Videnskabsteori, -kommunikation og etik (SMAC) fall 2008 · Videnskabsteori, -kommunikation og etik (SMAC) fall 2008. Course Plan

• Course teachers

Ole K Andersen, dr scient ([email protected])

Patrik Kjærsdam Telleus (theory of science)

• Course secretary

Jette Damkjær (common secretary for 1st semester M.Sc., [email protected])

Vita Kammersgaard ([email protected])

• Course literature (OKA part)

– Leedy & Ormrod. Practical Research: Planning and Design, 8th edition. Merrill, Prentice Hall, 2004.

– Overheads: Available after each lecture

– Course homepage

www.hst.aau.dk/~oka/SMAC

Videnskabsteori, -kommunikation og

etik

(SMAC) fall 2008

Course Plan

• Lecture 1 Introduction to the SMAC course, research hypothesis

• Lecture 2 Scientific methods in science and engineering (OKA)

• Lecture 3 Theory (and history) of science – only S-SN students (PKT)


• Lecture 5 Ethics in science, with emphasis on biomedical sciences (OKA)



• Lecture 8 Scientific communication, examples on oral presentation

and poster presentation. Details on SEMCON (OKA)

See homepage!

PKT, Patrik Kjærsdam Telleus

SMAC last lecture:

Preparing the research report

• General principles

• Different means with different purposes

• A note on style

– SEMCON format

• Illustrative examples

Research Island

• Dissemination

– Public

– Scientific community

– make you famous - and facilitate continuous funding

21th SEMCON 19.12.2008

(semester conference)

Presentation of semester projects within a scientific framework

• First announcement: 12.09.2008

– Planning research paper

– Allocation of time and space

• Second (final) announcement: 21.11.2008

– Specific guidelines for abstracts, posters and oral presentations

– Preparation of abstract drafts

– Deadline for abstracts: 12.12.2008

– Submit by sending the abstract to: Anne Rotbøll Jensen [email protected]

– Final acceptance

– Abstract book available online ONLY

– Schedule of oral presentations and poster presentations in abstract book found at http://www.smi.auc.dk/~oka/SMAC/

SMAC

Contents• Scientific process

– 4 (+4) auditorium lectures

• Communication

• Poster and oral presentations should be independent

SEMCON 7th sem. project

- Abstract (not necessarily the same as in paper)

- Scientific paper

- Poster presentation - Worksheets

- Oral presentation - repeat poster+oral

SEMCON

AWARD

Based on this and your performance on the SEMCON the conference committee (chaired by OKA) will select the winner

– Participation in an IEEE conference on European soil

– Or other study relevant travelling

– Price of dkr 20.000 per group (or max kr 5000,- per member )

Planning the research report(1)

• The results of the research project must be ‘sold’ adequately

• Be careful with terminology – write precise, tiresome sentences

• Description of the problem

– Introduce and set the stage for the naive reader

– Reader must be able to understand the problem from this report only

– Provide rationale and background – the thrust behind the research work should be clear

– Emphasise what has been researched in this report and what has not (delimit the project)

– Present the hypotheses/aim

• Present the methods

– Utmost precision

– Reader should be able to replicate results

• Presentation of the data

– Use same structure/terminology as in methods

– From the problem (subproblems) follows the data

– Logic is imperative

– Complete presentation (tables, figures, appendices)

– Test of hypotheses (confirmation-rejection)

– Monotonous/uniform language is better than too many adjectives

• Interpretation of the data

– Presentation (what?) is one step - interpretation (why?) is the next and very important step

– Data may have more meanings than the ones you discover –present alternative interpretations if relevant – it may strengthen your chances for acceptance

– Tell what the data tell - not what you would like them to tell



• Interpretation of the data, cont.

– If the H0 hypothesis is accepted carefully review the methods

• Are the tools sufficiently sensitive? Reliable?

• Have you employed correct data analysis/statistics

• Insufficient power (sample too small or unreliable measures) type

II error (accept H0 even though it is false)

• Concluding remarks

– Overall conclusions

– Implications

– Future studies

General principles:a checklist before writing (1)

• Based on Leedy. Written communication (target, means etc.)

• The problem

– Is the problem clearly and concisely stated?

– Is the problem adequately narrowed down into a researchable problem?

– Is the problem significant enough to warrant a formal research effort?

– Is the relationship of the identified problem to previous research clear?

• Literature review

– Is the literature review logically organised?

– Does the review provide a critique of the relevant studies?

– Are gaps in knowledge about the research problem identified?

– Are important/relevant reference forgotten/omitted?


• Theoretical or conceptual framework

– Is the theoretical framework easily linked with the problem, or is it

“forced”?

– Are concepts/framework defined?

• Research variables

– Are the dependent and independent variables operationally defined?

