Download The Role of the Basal Ganglia in Habit Formation

The Role of the Basal Ganglia in Habit
Formation
Week 10
Group 1
Amanda Ayoub
Kindra Akridge
Barbara Kim
Alyona Koneva
Explain the difference between a goal directed
action and a habit, and provide a couple of your
own examples of each
•
•
•
A goal directed behavior is
when you are doing
something for a result
A habit is done without
regard for the consequence
but done as a reflex
Nail biting, smoking,
brushing teeth, etc
2.What is meant in the article by “levels of analysis” and how
will it shape this article?
• The Levels of Analysis are the different levels
at which we examine the application of
intentional actions.
• These levels include: molecular, cellular,
neuronal circuitry, brain structures, and
behaviors.
• This type of analysis specifically looks for the
circuitry and structures that allows behavior to
be intentional, purposeful, and to exude a
specific outcome.
• These levels also shape this article because
they allow us to examine the neural basis of
intentional action/habit formation, instead of
interpreting all behavior through the viewpoint
of a certain S-R (stimulus-response)
3. Show us the Basal Ganglia, and discuss
neurotransmitters and their functions …
3. Show us the Basal Ganglia, and discuss
neurotransmitters and their functions …
The following diagrams show 2 coronal slices that have
been superimposed to include the involved basal ganglia
structures.
Inhibitory GABAcontaining projection
neurons
Dopaminergic
pathway leads to
GABAergic (disinhibitory) direct
pathway
3. Show us…The main components of the basal
ganglia are the striatum, which consist of the caudate
nucleus and the putamen, and the globus pallidus.
• The largest component, the
striatum, receives input from
many brain areas but sends
output only to other components
of the basal ganglia.
• The pallidum receives its most
important input from the striatum
(either directly or indirectly), and
sends inhibitory output to a
number of motor-related areas,
including the part of the
thalamus that projects to the
motor-related areas of the
cortex.
Striatum
Pallidum
(inside)
4. Show us the kinds of cells in the
Basal Ganglia and their
behavior….
• (A) shows an aspiny neuron
which belongs to the pallidum
or the output nucleus.
• (B) shows a spiny neuron spiny neurons are found in
the striatum or the input
nucleus.
5. …and connections of the Basal Ganglia
with other brain regions…
• The striatum is the major
input nucleus of the BG
and receives massive input
from most of the cortex and
the intralaminar areas of
the thalamus
• Output to both segments of
the globuspallidus(GP) &
the substantianigra pars
reticulata(SNr)
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.
•
•
•
outcome and
antecedal
The
disinhibitory
pathway is the
most basic
direct pathway
The indirect
pathway:
inhibitory
control.
What is instrumental behavior?
•
Instrumental behavior occurs
whenever an outcome is
contingent on a response.
Instrumental behaviors
differs from reflexes and fixed
action patterns, which are not
controlled by the contingency
between behavior and its
consequences.
•
Lesions to the basal ganglia (particularly the
striatum) disrupt “instrumentality” of actions.
Animals that were tested could no longer perform or
acquire actions in order to earn specific rewards or
avoid aversive stimuli.
What’s the point of
running the maze
anyways?
8. What impact did early theories about instrumental learning
have on discovering the nature of basal ganglia function?
• Previously, the dominant paradigm was S-R: all behavior was
elicited by some antecedent stimuli from the external
environment. Intentionality, expectancy and internal
representation were considered “unscientific.”
• This paradigm dismissed the obvious option that behavior can
be goal directed. It limited the thinking about behavior for a
long time. Basically, it prevented the questions from even
being asked.
• So, the dominant paradigm slowed the discovery of a model
for intentional behavior by understanding the functions of the
basal ganglia.