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Post-Doc, Columbia University, Mahoney-Keck Center for Brain & Behavior Research (2008-2010)
Post-Doc, Nathan Kline Institute for Psychiatric Research, Cognitive Neurophysiology Lab (2005-2008)
Ph.D., University College Dublin, Biomedical Engineering, (2001-2005)
B.E., University College Dublin, Electronic Engineering, (1997-2001)
Research in the Kelly Lab is focused on measuring and characterizing perceptual and cognitive brain signals that relate to behavior. We are particularly interested in linking non-invasively recorded electrical brain signals (EEG) in humans to specific neural computations involved in perception, attention and decision making. Our focus is on paradigm development and basic research findings, but we continually deploy our paradigms and dependent measures to studies of neurological and psychiatric disorders through several active clinical collaborations.
Our current research questions and projects include:
• The "details" of attention: when you know something about a sensory event before it happens, you're better at parsing that event to get the information you need, for the situation you're in. This ability is known as selective attention. We know that the underlying brain mechanisms involve alteration of activity in the brain's sensory hardware. But the details of this alteration remain a mystery. For example, under what special conditions will attention cause a change in neural activity at the very moment sensory information hits the cortex (see Kelly et al 2008)? We are currently resolving these details through quantitative characterization of behavior and careful manipulation of task demands, drawing on principles of sensory physiology and computational models of perceptual decision making.
• Neural mechanisms for perceptual decisions: When interacting with our sensory environment, we need to be sure about what we're looking at or hearing in order to decide how to act. This often requires gathering sensory evidence over time until a criterion level of certainty is reached. In collaboration with Redmond O'Connell of Trinity College Dublin, we have developed paradigms that allow us to isolate neural signals responsible for 1) encoding the relevant sensory quantity that is being decided upon (e.g. color or brightness), 2) integrating that information into a decision variable that traces the likelihood that the emerging decision is correct, and 3) preparing to act upon that decision. These are the three major stages of brain processing intervening between sensation and action, and our ability to provide a window onto each in isolation has considerable implications for understanding brain dysfunction. We are collaborating with Felice Ghilardhi and Clara Moisello of Sophie Davis School of Biomedical Education, CCNY to apply this approach in Parkinson's Disease (PD), Parkinson's with dementia (PDD) and dementia with Lewy Bodies (DLB); and we are collaborating with Michael Milham of the Child Mind Institute to apply the approach in neurodevelopmental disorders.
• Neural mechanisms for value-based decisions: We make choices according to the relative value of competing options. How does the brain represent the spatial positions of objects of different value? How does it represent how much more valuable one object is than another? We are currently characterizing electrical brain signals that provide such representations, and establishing their dynamics and association with actions used to acquire the valuable objects.
• Visual signals for contrast perception: The amplitude of visual activity driven by inputs of varying intensity and location can be measured efficiently by flickering visual stimuli in particular ways. These stimulation techniques are invaluable for examining fundamental visual processing mechanisms in humans and assessing deficits in the clinic. We are developing ways to enhance these measures by exploiting basic principles of sensory physiology and employing elementary signal processing. Our technique provides more robust indices of contrast perception, allowing us to examine the basic issue of how signals in visual neurons relate to what an observer reports seeing, and the influence of inhibitory neural interactions on visual perception. In collaboration with Fred Lado and Stephan Bickel of Montefiore Medical Center, we are applying this approach to the study of epilepsy, a condition related to neuronal over-excitation.
• The origin of the brain's "system failures": Even when doing simple tasks, behavioral performance fluctuates and errors occur. Sometimes the brain's sensory analyzers are just not good enough. Other times, we just drift off the task through mind-wandering or simply because we momentarily loosen our focus. What's going on in the brain when this happens, and to what degree does it depend on the nature of the task at hand? In certain continuous monitoring situations, neural signatures of an impending error are evident in global brain signals as much as 20 seconds before the error occurs (see O' Connell et al 2009). How specific are these error-predicting signals to the parameters of our continuous monitoring task - do they generalize to the corresponding situations in real life, e.g. when driving a car?
