Petro Julkunen

Summary

Affiliation: Kuopio University Hospital
Country: Finland

Publications

  1. doi request reprint TMS-EEG reveals impaired intracortical interactions and coherence in Unverricht-Lundborg type progressive myoclonus epilepsy (EPM1)
    Petro Julkunen
    Department of Clinical Neurophysiology, Kuopio University Hospital, Kuopio, Finland
    Epilepsy Res 106:103-12. 2013
  2. doi request reprint Feasibility of automated analysis and inter-examiner variability of cortical silent period induced by transcranial magnetic stimulation
    Petro Julkunen
    Department of Clinical Neurophysiology, Kuopio University Hospital, Kuopio, Finland
    J Neurosci Methods 217:75-81. 2013
  3. pmc A review of the combination of experimental measurements and fibril-reinforced modeling for investigation of articular cartilage and chondrocyte response to loading
    Petro Julkunen
    Department of Clinical Neurophysiology, Kuopio University Hospital, FI 70211 Kuopio, Finland
    Comput Math Methods Med 2013:326150. 2013
  4. doi request reprint Within-subject effect of coil-to-cortex distance on cortical electric field threshold and motor evoked potentials in transcranial magnetic stimulation
    Petro Julkunen
    Department of Clinical Neurophysiology, Kuopio University Hospital, Kuopio, Finland
    J Neurosci Methods 206:158-64. 2012
  5. doi request reprint Does second-scale intertrial interval affect motor evoked potentials induced by single-pulse transcranial magnetic stimulation?
    Petro Julkunen
    Department of Clinical Neurophysiology, Kuopio University Hospital, Kuopio, Finland
    Brain Stimul 5:526-32. 2012
  6. doi request reprint Navigated TMS combined with EEG in mild cognitive impairment and Alzheimer's disease: a pilot study
    Petro Julkunen
    Department of Clinical Neurophysiology, Kuopio University Hospital, POB 1777, Kuopio, Finland
    J Neurosci Methods 172:270-6. 2008
  7. pmc Effects of growth and exercise on composition, structural maturation and appearance of osteoarthritis in articular cartilage of hamsters
    Petro Julkunen
    Department of Clinical Neurophysiology, Kuopio University Hospital, Kuopio, Finland
    J Anat 217:262-74. 2010
  8. doi request reprint Comparison of single-phase isotropic elastic and fibril-reinforced poroelastic models for indentation of rabbit articular cartilage
    Petro Julkunen
    Department of Clinical Neurophysiology, Kuopio University Hospital, Kuopio, Finland
    J Biomech 42:652-6. 2009
  9. doi request reprint Biomechanical, biochemical and structural correlations in immature and mature rabbit articular cartilage
    P Julkunen
    Department of Clinical Neurophysiology, Kuopio University Hospital, Kuopio, Finland
    Osteoarthritis Cartilage 17:1628-38. 2009
  10. doi request reprint Contribution of tissue composition and structure to mechanical response of articular cartilage under different loading geometries and strain rates
    Petro Julkunen
    Department of Clinical Neurophysiology, Kuopio University Hospital, P O Box 1777, Kuopio 70211, Finland
    Biomech Model Mechanobiol 9:237-45. 2010

Detail Information

Publications46

  1. doi request reprint TMS-EEG reveals impaired intracortical interactions and coherence in Unverricht-Lundborg type progressive myoclonus epilepsy (EPM1)
    Petro Julkunen
    Department of Clinical Neurophysiology, Kuopio University Hospital, Kuopio, Finland
    Epilepsy Res 106:103-12. 2013
    ..Our results suggest abnormal reactivity in EPM1, and may indicate impaired cortico-cortical inhibition and attenuation of subsequent cortical circuits or the thalamic or subcortical nuclei...
