Hello everyone, in this section we’re going to be examining plains of
orientation that we use in Physiological Psychology and in this understand
how we look at the brain [and the way that we look at the brain and the way
we look at it and kind of get an idea of where things are, so when I’m
talking to you, you have an idea about where I’m talking about in
particular]. So let’s begin by looking at what we call the neuroaxis on
page two. The neuroaxis basically is an imaginary line drawn through the
spinal cord and the brain. Basically what you have is a set of directions
that you can use based upon that neuroaxis. In relation to that, there are
a variety of different types of cuts and locations that we use to help us to
locate things within the brain. These cuts begin on page four.
Think about me with a machete. What I’m going to do is
take a machete and, as we see on this little line, start at the top and
start making cuts all the way from the top of this line, all the way down to
the bottom. The cuts are what are called horizontal cuts. What these cuts
allow us to do is give a direction of two different types of orientations.
These orientations are seen on slide five.
We see on the top of the cut is what we call dorsal, ala,
if you think of a fish, the dorsal fin and toward the bottom we think of as
ventral, ala, ventral fins of a fish. Toward the front of the organism, or
toward the nose, we think of as rostral, and toward the back we think of as
caudal. So, when I’m talking about something dorsal to some particular
structure, what that means is up.
The second type of cut that we see on slide six are what
we call coronal cuts. Coronal cuts are also called frontal or transverse
cuts. Instead of going across the body, they go vertical to the body. So,
we start at the tip of the nose, as we see here in our little line and go
all the way back to the end of the tale. The tail and each of these have a
different slice of tissue that we can look at. Again, toward the front or
toward the nose is rostral, toward the tail is caudal.
So, as we see in slide seven, we see rostral meaning
toward the nose, caudal meaning toward the tail; dorsal meaning toward the
back or up, and ventral meaning toward the bottom or the abdomen. Within
each of these orientations I can get an idea about where a particular cut
and a particular orientation is within an organism.
Now humans are a little bit different. Humans stand on
two legs instead of four legs. So how do we compare or make comparisons of
humans to other types of organisms (specifically animals)? Well, as we see
on slide nine, the orientation is a little bit different. Rostral again
means toward the nose and caudal means toward the back of the head. Dorsal
meaning superior, meaning above, toward the top of the head and ventral
meaning inferior, below, or toward the jaw.
Let’s go back and look at slide six. In slide six what we
saw, is that as we begin to make cuts within the organism, we start at the
nose and we’re starting toward the tail. When we do that, as the
orientation gets to the hind brain, basically the medullary structures,
there is kind of a shift. As a result of that shift, you begin to get a
change in the way that we orient our particular pictures. That gives our
dorsal meaning superior or above (toward the top of the head) and ventral
meaning inferior or below toward the jaw.
Now in the spinal cord, we also have some similar
orientations. Rostral (as we see in slide 10), meaning toward the neck and
head, whereas caudal means toward the coccyx bone, which is your tailbone.
Ventral means toward the abdomen, so if you were on all fours, you would
have your abdomen toward the ground (that would be ventral), and again
dorsal meaning toward the back.
So we’ve now talked about horizontal cuts and corronal
cuts. There are another couple of cuts that we need to know as well. These
are what are called sagital and parasagital cuts. So let’s show a mid-sagital
cut on slide 12. Basically a mid-sagital cut is a vertical cut that goes
right down the center of the body and cuts through the eyes, right through
the middle of the nose, the mouth and right down through the middle of the
spinal cord. In essence basically what it’s going to do is split the body
into a left side and a right side.
Parasagital as we see in the next slide is a little bit
different. Here the cut is not through the center of the eyes or the nose
or the mouth. What happens is that the cut moves away from the center and
moves toward the outside or what is called lateral. Now what we have are
some other terms that we need to know and these other terms are listed in
slide 14. Lateral meaning moving away from the body midline and medial
meaning toward the body midline. Now that we have two sides, there are two
other terms that we need to know as well. One is ipsilateral. Ipsilateral
means things are happening on the same side of the brain. So, when I talk
about left brain structures and I say something is ipsilateral to that, it
means it’s on the left side, whereas contralateral means on the opposite
side of the brain or the body. So, if we talk about the left side of the
brain, the contralateral side is the right side of the brain or the right
side of the body, whereas ipsilateral would be on the left side of the brain
and left side of the body.
The final thing that you need to look at is figure 3.2 in
Carlson. That is also listed on the last slide as well. Basically what
Carlson does is give you the different types of planes and how they relate
to the nervous system. So, I encourage you to go back through Carlson to
see what is going on with the corronal cuts and when they begin to start to
change while moving down the spinal column.
So now that we’ve kind of had some overviews of the
systems and kind of looked at some basic background information, in the next
section what we’re going to be doing is talking about some techniques we use
in Physiological Psychology. And so until that time, we hope you have
yourself a great day.
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