MINI-RESEARCH PROJECT #3 "The Abstraction Challenge"
the Abstraction Challenge
The final task is to write 12 sentences. These sentences will comprise the abstract and therefore a summary of the scientific paper provided. (It is widely viewed that a sentence should not exceed 15-20 words, to retain readability). This is an exercise in disciplined scientific writing and also another opportunity to read the source scientific literature and to think about a specific scientific finding.
Your twelve sentences should be constructed as follows:
1 & 2 (the Introduction) : What is the topic? Introduce the
oad area, then the specific area. Have people failed to address this question before, is this a new perspective on an earlier question?
3 & 4 (the Problem) : What is the research question? These sentences should flow directly from sentences 1 and 2. These are often the hardest sentences when writing an abstract, and may need the most work, work hard on them until you have concise, precise and understandable questions.
5 & 6 (the Methodological Approach) : What design and methods were selected and used? This may end up being your longest sentence, remember abstract means a summary, you don’t need all of the methodological details, just explain how the experiment was done.
7 & 8 (the Results) : What were the major findings / What are the findings directly relevant to
9 & 10 (the Conclusions) : What can you conclude from the results. What do the results mean?
11 & 12 (the Implications) : Can you summarise the implications of the conclusions? What is the key impact of the research? What does it all mean? How might these findings be used in the future?
MINI-RESEARCH PROJECT #3 "The Abstraction Challenge"
the Abstraction Challenge
The final task is to write 12 sentences. These sentences will comprise the abstract and therefore a summary of the scientific paper provided. (It is widely viewed that a sentence should not exceed 15-20 words, to retain readability). This is an exercise in disciplined scientific writing and also another opportunity to read the source scientific literature and to think about a specific scientific finding.
Your twelve sentences should be constructed as follows:
1 & 2 (the Introduction) : What is the topic? Introduce the
oad area, then the specific area. Have people failed to address this question before, is this a new perspective on an earlier question?
3 & 4 (the Problem) : What is the research question? These sentences should flow directly from sentences 1 and 2. These are often the hardest sentences when writing an abstract, and may need the most work, work hard on them until you have concise, precise and understandable questions.
5 & 6 (the Methodological Approach) : What design and methods were selected and used? This may end up being your longest sentence, remember abstract means a summary, you don’t need all of the methodological details, just explain how the experiment was done.
7 & 8 (the Results) : What were the major findings / What are the findings directly relevant to
9 & 10 (the Conclusions) : What can you conclude from the results. What do the results mean?
11 & 12 (the Implications) : Can you summarise the implications of the conclusions? What is the key impact of the research? What does it all mean? How might these findings be used in the future?
1
Nerve Injury Alters Restraint-induced Activation of the Basolateral Amygdala
in Male Rats
School of Medical Sciences (Anatomy and Histology), Faculty of Medicine and Health, The
University of Sydney, NSW, Australia, 2037
Co
espondence:
Address: Brain and Mind Centre (M02G), 100 Mallet Street, Camperdown, NSW, Australia,
2050,
Key Words:
neuropathic pain; stress; emotion; c-Fos ; FosB ; ∆FosB ; Sprague-Dawley
3
A
eviations
CCI - chronic constriction injury of the right sciatic nerve
CTB - cholera toxin B
mPFC - medial prefrontal cortex
BLA – Basolateral amygdala
CeA – Central amygdala
MeA – Medial amygdala
PFA – 4% paraformaldehyde acetate-borate buffer
PBS – 0.1M phosphate buffered saline
NHS – 10% normal horse serum
DAB – 3, 3-diaminobenzidine tetrahydrochloride
CRF – Corticosterone releasing factor (CRF)
GR – Glucocorticoid receptor
LC – Locus coeruleus
NTS – Nucleus of the solitary tract
NAcc - Nucleus accumbens
vCA1 – Ventral CA1
SNI – spared nerve injury
4
Introduction
The amygdala is a crucial region of the
ain that integrates sensory and emotional
information and serves to coordinate our response to stress (LeDoux, XXXXXXXXXXSystematic
characterisation of the activation pattern of the
ain in response to different types of
stressors, including physical stressors, such as haemo
hage and immune challenges, or
psychological stressors, have shown the involvement of specific sub-nuclei of the amygdala
(Dayas et al., 2001a, Dayas et al., XXXXXXXXXXThese nuclei are particularly sensitive to activation
y stressors that contain a psychological/emotional component such as restraint (Dayas et
al., 2001b, Dayas et al., 1999), immobilisation (Ma and Morilak, 2005), forced swim (Cullinan
et al., 1995, Dayas et al., 2001b), social defeat (Chung et al., 1999, Nikulina et al., 2004)
and inescapable foot shock (Rosen et al., 1998).