– Are the experimental / intervening variables identified?

• Hypotheses

– Is a predicted relationship between (2) variables included in the

hypotheses?

– Are the hypotheses clear, testable, and specific?

– Are the hypotheses logically derived from the theoretical concept /

framework?

• Descriptive study

– Is the aim of the study clearly described and based on a solid introduction?


• Sampling

– Is the sample size adequate?

– Is the sample representative?

– Is the sampling method appropriate?

– Are the sample criteria for inclusion/exclusion into the study identified?

– Is there any sampling bias in the method?

• Research design

– Is the design adequately, appropriate and well described?

– Is there control for internal / external validity and reliability ?

• Data collection methods

– Are the methods appropriate for the study?

– Are the instruments described adequately?

• Data analysis

– Is the result section clearly and logically organized?

– Is the type of analysis appropriate for the level of measurement for each variable?


• Data analysis, cont.

– Are the tables and figures understandable?

– Is the statistical test appropriate for answering the question?

• Interpretation and discussion

– Are the interpretation based on the data? (or on what you had hoped to

find)

– Are the findings discussed in relationship to previous research and to the

conceptual framework?

– Does the cited authors distinguish between actual findings and

interpretations?

– Are unwarranted generalisations made beyond the data?

– Are the limitations of the results identified?

– Are implications of the results discussed?

– Are recommendations for future research identified?

– Are the conclusions justified?

Different means to present

science• Consider patent filing

• Scientific writing

– Original / full research reports

– Short communications

– Technical communications

– Topical reviews

– Books or book chapters

– Academic thesis

– Conference abstracts

• Oral presentations

– Layman presentation

– Short/free communication

– Symposium/plenary lecture (invited)

• Public relations

– Media - press release

– Internet

Research papers

• Consider where to publish

– Impact - impact factors

– Relevance / scope of journal

– Audience / readers

– Time (review process, publisher delay, becomes gradually more important)

– Internet publications – indexed!?!

• IMRAD style

– Introduction

– Materials and Methods

– Results

– and Discussion

past-tense

present tense

Research papers

• Passive/active voice“the data were sampled by the computer”

“the computer sampled the data”

• Consistency in style is crucial

• Instruction to authors

– Different for every journal

J Neuroscience methods -

exampleGuide for Authors

The kind of papers which will be accepted are full- length articles and review-type articles on methods,

including their development, applicability and present status. Manuscripts should be sent to one of the

Editors-in-Chief.

Preparation of the text The length of articles should be restricted to 10 printed pages; i.e., approximately 18

manuscript pages. The manuscript should be accompanied by a title page, a list of 6-8 key words and an

abstract.

In order to expedite publication, the original and three copies (including figures) are required.

(a) The covering letter, addressed to the Editor-in-Chief, should include the names (with address, phone, fax

and e-mail details) of up to four potential reviewers.

(b) Manuscripts should be typewritten with double spacing and wide margins. Words to be printed in 'italics’

should be underlined. The metric system is to be used throughout. Manuscripts should be organized as

follows:

Abstract, Introduction, Methods, Results, Discussion, References, Tables, Figures and Legends.

Acknowledgements for personal and technical assistance should follow the Discussion section. Financial

support should be indicated in the Acknowledgements.

(c) The title page should be supplied as a separate sheet, to include the title, the name(s) of the author(s) and

their affiliations.

(d) An abstract of not more than 200 words should be on a separate sheet. It will appear at the beginning of

the paper.

References

References in the text should start with the name of the author(s), followed by the publication date in

brackets, e.g. Jones (1970) has shown the importance of. . ., or . . . has been described (Jones, 1970; Brown

The process of publication

• Write the paper bearing the selected journal in mind

• Submit the paper according to guidelines

• The Editor selects 2-3 reviewers. These remain unknown to the author

• Wait and hope

• The response– Rejected

– Conditionally accepted

– Accepted

• Material send to publisher by editor

• Authors proof read paper

• Printed/indexed

Academic thesis

• Master of Science (M.S.)– Monograph (report) based on 1-2 studies

– IMRAD-design

• Philosophy Doctor (Ph.D.)– Review and discussion of literature including own 3-4

published studies

– Monograph

– Public defence

• Doctoral thesis (dr. tech., dr. scient, dr. med,)– Review and discussion of literature including own 7-10

published studies (depending on type of work)

– Monograph

– Public defence

Conference abstracts

• Short communications of most recent research

• Traditions are different. Some professional areas reject papers others accept almost every submission (economy of the conference...)