  2. doi request reprint Feasibility of automated analysis and inter-examiner variability of cortical silent period induced by transcranial magnetic stimulation
    Petro Julkunen
    Department of Clinical Neurophysiology, Kuopio University Hospital, Kuopio, Finland
    J Neurosci Methods 217:75-81. 2013
    ..Hence, we believe the introduced cSP detection routine would be feasible for online cSP detection, in such a way that is presently used to detect the motor evoked potentials...
  3. pmc A review of the combination of experimental measurements and fibril-reinforced modeling for investigation of articular cartilage and chondrocyte response to loading
    Petro Julkunen
    Department of Clinical Neurophysiology, Kuopio University Hospital, FI 70211 Kuopio, Finland
    Comput Math Methods Med 2013:326150. 2013
    ..At the end, we discuss the prospects for patient-specific models when aiming to use finite element modeling analysis and evaluation of articular cartilage function, cellular responses, failure points, OA progression, and rehabilitation...
  4. doi request reprint Within-subject effect of coil-to-cortex distance on cortical electric field threshold and motor evoked potentials in transcranial magnetic stimulation
    Petro Julkunen
    Department of Clinical Neurophysiology, Kuopio University Hospital, Kuopio, Finland
    J Neurosci Methods 206:158-64. 2012
    ..In conclusion, EF(MT) can be used as a measure of corticospinal excitability instead of SI(MT) to reduce the effect of within-subject variation in CCD...
  5. doi request reprint Does second-scale intertrial interval affect motor evoked potentials induced by single-pulse transcranial magnetic stimulation?
    Petro Julkunen
    Department of Clinical Neurophysiology, Kuopio University Hospital, Kuopio, Finland
    Brain Stimul 5:526-32. 2012
    ..This was performed to challenge the common assumption of time invariance of such amplitudes...
  6. doi request reprint Navigated TMS combined with EEG in mild cognitive impairment and Alzheimer's disease: a pilot study
    Petro Julkunen
    Department of Clinical Neurophysiology, Kuopio University Hospital, POB 1777, Kuopio, Finland
    J Neurosci Methods 172:270-6. 2008
    ..This pilot study suggests that the method may provide a novel tool for examining the degree and progression of dementia...
  7. pmc Effects of growth and exercise on composition, structural maturation and appearance of osteoarthritis in articular cartilage of hamsters
    Petro Julkunen
    Department of Clinical Neurophysiology, Kuopio University Hospital, Kuopio, Finland
    J Anat 217:262-74. 2010
    ..This may be considered beneficial. However, exercise at a young age demonstrated adverse effects on cartilage at a later age with a significant increase in the incidence of osteoarthritis...
  8. doi request reprint Comparison of single-phase isotropic elastic and fibril-reinforced poroelastic models for indentation of rabbit articular cartilage
    Petro Julkunen
    Department of Clinical Neurophysiology, Kuopio University Hospital, Kuopio, Finland
    J Biomech 42:652-6. 2009
    ..Thereby, this study highlights the feasibility of a simple indentation analysis...
  9. doi request reprint Biomechanical, biochemical and structural correlations in immature and mature rabbit articular cartilage
    P Julkunen
    Department of Clinical Neurophysiology, Kuopio University Hospital, Kuopio, Finland
    Osteoarthritis Cartilage 17:1628-38. 2009
    ..These changes lead to alterations in the mechanical properties of cartilage. In the present study, biomechanical, biochemical and structural relationships of articular cartilage during growth and maturation of rabbits are investigated...
  10. doi request reprint Contribution of tissue composition and structure to mechanical response of articular cartilage under different loading geometries and strain rates
    Petro Julkunen
    Department of Clinical Neurophysiology, Kuopio University Hospital, P O Box 1777, Kuopio 70211, Finland
    Biomech Model Mechanobiol 9:237-45. 2010
    ..These findings highlight how the results from mechanical tests of articular cartilage under different loading conditions are dependent upon tissue composition and structure...