These amygdala nuclei play crucial roles in the expression of pain behaviours and emotional
ehaviours in the chronic pain state. Following the induction of neuropathic pain, amygdala
nuclei undergo neuroplastic changes as well as enhanced stimulus-evoked activity that is
co
elated to the tactile allodynic responses (Ikeda et al., 2007, Goncalves and Dickenson,
2012). Further, bilateral ablation of amygdala nuclei prior to the induction of neuropathic
injury/pain abolishes the development of mechanical allodynia (Li et al., XXXXXXXXXXDisruptions
of the excitatory state of the amygdala neurons may facilitate the transition from the acute to
the chronic pain state (Usdin and Dimitrov, 2016), with numerous studies providing evidence
for significant changes in the activation of amygdala neurons following sciatic nerve injury
(Jiang et al., 2014), and inflammatory pain (Ji and Neugebauer, 2011, Ji et al., 2010) that
co
espond to changes in affective and cognitive behaviours. One of the major output targets
of the amygdala neurons is the medial prefrontal cortex (mPFC) (Kita and Kitai, 1990,
Ga
ott et al., XXXXXXXXXXThe amygdala to mPFC connections serve as an important pathway
for the regulation of cortical functions important for emotional and cognitive behaviours
(Sharp, 2017).
The general aims of the study were to investigate whether a peripheral nerve injury known
as the chronic constriction injury of the sciatic nerve (CCI), a model of neuropathic pain, can
alter the neuronal activation of the amygdala in response to an acute stress. We hypothesise
that (i) the amygdala neurons that respond to acute restraint stress will be differentially
activated by the induction of a neuropathic injury, and that (ii) neuropathic injury will sensitise
amygdala cells that project to the mPFC to an acute restraint stress.
5
Materials and Methods
Animals
Experimental procedures were performed on 61 out
ed male Sprague-Dawley rats
weighing 220-240g on a
ival (ARC, Perth, Australia). Rats were group housed (4/cage) and
were allowed to habituate to their new environment on a reverse dark-light cycle (12:12 hrs)
for 7 days with ad libitum access to food (standard laboratory chow) and water (tap water).
Environmental enrichment consisted of cardboard boxes and tubes, PVC piping, nesting
materials, paper tissues and towels, and novel food and seeds were offered 2-3 times per
week. All experimental procedures were ca
ied out with the approval of the Animal Care
and Ethics Committee of the University of Sydney and in accordance with the guidelines of
the Code for the Care and Use of Animals in Research Australia, and the Ethical Guidelines
for Investigation Association for the Study of Pain (Zimmermann, 1983).
Experimental Design
Following the seven-day habituation period, rats received a bilateral retrograde tracer
injection. Rats weighed approximately 250-300g at the time of surgery. Retrograde tracer
injections were followed by a seven-day post-operative recovery period. Following this
period, rats received either: (i) isoflurane anaesthesia only (Anaesthetised, n=19); (ii) sham
chronic constriction injury of the right sciatic nerve (Sham-injured, n=20); or (iii) chronic
constriction injury of the right sciatic nerve (CCI, n=22). Rats received no intervention for 11
days, with the only inte
uption during this time being related to general husbandry. On the
twelfth day post-CCI, rats received either an acute restraint stress for 15 minutes (n=34), or
identical handling procedures, but no restraint (n=27). Rats were perfused two hours after
the final acute restraint or handling procedures and were processed for Fos
immunoreactivity on three sub-nuclei of the amygdala; the medial amygdala (MeA), central
amygdala (CeA) and basolateral amygdala (BLA).
Retrograde Tracer Injections
Retrograde tracer injections were performed in 61 rats that were anaesthetised with an i.m.
injection of ketamine (40mg/kg) and xylazine (2.5mg/kg) before being placed in a stereotaxic
frame in the ‘flat-skull’ position. Under local anaesthesia (2% lignocaine) applied
subcutaneously, a midline incision was made in the scalp and the skin and muscles were
eflected to reveal the frontal and parietal bone. A small craniotomy was made ~3mm rostral
from
egma to reveal the dorsal surface of the frontal cortices.
6
A single ba
el glass micropipette was lowered 2.75mm from the dorsal surface of the frontal
cortex at an AP of +3.2mm from
egma and a laterality of 0.45mm left and right of the
midline (determined by the presence of the superior sagittal sinus). Fluorogold and cholera
toxin B (CTB) was delivered to the prelimbic cortex via iontophoresis (20min, 2s ON/ 2s
OFF, +5-10A) sequentially into the prelimbic cortex of each hemisphere. Each rat received
one tracer per hemisphere, and the hemispheres were counte
alanced across rats. This
was followed by a 10-minute period of no cu
ent to prevent the formation of dye tracks
eing left on the removal of the glass pipette.
Following the removal of the micropipette, the rat was removed from the stereotaxic frame,
the craniotomy was sealed with gel foam to increase blood clotting, the scalp was sutured
closed and topical antibiotic powder was applied. Each animal subsequently received 2.0ml
saline i.p. before being placed in a temperature regulated recovery cage. Once rats were
ambulatory, eating and drinking, they were returned to their home cage.
Chronic Constriction Injury Surgery
Anaesthesia was induced using isoflurane anaesthesia (5% in 100% oxygen), delivered via
an airtight induction chamber, anaesthesia was maintained at 2-3% isoflurane in 100%
oxygen via a custom-made facemask for a period of approximately 20 minutes. As described
y Bennett and Xie XXXXXXXXXXunder isoflurane anaesthesia, the right sciatic nerve was exposed
via blunt dissection through the biceps femoris muscle and four chromic gut ligatures