• Normally immediately prior to publication of data in full research paper

– Feedback

– Direct interaction often leads to new ideas/collaboration

– Faster distribution of news

FACILITATION OF THE HUMAN WITHDRAWAL REFLEX BY REPEATED

ELECTRICAL STIMULI - A STUDY ON CENTRAL INTEGRATION

O.K. Andersen, F.A. Sonnenborg, L. Arendt-Nielsen

Aalborg University, Lab. for Experimental Pain Research, Center for Sensory-

Motor Interaction, Aalborg, Denmark

Aim: To study spinal sensory integration of repetitive painful and non-painful

electrical stimulation of varying frequencies (temporal summation) and intensities

(spatial summation) by measuring the withdrawal reflex and sensory intensity.

Methods: Thirteen volunteers participated in the study (243y). Electrical stimuli

were delivered to the dorsal foot to evoke withdrawal reflexes in semitendinosus.

Reflexes were evoked by a single stimulus and by trains of repetitive stimuli.

Five different stimulus intensities (0.4, 0.5, 0.6, 0.7, and 0.8 times the reflex

threshold, RT) were used. For the repetitive stimulation, the duration of the train

was 2s and the frequency varied between 0.5, 1, 3, 5, 10, and 20Hz in random

sequence. All combinations of stimulus frequency and intensity were used with

five repetitions of each combination.

Results: Only the high stimulus intensity (10.3mA) was above the pain threshold

(9.1mA). For the repetitive stimuli, the intensity that evoked pain was lower than

the intensity required by a single stimulus to evoke pain. For high frequency

trains (10Hz) the low stimulus intensity (0.5RT) evoked pain, while for low

frequencies (1 Hz), intensities above 0.7RT was required to evoke pain. The

withdrawal reflex increased gradually through the train of repetitive stimulation

for frequencies above 1 Hz. The reflex facilitation was dependent on both

stimulus frequency and intensity (P<0.001). Thus, the strongest facilitation, and

Example of abstract

• Introduction often skipped – depends on type of conference/call for

abstracts

• Almost telegraph-style

• Minimal dicussion, conclusion=’take home message’

Short oral communication• Organisation of the talk

– Similar to paper: what was the problem - what is the solution? (IMRAD)

– Adapt to the expected knowledge level of the audience

– Trim down theoretical content and data and details to the essentials (e.g. 10 min)

– 3-repeat:

• state what you want to talk about

• talk about it

• summarise what you have talked about

– Use of AV-equipment

• Blackboard, Overheads, Video, Slides, audio

– Do not overload with text, graphs

– Sufficient contrast

– Use animation where relevant

Poster exampleHUMAN WITHDRAWAL REFLEX RECEPTIVE FIELDS TO FOOT SOLE STIMULATION IN SYMMETRICAL STANDING POSITION

O.K. Andersen, Z. Matjačić 2, T. Graven-Nielsen*, L. Arendt-Nielsen

Department of Health Science and Technology, Aalborg University, Denmark, 2Institute for Rehabilitation, Ljubljana, Slovenia

HUMAN WITHDRAWAL REFLEX RECEPTIVE FIELDS TO FOOT SOLE STIMULATION IN SYMMETRICAL STANDING POSITIONO.K. Andersen, Z. Matjačić 2, T. Graven-Nielsen*, L. Arendt-Nielsen


SFN 2003

914.9

INTRODUCTION

A modular organization has been shown to control nociceptive withdrawal

reflexes based on observations in rats [9], cats [4], and humans [1] during resting

conditions. Each muscle has a unique cutaneous reflex receptive field (RRF) that

is withdrawn by contraction of the muscle.

Cutaneous reflexes have been studied during stance using painful [2],[3],[8] and

non-painful intensities [6] but these studies did not investigate the spatial

topography of the reflex organisation. During standing and locomotion

preservation of balance is important and seems to govern spinal reflexes [7].

OBJECTIVE

Human RRF was assessed in ten healthy subjects during standing with even

support on both legs in order to describe RRF in a functional context.

METHODS & MATERIALSSubjects

10 volunteers (eight males and two females, mean age 24.1 years, range 20-28

years) participated in the study

Experimental Setup

Two electrical stimulus intensities (1.2 and 2.2 times the pain threshold) were

used. The stimulus was delivered to one of 12 electrodes (diameter 0.8 cm)

distributed on the foot sole with a common reference on the foot dorsum (710

cm). All 12 electrode positions were stimulated five times at both intensities all

in random order. Each stimulus consisted of a constant current pulse train of five

individual 1 ms pulses delivered at 200 Hz.

Recordings

Tibialis anterior (TA), soleus (SO), vastus lateralis (VL), semintendinosus (ST),

and iliopsoas (IL) reflexes were recorded. Further, the vertical force was

recorded and the centre or pressure (CoP) was assessed in the frontal and sagittal

planes on both legs.

Postural feedback

Visual feedback was provided to the subject to ensure standardized posture.

