Questions on: The Role of the Basal Ganglia in Habit Formation
Instructions
Please use blue for factual answers to the questions and green for your thoughts and
reflections in response to the questions both for headings and text. One way to spur
such thinking is to ask “why is this important?” or “how does this relate to something
else I have read in or out of this class?” or “how does this relate to something I have
observed in life?” but you can also respond in any other way. Please include the
Figures from the articles where appropriate.
We have covered now the frontal lobes (at least in part), sensory processing (vision, the
most studied example of perception), the emotional brain, and the development of the
brain through critical periods with infant-mother attachment being the primary example.
By the time we finish the course, we will have surveyed the most important systems that
contribute to our psychological functioning. If we had a few more weeks, I would also
add the cerebellum, brain laterality (left and right hemisphere specialization), plasticity,
and various pathologies to make a fairly complete picture, but semesters are slightly too
short.
Continuing out examination of the major components of brain function, we now turn to
the basal ganglia and how our behavior is controlled by both habit and goal-seeking.
How the basal ganglia interact with the thalamus and cortex is at the heart of how the
brain as a whole controls our behavior and action. You already understand how the
frontal lobes control conscious goal-seeking behaviors. But we need to be able to
interact with the world without deliberating every small action. Indeed, simpler animals
don’t have the deliberative powers that we do, yet still navigate the world pretty well.
How that happens will be clearer after you have read this weeks’ article.
These are used without much explanation so I will explain them here.
1. Lateral inhibition: When you perceive something, the thing perceived could be a
square or a circle, red or green, and so on. Groups of neurons compete to “win:”
to become the final representation of what is perceived, e.g., a red circle and not
a green circle, green square, or red square. The square neurons have inhibitory
connections to the circle neurons and vice-versa. The same is true with the
groups for red and green. Thus, the circle group tries to turn off the square group.
The more information from the eyes feeding into the circle group, the more the
circle group starts winning, and the stronger it inhibits the square group. Finally,
circle group wins, completely inhibiting square group. Same happens with color.
Lateral inhibition is used in many brain structures and functions, it is
fundamental. There are good explanations of lateral inhibition on Youtube, such
as this explanation of edge enhancement in vision:
http://www.youtube.com/watch?v=sItlLNhhiLg
2. Hippocampus and place: The hippocampus was long believed to form maps of
the environment called cognitive maps. When a mouse passes a point in a maze,
a certain hippocampus cell fires. There are cells for each place in the maze. We
now know that hippocampus serves other purposes as you’ll see with the last
article, but its role in learning and representing place maps is dominant. As you
can imagine, knowing “where one is” is one of the most important cognitive
representations for an animal to learn. Different colors represent different
hippocampal cells in this video:
http://www.youtube.com/watch?v=lfNVv0A8QvI
(optional) Why is the dark blue neuron’s trail at the first curve longer than the
following green neuron’s trail? At what points is the mouse looking (or trying to
look) across at another part of the maze? When is a cell responding to the place
the mouse is at, and when is one responding to a larger picture of the maze?
Medial temporal lobe is where hippocampus and its surrounding entorhinal cortex
is located. References to medial temporal lobe usually involve hippocampal
function, which also depends on its surrounding entorhinal cortex.
Note: learning about place is explicit. We are aware of our knowledge of place.
There are circuits of connections going both ways between cortex and BG, and there
are others between thalamus and cortex. It is not agreed on just what these do, or the
nature of how corticostriatal circuits and corticothalamic circuits interact. Here is one
diagram just to give you the flavor of such circuits.
Group 1
1. Explain the difference between a goal directed action and a habit, and provide a
couple of your own examples of each (not the light switch).
2. What is meant in the article by “levels of analysis” and how will it shape this
article?
3. Show us the BG, and discuss neurotransmitters and their functions …multiple
pictures will help because the BG are hard to visualize from a 2D picture (I
have provided some good links at the end for you to pick from, don’t use them
all)…..
4. …and kinds of cells in the BG and their behavior….
5. …and connections of the BG with other brain regions…
6. It seems like the basal ganglia do two things, one involving steps using inhibition
and (tonic) excitation to cause actions to happen, and one that inhibits
actions. Explain (with diagrams).
7. What is instrumental behavior?
8. What impact did early theories about instrumental learning have on discovering
the nature of basal ganglia function?
Group 2
9. If behavior was dominated in the past by Hull’s S-R-reinforement paradigm, what
paradigm is it dominated by today?
10. Explain the two important contributors to behavior: the remembered value of the
expected outcome, and the knowledge of the causal relationship between the
action and the outcome.
11. Explain the experimental paradigms used to study these two psychological
functions.
12. What are the A–O system and the S–R system?
13. What is habit formation?
14. What are interval and ratio schedules and how do they relate to research on
understanding BG function?
Group 3
15. Discuss the relationship of BG and hippocampus to place and response
strategies.
16. How does performance learning in different tasks tell us something about the
different functions of the two learning systems? Are the two systems always
operating in a mutually exclusive way?
