scholarly journals Prominent lateral spread of imaged evoked activity beyond cortical columns in barrel cortex provides foundation for coding whisker identity

2017 ◽  
Author(s):  
Nathan S. Jacobs ◽  
Ron D. Frostig
Keyword(s):  
Optical Imaging ◽  
Barrel Cortex ◽  
Classification Performance ◽  
Lateral Spread ◽  
Mammalian Brain ◽  
Intrinsic Signal ◽  
Columnar Organization ◽  
Sensory Cortices ◽  
Evoked Activity ◽  
Stimulus Classification

AbstractThe posterior medial barrel subfield (PMBSF) of rat primary somatosensory cortex exquisitely demonstrates topography and columnar organization, defining features of sensory cortices in the mammalian brain. Optical imaging and neuronal recordings in rat PMBSF demonstrates how evoked cortical activity following single whisker stimulation also rapidly spreads laterally into surrounding cortices, disregarding columnar and modality boundaries. The current study quantifies the spatial prominence of such lateral activity spreads by demonstrating that functional connectivity between laterally spaced cortical locations is actually stronger than between vertically spaced cortical locations. Further, the total amount of evoked activity within and beyond single column boundaries was quantified based on intrinsic signal optical imaging, single units and local field potentials (LFPs) recordings, revealing that the vast majority of whisker evoked activity in PMBSF occurs beyond columnar boundaries. Finally, a simple two layer artificial neural network model of PMBSF demonstrates the capacity of extra-columnar evoked activity spread to provide a foundation for accurate whisker stimulus classification that is robust to random scaling of inputs and local noise. Indeed, classification performance improved when more of the lateral spread was included in the model, providing further evidence for the relevance of the lateral spread.

scholarly journals Varying the Degree of Single-Whisker Stimulation Differentially Affects Phases of Intrinsic Signals in Rat Barrel Cortex

1999 ◽  
Vol 81 (2) ◽  
pp. 692-701 ◽  
Author(s):  
Daniel B. Polley ◽  
Cynthia H. Chen-Bee ◽  
Ron D. Frostig
Keyword(s):  
Time Course ◽  
Barrel Cortex ◽  
Large Area ◽  
Intrinsic Signals ◽  
Intrinsic Signal ◽  
Point Spread ◽  
Signal Activity ◽  
Whisker Stimulation ◽  
Evoked Activity ◽  
Cortical Point

Varying the degree of single-whisker stimulation differentially affects phases of intrinsic signals in rat barrel cortex. . Neurophysiol. 81: 692–701, 1999. Using intrinsic signal optical imaging (ISI), we have shown previously that the point spread of evoked activity in the rat barrel cortex in response to single-whisker stimulation encompasses a surprisingly large area. Given that our typical stimulation consists of five deflections at 5 Hz, the large area of evoked activity might have resulted from repetitive stimulation. Thus in the present study, we use ISI through the thinned skull to determine whether decreasing the degree of single-whisker stimulation decreases the area of the cortical point spread. We additionally outline a protocol to quantify stimulus-related differences in the temporal characteristics of intrinsic signals at a fine spatial scale. In 10 adult rats, whisker C2 was stimulated randomly with either one or five deflections delivered in a rostral-to-caudal fashion. Each deflection consisted of a 0.5-mm displacement of the whisker as measured at the point of contact, 15 mm from the snout. The number of whisker deflections did not affect the area or peak magnitude of the cortical point spread based on the intrinsic signal activity occurring from 0.5 up to 1.5 s poststimulus onset. In contrast, the magnitude and time course of intrinsic signal activity collected after 1.5-s poststimulus onset did reflect the difference in the degree of stimulation. Thus decreasing the degree of stimulation differentially affected the early and late phases of the evoked intrinsic signal response. The implications of the present results are discussed in respect to probable differences in the signal source underlying the early versus later phases of evoked intrinsic signals.

Temporal Modulation of Spatial Borders in Rat Barrel Cortex

1998 ◽  
Vol 79 (1) ◽  
pp. 464-470 ◽  
Author(s):  
Bhavin R. Sheth ◽  
Christopher I. Moore ◽  
Mriganka Sur
Keyword(s):  
Optical Imaging ◽  
Barrel Cortex ◽  
Neuronal Response ◽  
Imaging Data ◽  
Neuronal Responses ◽  
Temporal Modulation ◽  
Intrinsic Signals ◽  
Intrinsic Signal ◽  
Electrode Recording ◽  
Peripheral Site

