The role of thalamic synchrony in gating information flow to cortex A ubiquitous property of sensory pathways is that they continuously adapt to changes in the properties of the sensory input. Adaptation is not simply fatigue or attenuation of neural activity, but instead can fundamentally change the features to which the sensory pathway are sensitive and thus changes what the pathway encodes. We have recently shown that adaptation through ongoing tactile stimulation in the rat vibrissa system induces a fundamental change in what behaviorally relevant features the cortex encodes: from detection of a tactile contact to discrimination between different speeds of the tactile/whisker input. To what extent this observation is general and whether it manifests perceptually has not been well studied. In this project, using a combination of electrophysiology and related functional measures and behavior, we will determine whether adaptation enhances discrimination at the expense of detection through modulation of the timing synchrony of thalamic input to cortex. We do so through an integrated, parallel study using multiple recording techniques in the vibrissa pathway of the anesthetized rat, and using behavioral tasks focused on detection of and discrimination between tactile stimuli. Specifically, we will test whether adaptation switches the fundamental cortical processing mode from detection to discrimination through modulation of synchrony of projecting thalamic input (AIM 1). We will directly test the generality of this central hypothesis across whisker deflection speed and direction, and in the context of spatial acuity across whiskers, and determine how this phenomenon is shaped by the statistics of the adapting tactile input. Second, we will directly test whether adaptation switches perceptual performance from detector to discriminator during behavior and whether modulation of thalamic synchrony mediates the switch (AIM 2). Rats will be trained to either detect whisker contact or discriminate between contacts of nearby whiskers, while we monitor population activity in VPm thalamus through chronically implanted multi-electrodes within and across vibrissa-specific regions. Significance: It has long been posited that adaptation acts to enhance information flow in sensory pathways and human psychophysical studies have indeed shown that in certain circumstances adaptation acts to enhance discriminability of tactile inputs. However, the precise link between the underlying neural representations in the thalamocortical circuit and the resultant percept remains a major open question in neuroscience. Success of our aims will directly determine how the cortical representation changes through modulation in thalamic input and the consequences of this on perception. Broad Impacts: Various brain pathologies such as autism, concussive injuries, and alcoholism result in an impaired effect of adaptation on spatial acuity. Success of our aims will provide a more solid foundation for sensory-based diagnostics, and may help to shed light on the pathophysiology associated with these life-altering disorders. Further, one mechanism that we explore is that of thalamic synchrony and its effect on cortical activation, which has been implicated in seizure generation and thalamic pain.

Public Health Relevance

Sensory input is critical in our daily lives, for both the perception of the world around us, and in providing feedback for our muscle systems that help us interact with the external world. How the nervous system performs this feat, and precisely how this helps us in our environment, is unknown. Discovery in this area can potentially help us understand a number of disorders/diseases of the nervous system for which individuals exhibit loss of acuity/sensitivity, and do not have the ability to adapt to changes in the sensory environment.

National Institute of Health (NIH)
National Institute of Neurological Disorders and Stroke (NINDS)
Research Project (R01)
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Sensorimotor Integration Study Section (SMI)
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Gnadt, James W
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Georgia Institute of Technology
Engineering (All Types)
Schools of Engineering
United States
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Bolus, M F; Willats, A A; Whitmire, C J et al. (2018) Design strategies for dynamic closed-loop optogenetic neurocontrol in vivo. J Neural Eng 15:026011
Puntkattalee, M Jane; Whitmire, Clarissa J; Macklin, Alix S et al. (2016) Directional acuity of whole-body perturbations during standing balance. Gait Posture 48:77-82
Gollnick, Clare A; Millard, Daniel C; Ortiz, Alexander D et al. (2016) Response reliability observed with voltage-sensitive dye imaging of cortical layer 2/3: the probability of activation hypothesis. J Neurophysiol 115:2456-69
Whitmire, Clarissa J; Stanley, Garrett B (2016) Rapid Sensory Adaptation Redux: A Circuit Perspective. Neuron 92:298-315
Whitmire, Clarissa J; Waiblinger, Christian; Schwarz, Cornelius et al. (2016) Information Coding through Adaptive Gating of Synchronized Thalamic Bursting. Cell Rep 14:795-807
Millard, Daniel C; Whitmire, Clarissa J; Gollnick, Clare A et al. (2015) Electrical and Optical Activation of Mesoscale Neural Circuits with Implications for Coding. J Neurosci 35:15702-15
Newman, Jonathan P; Fong, Ming-fai; Millard, Daniel C et al. (2015) Optogenetic feedback control of neural activity. Elife 4:e07192
Zheng, He J V; Wang, Qi; Stanley, Garrett B (2015) Adaptive shaping of cortical response selectivity in the vibrissa pathway. J Neurophysiol 113:3850-65
Kelly, Sean T; Kremkow, Jens; Jin, Jianzhong et al. (2014) The role of thalamic population synchrony in the emergence of cortical feature selectivity. PLoS Comput Biol 10:e1003418
Ollerenshaw, Douglas R; Zheng, He J V; Millard, Daniel C et al. (2014) The adaptive trade-off between detection and discrimination in cortical representations and behavior. Neuron 81:1152-1164

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