17. What evidence suggests that the picture of BG function in learning is more
complex than simple habit formation? How does “habit formation” fail to
describe this function?
18. Use some diagrams to make clear the anatomy discussed here: “The caudate in
primates is part of the ‘associative striatum’, which receives inputs from
association cortices. It corresponds to the dorsomedial striatum (DMS) in
rodents, whereas the putamen is part of the sensorimotor striatum,
corresponding to the dorsolateral striatum (DLS) in rodents.”
19. Discuss physical and functional differences between DLS and DMS systems.
20. Explain this statement: ” It appears that because their habit system was disrupted
by the lesion, the alternative A–O system assumed control over behaviour.
However, a similar effect was not observed in rats with DMS lesions. “
Group 4
21. What happens with pDMS lesions, and what does this show us?
22. Do you think there are times when information represented by activity in
hippocampal place cells is being compared to activity in BG goal
representation cells? Why is it?
23. What did Baleine et al. show about how PFC plays a role in learning?
24. The authors of this article propose a model of learning in basal ganglia and
cortex. In their model, what is a cortico-basal ganglia network?
25. What is wrong with this assertion: “For instance, it is often asserted that the
neocortex mediates a particular function, whereas the striatum subserves
another?”
26. Explain in what circumstances the associative network and the sensorimotor
network are in control of behavior.
[ don’t use the section on Potential mechanisms for serial adaptation to
answer any questions…it’s very abstract and speculative and depends on a
lot of previous knowledge ]
27. Pavlovian conditioning involves associating a conditioned stimulus (CS, the bell)
with a conditioned response (CR, salivating to the bell). It can explain and
predict addictive behavior. One way is that context cues (the place drugs are
taken) become CSs which connect with the CR (drug taking when around this
place). This is like responses elicited by a stimulus (not a goal) as discussed
earlier. This can interact with instrumental behavior, or behavior based on
intention to achieve a goal, as discussed earlier, because it reinforces it. A
transfer from Pavlovian stimulus-caused behavior to instrumental behavior
can happen with long exposure to the conditioned stimulus (CS) such as
when an addict is often around the place they take drugs for long periods and
takes drugs as a result. So the CS can get more strongly connected with
instrumental, goal-directed behavior such as seeking or taking drugs. These
connections may underlie addiction and the Pavlovian side of this may be
why effortful control of our instrumental behavior so often fails.
In this light, explain the findings discussed in the last paragraph before the
conclusions.
Basal Ganglia Diagrams
http://www.google.com/imgres?hl=en&client=firefoxa&hs=myN&sa=X&rls=org.mozilla:enUS:official&biw=2689&bih=1652&tbm=isch&prmd=imvns&tbnid=2vE1UwHPR
CWrSM:&imgrefurl=http://brainmind.com/BasalGanglia.html&docid=1n4EBHV
AJOiC0M&imgurl=http://brainmind.com/images/basalganglia21.jpg&w=548&h
=561&ei=2T93T8TxLo2HsALb8MygBA&zoom=1&iact=rc&dur=196&sig=1045
80850644787004754&page=1&tbnh=94&tbnw=93&start=0&ndsp=190&ved=
1t:429,r:3,s:0&tx=53&ty=46
http://drugster.info/img/ail/1383_1393_3.jpg
http://drugster.info/img/ail/1383_1393_2.gif
http://www.google.com/imgres?hl=en&client=firefoxa&hs=myN&sa=X&rls=org.mozilla:enUS:official&biw=2689&bih=1652&tbm=isch&prmd=imvns&tbnid=AbFj3_INvhY
vdM:&imgrefurl=http://scienceblogs.com/purepedantry/2006/12/brain_stimulat
ion_is_an_effect.php&docid=dMst2f4s8UFXfM&imgurl=http://scienceblogs.co
