|
|
|
Research Focus
During mechanical deformations of soft tissues (e.g., skin, ligaments,
and muscles), mechanically sensitive neurons are activated giving rise
to our perceptions of touch, stretch, pressure, proprioception, and/or
pain. The receptor endings of these neurons do not experience the global
state of deformation; rather, they only experience the local mechanical
state developed in their immediate environs. This local mechanical state
is characterized by the stress (related to force) and strain (related
to deformation) tensors. In normal skin and ligaments, we have discovered
that both mechanoreceptors (neurons signaling non-noxious stimuli) and
nociceptors (neurons signaling noxious stimuli) encode the mechanical
stress rather than the strain developed during tissue loading. Further,
cutaneous nociceptors have been found to be much more sensitive to tensile
stress than to compressive stress. Thus, during noxious indentations of
skin overlying a soft substrate (like muscle or fat), a population of
nociceptors would likely be activated to encode the stimuli. We have developed
a model that predicts the extent and magnitude of the nociceptor population
activation. Experiments are being undertaken to test the validity of the
model and to further refine it.
The development of a direct neural interface has been a long-sought goal
of both the neuroscience and biomedical engineering communities. Such
an interface would be useful for examining basic neuroscience questions
and for use with patients who have suffered neural lesions. An interface
to a peripheral nerve must solve a number of problems that span engineering
and neuroscience disciplines. Advanced signal processing techniques must
be incorporated with sensor designs in order to record the small magnitude
signals from individual neurons that comprise the nerve. For chronic implantation,
the sensor and its wiring must be biocompatible and durable. Research
into the development of such a sensor is underway.
Low back pain afflicts 80% of adults in America sometime during their
lives. One of the causes of low back pain is due to stimulation of mechano-nociceptors
(high-threshold, mechanically sensitive neurons) that innervate the lumbar
facet joint capsule. The capsule is a planar ligament that covers the
dorsal aspect of the facet joint. Mechanically, it helps to constrain
the motion of the facet joints. If mechanical loads exerted on the capsule
during motion of the spine are too large, then mechano-nociceptors will
be stimulated. Research is being conducted to measure mechanical strain
(a quantitative measure of stretch) in the facet capsule during physiological
motions of the spine (e.g., flexion, extension, side bending). These data
will be incorporated into a computational model of the spine (using the
finite element method) to be able to predict how mechanoreceptors and
nociceptors respond to different types spinal loadings encountered in
ordinary physical activities (e.g., sitting and walking) as well as traumatic
events.
Fig. 1. Co-localization, using double labeling, of function-blocking
anti-integrin a2 mAb and anti-peripherin antibody in a cutaneous
mechanoreceptor. Images show the presence of the terminal ending
(arrow) and its axon (arrowhead) of a single neuron present in the
dermis, but near the epidermis (Ep), and labeled strongly for both
integrin a2 (A) as well as for peripherin (B). Superimposed A and
B images are shown in C. Digital subtraction of everything except
the sites of co-localization (D) clearly indicates strong and weaker
co-localization of integrin a2 and peripherin at the ending and
axon of this neuron, respectively. Adjacent sections were stained
with secondary antibody alone (which served as a negative control),
and resulted in sections without any labeling. Due to minor folding
at the edge of the section, the epidermis also stained for peripherin.
Scale bar = 50 micrometers. |
Education
- Post-Doc. - Neurophysiology, Yale University School of Medicine, 1995-96
- Ph.D. - Biomedical Sciences, Worcester Polytechnic Institute & Univ.
