Experiment Design Report: Basal Ganglia Involvement in Dyskinesia

This report details an experiment designed to investigate the involvement of the basal ganglia domains (limbic, associative, and sensorimotor) in L-dopa induced dyskinesia, a significant complication of Parkinson's disease treatment. The study employs 2-deoxyglucose (2-DG) uptake to measure metabolic activity in various brain regions of monkeys, including the globus pallidus, subthalamic nucleus, and thalamic nuclei. The experiment aims to determine if modulation within the basal ganglia loops alters the output in other loops. The methods involve administering L-dopa to monkeys, inducing dyskinesia in some, and then using 2-DG to assess metabolic changes in different brain areas. The results indicate that neural mechanisms related to dyskinesia may involve associative and limbic domains, but not the sensorimotor domain. The findings suggest a link between dyskinesia and pathological metabolic activity in associative and limbic structures, potentially expanding the understanding of dyskinesia beyond a mere movement disorder to include motivational, affective, and cognitive aspects. The report discusses the advantages and limitations of the experiment design, along with a comparison of the findings to previous research, and highlights the need for further research to establish causal relationships. The report concludes by emphasizing the importance of considering the continuous flow of information between the limbic, associative, and sensorimotor domains in the context of dyskinesia.

Running head: EXPERIMENT DESEGN 1
Experiment Design
Student’s Name
University Affiliation

EXPERIMENT DESIGN 2
Involvement of the Basal Ganglia Domains (Limbic, Associative and Sensorimotor) In
Induced Dyskinesia
Introduction
The management of Parkinson’s illness people with a dopamine precursor like the L-
dopa boosts the growth of severe changes in motor response as well as involuntary movements
referred to as L-dopa induced dyskinesia, a serious complication of L-dopa therapy associated
with Parkinson’s ailment. The true nature of such manifestations can result to experiments
concerning the abnormalities of neural function especially in the corticobasal ganglia motor
circuit. However, since the modern theory regarding the arrangement of basal ganglia pathways
suggests that both the basal ganglia plus the frontal cortex are put in segregated circuits that are
parallel, there is a tremendous proof showing the consistence for associative, limbic and
sensorimotor domains (Le Jeune et al., 2008).
Ideally, research shows that the motor components of a sub thalamic nucleus as well as
the dorso lateral tip have a usual terminal activity at the chorea which is of signifance in
dystonia. On the other hand, the metabolic activity of the limbic and associative sub thalamic
nucleus is impaired in both scenarios. However, the result initially showed that there exists a
pathophysiological disparity between dystonia and the L-dopa induced chorea. According to Le
Jeune et al., (2008), it can now be hypothesized that can also reflect the association of opposite
pathways in a lopa induced dyskinesia hence increasing the likelihood that it as well relates to
the unusual processing of the either associative or limbic information.
Hence the rationale of this paper is to design an experiment that identifies if or not the
modulation of a loop in the basal ganglia can alter the output in other loops in the systematic

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fashion. The write up also looks at the changes in the 2DG accumulation in associative,
sensorimotor plus the limbic domains of the basal ganglia and thalamic nuclei of groups that are
not primate.
Materials and Methods Used In the Experiment
Nineteen female monkeys were put in separate primate rooms under controlled
conditions of light, temperature and humidity. Both food as well as water was provided and
animal care was being ensured by a registered veterinarian. The experiment was conducted in
respect to the European community’s council directive of September for proper care of
laboratory animals.
For the experiment protocol, the demographic property showed that every methyl phenyl
treated animals monkeys showed a comparable phase of lesion as well as different behaviours.
Both the control plus the methyl phenyl treated animals corresponds to those animals in the D25
and D0 groups while dsykinetic plus the nondyskinetic species originated from a population of
those animals validated earlier. For the later animals, they were created administration of L-dopa
twice a day for up to eight months at a modified dose made to give complete reversal of
Parkinson’s condition. The animals that contracted serious and reproducible dyskinesia were five
while four did not.
Regarding the behavioural evaluation, the parkinsonian condition was determined on an
animal rating scale using video tape recordings of the animals. After the evaluated a score of
zero represented a normal monkey while the score of six and above represented the parkinsonian
animal. However, the degree of dyskinesia was measured by use of a dyskinesia disability scale
abbreviated as DDS. Zero meant dyskinesia was absent; one meant the condition was mild with