Based on the force-platform signals, eight arrows separated by 45 were depicted

for both feet on a computer monitor right in front of the volunteers. An arrow

was turned on when the CoP of a foot was more that 1cm out of balance in the

frontal plane or more than 2 cm in the sagittal plane. In addition, a light was

turned on when the mean weight distribution was more than 4% out of balance.

A stimulus was released manually when the subject was in balance.

Data analysis

The root mean square amplitude of the individual reflexes in all muscles was

calculated in a 60-120 ms post-stimulation interval (short latency reflex, SLR)

and in a 120-220 ms interval (long latency reflex, LLR). The peak change in

down-force was extracted for both feet and the peak change in the CoP was

calculated in both the frontal and sagittal planes. Onset latencies were determined

by the first signal component 5 times larger than the background noise for a

period of more than 7 ms. Inhibition was detected as the first signal component

with an amplitude suppression of 60% of the background activity.

INTRODUCTION









OBJECTIVE






Experimental Setup







Recordings





Postural feedback








Data analysis









DISCUSSIONWhen standing the ankle extensor played a dominant role in the withdrawal

pattern in contrast to previous human studies during sitting, relaxed conditions.

This was associated with the largest limb unloading compared with stimulation at

the distal part of the foot sole. The unloading is accomplished by an anterior

move of the centre of pressure in the ipsilateral leg.

All in all balance is maintained while at the same time the stimulated limb is

withdrawn by a shift of the load in the transversal direction. A similar transversal

shift in the CoP towards the limb being stimulated has been observed recently

[2], [5] and interpreted as a preparatory balance reaction prior to actual

withdrawal. The largest change in CoP towards the stimulated limb is seen when

the limb carries the majority of the body weight [2].

For further reading see Exp. Brain Res. (2003) 152: 434-443.

ACKNOWLEDGEMENT

The Danish Technical Research Council (STVF) supported this study

REFERENCES[1] Andersen OK, Sonnenborg FA, Arendt-Nielsen L (1999) Modular organization of human leg withdrawal reflexes elicited by electrical stimulation

of the foot sole. Muscle Nerve 22: 1520-1530

[2] Bent LR, Potvin JR, Brooke JD, McIlroy WE (2001) Medio-lateral balance adjustments preceding reflexive limb withdrawal are modified by

postural demands. Brain Res. 914: 100-105

[3] Decchi B, Zalaffi A, Spidalieri R, Arrigucci U, Di TA, Rossi A (1997) Spinal reflex pattern to foot nociceptive stimulation in standing humans.

Electroencephalogr.Clin Neurophysiol 105: 484-489

[4] Levinsson A, Garwicz M, Schouenborg J (1999) Sensorimotor transformation in cat nociceptive withdrawal reflex system. Eur.J.Neurosci. 11:

4327-4332

[5] McIlroy WE, Bent LR, Potvin JR, Brooke JD, Maki BE (1999) Preparatory balance adjustments precede withdrawal response to noxious

stimulation in standing humans. Neurosci Lett. 267: 197-200

[6] Paquet N, Tam F, Hui-Chan CW (1996) Functional modulation of the human flexion and crossed extension reflexes by body position.

Neurosci.Lett. 209: 215-217

[7] Rietdyk S, Patla AE (1998) Context-dependent reflex control: some insights into the role of balance. Exp.Brain Res. 119: 251-259

[8] Rossi A, Decchi B (1994) Flexibility of lower limb reflex responses to painful cutaneous stimulation in standing humans: evidence of load-

dependent modulation. J Physiol, London 481: 521-532

[9] Schouenborg J, Kalliomäki J (1990) Functional organization of the nociceptive withdrawal reflexes. I. Activation of hindlimb muscles in the rat.

Exp.Brain Res. 83: 67-78













ACKNOWLEDGEMENT









4327-4332










Around the ankle joint, SO reflexes dominated with a RRF

covering the proximal part of the sole including the central pads.

Only results for the high stimulus intensity are shown. SLR

denotes short loop reflex, LLR long loop reflex

SLR

LLR

SOL

29.5

VL

11.1

25-50%

75-100%

50-75%

0-25%

ST

10.0

IL

18.2

TA

10.8Mean peakreflexsize (V)

