WEBVTT 00:00:00.000 --> 00:00:02.720 It's always a delay. Okay. Back with the basal 00:00:02.720 --> 00:00:05.719 ganglia. So last time we talked about the go 00:00:05.719 --> 00:00:09.439 area and the no -go area. Okay. Action and inaction. 00:00:09.800 --> 00:00:14.500 And these are operating simultaneously. Non -stop 00:00:14.500 --> 00:00:17.500 action here through these five sub -cortical 00:00:17.500 --> 00:00:21.879 areas. Okay. Just remember the input areas or 00:00:21.879 --> 00:00:25.899 the cadet. Remember this is the midline here. 00:00:25.920 --> 00:00:28.519 Okay. So this is one hemisphere and this is the 00:00:28.519 --> 00:00:32.960 other. so ipsilateral, contralateral okay so 00:00:32.960 --> 00:00:38.899 the cadet the cadet nucleus is here and the putamen 00:00:38.899 --> 00:00:43.060 here these are the inputs area receiving inputs 00:00:43.060 --> 00:00:47.140 from basically the cortex a lot of excitation 00:00:47.140 --> 00:00:53.359 here okay then the relay stations in purple globus 00:00:53.359 --> 00:00:58.200 pallidus external globus pallidus external subthalamic 00:00:58.200 --> 00:01:02.679 nucleus, which is basically an assistant for 00:01:02.679 --> 00:01:06.620 the thalamus. The thalamus is a workhorse. And 00:01:06.620 --> 00:01:11.019 then the output areas in blue. Globus pallidus 00:01:11.019 --> 00:01:14.939 internal. Remember the Globus pallidus kind of 00:01:14.939 --> 00:01:18.659 makes a triangle. And the substantia nigra pars 00:01:18.659 --> 00:01:23.620 reticulata. This is GABA. Substantia nigra pars 00:01:23.620 --> 00:01:28.540 compacta. is dopamine, both excitatory, D1, dopamine, 00:01:28.900 --> 00:01:32.959 and inhibitory, D2, dopamine. Parascompacta is 00:01:32.959 --> 00:01:36.260 a modulator. It intensifies. It amplifies the 00:01:36.260 --> 00:01:40.099 signals. Wherever the living organism is experiencing 00:01:40.099 --> 00:01:45.260 this dopamine intensifies it. Pay attention to 00:01:45.260 --> 00:01:47.540 this. This is valuable. This is rewarding. This 00:01:47.540 --> 00:01:51.400 is worth doing again. Or this is bad. Avoid this. 00:01:52.109 --> 00:01:55.409 Type of thing. So we talked about habits, right? 00:01:55.469 --> 00:01:58.569 We talked about this we extracted a specific 00:01:58.569 --> 00:02:02.209 cell out of here and highlighted it here and 00:02:02.209 --> 00:02:06.370 then we zoomed in and extracted a specific spine 00:02:06.370 --> 00:02:10.669 from the dentrite right here and a good way of 00:02:10.669 --> 00:02:13.090 thinking about this I want to cover this now 00:02:13.090 --> 00:02:19.009 is Let's just say the most severe case of the 00:02:19.009 --> 00:02:22.469 basal ganglia being hijacked being hijacked by 00:02:22.469 --> 00:02:27.129 habits and learning and so forth is OCD. OCD 00:02:27.129 --> 00:02:31.389 is heavily involved with the basal ganglia. So 00:02:31.389 --> 00:02:34.129 the spine right here, okay, remember we talked 00:02:34.129 --> 00:02:37.870 about morphology and how these bigger connections. 00:02:38.330 --> 00:02:42.069 When you think about morphology is you have a 00:02:42.069 --> 00:02:45.129 synaptic connection here but they will grow in 00:02:45.129 --> 00:02:50.870 size. So it's grown. It's almost doubled in size 00:02:50.870 --> 00:02:55.430 right here. Okay, and the bigger one the bigger 00:02:55.430 --> 00:03:00.150 connections will have preference and We can think 00:03:00.150 --> 00:03:03.590 about OCD like this OCD is I need to draw this 00:03:03.590 --> 00:03:10.909 out here OCD is corticosteroidal thalamom or 00:03:10.909 --> 00:03:17.110 thalamic Sometimes it's thalamocortical corticosteroidal 00:03:18.969 --> 00:03:22.750 striato thalamom cortical or sometimes it's just 00:03:22.750 --> 00:03:27.889 cortico striato thalamic but this is a loop remember 00:03:27.889 --> 00:03:35.530 we talked about okay remember the beds of ganglia 00:03:35.530 --> 00:03:38.870 is right through here we got the thalamus the 00:03:38.870 --> 00:03:43.530 cadet nucleus here butamen putamen right these 00:03:43.530 --> 00:03:47.120 are subcortical areas with OCD you might have 00:03:47.120 --> 00:03:49.960 a lot of connections let's just say right through 00:03:49.960 --> 00:03:53.840 here the sensory motor because a lot of habits 00:03:53.840 --> 00:03:56.280 will live here we like to shift our things to 00:03:56.280 --> 00:03:59.719 here for the habits this is the primary input 00:03:59.719 --> 00:04:02.900 area to the cadet and the pertainment not the 00:04:02.900 --> 00:04:06.379 only one