EXPERIMENT DESIGN 4
rare dyskinetic movements as well as postures. A scale of two mean moderate with outstanding
unusual movements and not interfering greatly with the usual behaviour. Three marked regular
and sometimes continuous dyskinesia entering via the normal repertoire of activity. A scale of
four represented severe continuous dyskinetic activity rendering the animal disabled as well as
replacing the actual behaviour (Kirch et al., 2013).
2-DG Procedure
During the event the monkeys were killed, they were injected with 2DG deoxy glucose
which was sterile saline. After almost one hour, all the monkeys were killed by a pentobarbital
overdose , while the L-dopa treated monkeys got their modified dose of L-dopa a quarter an hour
prior to the introduction of 2DG. Their brains were removed and stored in a chemical substance
to freeze. The inner tissues were cut into pieces of 20 micrometres where they were thaw
mounted onto slides containing gelatine substance. After they were freeze dried, the auto
radiographic methyl methacrylate standards plus the serial sections were put to hpyerfilm for
sixty days at a temperature of 30 degrees Celsius. After two months, densitometry analysis of
autoradiograph was done by means of an image analysis method. Each animal was analysed
according to four sections per nucleus by an examiner in respect to the radioactivity levels found
in contrast with the standards. Later on, the SEM plus the mean bound radioactivity were
subsequently found for every group.
Statistical analysis
For different comparisons of information, a one-way ANOVA table was employed to
check for the general significance followed by a t test for different comparisons. For the

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behavioural assessment of different comparisons, the kruskal Wallis non parametric test was
employed to test the entire significance followed by a t test corrected by different comparisons
via Dunn’s technique. The data were normally distributed plus the significance level of the t test
attuned for inequality of measures dispersion like variance if appropriate. Lastly, the analysis
was completed using a strata program where a p< 0.05 was taken to be significant.
Results
The 2 deoxy glucose uptake was measured with associative, limbic plus sensorimotor
domains of basal ganglia as well as in other target groups of such domains. In that aspect, the
outer part of the globus pallidus was classified into three territories namely the associative,
sensorimotor and limbic as mentioned earlier. The sub thalamic nucleus was split into
associative-limbic and sensorimotor domains. The accumulation of the 2DG was calculated as a
whole in the inner parts of globus pallidus as well as in the substantial migra reticulate. There are
two outputs of the ganglia due to the continuous overlap between the domains in the nuclei.
Ideally, three nuclei were observed in the thalamus. Both the ventral lateral nuclei plus the
ventral anterior are known to be thalamic targets of motor loop. The ventral anterior was
measured on tiny sections of four millimetres anterior to the anterior commisura where the sub
thalamic nucleus is absent and the central lateral was measured according to sections of six
millimetres to anterior commisura where the sub thalamic nucleus is present. However, a
mediodorsal nucleus is referred to as the thalamic output of the associative loop of the BG
commonly known as basal ganglia. However, the nucleus of the terminus of the stria was
considered to be the limbic output of the basal ganglia.

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Advantages of the Designed Experiment
 The experiment design is simple and can be applied in different disciplines.
 The research designs are repeatable hence results can be rechecked as well as
verified.
 The researcher can tailor the experiment as well as maintain validity of the design
Limitations of the Experiment Design
 It was not possible to control the extraneous variable
 The results obtained in the experiment may not be generalised to a larger
population.
 The reaction of the test subjects cannot be true indicators.
 Human errors can also play a key role in validity of the subjects.
 The reaction of the test subjects cannot be true indicators of behaviour in non-
experimental environments.
In the whole domains of the globus pallidus, 2 deoxy glucose was relatively higher in
parkisonian monkeys than the normal monkeys. Both the dyskinetic as well as nondsykinetic
animals showed normalised levels of 2 deoxy glucose accumulation in the globus pallidus
sensorimotor and limbic. Also, those dyskinetic showed a reduced 2 deoxy glucose uptake in the
globus pallidus associative contrary to the methyl phenyl treated as well as non dsykinetic
organisms. The 2 deoxy glucose in the two domains were defined in the ST nucleus. Those
animals treated with methyl phenyl showed a tremendous decline in 2 deoxy glucose
accumulation in the limbic and sensiromotor domains. However, the L- dopa treatments led to a