Reflex receptive fields

CoP changetransversal direction

0.17 – 0.32 cm

0.46 – 0.61 cm

0.32 – 0.46 cm

0.03 – 0.17 cm

Right footLeft foot

-0.07 – 0.05 cm

0.18 – 0.31 cm

0.05 – 0.18 cm

-0.20 – -0.07 cm

CoP changesagittal direction

Right footLeft foot

-1.00 – -0.57 cm

-0.14 – 0.30 cm

-0.57 – -0.14 cm

-1.43 – -1.00 cm

0.44 – 0.78 cm

1.12 – 1.46 cm

0.78 – 1.12 cm

0.10 – 0.44 cm

Down Force

Right footloading

Left footunloading

7.18 – 14.4 N

21.5 – 28.7 N

14.4 – 21.5 N

0 – 7.18 N

6.67 – 13.3 N

20.0 – 26.7 N

13.3 – 20.0 N

0 – 6.67 N

For CoP positive direction is in the anterior direction in the sagittal plane, and in the lateral direction on the left foot in

the transversal plane. Results for the high stimulus intensity are shown. The shift in vertical force was accomplished by a

move of the CoP in the anterior direction on the stimulated limb (mean latency of 1407.90 ms). The right foot changes

are illustrated for the atimulus postion on the left foot.

Force platform recordings

Pain threshold

0

4

8

12

16 mA

Images from experiments

RESULTSRESULTS

60

120

220

0

15 V

TA

1

2

3

4

5

6

7

8

9

10

11

12

60

120

220

0

Low intensity High intensity

109(4)

82.9(3)

96.5(4)

91.8(4)

89.6(4)

84.5(7)

97.1(6)

80.9(4)

86.2(4)

82.8(2)

97.4(5)

86.5(5)

burst100(6)

86.6(3)

95.9(7)

101(6)

95.3(5)

88.5(7)

87.7(8)

89.3(6)

95.7(6)

91.2(3)

93.6(7)

89.2(3)

burst

10

5

1

3 4

6 78

9

11 12

2

20 V

Low intensity High intensitySO

106(2)

77.1(2)

98.3(1)

105(3)

90.5(1)

118(2)

103(1)

92.5(1)

97.9(4)

94.5(3)

109 (4)

99.5(1)

96.8(1)

93.6(1)

107(1)

(0)

102(5)

96.2(3)

125(3)

135(3)

94.6(2)

104(2)

107(5)

109(2)

1

2

3

4

5

6

7

8

9

10

11

12

80.6(7)

78.9(7)

78.3(7)

84.4(8)

73.3(8)

82.7(8)

68.8(7)

69.9(9)

86.6(8)

95.8(8)

90.9(7)

88.5(9)

84.0(10)

73.8(8)

78.7(8)

70.0(8)

77.5(6)

73.6(6)

73.2(9)

69.8(8)

89.9(7)

75.1(9)

77.4(8)

98.2(8)

silent per.burst silent per. burst

60

120

220

0 60

120

220

0

site site

Grand mean reflexes in ankle flexor and extensor

[email protected]

