Dr. Diaz Laboratory
We have federal funded projects focused on assessing the role of sensory feedback (sensory information) coming from our lower limbs via peripheral nerves onto networks (groups) of cells located in our spinal cord after a spinal cord injury (SCI). We also have projects studying the role of spinal networks and its component neurons in the control of locomotion and its changes due to the use of neuromodulatory substances such as caffeine, ethanol, taurine, and others.
To perform the experiments which are relevant to the projects described above, we use electrophysiological techniques, such as intracellular whole-cell patch clamp recordings and extracellular nerve recordings, confocal imaging, and immunohistochemistry.
Our research and mentoring objectives:
1) Neuromodulation of cellular networks
The effects of that neural chemicals known as neurotransmitters or neuropeptides can have on basic mechanisms that occur in our central nervous system is well documented and is known to be very significant. The consumption of known natural or artificial psychostimulants, such as caffeine, by animals or humans can have a significant impact on the short and long-term performance of cognitive and/or motor skills. These results support the stimulant effects of caffeine onto adenosine receptors located within the spinal network controlling walking, acting mostly through the inhibition of A1 adenosine receptors. We want to understand the cellular mechanisms by which adenosine receptor antagonists and agonist modulates the firing properties of the spinal CPG network for locomotion since adenosine receptors have been related to the reduction of inflammation and neuroprotection after a spinal cord injury.
2) Identification of the segmental neural circuits controlling trunk motor coordination
Trunk motor control is crucial after a spinal cord injury (SCI) for both animals and humans. Several rehabilitative strategies are aimed at enhancing trunk stabilization and postural control after an SCI. It has been recently shown that SCI rats that can still support weight show increased compression and stiffening of the trunk as a compensating mechanism to improve overall motor activity patterns during standing and walking. Additionally, effective robot rehabilitation training on adult rats spinally transected as neonates has shown significant reorganization of the trunk motor cortex to be induced and a partial reversal of some plastic changes that may be adaptive in non-stepping paraplegia after SCI. Trunk stabilization has also been proven to be essential for numerous wheel chair activities and for postural control and propulsion during assisted locomotion in human SCI patients. Thus the study of the thoracic neural network involved in trunk stabilization and postural control will refine current therapeutic strategies for treating SCI patients by including the reacquisition of trunk-related motor activity as part of the rehabilitation process.
3) Mentoring impact
These studies expose students from underrepresented groups in science (including hispanics and women) to advanced instrumentation and experimental techniques. Furthering the scientific career of underrepresented groups in science is of high priority in our research laboratory and aligned to the programmatic mission of federal organizations such as the National Institute of Health (NIH) and the National Science Foundation (NSF).
- Mildred Camacho, B.S.
- Garrett Seale, Ph.D.
- Marla S. Rivera-Oliver, B.S.
- Ernesto Cabezas-Bou, B.S.
- Yocasta Alvarez-Bagnarol, B.S.
- Lauren Rivera-Pagan
- Christian Ayala
- Ariana Saadipour-Selles
- Jean M. Acevedo, Ph.D.
- Nikol Matos-Vergara, M.S. Student
- Alexandra Santana, B.S.
Díaz-Ríos M., Dombeck D., Webb W.W., and Harris-Warrick R. M. Serotonin modulates dendritic calcium influx in commissural interneurons in the mouse spinal locomotor network. (2007) J Neurophysiol 98(4):2157-67.
Wilson J., Dombeck D., Díaz-Ríos M., Harris-Warrick R.M., and Brownstone R.M. Two-photon calcium imaging of network activity in XFP expressing neurons in the mouse. (2007) J Neurophysiol. 97(4):3118-25.
Zhong G., Díaz-Ríos M., and Harris-Warrick R.M. Intrinsic and functional differences among commissural interneurons in the central pattern generator for locomotion in the neonatal mouse. (2006) J Neurosci. 26(24):6509-17.
Díaz-Ríos M., and Miller M.W. Target-specific regulation of synaptic efficacy in the feeding central pattern generator of Aplysia: Potential substrates for behavioral plasticity? (2006) Biol Bull. 210(3):215-29.
Zhong G., Díaz-Ríos M. and Harris-Warrick R.M. Serotonin modulates the properties of ascending commissural interneurons in the neonatal mouse spinal cord. (2006) J Neurophysiol. 95(3):1545-55. Epub 2005 Dec 7.
Díaz-Ríos M., and Miller M.W. Rapid Dopaminergic Signaling by Interneurons that Contain Markers for Catecholamines and GABA in the Feeding Circuitry of Aplysia. (2005) J. Neurophysiol. 93(4): 2142-56.
Walters E.T., Bodnarova M., Billy A.J., Dulin M.F., Diaz-Rios M., Miller M.W., and Moroz L.L. Somatotopic organization and functional properties of mechanosensory neurons expressing sensorin-A mRNA in Aplysia californica. (2004) J. Comp. Neurol. 471(2); 219-240.
Wu J.S., Jing J., Díaz-Ríos M., Miller M.W., Kupfermann I. and Weiss K.R. Identification of a GABA-containing Cerebral-Buccal Interneuron-11 in Aplysia californica. (2003) Neurosci. Lett.;341(1):5-8.
1) NIH 1P20GM103642-01A1 Treistman (PD) / Diaz-Ríos (PI) 07/01/13 – 06/30/18
Center for Neuroplasticity at the University of Puerto Rico
Subproject title: The Role of Sensory Input to Mammalian Locomotion After the Loss of Supraspinal Inputs
1) DoD W911NF-07-R-002 Miller (PI) 09/01/07 – 08/31/09