the amygdala is part of the cortex we kind of call it corticoid and rather than because it's so old
how old is it well it's so old that it doesn't even have layers and so if we look at the cortex
which is all out here this is all our beautiful six layered cortex and we watched come around and
just totally merge with the amygdala right here so it is part of the cortex but like I said it's
really old it's even older than our key cortex because it doesn't have any any layers at all
it's in the anterior pole of your temporal lobe and the surface let me read a race and redraw this
surface is this bump here that kind of projects out underneath the surface of the brain and they
call it the uncus they named everything based on kind of what it looked like when they first
were discovering the brain and so they found this lump under the under surface and they called it
the Uncus Uncus means lump they had no idea that the amygdala was just right underneath of it but
since we know now but it we're still stuck with the name Uncus so the function of the amygdala
really involves mostly negative mostly negative emotions so general limbic emotions and behaviors
and these include fear anger arousal which isn't really so negative it's being awakened alert and
your reactions to the environment if you stimulate the amygdala you end up eliciting fear and rage
and if you there are lots of videos or when I was in graduate school in an undergraduate they would
show you this videos of a cat whose amygdala was being stimulated and the cat would be arched back
hair standing up hissing and spitting and you know clawing and they call it sham rage I'm
sure to the cat it felt like real rage but it's called sham rage because there's no external cause
for the rage it's all internally generated by the electrode if you oblate the the amygdala you end
up with an experimental animal that's incredibly passive and doesn't really care about anything it
is also not afraid of things that it should be afraid of there are have been experiments in in
animal models where they have laid the up the amygdala and you put food on one side of the
animals cage and something dangerous like a rubber snake it rubber snake isn't really dangerous but
should look dangerous the animal will just walk right over the rubber snake to get the food and
not even worry that there's something that he should be afraid of in in between it and its goal
so the amygdala is mostly associated with fear and rage and not too many happy things unfortunately
the afferrent connections of the amygdala include it gets a lot of information from your sensory
cortex especially those association areas and a lot of information coming in from the olfactory
system and remember when we talked about the special sense of olfaction we mentioned that
it goes straight to cortex before it goes it it doesn't have to go to the thalamus before it goes
to cortex well this is part of that explanation the olfactory bulb projects directly to amygdala
and in doing so bypasses all of your other kind of cortical processing which explains why olfactory
information has such a powerful and immediate emotional consequences the amygdala also gets
lots of connections from in lots information from your frontal cortex and from your fore brain the
amygdala sends information to all kinds of places in the brain most of the cortex the
brainstem and the hypothalamus and remember the hypothalamus and it's connections to the brainstem
are regulating your autonomic s-- so this is one of the ways in which cortical structures can be
through the hypothalamus which regulates your autonomics and then activate those autonomic
systems usually sympathetics it also has lots of connections to the hippocampal formation and in
the next lecture we'll talk about the hippocampus but if just to give you a preview the hippocampus
is really important for learning and memory so the I'd like to turn on my drawing tool
here's the amygdala and amygdala quite literally means almond and the amygdala is kind of shaped
like an almond and then here's the hippocampus the hippocampal formation behind it so you can
see how close together they are you need your amygdala to talk to your hippocampus so that
you can remember what made you afraid in the next section we'll talk more specifically about some
of the subdivisions within the amygdala and some of their more specific connections and functions