HUMAN WITHDRAWAL REFLEX RECEPTIVE FIELDS TO FOOT SOLE STIMULATION IN SYMMETRICAL STANDING POSITION





HUMAN WITHDRAWAL REFLEX RECEPTIVE FIELDS TO FOOT SOLE STIMULATION IN SYMMETRICAL STANDING POSITION





SFN 2003

914.9

INTRODUCTION









OBJECTIVE






Experimental Setup







Recordings





Postural feedback








Data analysis









INTRODUCTION









OBJECTIVE






Experimental Setup







Recordings





Postural feedback








Data analysis





















ACKNOWLEDGEMENT









4327-4332






















ACKNOWLEDGEMENT









4327-4332














SLR

LLR

SOL

29.5

VL

11.1

25-50%

75-100%

50-75%

0-25%

ST

10.0

IL

18.2

TA







SLR

LLR

SOL

29.5

SOL

29.5

VL

11.1

VL

11.1

25-50%

75-100%

50-75%

0-25%

25-50%25-50%

75-100%75-100%

50-75%50-75%

0-25%0-25%

ST

10.0

ST

10.0

IL

18.2

IL

18.2

TA

10.8

TA




0.17 – 0.32 cm

0.46 – 0.61 cm

0.32 – 0.46 cm

0.03 – 0.17 cm

Right footLeft foot

-0.07 – 0.05 cm

0.18 – 0.31 cm

0.05 – 0.18 cm

-0.20 – -0.07 cm


Right footLeft foot

-1.00 – -0.57 cm

-0.14 – 0.30 cm

-0.57 – -0.14 cm

-1.43 – -1.00 cm

0.44 – 0.78 cm

1.12 – 1.46 cm

0.78 – 1.12 cm

0.10 – 0.44 cm

Down Force

Right footloading

Left footunloading

7.18 – 14.4 N

21.5 – 28.7 N

14.4 – 21.5 N

0 – 7.18 N

6.67 – 13.3 N

20.0 – 26.7 N

13.3 – 20.0 N

0 – 6.67 N






Pain threshold

0

4

8

12

16 mA



0.17 – 0.32 cm

0.46 – 0.61 cm

0.32 – 0.46 cm

0.03 – 0.17 cm

Right footLeft foot

-0.07 – 0.05 cm

0.18 – 0.31 cm

0.05 – 0.18 cm

-0.20 – -0.07 cm

0.17 – 0.32 cm

0.46 – 0.61 cm

0.32 – 0.46 cm

0.03 – 0.17 cm

0.17 – 0.32 cm

0.46 – 0.61 cm

0.32 – 0.46 cm

0.03 – 0.17 cm

0.17 – 0.32 cm0.17 – 0.32 cm

0.46 – 0.61 cm0.46 – 0.61 cm

0.32 – 0.46 cm0.32 – 0.46 cm

0.03 – 0.17 cm0.03 – 0.17 cm

Right footLeft foot

-0.07 – 0.05 cm

0.18 – 0.31 cm

0.05 – 0.18 cm

-0.20 – -0.07 cm

-0.07 – 0.05 cm

0.18 – 0.31 cm

0.05 – 0.18 cm

-0.20 – -0.07 cm

-0.07 – 0.05 cm-0.07 – 0.05 cm

0.18 – 0.31 cm0.18 – 0.31 cm

0.05 – 0.18 cm0.05 – 0.18 cm

-0.20 – -0.07 cm-0.20 – -0.07 cm


Right footLeft foot

-1.00 – -0.57 cm

-0.14 – 0.30 cm

-0.57 – -0.14 cm

-1.43 – -1.00 cm

-1.00 – -0.57 cm

-0.14 – 0.30 cm

-0.57 – -0.14 cm

-1.43 – -1.00 cm

-1.00 – -0.57 cm-1.00 – -0.57 cm

-0.14 – 0.30 cm-0.14 – 0.30 cm

-0.57 – -0.14 cm-0.57 – -0.14 cm

-1.43 – -1.00 cm-1.43 – -1.00 cm

0.44 – 0.78 cm

1.12 – 1.46 cm

0.78 – 1.12 cm

0.10 – 0.44 cm

0.44 – 0.78 cm

1.12 – 1.46 cm

0.78 – 1.12 cm

0.10 – 0.44 cm

0.44 – 0.78 cm0.44 – 0.78 cm

1.12 – 1.46 cm1.12 – 1.46 cm

0.78 – 1.12 cm0.78 – 1.12 cm

0.10 – 0.44 cm0.10 – 0.44 cm

Down Force

Right footloading

Left footunloading

7.18 – 14.4 N

21.5 – 28.7 N

14.4 – 21.5 N

0 – 7.18 N

6.67 – 13.3 N

20.0 – 26.7 N

13.3 – 20.0 N

0 – 6.67 N

Right footloading

Left footunloading

7.18 – 14.4 N

21.5 – 28.7 N

14.4 – 21.5 N

0 – 7.18 N

7.18 – 14.4 N

21.5 – 28.7 N

14.4 – 21.5 N

0 – 7.18 N

7.18 – 14.4 N7.18 – 14.4 N

21.5 – 28.7 N21.5 – 28.7 N

14.4 – 21.5 N14.4 – 21.5 N

0 – 7.18 N0 – 7.18 N

6.67 – 13.3 N

20.0 – 26.7 N

13.3 – 20.0 N

0 – 6.67 N

6.67 – 13.3 N

20.0 – 26.7 N

13.3 – 20.0 N

0 – 6.67 N

6.67 – 13.3 N6.67 – 13.3 N

20.0 – 26.7 N20.0 – 26.7 N

13.3 – 20.0 N13.3 – 20.0 N

0 – 6.67 N0 – 6.67 N






Pain threshold

0

4

8

12

16 mA

0

4

8

12

16 mA


RESULTSRESULTS

60

120

220

0

15 V

TA

1

2

3

4

5

6

7

8

9

10

11

12

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120

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109(4)

82.9(3)

96.5(4)

91.8(4)

89.6(4)

84.5(7)

97.1(6)

80.9(4)

86.2(4)

82.8(2)

97.4(5)

86.5(5)

burst100(6)

86.6(3)

95.9(7)

101(6)

95.3(5)

88.5(7)

87.7(8)

89.3(6)

95.7(6)

91.2(3)

93.6(7)

89.2(3)

burst

10

5

1

3 4

6 78

9

11 12

2

20 V


106(2)

77.1(2)

98.3(1)

105(3)

90.5(1)

118(2)

103(1)

92.5(1)

97.9(4)

94.5(3)

109 (4)

99.5(1)

96.8(1)

93.6(1)

107(1)

(0)

102(5)

96.2(3)

125(3)

135(3)

94.6(2)

104(2)

107(5)

109(2)

1

2

3

4

5

6

7

8

9

10

11

12

80.6(7)

78.9(7)

78.3(7)

84.4(8)