Mass. Medical School, 1992-95
- M.Sc. - Biomed. Engineering, Boston University, Boston, MA, 1989-91
- B.S., D.C. - Chiropractic, L. A. College of Chiropractic, Glendale,
CA, 1976-80
Academic Appointments
- 1992 - 1995: Post-Doctoral Fellow, Univ of Mass. Medical School, Dept.
of Physiology, Worcester, MA
- 1995 - 1996: Post-Doctoral Associate, Dept. of Anesthesiology, School
of Medicine, Yale University
- 1996 - 1997: Associate Research Scientist, Dept. of Anesthesiology,
School of Medicine, Yale University
- 1996 - 1997: Faculty Member, Biomedical Engineering Program, Yale
University
- 1999 - current: Faculty Member, Program in Neurobiology & Behavior,
S.U.N.Y. Stony Brook
- 1999 - current: Graduate Program Director, Program in Biomedical Eng.,
S.U.N.Y. Stony Brook
- 2003 - current: Assoc. Professor (tenured) of Biomedical Engineering,
S.U.N.Y. Stony Brook
Publications
Click
here to search Partap Khalsa's PubMed listings
Peer-Reviewed Publications
- Khalsa PS and Ge W. Encoding
of tensile stress during stretch by group III and IV muscle mechano-nociceptors
in rat gracilis muscle. Muscle & Nerve 30(2):216-224, 2004.
- Khalsa PS. Biomechanics
of Musculoskeletal Pain: Dynamics of the Neuromatrix. Journal of
Electromyography and Kinesiology (Invited review, Accepted August 2003).
- Ianuzzi A, Little J, Chiu J, Baitner A, Kawchuk G, and Khalsa
PS. Human
lumbar facet joint capsule strains: I. During physiological motions.
The Spine Journal (Accepted, July 2003; Runner-up in Outstanding Paper
Competition).
- Little J, Ianuzzi A, Chiu J, Baitner A, Khalsa PS.
Human
lumbar facet joint capsule strains. II. Alteration of strains subsequent
to anterior interbody fixation. The Spine Journal (Accepted, July
2003; Runner-up in Outstanding Paper Competition).
- Ge W and Khalsa PS. Encoding
of compressive stress during indentation by group III and IV muscle
mechano-nociceptors rat gracilis muscle. J Neurophysiology 89(2):785-792,
2003.
- Friedman RM, Khalsa PS, Greenquist K, and LaMotte
RH. Feature
coding by spatially distributed populations of slowly and rapidly adapting
mechanoreceptor: Location and direction of motion of objects stroked
across the monkey fingerpad. J Neuroscience 22(21):9556-9566, 2002.
- Ge W, Khalsa PS. Encoding
of compressive stress during indentation by slowly adapting type I mechanoreceptors
in rat hairy skin. J Neurophysiol. 2002 Apr;87(4):1686-93.
- Khalsa PS, Zhang C, Sommerfeldt D, Hadjiargyrou M. Expression
of integrin alpha2beta1 in axons and receptive endings of neurons in
rat, hairy skin. Neurosci Lett. 2000 Oct 20;293(1):13-6.
- Khalsa PS, Zhang C, Qin YX. Encoding
of location and intensity of noxious indentation into rat skin by spatial
populations of cutaneous mechano-nociceptors. J Neurophysiol. 2000
May;83(5):3049-61.
- Khalsa PS. Muscle pain due to mechanical stimuli: A review.
J Neuromusculoskeletal System 7(1):1-8, 1999.
- LaMotte, R.H, Friedman, R.M., Lu, C., Khalsa, P.S. and Srinivasan,
M.A., Raised
object on a planar surface stroked across the fingerpad: Responses of
cutaneous mechanoreceptors to shape and orientation. J Neurophysiology
80: 2446-2466, 1998.
- Khalsa PS, Friedman RM, Srinivasan MA, and LaMotte RH. Encoding
of shape and orientation of objects indented into the monkey fingerpad
by populations of slowly and rapidly adapting mechanoreceptors.
J Neurophysiology 79(6): 3238-3251, 1998.
- Khalsa PS, LaMotte RH and Grigg P. Tension
and compression responses of nociceptors in rat hairy skin. J Neurophysiology
77(7):492-505, 1997.
- Khalsa PS and Eisenberg SR. Compressive
behavior of articular cartilage is not completely explained by proteoglycan
osmotic pressure. J Biomechanics 30:589-594, 1997.
- Khalsa PS, Hoffman AH and Grigg P. Mechanical
states encoded by stretch sensitive neurons in feline joint capsule.
J Neurophysiology 76(1): 175-187, 1996.