but let's just say this cell right here 00:04:06.379 --> 00:04:10.280 from the pertainment is receiving an axon and 00:04:10.280 --> 00:04:13.900 this spine is receiving an axon from a cell right 00:04:13.900 --> 00:04:19.709 here and sending down to the containment, okay? 00:04:20.670 --> 00:04:24.889 The instructions from this cell can't execute 00:04:24.889 --> 00:04:28.730 the motor function. So that's why the basal ganglia 00:04:28.730 --> 00:04:32.629 is recruited. Remember, all of our actions or 00:04:32.629 --> 00:04:34.829 movements are orchestrated through the basal 00:04:34.829 --> 00:04:38.250 ganglia, except for the reflexes. So this information 00:04:38.250 --> 00:04:42.430 coming down, each synapsis, each synaptic connection 00:04:42.430 --> 00:04:45.689 is building a little summary. and then it's overall 00:04:45.689 --> 00:04:48.250 building a story. All of these connections are 00:04:48.250 --> 00:04:51.490 coming together. All of these inputs, these neural 00:04:51.490 --> 00:04:54.509 correlates are coming together to form a story 00:04:54.509 --> 00:04:57.649 that's very specific to the living organism. 00:04:57.850 --> 00:05:01.490 So this cell here that's sending an axon down 00:05:01.490 --> 00:05:05.889 is just carrying information. It cannot execute 00:05:05.889 --> 00:05:08.990 the function, the motor movement, the action. 00:05:10.269 --> 00:05:13.189 But this cell right here is saying flip the light 00:05:13.189 --> 00:05:16.490 switch. Flip the light switch flip the light 00:05:16.490 --> 00:05:19.730 switch flip the light switch. It can't flip the 00:05:19.730 --> 00:05:23.129 light switch So it has to recruit the basal ganglia 00:05:23.129 --> 00:05:26.410 here. So let's just say a specific cell here 00:05:26.410 --> 00:05:30.129 in the containment let's just say it's this one 00:05:30.129 --> 00:05:34.310 and Let's just say this spine Specifically is 00:05:34.310 --> 00:05:37.290 the one that receives the information to flip 00:05:37.290 --> 00:05:41.689 the light switch flip the light switch so this 00:05:41.689 --> 00:05:45.930 connection This spine from this cell will say, 00:05:46.209 --> 00:05:48.389 OK, I can flip the light switch. It doesn't know 00:05:48.389 --> 00:05:50.509 any better. It's just responding to the information 00:05:50.509 --> 00:05:53.949 coming down. So it executes the light switch. 00:05:54.050 --> 00:05:58.889 It will orchestrate this light switch. And it's 00:05:58.889 --> 00:06:01.629 all happening within these five subcortical regions. 00:06:03.269 --> 00:06:07.850 The no ghost side will suppress any other alternative 00:06:07.850 --> 00:06:13.360 function, action, movement. And this go -side 00:06:13.360 --> 00:06:16.699 flips the light switch and then turns it back 00:06:16.699 --> 00:06:21.139 on probably or off whatever the sequence is for 00:06:21.139 --> 00:06:25.579 the OCD to have satisfaction. Flip the light 00:06:25.579 --> 00:06:28.740 switch again. Flip the light switch. Flip the 00:06:28.740 --> 00:06:32.339 light switch. This is all happening in the basal 00:06:32.339 --> 00:06:37.000 ganglia and this connection saying flip the light 00:06:37.000 --> 00:06:44.569 switch is strong in OCD. So this input area that 00:06:44.569 --> 00:06:48.529 is happening right here from this cell will say, 00:06:48.850 --> 00:06:50.610 okay, I need to flip the light switch. It doesn't 00:06:50.610 --> 00:06:53.649 know any better. It doesn't care. These things 00:06:53.649 --> 00:06:59.689 are dumb. It has no value. Value is coming outside 00:06:59.689 --> 00:07:03.310 of that. Things like this dopamine, yeah, it 00:07:03.310 --> 00:07:07.189 helps carry value and the ACC and so forth, which 00:07:07.189 --> 00:07:12.129 is here, you know, there's There's various functions 00:07:12.129 --> 00:07:16.389 here that are providing intact or inputs as well 00:07:16.389 --> 00:07:19.769 Context just say okay, that's valuable. Let's 00:07:19.769 --> 00:07:23.930 do that But with OCD there's this hijacked that 00:07:23.930 --> 00:07:27.750 cortical striatal thalamic loop So this is a 00:07:27.750 --> 00:07:30.889 good way of thinking about how powerful the basal 00:07:30.889 --> 00:07:34.189 ganglia are and these five subcortical areas 00:07:34.189 --> 00:07:40.660 here these input areas They don't care They're 00:07:40.660 --> 00:07:43.740 just going to respond. This is how the brain 00:07:43.740 --> 00:07:46.779 in the central nervous system works. We just 00:07:46.779 --> 00:07:50.000 respond. We don't like to think about things.