73.3(8)

82.7(8)

68.8(7)

69.9(9)

86.6(8)

95.8(8)

90.9(7)

88.5(9)

84.0(10)

73.8(8)

78.7(8)

70.0(8)

77.5(6)

73.6(6)

73.2(9)

69.8(8)

89.9(7)

75.1(9)

77.4(8)

98.2(8)


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RESULTSRESULTS

60

120

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0

15 V15 V15 V15 V

TA

1

2

3

4

5

6

7

8

9

10

11

12

1

2

3

4

5

6

7

8

9

10

11

12

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109(4)

82.9(3)

96.5(4)

91.8(4)

89.6(4)

84.5(7)

97.1(6)

80.9(4)

86.2(4)

82.8(2)

97.4(5)

86.5(5)

burst109(4)

82.9(3)

96.5(4)

91.8(4)

89.6(4)

84.5(7)

97.1(6)

80.9(4)

86.2(4)

82.8(2)

97.4(5)

86.5(5)

burst100(6)

86.6(3)

95.9(7)

101(6)

95.3(5)

88.5(7)

87.7(8)

89.3(6)

95.7(6)

91.2(3)

93.6(7)

89.2(3)

burst100(6)

86.6(3)

95.9(7)

101(6)

95.3(5)

88.5(7)

87.7(8)

89.3(6)

95.7(6)

91.2(3)

93.6(7)

89.2(3)

100(6)

86.6(3)

95.9(7)

101(6)

95.3(5)

88.5(7)

87.7(8)

89.3(6)

95.7(6)

91.2(3)

93.6(7)

89.2(3)

burst

10

5

1

3 4

6 78

9

11 12

2

10

5

1

3 4

6 78

9

11 12

2

20 V20 V


106(2)

77.1(2)

98.3(1)

105(3)

90.5(1)

118(2)

103(1)

92.5(1)

97.9(4)

94.5(3)

109 (4)

99.5(1)

106(2)

77.1(2)

98.3(1)

105(3)

90.5(1)

118(2)

103(1)

92.5(1)

97.9(4)

94.5(3)

109 (4)

99.5(1)

96.8(1)

93.6(1)

107(1)

(0)

102(5)

96.2(3)

125(3)

135(3)

94.6(2)

104(2)

107(5)

109(2)

96.8(1)

93.6(1)

107(1)

(0)

102(5)

96.2(3)

125(3)

135(3)

94.6(2)

104(2)

107(5)

109(2)

1

2

3

4

5

6

7

8

9

10

11

12

1

2

3

4

5

6

7

8

9

10

11

12

80.6(7)

78.9(7)

78.3(7)

84.4(8)

73.3(8)

82.7(8)

68.8(7)

69.9(9)

86.6(8)

95.8(8)

90.9(7)

88.5(9)

80.6(7)

78.9(7)

78.3(7)

84.4(8)

73.3(8)

82.7(8)

68.8(7)

69.9(9)

86.6(8)

95.8(8)

90.9(7)

88.5(9)

84.0(10)

73.8(8)

78.7(8)

70.0(8)

77.5(6)

73.6(6)

73.2(9)

69.8(8)

89.9(7)

75.1(9)

77.4(8)

98.2(8)

84.0(10)

73.8(8)

78.7(8)

70.0(8)

77.5(6)

73.6(6)

73.2(9)

69.8(8)

89.9(7)

75.1(9)

77.4(8)

98.2(8)


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[email protected]

Experience from meeting: too much text, but good for handouts

• Reflexes were evoked at all sites and temporal

summation was observed by gradually larger reflexes

during the train, see figure 1 and figure 5.

• A plateau in reflex size was observed during the

stimulus train often followed by even smaller reflexes

(figure 1) in agreement with observations in spinal

intact subjects (Andersen et al. 2005). However,

observations in spinal rats indicate no such plateau

(Gozariu et al. 1997).

• The larger RRF was only observed immediately after

the capsaicin injection (first assessment of the RRF).

• The reflex facilitation triggered by capsaicin was not

observed in 6 subjects but very pronounced in 9

subjects.

CONCLUSION•An expansion of the reflex receptive field was found

following i.m. capsaicin in patients with complete spinal

cord injury. This is interpreted as a consequence of the

lacking descending inhibitory control following the

capsaicin injection.

•The expansion in RRF size was very short-lived. This

could indicate that the larger reflexes is a results of a

summation effect between capsaicin evoked afferent

activity and the electrical stimulation rather than central

sensitisation.

REFERENCES

Andersen et al. Clin Neurophysiol 115 (2004) 2798-2810.

Andersen et al. Brain Res. 1042 (2005) 194-204.

Gozariu et al. J.Neurophysiol. 78 (1997) 3165-3179.