- Khalsa PS and Grigg P. Responses
of mechanoreceptor neurons in cat knee joint capsule before and after
ACL transection. J Orthopaedic Research 14(1):114-122, 1996.
Abstracts and Conference Presentations
- Ge W and Khalsa PS. Mechanical States Encoded by
Muscle Nociceptors during Tension in Isolated Rat Gracilis Muscle. Abstracts
of the Society for
Neuroscience 29: 2003 .
- Ianuzzi A, Little J, and Khalsa PS. Human lumbar
facet joint capsule
strains during simulated spinal manipulation. Annals of Biomedical
Engineering 31: October 2003 (11.5.3).
- Little J, Ianuzzi A, and Khalsa PS. Material Properties:
Optically
measuring facet joint capsule plane strain using image correlation.
Annals of Biomedical Engineering 31: October 2003 (11.P5.20).
- Khalsa PS. Traditional and non-Traditional Pain Perspectives
(Invited
Lecture), The State-of-the-Art Research (STAR) Symposium: Perspectives
on Musculoskeletal Disorder Causation and Control, Sponsored by NIOSH
(May 2003)
- Khalsa PS. Impact of BioSensor Technology on Life
Sciences (Invited
Presentation), Annual Life Science Summit, Hauppauge, NY (May 2003)
- Little, J; Ianuzzi, A; Baitner, A; Chiu, J; and Khalsa,
P. Altered facet
capsule strains as a result of lumbar vertebrae fixation. Proceedings
of the Bioengineering Conference (June 2003).
- Ianuzzi, A; Little, J; Baitner, A; Chiu, J; Kawchuk, G., and Khalsa,
P.
Facet Joint Capsule Strains of Human Lumbar Spine Specimens During
Physiological Motions. Proceedings of the Bioengineering Conference
(June 2003: awarded First Place in the 20d03 ASME Summer Bioengineering
Conference, Master's Level Best Paper Competition).
- Khalsa PS. Facet joint capsule and spinal manipulation
(Invited
Presentation). 7th Annual Research Agenda Conference, Sponsored by U.S.
Public Health Service, New Orleans, LA (March 2003)
- Ge W and Khalsa PS. Mechanical States Encoded by
Muscle Nociceptors during Indentation in Isolated Rat Gracilis Muscle.
Abstracts of the Society
for Neuroscience 28: 2002.
- Saldanha A, Qin YC, and Khalsa PS. Finite element
analysis of mechanical
states in human lumbar facet joint capsule. Annals of Biomedical
Engineering 30 (S1): October 2002.
- Khalsa PS, Chiu J, Aliberti N, and Sileo M. Biomechanical
evidence for
proprioceptive function of lumbar facet joint capsule (Invited
Presentation). 4th World Congress on Biomechanics (August 2002).
- Khalsa PS. Laboratory Methods in Chiropractic Research
(Invited
Presentation). Research Agenda Conference VII, March 16, 2002, New
Orleans, LA
- Khalsa PS. Trends in CAM Research in Neurophysiology.
(Invited
Presentation). Florida State University Symposium on Complementary and
Alternative Medicine, Tallahassee, FL, January 2002.
- Chiu J, Baitner A, Khalsa PS. Human Lumbar Spine
Facet Joint Capsule
Strains during Physiological Motions. Annals of Biomedical Engineering,
29 (S1): S18,3.1.6, 2001.
- Khalsa PS, Ge W, Hadjiargyrou M. Integrin alpha 2
beta 1 antibody modulates mechanoreceptor response in rat hairy skin.
Abstracts of the Society
for Neuroscience 27: 392.3, 2001.
- Khalsa PS, Bluestein D, Otter M, Hadjiargyrou M,
Qin YX and McLeod K.
Engineering Methods in Biomechanics: A Contextual Learning Strategy
for
Biomedical Engineering Pedagogy. Proceedings of ASEE Annual Conference
June 24-27, 2001, Albuquerque, NM.
