@article {4446, title = {Characterization and adaptive optical correction of aberrations during in vivo imaging in the mouse cortex.}, journal = {Proceedings of the National Academy of Sciences of the United States of America}, volume = {109}, year = {2012}, month = {2012 Jan 3}, pages = {22-7}, abstract = {

The signal and resolution during in vivo imaging of the mouse brain is limited by sample-induced optical aberrations. We find that, although the optical aberrations can vary across the sample and increase in magnitude with depth, they remain stable for hours. As a result, two-photon adaptive optics can recover diffraction-limited performance to depths of 450\ μm and improve imaging quality over fields of view of hundreds of microns. Adaptive optical correction yielded fivefold signal enhancement for small neuronal structures and a threefold increase in axial resolution. The corrections allowed us to detect smaller neuronal structures at greater contrast and also improve the signal-to-noise ratio during functional Ca(2+) imaging in single neurons.

}, issn = {1091-6490}, doi = {10.1073/pnas.1109202108}, author = {Ji, Na and Sato, Takashi R and Betzig, Eric} } @article {4296, title = {The functional properties of barrel cortex neurons projecting to the primary motor cortex.}, journal = {The Journal of Neuroscience}, volume = {30}, year = {2010}, month = {2010 Mar 24}, pages = {4256-60}, abstract = {

Nearby neurons, sharing the same locations within the mouse whisker map, can have dramatically distinct response properties. To understand the significance of this diversity, we studied the relationship between the responses of individual neurons and their projection targets in the mouse barrel cortex. Neurons projecting to primary motor cortex (MI) or secondary somatosensory area (SII) were labeled with red fluorescent protein (RFP) using retrograde viral infection. We used in vivo two-photon Ca(2+) imaging to map the responses of RFP-positive and neighboring L2/3 neurons to whisker deflections. Neurons projecting to MI displayed larger receptive fields compared with other neurons, including those projecting to SII. Our findings support the view that intermingled neurons in primary sensory areas send specific stimulus features to different parts of the brain.

}, keywords = {Afferent Pathways, Aniline Compounds, Animals, Brain Mapping, Calcium, Evoked Potentials, Functional Laterality, Genetic, Luminescent Proteins, Mice, Motor Cortex, Neurons, Newborn, Physical Stimulation, Somatosensory, Somatosensory Cortex, Transduction, Vibrissae, Xanthenes}, issn = {1529-2401}, doi = {10.1523/JNEUROSCI.3774-09.2010}, author = {Sato, Takashi R and Svoboda, Karel} } @article {4288, title = {Learning-related fine-scale specificity imaged in motor cortex circuits of behaving mice.}, journal = {Nature}, volume = {464}, year = {2010}, month = {2010 Apr 22}, pages = {1182-6}, abstract = {

Cortical neurons form specific circuits, but the functional structure of this microarchitecture and its relation to behaviour are poorly understood. Two-photon calcium imaging can monitor activity of spatially defined neuronal ensembles in the mammalian cortex. Here we applied this technique to the motor cortex of mice performing a choice behaviour. Head-fixed mice were trained to lick in response to one of two odours, and to withhold licking for the other odour. Mice routinely showed significant learning within the first behavioural session and across sessions. Microstimulation and trans-synaptic tracing identified two non-overlapping candidate tongue motor cortical areas. Inactivating either area impaired voluntary licking. Imaging in layer 2/3 showed neurons with diverse response types in both areas. Activity in approximately half of the imaged neurons distinguished trial types associated with different actions. Many neurons showed modulation coinciding with or preceding the action, consistent with their involvement in motor control. Neurons with different response types were spatially intermingled. Nearby neurons (within approximately 150 mum) showed pronounced coincident activity. These temporal correlations increased with learning within and across behavioural sessions, specifically for neuron pairs with similar response types. We propose that correlated activity in specific ensembles of functionally related neurons is a signature of learning-related circuit plasticity. Our findings reveal a fine-scale and dynamic organization of the frontal cortex that probably underlies flexible behaviour.