EXPERIMENT DESIGN 7
raise in the 2 deoxy glucose levels in the nondsykinetic as well as the nondsykinetic groups.
Also, there was no significance group noted within the control groups.
The afore mentioned results shows that while nondsykinetic animals presented
normalised metabolic activity compared to the control groups dsykinetic organism were
distinguished by a tremendous shifts in the 2 deoxy glucose accumulation in associative plus
limbic linked structures but not by sensorimotor nuclei (Kirch et al., 2013). The results were
obtained from all the animals and those that had died half an hour following L-dopa
administration. During this period the D5 parkinsonian symptoms were developed and none of
the LID was noted. Instead, LID erupted in the 45th minute onwards in the dsykinetic group and
since data obtained from one group is not enough for statistical analysis, a qualitative analysis
would provide more insights. Following half an hour after dopamine was administered, 2 deoxy
glucose levels in motor nuclei were similar to the nondsykinetic and dsykinetic organisms at an
hour after L-dopa was administered.
Discussion
The primary finding of this experiment is that neural mechanism accountable for LID
expressions may too involve associative plus limbic domains but not the sensorimotor domain.
Besides, qualitative temporal analysis supports such aspect since in the dsykinetic organism
killed when parkiansonian motor abnormalities were developed and prior to the appearance of
LID (Kravitz et al., 2010). Therefore, it can be argued that dsykinesia is associated with the
pathological metabolic movement in the associative limbic nuclei. The later should not be
considered as a movement disorder but also as entailing motivational , affective as well as
cognitive aspects of an individual behaviour which been investigated partially in the clinic.

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The pattern of changes of 2 deoxyglucose accumulation in this experiment matches the
original findings from other scholars. For instance, it can be conformed the differential metabolic
activity between the components of the ST nucleus and the dorso lateral tip in dsykinetic and
nondsykinetic organisms (Sebastianutto et al., 2017). Also, the metabolic activity of basal
ganglia motor related structure was not affected in any way in the dsykinetic organism compared
to the nondsykinetic. However increased 2 deoxy glucose intake in the GPI must conform to the
increased GABAergic tone emanating from the striatum and also from the GPe. According to
Kravitz et al., (2010), the reduced 2 deoxy glucose accumulation in the MD of dsykinetic
organisms would therefore be the signature impairment of the whole circuit. Since the present
study only presents a contaminant variation, it does not at any given moment create a causative
connection that remains to be demonstrated directly.
Since basal ganglia pathways are considered to be arranged parallel in segregated circuits there is
proof showing the continuous funnelling information between the limbic, associative and
sensorimotor domains. The same concept was further developed by different scholars by
postulating that the same information is continuously by diverse functional domains of basal
ganglia via the certain pathways of functional interaction via the basal ganglia circuits. This
hypothesis has received lots of accolade from the demonstration that cocaine self-administration
produces a continuous involvement sensorimotor, limbic and associative domains. However,
chronic L-dopa treatment as well as cocaine administration lead to raised dopamine levels within
the striatum can lead to continuous dissemination of information rather than focused processing
(Kirch et al., 2013). However, in this write up evidence for comparable mechanisms is being
provided but not in the same order that is sensorimotor, followed by limbic land lastly is
associative domain.

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Together with clinical observations reporting reward deficiency syndrome or the learning
deficits in the L-dopa treated persons, it can be postulated that dsykinesia needs no to be seen as
a movement disorder, but also as a motivational, affective as well as cognitive disorder. Since the
qualitative temporary analysis shows that causative duty of involvement of limbic plus
associative nuclei and the direct electrophysiological are mandatory when it comes to the
establishment of casual; relationships. Ideally, a shift in the 2 deoxy glucose uptake does not
show alteration in firing activity of neurons but shows the integration of shifts during the 45th
minute in the entire phase of intrinsic synaptic activity. Moreover, a significant result of this
experiment is that LID cannot be continued to being analysed via investigating the motor areas
thus rendering unreliable each and every other study that does not pay close attention to the
functional organisation of the ganglia loops (Le Jeune et al., 2008). Viewing LID is caused as a
result of unwanted involvement of limbic as well as associative aspects or as having the or by
having limbic and cognitive abnormalities counterparts of LID as is regularly reported by the
hyperkinetic complications. For example, say the electrophysiological investigations conforms to
the causative hypothesis , modulating the activity of non-motor areas would drastically lower
severity of LID , hence offering new drug targets for treatment of the same condition.

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Kravitz, A. V., Freeze, B. S., Parker, P. R., Kay, K., Thwin, M. T., Deisseroth, K., & Kreitzer, A.
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Sebastianutto, I., Cenci, M. A., & Fieblinger, T. (2017). Alterations of striatal indirect pathway
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