Research

1. Neural encoding of sensorimotor information:
   For the past 20 years, I have studied how sensory and motor information is encoded in the cortex. For my PhD and during my first post-doc period I examined the impact of shizophrenia on sensory information processing. Following that work, I transitioned to sensorimotor encoding and used the rat whisker system and the rat forepaw and hindpaw system. These studies elucidated the role that the precise timing of individual action potentials, or spikes, play in encoding information. This work developed several novel methods to assess neural encoding. Importantly, this work helped to explain that trial-to- trial variability contributes to the representation of information by autocorrelations and how movement timing is encoded.

   Selected Publications:

   • Knudsen EB, Flint RD, Moxon KA. Encoding of temporal intervals in the rat hindlimb sensorimotor cortex. Front Syst Neurosci. 2012;6:67. PubMed PMID: 23055956; PubMed Central PMCID: PMC3458261.
   • Moxon KA, Hale LL, Aguilar J, Foffani G. Responses of infragranular neurons in the rat primary somatosensory cortex to forepaw and hindpaw tactile stimuli. Neuroscience. 2008 Oct 28;156(4):1083-92. PubMed PMID: 18775766.
   • Leiser SC, Moxon KA. Responses of trigeminal ganglion neurons during natural whisking behaviors in the awake rat. Neuron. 2007 Jan 4;53(1):117-33. PubMed PMID: 17196535.
   • Tutunculer B, Foffani G, Himes BT, Moxon KA. Structure of the excitatory receptive fields of infragranular forelimb neurons in the rat primary somatosensory cortex responding to touch. Cereb Cortex. 2006 Jun;16(6):791-810. PubMed PMID: 16120794.
2. Impact of therapy on supraspinal reorganization after SCI (spinal cord injury):
   My lab is especially interested in how the brain encodes information and the impact of neural injury and disease on that encoding. Most of our efforts have been applied to SCI and we were the first to show how therapy alters cortical reorganization in neonatally animals and how some therapies can by synergistic while others are competing therapies for cortical reorganization (manusript in press, Foffani et al., Journal of Neurorehabilitation and Repair).

   Selected Publications:

   • Foffani G, Shumsky J, Knudsen EB, Ganzer PD, Moxon KA. Interactive Effects Between Exercise and Serotonergic Pharmacotherapy on Cortical Reorganization After Spinal Cord Injury. Neurorehabil Neural Repair. 2016 Jun;30(5):479-89. PubMed PMID: 26338432; PubMed Central PMCID:
     PMC4777689.
   • Ganzer PD, Manohar A, Shumsky JS, Moxon KA. Therapy induces widespread reorganization of motor cortex after complete spinal transection that supports motor recovery. Exp Neurol. 2016 May;279:1-12. PubMed PMID: 26826448.
   • Moxon KA, Kao T, Shumsky JS. Role of cortical reorganization on the effect of 5-HT pharmacotherapy for spinal cord injury. Exp Neurol. 2013 Feb;240:17-27. PubMed PMID: 23159333.
   • Kao T, Shumsky JS, Murray M, Moxon KA. Exercise induces cortical plasticity after neonatal spinal cord injury in the rat. J Neurosci. 2009 Jun 10;29(23):7549-57. PubMed PMID: 19515923; PubMed Central PMCID: PMC2743445.
3. Brain-machine Interface Technology:
   I have worked in collaboration with several other groups to advance technology for brain-machine interfaces. In addition, within my own lab, I have developed novel techniques to improve the longevity of microelectrodes and neural recordings from awake, freely moving animals. Results of this work have established 1) that ceramic is an ideal insulator for chronic, thin-film microelectrodes and has been adopted by many labs and 2) that porous silicon can you be used in thin-flim microelectrodes to deliver drugs that are neuroprotective. More recently, we have moved to human studies to record single neurons from epilepsy patients to develop seizure prevention systems.

