Mental number representation as assessed by the number bisection task: a combined reaction time and fMRI study [Elektronische Ressource] / vorgelegt von Barbara Elisabeth Geppert

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Informations

• Publié par: rheinisch-westfalischen_technischen_hochschule_-rwth-_aachen
• Publié le: 01 janvier 2005
• Nombre de lectures: 10
• Langue: English
• Poids de l'ouvrage: 8 Mo

Extrait

Mental number representation as assessed
by the number bisection task:

A combined reaction time and fMRI study




Von der Medizinischen Fakultät
der Rheinisch-Westfälischen Technischen Hochschule Aachen
zur Erlangung des akademischen Grades einer Doktorin der Medizin
genehmigte Dissertation

vorgelegt
von
Barbara Elisabeth Geppert
aus
Oberhausen


Berichter: Herr Universitätsprofessor
Dr. rer. nat. Klaus Willmes-von Hinckeldey

Herr Universitätsprofessor
Dr. med. Dr. rer. soc. Frank Schneider

Tag der mündlichen Prüfung: 11. Januar 2005

Diese Dissertation ist auf den Internetseiten der Hochschulbibliothek online verfügbar.



Acknowledgments


Especially, I want to thank Prof. Dr. Klaus Willmes- von Hinckeldey for giving me the
possibility to do my dissertation under his supervision. At all stages of my work, he was
extremely friendly and helpful. He also opened up the opportunity to present my work at
different workshops and congresses. I am grateful to Dr. Hans-Christoph Nuerk who always
supported me when I needed it and taught me a lot of very useful things. I learned very much
from both of them during my dissertation and also when working for them, both for my
research and for my life.

Further on, I want to thank Ralph Schnittker who always answered all my questions with a lot
of patience. He even made a backup of my data in a day’s work, which became more
important than we expected. The rest of the staff from the “Interdisciplinary Center for
Clinical Research” (IZKF) was also very helpful in this work which I greatly appreciate.

Due to the help of Prof. Dr. A. Thron and the Department of Neuroradiology of the Medical
Faculty of the Technical University of Aachen this study with functional Magnetic Resonance
Imaging could be realized. Thank you very much.

Without the 26 volunteers this work would not have been possible. Thank you as well. I must
apologize to the 6 persons whose data could not be used due to technical problems. I am
grateful to Daniel Nilsson, who gave me a lot of energy to fulfill this work and helped me
with a lot of computer problems. Last but not least, I also want to thank my family, which
encouraged me and gave me very useful advices.

This work is dedicated to my family.
Table of contents 5
Table of contents
1 Summary.......................................................................................................................... 11
2 Introduction..................................................................................................................... 12
3 Theoretical background.................................................................................................. 13
3.1 The triple-code model of Dehaene and Cohen......................................................... 13
3.1.1 The number bisection task................................................................................ 15
3.1.2 The assessment of number processing deficits ................................................ 16
3.2 Numerical effects as an indication of internal number representation..................... 17
3.2.1 Effects indicating quantity representation........................................................ 17
3.2.2 Effects indicating parity representation............................................................ 21
3.2.3 Evidence of verbal rote memory representation from patient data .................. 23
3.3 Functional activation in number processing............................................................. 24
3.3.1 Functional activation as an indication of quantity representation.................... 24
3.3.2 tion of parity representation........................ 30
3.3.3 tion of verbal rote knowledge..................... 30
4 Hypotheses and research questions ............................................................................... 35
4.1 Possible determinants in the number bisection task................................................. 35
4.1.1 Numerical magnitude.......................................................................................35
4.1.2 Verbal rote knowledge.....................................................................................36
4.1.3 Bisection possibility (related to parity) ............................................................ 36
4.2 Research questions...................................................................................................36
4.2.1 Research questions concerning reaction times................................................. 36
4.2.2 Research concerning functional activation patterns......................... 37
5 Methods............................................................................................................................ 39
5.1 Participants............................................................................................................... 39
5.2 Stimuli and design.................................................................................................... 39
5.3 Procedure.................................................................................................................. 40
5.4 Technical data / Scanning procedure / Data acquisition .......................................... 41
6 Results...... 44
6.1 Reaction time............................................................................................................44
6.1.1 Bisectable trials................................................................................................44
6.1.2 Non-bisectable trials.........................................................................................47
6.2 fMRI results..............................................................................................................49
6.2.1 Main effects of item properties ........................................................................ 50
6 Table of contents
6.2.2 Modelling of individual item set characteristics .............................................. 55
6.2.3 Masked effects..................................................................................................58
7 Discussion......................................................................................................................... 59
7.1 Reaction times..........................................................................................................59
7.1.1 Quantity representation....................................................................................59
7.1.2 Multiplicativity.................................................................................................60
7.1.3 Bisection possibility.........................................................................................60
7.1.4 Additional representation for tens and units .................................................... 62
7.2 Activation pattern.....................................................................................................62
7.2.1 Quantity............................................................................................................62
7.2.2 Multiplicativity72
7.2.3 Bisection possibility78
8 General Discussion.......................................................................................................... 80
8.1 Comparison between reaction time and fMRI results.............................................. 80
8.2 Interpretation within the model framework of Dehaene and Cohen........................ 83
8.2.1 Quantity83
8.2.2 Parity................................................................................................................84
8.2.3 Verbal rote knowledge.....................................................................................84
8.2.4 The mental number line.................................................................................... 85
8.3 The number bisection task as an assessment tool .................................................... 85
9 Conclusion........................................................................................................................ 91
10 References... 93
11 Appendix ........................................................................................................................ 103
11.1 Participants.............................................................................................................103
11.2 Instructions for the participants.............................................................................. 104
11.2.1 Questions before the experiment.................................................................... 104
11.2.2 Example and instructions for the participants................................................ 105
11.2.3 Questions after the experiment....................................................................... 106
11.3 Stimuli.................................................................................................................... 107
11.4 Tables concerning reaction times........................................................................... 108
11.5 fMRI – consent form............................................................