- Kawchuk G, Khalsa PS, Cholewicki J (2000) In situ
quantification of
capsular strain from lumbar zygapophyseal joints. Proceedings of the
Consortium of Canadian Chiropractic Research Centres: 2nd Symposium,
Toronto, Ontario (10/21-22, 2000),17.
- Saldanha A, Kawchuk G, Tateosian V, Khalsa PS. Control
Software for
Measuring Physiological, Dynamic Facet Capsule Strains in Human, Lumbar
Spine Specimens. Annals of Biomedical Engineering 28(S1): S11,T1.71,
2000.
- Khalsa PS, Kawchuk G, Tateosian V, Cholewicki J.
Facet Capsule Plane
Strains in Human, Lumbar Spine Specimens. Annals of Biomedical
Engineering 28(S1): S49, T5.36, 2000.
- Otter MW, McLeod KJ, Khalsa PS, Qin YX, Hadjiargyrou M, and
Bluestein D. Contextual Learning Modules -A New Approach to Biomedical
Engineering Education. Proceedings of ASEE Annual Conference June 18-21,
2000, St. Louis, MO
- Hadjiargyrou M, Ahrens W and Khalsa PS. Expression of integrin
a2 in receptive endings of cutaneous neurons. Abstracts of the Society
for Neuroscience 25: 400.4, 1999. Khalsa PS and Grigg P. Cutaneous nociceptor
population representation of noxious indentation. Abstracts of the Society
for Neuroscience 25: 161.3, 1999.
- Qin YX and Khalsa PS. Nonlinear, orthotropic, phenomenological
model of facet joint capsule. Transactions of the BMES Conference (October,
1999).
- Khalsa PS. Cutaneous Nociceptor Population Representation of
Noxious Indentation. Abstracts of The Whitaker Foundation BME Conference,
1999.
- Qin YX and Khalsa PS. Compressive compliance of muscle emulated
with multi-layer silicone substrate. ORS Transactions 24:531, 1999.
- Friedman RM, Khalsa PS, Greenquist K, and LaMotte RH. Mechanoreceptor
population coding of the location, stroke direction, and orientation
of an object stroked across the fingerpad. Abstracts of the Society
for Neuroscience 24:247.3, 1998.
- Khalsa PS, Friedman RM, Greenquist K, Lu C, and LaMotte RH.
Shape and orientation encoding during indentation by a population of
mechanoreceptors in monkey fingerpad. Abstracts of the Society for Neuroscience
23: 396.4, 1997.
- Khalsa PS, LaMotte RH and Grigg P. Tension and compression
sensitivity of nociceptors in rat hairy skin. Abstracts of the Society
for Neuroscience 22: 790.13, 1996
- Friedman RM, Khalsa PS, Kennins P, Lu C, Fuglevand AJ, Srinivasan
MA and LaMotte RH. Shape encoding by spatial population of mechanoreceptors
in monkey fingerpad. Abstracts of the Society for Neuroscience 22: 710.10,
1996
- Khalsa PS. Biomechanics of Pain. Invited speaker at the John
B. Pierce Laboratory Seminar Series, New Haven, CT, Oct. 28, 1996.
- Khalsa PS, Friedman RM and LaMotte RH. Peripheral and cortical
encoding of shape. Invited speaker at the Workshop on the Effects of
Tissue Mechanics on Somatosensation, Institute for Sensory Research,
Syracuse University, June 10 - 11, 1996.
- Khalsa PS and Grigg P. Mechanical states encoded by joint capsule
afferents. Abstracts of the Society for Neuroscience 21(2):455.1, 1995
- Khalsa PS, Baba K, Prandi JL, and Eisenberg SR. Axial and radial
confining stresses in calf epiphyseal cartilage during uniaxial confined
compression. Annals of Biomedical Engineering 23(S1): 107, 1995
- Khalsa PS and Eisenberg SR. Direct measurement of axial and
radial confining stress in articular cartilage during uniaxial confined
compression. Transactions of the Orthopaedic Research Society 20(2):519,
1995
- Khalsa PS and Grigg P. Effects of ACL deficiency on mechanoreceptor
output. Abstracts of the 2nd World Congress on Biomechanics II:301b,
1994
Courses
|
|