  11. doi request reprint Maturation of collagen fibril network structure in tibial and femoral cartilage of rabbits
    P Julkunen
    Department of Clinical Neurophysiology, Kuopio University Hospital, Kuopio, Finland
    Osteoarthritis Cartilage 18:406-15. 2010
    ..These changes modulate the functional properties of cartilage. We studied maturation-related changes in the collagen network organization of cartilage as a function of tissue depth...
  12. doi request reprint Comparison of navigated and non-navigated transcranial magnetic stimulation for motor cortex mapping, motor threshold and motor evoked potentials
    Petro Julkunen
    Department of Clinical Neurophysiology, Kuopio University Hospital, Kuopio, Finland
    Neuroimage 44:790-5. 2009
    ..In summary, MEPs exhibit significant differences depending on whether navigation is used. However, the MTs are not significantly dependent on the discrete stimulation site...
  13. doi request reprint Effect of electrode cap on measured cortical motor threshold
    Petro Julkunen
    Department of Clinical Neurophysiology, Kuopio University Hospital, P O Box 1777, FI 70211 Kuopio, Finland
    J Neurosci Methods 176:225-9. 2009
    ..The electrode cap affects significantly the cortical MT measured as stimulation intensity making the comparison of MTs difficult with other studies not having used an electrode cap...
  14. pmc Composition of the pericellular matrix modulates the deformation behaviour of chondrocytes in articular cartilage under static loading
    Petro Julkunen
    Department of Clinical Neurophysiology, Kuopio University Hospital, Kuopio, Finland
    Med Biol Eng Comput 47:1281-90. 2009
    ..The development of cartilage repair materials could benefit from this information...
  15. doi request reprint Threshold curves for transcranial magnetic stimulation to improve reliability of motor pathway status assessment
    Petro Julkunen
    Department of Clinical Neurophysiology, Kuopio University Hospital, Kuopio, Finland
    Clin Neurophysiol 122:975-83. 2011
    ..To provide a new protocol for a simple determination of resting motor threshold (MT) and assessment of excitation-inhibition balance in motor cortex and pathways...
  16. ncbi request reprint Efficient reduction of stimulus artefact in TMS-EEG by epithelial short-circuiting by mini-punctures
    P Julkunen
    Department of Clinical Neurophysiology, Kuopio University Hospital, P O Box 1777, FI 70211 Kuopio, Finland
    Clin Neurophysiol 119:475-81. 2008
    ..We aimed at comparing the effects of two different electrode-to-skin contact preparation techniques on the stimulus artefact induced by transcranial magnetic stimulation (TMS) in electroencephalography (EEG) signals...
  17. doi request reprint Altered cortical inhibition in Unverricht-Lundborg type progressive myoclonus epilepsy (EPM1)
    Nils Danner
    Department of Clinical Neurophysiology, Kuopio University Hospital and University of Kuopio, POB 1777, Kuopio FI 70211, Finland
    Epilepsy Res 85:81-8. 2009
    ..The aim of this study was to assess the function of the motor cortex in Unverricht-Lundborg disease (ULD), progressive myoclonus epilepsy type 1 (EPM1)...
  18. ncbi request reprint Uncertainties in indentation testing of articular cartilage: a fibril-reinforced poroviscoelastic study
    Petro Julkunen
    Department of Physics, University of Kuopio, Kuopio, Finland Department of Clinical Neurophysiology, Kuopio University Hospital, Kuopio, Finland
    Med Eng Phys 30:506-15. 2008
    ....
  19. doi request reprint Navigated transcranial magnetic stimulation and computed electric field strength reduce stimulator-dependent differences in the motor threshold
    Nils Danner
    Department of Clinical Neurophysiology, Kuopio University Hospital, Kuopio, Finland
    J Neurosci Methods 174:116-22. 2008
    ..In addition, cortical excitability can be evaluated by using computed electric field strength as well as stimulator-dependent MT...