m/purepedantry/upload/2006/12/basalganglia.jpg&w=360&h=364&ei=2T93T8TxLo2HsALb8MygBA&zoom=1&iact=
hc&vpx=1102&vpy=149&dur=241&hovh=226&hovw=223&tx=120&ty=117&si
g=104580850644787004754&page=1&tbnh=94&tbnw=93&start=0&ndsp=190
&ved=1t:429,r:8,s:0
http://www.google.com/imgres?hl=en&client=firefoxa&hs=myN&sa=X&rls=org.mozilla:enUS:official&biw=2689&bih=1652&tbm=isch&prmd=imvns&tbnid=06tm2A6sE1i
phM:&imgrefurl=http://www.benbest.com/science/anatmind/anatmd2.html&do
cid=he2w2VKgcCYWsM&imgurl=http://www.benbest.com/science/anatmind/F
igII9.gif&w=653&h=583&ei=2T93T8TxLo2HsALb8MygBA&zoom=1&iact=rc&d
ur=206&sig=104580850644787004754&page=1&tbnh=94&tbnw=105&start=0
&ndsp=190&ved=1t:429,r:10,s:0&tx=47&ty=33
http://www.google.com/imgres?hl=en&client=firefoxa&hs=myN&sa=X&rls=org.mozilla:enUS:official&biw=2689&bih=1652&tbm=isch&prmd=imvns&tbnid=LFZZ7SZm4
dWzCM:&imgrefurl=http://www.sciencephoto.com/media/133795/enlarge&doc
id=TPwlwQb4YfcPMM&imgurl=http://www.sciencephoto.com/image/133795/l
arge/C0070796-Basal_ganglia,_artwork-
SPL.jpg&w=530&h=530&ei=2T93T8TxLo2HsALb8MygBA&zoom=1&iact=rc&
dur=15&sig=104580850644787004754&page=1&tbnh=94&tbnw=96&start=0
&ndsp=190&ved=1t:429,r:11,s:0&tx=32&ty=33
http://www.google.com/imgres?hl=en&client=firefoxa&hs=myN&sa=X&rls=org.mozilla:enUS:official&biw=2689&bih=1652&tbm=isch&prmd=imvns&tbnid=qqqXPuaf7KR3M:&imgrefurl=http://www.benbest.com/science/anatmind/anatmd2
.html&docid=he2w2VKgcCYWsM&imgurl=http://www.benbest.com/science/a
natmind/FigII10.gif&w=543&h=663&ei=2T93T8TxLo2HsALb8MygBA&zoom=
1&iact=hc&vpx=1688&vpy=138&dur=130&hovh=248&hovw=203&tx=111&ty=
124&sig=104580850644787004754&page=1&tbnh=94&tbnw=81&start=0&nd
sp=190&ved=1t:429,r:13,s:0
http://www.google.com/imgres?hl=en&client=firefoxa&hs=myN&sa=X&rls=org.mozilla:enUS:official&biw=2689&bih=1652&tbm=isch&prmd=imvns&tbnid=S4kKkAkIQb
cIpM:&imgrefurl=http://homepage.ntlworld.com/teversal/myweb/CNS/basal_n
uclei.htm&docid=MEblSg3NInf7tM&imgurl=http://homepage.ntlworld.com/teve
rsal/myweb/CNS/Images/basal_ganglia1.jpg&w=640&h=480&ei=2T93T8TxLo
2HsALb8MygBA&zoom=1&iact=rc&dur=103&sig=104580850644787004754&
page=1&tbnh=94&tbnw=127&start=0&ndsp=190&ved=1t:429,r:15,s:0&tx=106
&ty=32
http://www.google.com/imgres?hl=en&client=firefoxa&hs=myN&sa=X&rls=org.mozilla:enUS:official&biw=2689&bih=1652&tbm=isch&prmd=imvns&tbnid=0lvjvAwhlISo
QM:&imgrefurl=http://brainmind.com/BasalGanglia.html&docid=1n4EBHVAJO
iC0M&imgurl=http://brainmind.com/images/basalGanglia82.jpg&w=514&h=47
2&ei=2T93T8TxLo2HsALb8MygBA&zoom=1&iact=rc&dur=239&sig=1045808
50644787004754&page=1&tbnh=94&tbnw=102&start=0&ndsp=190&ved=1t:
429,r:19,s:0&tx=42&ty=38
http://www.google.com/imgres?hl=en&client=firefoxa&hs=myN&sa=X&rls=org.mozilla:enUS:official&biw=2689&bih=1652&tbm=isch&prmd=imvns&tbnid=kNmlWJvwJy
IXM:&imgrefurl=http://www.holisticonline.com/remedies/parkinson/pd_brain.ht
m&docid=GRWidgFZEEqrcM&imgurl=http://www.holisticonline.com/images/P
D-ama-
schematic1.GIF&w=504&h=564&ei=2T93T8TxLo2HsALb8MygBA&zoom=1&i
act=rc&dur=227&sig=104580850644787004754&page=1&tbnh=93&tbnw=83
&start=0&ndsp=190&ved=1t:429,r:41,s:0&tx=67&ty=40
Cortico-striatal circuit diagrams (just for your information….the nature of these
circuits is not settled:
http://www.google.com/imgres?um=1&hl=en&client=firefoxa&sa=N&rls=org.mozilla:enUS:official&biw=2689&bih=1652&tbm=isch&tbnid=iu3RA_R2lnU47M:&imgrefurl=
http://en.wikipedia.org/wiki/Striatum&docid=Iof7O7xOItqGM&imgurl=http://upload.wikimedia.org/wikipedia/commons/thumb/9/9
e/Basal_ganglia_circuits.svg/360pxBasal_ganglia_circuits.svg.png&w=360&h=518&ei=5m53T86CB9DJiQKY88mnD
g&zoom=1&iact=hc&vpx=281&vpy=110&dur=722&hovh=114&hovw=79&tx=92&t
y=149&sig=104580850644787004754&page=1&tbnh=114&tbnw=79&start=0&nd
sp=199&ved=1t:429,r:1,s:0
http://www.nature.com/nrn/journal/v6/n10/fig_tab/nrn1764_F5.html#figure-title