or our ROM, our hard drive that
keeps up with the procedures that become rote for us like the riding of the
bicycle, washing dishes, driving a car things that we hardly give any thought
to because we filed it away as a memory that's in our hard drive that we can
easily draw from. So now that you have an earful about different types of memories
suffice it to say that it's the forming of these memories and enabling us to be
able to think and process and be sharp and on our toes is very dependent on how
much sleep we get. So next lecture is health problems that turn up when you
don't get enough sleep