  20. doi request reprint Motor cortical plasticity is impaired in Unverricht-Lundborg disease
    Nils Danner
    Department of Clinical Neurophysiology, Kuopio University Hospital, Kuopio, Finland
    Mov Disord 26:2095-100. 2011
    ..The impaired cortical plasticity may be associated with the previously reported structural and physiological abnormalities of the primary motor cortex...
  21. doi request reprint Factors influencing cortical silent period: optimized stimulus location, intensity and muscle contraction
    Laura Säisänen
    Department of Clinical Neurophysiology, Kuopio University Hospital, Kuopio, Finland
    J Neurosci Methods 169:231-8. 2008
    ..MEP should be included in SP as the error from marking the onset diminishes. This study provides a guideline for the consistent measurement of SP, which is applicable when using navigated or traditional TMS...
  22. doi request reprint Corticospinal output and cortical excitation-inhibition balance in distal hand muscle representations in nonprimary motor area
    Selja Vaalto
    Department of Clinical Neurophysiology, University of Eastern Finland, Kuopio, Finland
    Hum Brain Mapp 32:1692-703. 2011
    ..The lower SICI in NPMA at an ISI of 2 ms may reflect less strict topographic organization and readiness to reorganization of neural circuits during motor learning or after motor deficits...
  23. ncbi request reprint Characterization of articular cartilage by combining microscopic analysis with a fibril-reinforced finite-element model
    Petro Julkunen
    Department of Physics, University of Kuopio, Kuopio, Finland
    J Biomech 40:1862-70. 2007
    ..The present study demonstrates that modern quantitative microscopic methods in combination with the FRPVE model are feasible methods to characterize the structure-function relationships of articular cartilage...
  24. doi request reprint Motor potentials evoked by navigated transcranial magnetic stimulation in healthy subjects
    Laura Säisänen
    Department of Clinical Neurophysiology, Kuopio University Hospital, Kuopio, Finland
    J Clin Neurophysiol 25:367-72. 2008
    ..In conclusion, we provide a modified baseline of TMS-related parameters for healthy subjects. Earlier such large-scale baseline material has not been available...
  25. ncbi request reprint Collagen network primarily controls Poisson's ratio of bovine articular cartilage in compression
    Panu Kiviranta
    Department of Clinical Physiology and Nuclear Medicine, Kuopio University Hospital and University of Kuopio, Kuopio, Finland
    J Orthop Res 24:690-9. 2006
    ..We conclude that Poisson's ratio of articular cartilage is primarily controlled by the content and organization of the collagen network...
  26. ncbi request reprint Ultrasound speed in articular cartilage under mechanical compression
    Heikki J Nieminen
    Department of Physics, University of Kuopio, Kuopio, Finland
    Ultrasound Med Biol 33:1755-66. 2007
    ..A method to eliminate the compression-related errors in measured strain and elastic properties may be needed in mechano-acoustic measurements of articular cartilage...
  27. doi request reprint Non-invasive preoperative localization of primary motor cortex in epilepsy surgery by navigated transcranial magnetic stimulation
    Laura Säisänen
    Department of Clinical Neurophysiology, Kuopio University Hospital, Kuopio, Finland
    Epilepsy Res 92:134-44. 2010
    ..Navigated transcranial magnetic stimulation (nTMS) is a non-invasive method to localize the primary motor cortex (M1)...
  28. doi request reprint Group-level variations in motor representation areas of thenar and anterior tibial muscles: Navigated Transcranial Magnetic Stimulation Study
    Eini Niskanen
    Department of Clinical Neurophysiology, Kuopio University Hospital, Finland
    Hum Brain Mapp 31:1272-80. 2010
    ..Furthermore, it is proposed that the presented methodology to study TMS locations at the group level on standard space will be a suitable tool for research purposes in population studies...
  29. doi request reprint Short- and intermediate-interval cortical inhibition and facilitation assessed by navigated transcranial magnetic stimulation
    Laura Säisänen
    Department of Clinical Neurophysiology, Kuopio University Hospital, Kuopio, Finland
    J Neurosci Methods 195:241-8. 2011
    ....
