The Kara lab solves puzzles in sensory perception and neurovascular coupling in the mammalian brain.
Our long-term goal is to obtain a comprehensive view of how the brain adapts to change in adulthood, development, and disease. The short-term goals of our current projects are to (1) resolve aspects of neural coding of binocular signals in the visual cortex, (2) determine the underpinnings of functional magnetic resonance imaging (fMRI) using rodent and non-rodent animal model systems, and (3) build microcircuits for neurovascular coupling in the neocortex across different species.
At a coarse anatomical scale, the neocortex seems very similar across different mammalian species. Yet there are some remarkable differences in the functional micro-architecture. Thus, we have a comparative approach, performing similar tests across a few different mammals. We use two-photon and three-photon imaging, optogenetics, and electrophysiological techniques. More specifically, we typically assay synaptic and spiking activity along with the responses of individual blood vessels to sensory stimuli and optogenetic activation. In addition to resolving aspects of neural coding and the ways in which neurons talk to blood vessels (neuro-vascular coupling), our advanced optical imaging methods helps us to understand fMRI signals. The brain has a mechanism for locally increasing blood flow to regions with increased neural activity and fMRI tracks increases in blood flow. But fMRI cannot tell us exactly how many neurons are firing at any given time, and which neurons are triggering the changes in blood flow.
Our lab website is https://www.karalab.org
- Cho S, Roy A, Liu CJ, Idiyatullin D, Zhu W, Zhang Y, Zhu XH, O'Herron P, Leikvoll A, Chen W, Kara P, Uğurbil K. Cortical layer-specific differences in stimulus selectivity revealed with high-field fMRI and single-vessel resolution optical imaging of the primary visual cortex. Neuroimage. 2022 May 1;251:118978.
- Farinella DM, Roy A, Liu CJ, Kara P. Improving laser standards for three-photon microscopy. Neurophotonics. 2021 Jan;8(1):015009.
- Liu CJ, Roy A, Simons AA, Farinella DM, Kara P. Three-photon imaging of synthetic dyes in deep layers of the neocortex. Sci Rep. 2020 Oct 1;10(1):16351.
- O'Herron P, Levy M, Woodward JJ, Kara P. An unexpected dependence of cortical depth in shaping neural responsiveness and selectivity in mouse visual cortex. eNeuro. 2020 Mar 23;7(2):ENEURO.0497-19.2020.
- O'Herron P, Summers PM, Shih AY, Kara P, Woodward JJ. In vivo two-photon imaging of neuronal and brain vascular responses in mice chronically exposed to ethanol. Alcohol. 2020;85:41-47.
- O’Herron P, Chhatbar PY, Levy M, Shen Z, Schramm AE, Lu Z, Kara P. Neural correlates of single vessel hemodynamic responses in vivo. Nature. 2016;534:378-382.
- Levy M, Lu Z, Dion G, Kara P. The shape of dendritic arbors in different functional domains of the cortical orientation map. J Neurosci. 2014;34:3231-3236.
- Chhatbar PY, Kara P. Improved blood velocity measurements with a hybrid image filtering and iterative Radon transform algorithm. Front Neurosci. 2013;7:106
- Levy M, Schramm AE, Kara P. Strategies for mapping synaptic inputs on dendrites in vivo by combining two-photon microscopy, sharp intracellular recording, and pharmacology. Fronti Neural Circuits. 2012;6:101.
- O’Herron P, Shen Z, Lu Z, Kara P. Targeted labeling of neurons in a specific functional micro-domain of the neocortex by combining intrinsic signal and two-photon imaging. J Vis Exp. 2012;70:e50025.
- Shen Z, Lu Z, Chhatbar PY, O’Herron P, Kara P. An artery-specific fluorescent dye for studying neurovascular coupling in vivo. Nature Meth. 2012;9:273-276.