   Selected Publications:

   • Misra A, Burke JF, Ramayya AG, Jacobs J, Sperling MR, Moxon KA, Kahana MJ, Evans JJ, Sharan AD. Methods for implantation of micro-wire bundles and optimization of single/multi-unit recordings from human mesial temporal lobe. J Neural Eng. 2014 Apr;11(2):026013. PubMed PMID: 24608589;
     PubMed Central PMCID: PMC4019382.
   • Misra A, Kondaveeti P, Nissanov J, Barbee K, Shewokis P, Rioux L, Moxon KA. Preventing neuronal damage and inflammation in vivo during cortical microelectrode implantation through the use of poloxamer P-188. J Neural Eng. 2013 Feb;10(1):016011. PubMed PMID: 23337321; PubMed Central
     PMCID: PMC4470293.
   • Moxon KA, Hallman S, Sundarakrishnan A, Wheatley MS, Nissanov J, Barbee K. Long-term recordings of multiple, single-neurons for clinical applications: the emerging role of the bioactive microelectrode. Materials . 2009; 2(4):1762-1794..
   • Moxon KA, Kalkhoran NM, Markert M, Sambito MA, McKenzie JL, Webster JT. Nanostructured surface modification of ceramic-based microelectrodes to enhance biocompatibility for a direct brain-machine interface. IEEE Trans Biomed Eng. 2004 Jun;51(6):881-9. PubMed PMID: 15188854.
4. Neuronal plasticity and brain-machine interface experimental paradigms after SCI (spinal cord injury):
   We extended some of our earliest work on BMI to develop a BMI for restoration of hindlimb function. We used this novel BMI paradigm to study neuronal plasticity after SCI. Our results show that the rat model is a good model of BMI plasticity in that the impact of BMI on neuronal encoding in the rat is simialr toat of non-human primates. Furthermore, we used this lower limb BMI to study the impact of BMI on neuronal plasticity after SCI.

   Selected Publications:

   • Liu C, Foffani G, Scaglione A, Aguilar J, Moxon KA. Adaptation of Thalamic Neurons Provides Information about the Spatiotemporal Context of Stimulus History. J Neurosci. 2017 Oct 11;37(41):10012-10021. PubMed PMID: 28899918; PubMed Central PMCID: PMC5637111.
   • Knudsen EB, Powers ME, Moxon KA. Dissociating movement from movement timing in the rat primary motor cortex. J Neurosci. 2014 Nov 19;34(47):15576-86. PubMed PMID: 25411486; PubMed Central PMCID: PMC4236394.
   • Graziano A, Foffani G, Knudsen EB, Shumsky J, Moxon KA. Passive exercise of the hind limbs after complete thoracic transection of the spinal cord promotes cortical reorganization. PLoS One. 2013;8(1):e54350. PubMed PMID: 23349859; PubMed Central PMCID: PMC3551921.
   • Manohar A, Flint RD, Knudsen E, Moxon KA. Decoding hindlimb movement for a brain machine interface after a complete spinal transection. PLoS One. 2012;7(12):e52173. PubMed PMID: 23300606; PubMed Central PMCID: PMC3531410.
5. Development of seizure control system:
   Through animal models, and most recently in humans (manuscript under review), we have been working to understand how seizures initiate and spread throughout the brain. This work has highlighted the role of synchronous inhibition and how local fields can influence the activity of populations of interneurons to spread seizures. This work has also produced two patents.

   Selected Publications:

   • Karunakaran S, Grasse DW, Moxon KA. Role of CA3 theta-modulated interneurons during the transition to spontaneous seizures. Exp Neurol. 2016 Sep;283(Pt A):341-52. PubMed PMID: 27353968.
   • Grasse DW, Karunakaran S, Moxon KA. Neuronal synchrony and the transition to spontaneous seizures. Exp Neurol. 2013 Oct;248:72-84. PubMed PMID: 23707218.
   • Karunakaran S, Grasse DW, Moxon KA. Changes in network dynamics during status epilepticus. Exp Neurol. 2012 Apr;234(2):454-65. PubMed PMID: 22309830.
   • Grasse DW, Moxon KA. Correcting the bias of spike field coherence estimators due to a finite number of spikes. J Neurophysiol. 2010 Jul;104(1):548-58. PubMed PMID: 20484529.

1.

Encoding of temporal intervals in the rat hindlimb sensorimotor cortex

 
 
 
 
 
 
 
 
 
2.

Therapy induces widespread reorganization of motor cortex after complete spinal transection that supports motor recovery

3.

Long-Term Recordings of Multiple, Single-Neurons for Clinical Applications: The Emerging Role of the Bioactive Microelectrode

4.

Dissociating movement from movement timing in the rat primary motor cortex

5.

Long-Term Recordings of Multiple, Single-Neurons for Clinical Applications: The Emerging Role of the Bioactive Microelectrode