  30. doi request reprint Alterations of motor cortical excitability and anatomy in Unverricht-Lundborg disease
    Nils Danner
    Institute of Clinical Medicine, School of Medicine, Faculty of Health Sciences, University of Eastern Finland, Kuopio, Finland Department of Clinical Neurophysiology, Kuopio University Hospital, Kuopio, Finland
    Mov Disord 28:1860-7. 2013
    ..This is the largest clinical series on Unverricht-Lundborg disease and the first study describing parallel pathophysiological and structural alterations associated with the severity of the symptoms...
  31. doi request reprint Minor influence of lifelong voluntary exercise on composition, structure, and incidence of osteoarthritis in tibial articular cartilage of mice compared with major effects caused by growth, maturation, and aging
    Tommi Närhi
    Department of Anatomy, Institute of Biomedicine, University of Eastern Finland, Kuopio, Finland
    Connect Tissue Res 52:380-92. 2011
    ....
  32. doi request reprint Primary motor cortex alterations in a compound heterozygous form of Unverricht-Lundborg disease (EPM1)
    Nils Danner
    Department of Clinical Neurophysiology, Institute of Clinical Medicine, School of Medicine, University of Eastern Finland and Kuopio University Hospital, POB 1777, FIN 70211 Kuopio, Finland
    Seizure 20:65-71. 2011
    ..202C>T mutation in the CSTB gene (chEPM1). There are no previous clinical or neurophysiological studies on these patients. Thus, we aimed to characterize possible functional alterations in primary motor cortical areas...
  33. doi request reprint Experimental and computational analysis of soft tissue mechanical response under negative pressure in forearm
    Jarkko T Iivarinen
    Department of Applied Physics, University of Eastern Finland, Kuopio, Finland
    Skin Res Technol 19:e356-65. 2013
    ..Instrumentation, relying on the use of negative pressure (suction), has been introduced to reduce pathological tissue swelling. Then, relative contribution of skin, adipose tissue and muscle, to the overall mechanical response is not known...
  34. doi request reprint Long-term plasticity may be manifested as reduction or expansion of cortical representations of actively used muscles in motor skill specialists
    Selja Vaalto
    Department of Clinical Neurophysiology, Helsinki University Central Hospital, Helsinki, Finland
    Neuroreport 24:596-600. 2013
    ..Larger cortical representations are related to skill demanding coactivation of proximal and distal lower limb muscles. ..
  35. doi request reprint Differences in acoustic properties of intact and degenerated human patellar cartilage during compression
    Panu Kiviranta
    Department of Physics, University of Kuopio, Kuopio, Finland
    Ultrasound Med Biol 35:1367-75. 2009
    ..The present results address the need to consider possible uncertainties in mechano-acoustic measurements of articular cartilage and call for methods to correct the effect of variable sound speed during compression...
  36. doi request reprint Precision of nanoindentation protocols for measurement of viscoelasticity in cortical and trabecular bone
    Hanna Isaksson
    Department of Physics and Mathematics, University of Eastern Finland, PO Box 1627, Kuopio 70211, Finland
    J Biomech 43:2410-7. 2010
    ..Our results indicate that several methods are feasible for the determination of viscoelastic properties of bone material. The high frequency semi-dynamic test showed the highest precision within the tested nanoindentation protocols...
  37. doi request reprint Stress-relaxation of human patellar articular cartilage in unconfined compression: prediction of mechanical response by tissue composition and structure
    Petro Julkunen
    Department of Clinical Neurophysiology, Kuopio University Hospital, POB 1777, FI 70211, Kuopio, Finland
    J Biomech 41:1978-86. 2008
    ..98). Our results suggest that specific information on tissue composition and structure might enable assessment of cartilage mechanics without mechanical testing...