Postdoctoral scientists: Annabelle Blangero
Graduate Students: Isabel Vanegas, Eleftheria Veneti, Natalie Steinemann
Undergraduate students: Genevieve Price, Sarita Tamang, Dario Pinos, Nigel Gebodh, Kelsang Bista
Bioelectrical Circuits (BME 20500, undergraduate)
Dynamical Systems and Modeling (BME 30500, undergraduate)
Neural Systems and Behavior (BME 3200, graduate)
O'Connell RG, Dockree PD, Kelly SP. A supramodal accumulation-to-bound signal that determines perceptual decisions in humans. Nat Neurosci. 2012 In Press. PDF
Kelly SP, Schroeder CE, Lalor EC, What does polarity inversion of extrastriate activity tell us about striate contributions to the early VEP? A comment on Ales et al (2010), NeuroImage, In Press. PDF
Kelly SP, Gomez-Ramirez M, Foxe JJ. Spatial Attention Modulates Initial Afferent Activity in Human Primary Visual Cortex. Cereb Cortex. 2008, 18(11):2629-36. PDF
O'Connell RG, Dockree PM, Robertson IH, Bellgrove MA, Foxe JJ, Kelly SP. Uncovering the Neural Signature of Lapsing Attention: electrophysiological signals predict errors up to 20 seconds before they occur. J Neurosci. 2009. 29(26):8604-11. PDF
Murphy JW, Kelly SP, Foxe JJ, Lalor EC. Isolating early cortical generators of visual-evoked activity: a systems identification approach. Exp Brain Res. 2012, In Press. PDF
Lalor EC, Kelly SP, Foxe JJ. Generation of the VESPA response to rapid contrast fluctuations is dominated by striate cortex: evidence from retinotopic mapping. Neuroscience. 2012, In Press. PDF
Gomez-Ramirez M, Kelly SP, Sehatpour P, Molholm S, Schwartz T, & Foxe JJ. Oscillatory Sensory Selection Mechanisms during Intersensory Attention to Rhythmic Auditory and Visual Inputs: A Human Electro-Corticographic Investigation, J Neurosci, 2011. 14;31(50):18556-67. PDF
Kelly SP, Foxe JJ, Newman G, Edelman JA. Prepare for Conflict: EEG correlates of the anticipation of target competition during overt and covert shifts of visual attention. Eur J Neurosci. 2010. 31(9):1690-700. PDF
Kelly SP, Gomez-Ramirez M, Foxe JJ. The strength of anticipatory spatial biasing predicts target discrimination at attended locations: A high-density EEG study. Eur J Neurosci. 2009. 30(11):2224-34. PDF
Frey HP, Kelly SP, Lalor EC, Foxe JJ. Early spatial attentional modulation of inputs to the fovea. J Neurosci. 2010. 30(13):4547-51. PDF
Lalor EC, Kelly SP, Pearlmutter BA, Reilly RB, Foxe JJ. Isolating endogenous visuo-spatial attentional effects using the novel visual-evoked spread spectrum analysis (VESPA) technique. Eur J Neurosci. 2007 26(12):3536-42. PDF
Kelly SP, Lalor EC, Reilly RB, Foxe JJ. Increases in alpha oscillatory power reflect an active retinotopic mechanism for distracter suppression during sustained visuospatial attention. J Neurophysiol. 2006 Jun;95(6):3844-51. PDF
Dockree PM, Kelly SP, Foxe JJ, Reilly RB, Robertson IH. Optimal sustained attention is linked to the spectral content of background EEG activity: greater ongoing tonic alpha (approximately 10 Hz) power supports successful phasic goal activation. Eur J Neurosci. 2007 25(3):900-7. PDF
Dockree PM, Kelly SP, Robertson IH, Reilly RB, Foxe JJ. Neurophysiological markers of alert responding during goal-directed behavior: a high-density electrical mapping study. NeuroImage. 2005 27(3):587-601. PDF
O'Connell RG, Dockree PM, Bellgrove MA, Kelly SP, Hester R, Garavan H, Robertson IH, Foxe JJ. The role of cingulate cortex in the detection of errors with and without awareness: a high-density electrical mapping study. Eur J Neurosci. 2007 25(8):2571-9. PDF
Krakowski AI, Ross LA, Snyder AC, Sehatpour P, Kelly SP, Foxe JJ. The neurophysiology of human biological motion processing: A high-density electrical mapping study. NeuroImage, In Press.
De Sanctis P, Ritter W, Molholm S, Kelly SP, Foxe JJ. Auditory scene analysis: the interaction of stimulation rate and frequency separation on pre-attentive grouping. Eur J Neurosci. 2008 27(5):1271-6. PDF
Senkowski D, Saint-Amour D, Kelly SP, Foxe JJ. Multisensory processing of naturalistic objects in motion: a high-density electrical mapping and source estimation study. NeuroImage. 2007 Jul 1;36(3):877-88. PDF
Foxe JJ, Morie KP, Laud PJ, Rowson MJ, de Bruin EA, Kelly SP, Assessing the effects of caffeine and theanine on the maintenance of vigilance during a sustained attention task. Neuropharmacology, 2012. 62(7):2319-2326.