}, keywords = {Animal, Animals, Axonal Transport, Behavior, Chemical, Choice Behavior, Inbred C57BL, Learning, Male, Mice, Motor Cortex, Motor Neurons, Neural Pathways, Odors, Pyramidal Cells, Reward, Stimulation, Time Factors, Tongue}, issn = {1476-4687}, doi = {10.1038/nature08897}, author = {Komiyama, Takaki and Sato, Takashi R and O{\textquoteright}Connor, Daniel H and Zhang, Ying-Xin and Huber, Daniel and Hooks, Bryan M and Gabitto, Mariano and Svoboda, Karel} } @article {5251, title = {Subcellular dynamics of type II PKA in neurons.}, journal = {Neuron}, volume = {62}, year = {2009}, month = {2009 May 14}, pages = {363-74}, abstract = {

Protein kinase A (PKA) plays multiple roles in neurons. The localization and specificity of PKA are largely controlled by A-kinase anchoring proteins (AKAPs). However, the dynamics of PKA in neurons and the roles of specific AKAPs are poorly understood. We imaged the distribution of type II PKA in hippocampal and cortical layer 2/3 pyramidal neurons in vitro and in vivo. PKA was concentrated in dendritic shafts compared to the soma, axons, and dendritic spines. This spatial distribution was imposed by the microtubule-binding protein MAP2, indicating that MAP2 is the dominant AKAP in neurons. Following cAMP elevation, catalytic subunits dissociated from the MAP2-tethered regulatory subunits and rapidly became enriched in nearby spines. The spatial gradient of type II PKA between dendritic shafts and spines was critical for the regulation of synaptic strength and long-term potentiation. Therefore, the localization and activity-dependent translocation of type II PKA are important determinants of PKA function.

}, keywords = {A Kinase Anchor Proteins, Animals, Cerebral Cortex, Cyclic AMP-Dependent Protein Kinases, Dendritic Spines, Hippocampus, Mice, Microtubule-Associated Proteins, Pyramidal Cells, Rats, Subcellular Fractions, Tissue Distribution, Transgenic}, issn = {1097-4199}, doi = {10.1016/j.neuron.2009.03.013}, author = {Zhong, Haining and Sia, Gek-Ming and Sato, Takashi R and Gray, Noah W and Mao, Tianyi and Khuchua, Zaza and Huganir, Richard L and Svoboda, Karel} } @article {4226, title = {The functional microarchitecture of the mouse barrel cortex.}, journal = {PLoS Biology}, volume = {5}, year = {2007}, month = {2007 Jul 10}, pages = {e189}, abstract = {

Cortical maps, consisting of orderly arrangements of functional columns, are a hallmark of the organization of the cerebral cortex. However, the microorganization of cortical maps at the level of single neurons is not known, mainly because of the limitations of available mapping techniques. Here, we used bulk loading of Ca(2+) indicators combined with two-photon microscopy to image the activity of multiple single neurons in layer (L) 2/3 of the mouse barrel cortex in vivo. We developed methods that reliably detect single action potentials in approximately half of the imaged neurons in L2/3. This allowed us to measure the spiking probability following whisker deflection and thus map the whisker selectivity for multiple neurons with known spatial relationships. At the level of neuronal populations, the whisker map varied smoothly across the surface of the cortex, within and between the barrels. However, the whisker selectivity of individual neurons recorded simultaneously differed greatly, even for nearest neighbors. Trial-to-trial correlations between pairs of neurons were high over distances spanning multiple cortical columns. Our data suggest that the response properties of individual neurons are shaped by highly specific subcolumnar circuits and the momentary intrinsic state of the neocortex.

}, keywords = {Algorithms, Aniline Compounds, Animals, Brain Mapping, Evoked Potentials, Fluorescent Dyes, Inbred C57BL, Mice, Models, Neural Pathways, Neurological, Organic Chemicals, Physical Stimulation, Sensory Receptor Cells, Somatosensory, Somatosensory Cortex, Vibrissae, Xanthenes}, issn = {1545-7885}, doi = {10.1371/journal.pbio.0050189}, author = {Sato, Takashi R and Gray, Noah W and Mainen, Zachary F and Svoboda, Karel} }