Schouenborg et al., Exp. Brain Res. 106 (1995) 19-27.

You et al., Brain Res. 960 (2003) 235-245.).

INTRODUCTION•Expansion of neuronal receptive fields following robust

nociceptive input has been observed in animals. The

nociceptive withdrawal reflex receptive field (RRF) most

likely reflects the receptive field of convergent dorsal

horn neurons located in the deep dorsal horn

(Schouenborg et al. 1995).

• Wind-up primarily occurs in deep dorsal WDR

neurones following C fibre activation and it correlates

with withdrawal reflex activity (You et al., 2003).

• In this study, variation in receptive field size following

i.m. capsaicin was studied in patients with complete

spinal cord injury. The hypothesis was that the

descending modulation may be impaired and affect the

RRF control following strong nociceptive input. In a

previous study, no effect of intramuscular capsaicin

was found on the RRF in spinal intact human

volunteers.

MATERIALS AND METHODS• 15 complete spinal cord injured male volunteers (mean 43

years, range 27-66 years) participated in the experiment. Thevolunteers were in supine position with the knee flexed aprox.30 degrees.

• Nociceptive withdrawal reflexes were elicited via eightelectrodes mounted on the sole of the foot. A common anode(710 cm) was placed on the foot dorsum. Each stimulusconsisted of a constant current pulse train of five 1 ms pulses(200 Hz).

• The intensity of the stimulus was adjusted based on the meanreflex threshold at positions 2, 4 and 6 (see figure 2). Thesame intensity was used at all stimulation sites (Andersen etal. 2004). A train of eight electrical stimuli were delivered at afrequency of 3Hz. The train was delivered in random order toone of the eight electrode sites. The variation in RRF wasevaluated during the stimulus train.

• Electromyographic activity (EMG) was recorded by surfaceelectrodes over the tibialis anterior muscle. The root meansquare amplitude of the EMG signals was calculated in the60-250 ms post-stimulation interval.

• Two-dimensional interpolation was used for deriving the RRF(figure 2). The RRF area was quantified using an EMGthreshold based on the level and variation in pre-stimulusEMG activity (see figure 3). The RRF volume was determinedby integration of the EMG activity within the RRF area.

• 10 g capsaicin in 0.1 ml volume was injected into the flexordigitorum brevis muscle.

• The RRF was assessed at baseline as a mean of foursuccessive assessments. Four RRF assessments wereacquired again stating one minute after the capsaicininjection. Finally the RRF was assessed 60 min postcapsaicin.

The RRF after each stimulus in the train for a single subject at baseline, after the capsaicin injection, and 60 min later.

1Repetitive stimulation

Baseline

1st stimpost-

capsaicin

2nd stimpost-

capsaicin

3rd stimpost-

capsaicin

60 minpost-

capsaicin

4th stimpost-

capsaicin

1st 2nd 8th stimulus in the train3rd 4th 5th 6th 7th

20 V

5

EXPANSION OF NOCICEPTIVE WITHDRAWAL REFLEX RECEPTIVE FIELDS IN SPINAL CORD INJURED

HUMANS FOLLOWING INJECTION OF INTRAMUSCULAR CAPSAICINOle K. Andersen*1,Nanna B. Finnerup2, Inger L. Johannesen3, Fin Biering-Sørensen4, Troels S. Jensen2, Lars Arendt-Nielsen1

1) Center for Sensory-Motor Interaction (SMI), Aalborg University, Denmark *Correspondence [email protected], 2) Danish Pain Research Center, Aarhus University Hospital, Denmark, 3) The Spinal Cord Unit, Viborg

Hospital, Viborg, Denmark, 4) Clinic for Spinal Cord Injuries, The Neuroscience Centre, Rigshospitalet, Copenhagen, Denmark.

PF 341

• A gradual build up in reflex size during the stimulus

train was observed. Notice the ‘after-discharge’.

5

30V

1 s

Mean RRF area (fraction of the area of the sole of the

foot) and RRF volume (mm2×V)

2

31 2

4 5

6

7 8

200 V

100 ms

Sensory nerve

Motor nerve

EMG

20 V

3

• The RRF area (white contour in C) was determined from

interpolated values only (B) by calculating Z-scores.

3BA C

90 V

30

60 V

RESULTS

• The mean RRF area across the eight stimuli in the

train assessed immediately after the capsaicin

injection was larger compared to the baseline

assessment (RMANOVA P<0.01, followed by post

hoc analysis, P<0.05) , see figure 4.

• However, no effect was seen on the RRF volume.

4

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RRF areaRRF volume

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Documents

Videnskabsteori, -kommunikation og etik (SMAC) fall 2008 · Videnskabsteori, -kommunikation og etik (SMAC) fall 2008. Course Plan