Main Menu (Mobile)- Block

Main Menu - Block

custom | custom

Search Results

general_search_page-panel_pane_1 | views_panes

7 Janelia Publications

Showing 1-7 of 7 results
Your Criteria:
    Looger LabSvoboda Lab
    11/01/10 | Functional imaging of hippocampal place cells at cellular resolution during virtual navigation.
    Dombeck DA, Harvey CD, Tian L, Looger LL, Tank DW
    Nature Neuroscience. 2010 Nov;13(11):1433-40. doi: 10.1038/nn.2648

    Spatial navigation is often used as a behavioral task in studies of the neuronal circuits that underlie cognition, learning and memory in rodents. The combination of in vivo microscopy with genetically encoded indicators has provided an important new tool for studying neuronal circuits, but has been technically difficult to apply during navigation. Here we describe methods for imaging the activity of neurons in the CA1 region of the hippocampus with subcellular resolution in behaving mice. Neurons that expressed the genetically encoded calcium indicator GCaMP3 were imaged through a chronic hippocampal window. Head-restrained mice performed spatial behaviors in a setup combining a virtual reality system and a custom-built two-photon microscope. We optically identified populations of place cells and determined the correlation between the location of their place fields in the virtual environment and their anatomical location in the local circuit. The combination of virtual reality and high-resolution functional imaging should allow a new generation of studies to investigate neuronal circuit dynamics during behavior.

    View Publication Page
    Svoboda Lab
    11/01/10 | The functional asymmetry of auditory cortex is reflected in the organization of local cortical circuits.
    Oviedo HV, Bureau I, Svoboda K, Zador AM
    Nature Neuroscience. 2010 Nov;13(11):1413-20. doi: 10.1038/nn.2659

    The primary auditory cortex (A1) is organized tonotopically, with neurons sensitive to high and low frequencies arranged in a rostro-caudal gradient. We used laser scanning photostimulation in acute slices to study the organization of local excitatory connections onto layers 2 and 3 (L2/3) of the mouse A1. Consistent with the organization of other cortical regions, synaptic inputs along the isofrequency axis (orthogonal to the tonotopic axis) arose predominantly within a column. By contrast, we found that local connections along the tonotopic axis differed from those along the isofrequency axis: some input pathways to L3 (but not L2) arose predominantly out-of-column. In vivo cell-attached recordings revealed differences between the sound-responsiveness of neurons in L2 and L3. Our results are consistent with the hypothesis that auditory cortical microcircuitry is specialized to the one-dimensional representation of frequency in the auditory cortex.

    View Publication Page
    Svoboda Lab
    09/23/10 | Neural activity in barrel cortex underlying vibrissa-based object localization in mice.
    O’Connor DH, Peron SP, Huber D, Svoboda K
    Neuron. 2010 Sep 23;67(6):1048-61. doi: 10.1016/j.neuron.2010.08.026

    Classical studies have related the spiking of selected neocortical neurons to behavior, but little is known about activity sampled from the entire neural population. We recorded from neurons selected independent of spiking, using cell-attached recordings and two-photon calcium imaging, in the barrel cortex of mice performing an object localization task. Spike rates varied across neurons, from silence to >60 Hz. Responses were diverse, with some neurons showing large increases in spike rate when whiskers contacted the object. Nearly half the neurons discriminated object location; a small fraction of neurons discriminated perfectly. More active neurons were more discriminative. Layer (L) 4 and L5 contained the highest fractions of discriminating neurons (\~{}63% and 79%, respectively), but a few L2/3 neurons were also highly discriminating. Approximately 13,000 spikes per activated barrel column were available to mice for decision making. Coding of object location in the barrel cortex is therefore highly redundant.

    View Publication Page
    Svoboda Lab
    04/22/10 | Learning-related fine-scale specificity imaged in motor cortex circuits of behaving mice.
    Komiyama T, Sato TR, O’Connor DH, Zhang Y, Huber D, Hooks BM, Gabitto M, Svoboda K
    Nature. 2010 Apr 22;464(7292):1182-6. doi: 10.1038/nature08897

    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.

    View Publication Page
    Svoboda Lab
    04/07/10 | Structural plasticity underlies experience-dependent functional plasticity of cortical circuits.
    Wilbrecht L, Holtmaat A, Wright N, Fox K, Svoboda K
    The Journal of Neuroscience. 2010 Apr 7;30(14):4927-32. doi: 10.1523/JNEUROSCI.6403-09.2010

    The stabilization of new spines in the barrel cortex is enhanced after whisker trimming, but its relationship to experience-dependent plasticity is unclear. Here we show that in wild-type mice, whisker potentiation and spine stabilization are most pronounced for layer 5 neurons at the border between spared and deprived barrel columns. In homozygote alphaCaMKII-T286A mice, which lack experience-dependent potentiation of responses to spared whiskers, there is no increase in new spine stabilization at the border between barrel columns after whisker trimming. Our data provide a causal link between new spine synapses and plasticity of adult cortical circuits and suggest that alphaCaMKII autophosphorylation plays a role in the stabilization but not formation of new spines.

    View Publication Page
    Svoboda Lab
    03/24/10 | The functional properties of barrel cortex neurons projecting to the primary motor cortex.
    Sato TR, Svoboda K
    The Journal of Neuroscience. 2010 Mar 24;30(12):4256-60. doi: 10.1523/JNEUROSCI.3774-09.2010

    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.

    View Publication Page
    Svoboda Lab
    02/03/10 | Vibrissa-based object localization in head-fixed mice.
    O’Connor DH, Clack NG, Huber D, Komiyama T, Myers EW, Svoboda K
    The Journal of Neuroscience. 2010 Feb 3;30(5):1947-67. doi: 10.1523/JNEUROSCI.3762-09.2010

    Linking activity in specific cell types with perception, cognition, and action, requires quantitative behavioral experiments in genetic model systems such as the mouse. In head-fixed primates, the combination of precise stimulus control, monitoring of motor output, and physiological recordings over large numbers of trials are the foundation on which many conceptually rich and quantitative studies have been built. Choice-based, quantitative behavioral paradigms for head-fixed mice have not been described previously. Here, we report a somatosensory absolute object localization task for head-fixed mice. Mice actively used their mystacial vibrissae (whiskers) to sense the location of a vertical pole presented to one side of the head and reported with licking whether the pole was in a target (go) or a distracter (no-go) location. Mice performed hundreds of trials with high performance (>90% correct) and localized to <0.95 mm (<6 degrees of azimuthal angle). Learning occurred over 1-2 weeks and was observed both within and across sessions. Mice could perform object localization with single whiskers. Silencing barrel cortex abolished performance to chance levels. We measured whisker movement and shape for thousands of trials. Mice moved their whiskers in a highly directed, asymmetric manner, focusing on the target location. Translation of the base of the whiskers along the face contributed substantially to whisker movements. Mice tended to maximize contact with the go (rewarded) stimulus while minimizing contact with the no-go stimulus. We conjecture that this may amplify differences in evoked neural activity between trial types.

    View Publication Page