Kelly SP, Gomez-Ramirez M, Montesi JL, Foxe JJ. L-theanine and caffeine in combination affect human cognition as evidenced by oscillatory alpha-band activity and attention task performance. Journal of Nutrition. 2008, 138(8):1572S-1577S. PDF
Gomez-Ramirez M, Kelly SP, Montesi JL, & Foxe JJ. The effects of L-theanine on alpha-band oscillatory brain activity during a visuo-spatial attention task. Brain Topography. 2009. 22(1):44-51. PDF
Kelly SP, Lalor EC, Finucane C, McDarby G, Reilly RB. Visual spatial attention control in an independent brain-computer interface. IEEE Trans Biomed Eng. 2005 52(9):1588-96. PDF
Kelly SP, Lalor EC, Reilly RB, Foxe JJ. Visual spatial attention tracking using high-density SSVEP data for independent brain-computer communication. IEEE Trans Neural Syst Rehabil Eng. 2005 13(2):172-8. PDF
Lalor EC, Kelly SP, Finucane C, Burke R, Smith R, Reilly RB, McDarby G. Steady-state VEP-based Brain Computer Interface Control in an Immersive 3-D Gaming Environment. EURASIP Journal on Applied Signal Processing. 2005:19, 3156–3164. PDF
Burke DP, Kelly SP, de Chazal P, Reilly RB, Finucane C. A parametric feature extraction and classification strategy for brain-computer interfacing. IEEE Trans Neural Syst Rehabil Eng. 2005 13(1):12-7. PDF
Lalor EC, Kelly SP, Finucane C, Burke R, Reilly RB, McDarby G. Brain Computer Interface Based on the Steady-State VEP for Immersive Gaming Control. Biomed Tech. 2004 49(1): 63-64. PDF
Adamo, N., Di Martino, A., Esu, L., Petkova, E., Johnson, K.A., Kelly, SP, Castellanos, F.X., Zuddas, A. Increased RT variability across different cognitive tasks in children with ADHD. Journal of Attention Disorders, 2012, In Press.
Foxe JJ, Yeap S, Snyder AC, Kelly SP, Thakore JH, Molholm S. The N1 auditory evoked potential component as an endophenotype for schizophrenia: high-density electrical mapping in clinically unaffected first-degree relatives, first-episode, and chronic schizophrenia patients. Eur Arch Psychiatry Clin Neurosci. 2011. 261(5):331-9.
Yeap S, Kelly SP, Reilly RB, Thakore JH, Foxe JJ. Visual sensory processing deficits in bipolar disorder revealed through high-density electrical mapping. J Psychiat Neurosci. 2009. 34(6):459-64. PDF
Yeap S, Kelly SP, Thakore JH, Foxe JJ. Visual sensory processing deficits in first-episode patients with Schizophrenia. Schizophrenia Research. 2008, 102(1-3):340-3. PDF
Yeap S, Kelly SP, Sehatpour P, Magno E, Garavan H, Thakore JH, Foxe JJ. Visual sensory processing deficits in Schizophrenia and their relationship to disease state. Eur Arch Psychiatry Clin Neurosci. 2008, 258(5):305-16. PDF
Yeap S, Kelly SP, Sehatpour P, Magno E, Javitt DC, Garavan H, Thakore JH, Foxe JJ. Early visual sensory deficits as endophenotypes for schizophrenia: high-density electrical mapping in clinically unaffected first-degree relatives. Arch Gen Psychiatry. 2006 63(11):1180-8. PDF
Johnson KA, Barry E, Bellgrove MA, Cox M, Kelly SP, Dáibhis A, Daly M, Keavey M, Watchorn A, Fitzgerald M, McNicholas F, Kirley A, Robertson IH, Gill M. Dissociation in response to methylphenidate on response variability in a group of medication naïve children with ADHD. Neuropsychologia. 2008, 46(5):1532-41. PDF
Johnson KA, Kelly SP, Robertson IH, Barry E, Mulligan A, Daly M, Lambert D, McDonnell C, Connor TJ, Hawi Z, Gill M, Bellgrove MA. Absence of the 7-repeat variant of the DRD4 VNTR is associated with drifting sustained attention in children with ADHD but not in controls. Am J Med Genet B Neuropsychiatr Genet. 2008, 147B(6):927-37. PDF
Johnson KA, Kelly SP, Bellgrove MA, Barry E, Cox M, Gill M, Robertson IH. Response variability in attention deficit hyperactivity disorder: evidence for neuropsychological heterogeneity. Neuropsychologia. 2007 45(4):630-8. PDF
Johnson KA, Robertson IH, Kelly SP, Silk TJ, Barry E, Dáibhis A, Watchorn A, Keavey M, Fitzgerald M, Gallagher L, Gill M, Bellgrove MA. Dissociation in performance of children with ADHD and high-functioning autism on a task of sustained attention. Neuropsychologia. 2007 Jun 11;45(10):2234-45. PDF
Barnett KJ, Foxe JJ, Molholm S, Kelly SP, Shalgi S, Mitchell KJ, Newell FN. Differences in early sensory-perceptual processing in synesthesia: a visual evoked potentials study. NeuroImage. 2008 43(3):605-13. PDF
Dockree PM, Kelly SP, Roche RA, Hogan MJ, Reilly RB, Robertson IH. Behavioural and physiological impairments of sustained attention after traumatic brain injury. Cogn Brain Res. 2004 Aug;20(3):403-14. PDF
Assistant Professor of Biomedical Engineering City College of New York, Steinman Hall
Kelly Lab [..]