  38. ncbi request reprint Collagen network of articular cartilage modulates fluid flow and mechanical stresses in chondrocyte
    Rami K Korhonen
    Department of Applied Physics, University of Kuopio, POB 1627, 70211, Kuopio, Finland
    Biomech Model Mechanobiol 5:150-9. 2006
    ..Therefore, the integrity of the collagen network may be an important determinant in cell stimulation and in the control of the matrix maintenance...
  39. doi request reprint Effect of individual anatomy on resting motor threshold-computed electric field as a measure of cortical excitability
    Nils Danner
    Institute of Clinical Medicine, School of Medicine, Faculty of Health Sciences, University of Eastern Finland, Kuopio, Finland
    J Neurosci Methods 203:298-304. 2012
    ..Computational electric field (EF) estimation could theoretically be applied to reduce the effect of anatomical differences, since it provides a more direct measure of corticospinal excitability...
  40. doi request reprint Experimental and computational analysis of soft tissue stiffness in forearm using a manual indentation device
    Jarkko T Iivarinen
    Department of Applied Physics, University of Eastern Finland, Kuopio, Finland
    Med Eng Phys 33:1245-53. 2011
    ..In conclusion, the present stiffness meter may be used to quantify in vivo mechanical properties of soft tissues in the forearm, sensitively modulated by soft tissue swelling and muscle loading...
  41. doi request reprint Assessment of the 3-D shape and mechanics of the proximal femur using a shape template and a bone mineral density image
    Sami P Väänänen
    Department of Physics and Mathematics, University of Eastern Finland, Kuopio, Finland
    Biomech Model Mechanobiol 10:529-38. 2011
    ..The method could provide more information of the mechanical characteristics of bone based on 2D BMD radiography and could ultimately lead to more sensitive diagnosis of osteoporosis...
  42. pmc Combining transcranial magnetic stimulation and electroencephalography may contribute to assess the severity of Alzheimer's disease
    Petro Julkunen
    Department of Clinical Neurophysiology, Kuopio University Hospital, POB 1777, 70211 Kuopio, Finland
    Int J Alzheimers Dis 2011:654794. 2011
    ..Given the small sample size, further studies may be needed to confirm the results...
  43. doi request reprint Mechanical characterization of articular cartilage by combining magnetic resonance imaging and finite-element analysis: a potential functional imaging technique
    P Julkunen
    Department of Physics, University of Kuopio, Kuopio, Finland
    Phys Med Biol 53:2425-38. 2008
    ..Contradictorily, high bulk T(2) can also be found in stiff cartilage with a multilaminar collagen fibril network. By emerging MRI and FEM, the present study establishes a step toward functional imaging of articular cartilage...
  44. doi request reprint Novel parameters indicate significant differences in severity of obstructive sleep apnea with patients having similar apnea-hypopnea index
    Antti Kulkas
    Department of Clinical Neurophysiology, Seinajoki Central Hospital, Hanneksenrinne 6, 60220 Seinajoki, Finland
    Med Biol Eng Comput 51:697-708. 2013
    ..Thus, the present results suggest that the novel parameters could bring new insight to the individual estimation of the severity of SAHS...
  45. doi request reprint Depth-wise progression of osteoarthritis in human articular cartilage: investigation of composition, structure and biomechanics
    S Saarakkala
    Department of Physics, University of Kuopio, Kuopio, Finland
    Osteoarthritis Cartilage 18:73-81. 2010
    ..e., collagen and proteoglycans (PGs), during OA progression. Further, it is unknown how the depth-wise changes affect local tissue strains during compression. Our aim was to address these issues...
  46. pmc Parallel input makes the brain run faster
    Tommi Raij
    MGH MIT HMS Athinoula A Martinos Center for Biomedical Imaging, Charlestown, MA 02129, USA
    Neuroimage 40:1792-7. 2008
    ..This arrangement could also allow very early top-down modulation of the bottom-up stream of sensory information...