Sheth, Bhavin R., Christopher I. Moore, and Mriganka Sur. Temporal modulation of spatial borders in rat barrel cortex. J. Neurophysiol. 79: 464–470, 1998. We examined the effects of varying vibrissa stimulation frequency on intrinsic signal and neuronal responses in rat barrel cortex. Optical imaging of intrinsic signals demonstrated that the region of cortex activated by deflection of a single vibrissa at 1 Hz is more diffuse and more widespread than the territory activated at 5 or 10 Hz. With the use of two different paradigms, constant time of stimulation and constant number of vibrissa deflections, we showed that the optically imaged spread of activity is more discrete at higher stimulation frequencies. We combined optical imaging with multiple electrode recording and confirmed that the neuronal response to individual vibrissa stimulation at the optically imaged center of activity is greater than the response away from the imaged center. Consistent with the imaging data, these recordings also showed no response to a second vibrissa deflection at 5 Hz at a peripheral recording site, though there was a significant response to a second vibrissa deflection at 1 Hz at the same peripheral site. These findings demonstrate that vibrissa stimulation at higher frequencies leads to more focused physiological responses in cortex. Thus the spread of activation in rat barrel cortex is modulated in a dynamic fashion by the frequency of vibrissa stimulation.

scholarly journals Functional neocortical microcircuitry demonstrated with intrinsic signal optical imaging in vitro

Neuroscience ◽  
1999 ◽  
Vol 95 (1) ◽  
pp. 51-62 ◽  
Author(s):  
A. Kohn ◽  
C. Metz ◽  
M. Quibrera ◽  
M.A. Tommerdahl ◽  
B.L. Whitsel
Keyword(s):  
Optical Imaging ◽  
Intrinsic Signal ◽  
Intrinsic Signal Optical Imaging

scholarly journals Optical imaging of the intrinsic signal as a measure of cortical plasticity in the mouse

2005 ◽  
Vol 22 (5) ◽  
pp. 685-691 ◽  
Author(s):  
JIANHUA CANG ◽  
VALERY A. KALATSKY ◽  
SIEGRID LÖWEL ◽  
MICHAEL P. STRYKER
Keyword(s):  
Visual Cortex ◽  
Optical Imaging ◽  
Critical Period ◽  
Cortical Plasticity ◽  
Ocular Dominance ◽  
Screening Method ◽  
Intrinsic Signals ◽  
Intrinsic Signal ◽  
The Mean ◽  
Mouse Visual Cortex

The responses of cells in the visual cortex to stimulation of the two eyes changes dramatically following a period of monocular visual deprivation (MD) during a critical period in early life. This phenomenon, referred to as ocular dominance (OD) plasticity, is a widespread model for understanding cortical plasticity. In this study, we designed stimulus patterns and quantification methods to analyze OD in the mouse visual cortex using optical imaging of intrinsic signals. Using periodically drifting bars restricted to the binocular portion of the visual field, we obtained cortical maps for both contralateral (C) and ipsilateral (I) eyes and computed OD maps as (C − I)/(C + I). We defined the OD index (ODI) for individual animals as the mean of the OD map. The ODI obtained from an imaging session of less than 30 min gives reliable measures of OD for both normal and monocularly deprived mice under Nembutal anesthesia. Surprisingly, urethane anesthesia, which yields excellent topographic maps, did not produce consistent OD findings. Normal Nembutal-anesthetized mice have positive ODI (0.22 ± 0.01), confirming a contralateral bias in the binocular zone. For mice monocularly deprived during the critical period, the ODI of the cortex contralateral to the deprived eye shifted negatively towards the nondeprived, ipsilateral eye (ODI after 2-day MD: 0.12 ± 0.02, 4-day: 0.03 ± 0.03, and 6- to 7-day MD: −0.01 ± 0.04). The ODI shift induced by 4-day MD appeared to be near maximal, consistent with previous findings using single-unit recordings. We have thus established optical imaging of intrinsic signals as a fast and reliable screening method to study OD plasticity in the mouse.

scholarly journals Emerging imaging methods to study whole-brain function in rodent models

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Marija Markicevic ◽  
Iurii Savvateev ◽  
Christina Grimm ◽  
Valerio Zerbi
Keyword(s):  
Large Scale ◽  
Functional Organization ◽  
Imaging Techniques ◽  
Brain Activity ◽  
Research Question ◽  
Careful Consideration ◽  
Mammalian Brain ◽  
High Temporal Resolution ◽  
Imaging Methods ◽  
Evoked Activity

AbstractIn the past decade, the idea that single populations of neurons support cognition and behavior has gradually given way to the realization that connectivity matters and that complex behavior results from interactions between remote yet anatomically connected areas that form specialized networks. In parallel, innovation in brain imaging techniques has led to the availability of a broad set of imaging tools to characterize the functional organization of complex networks. However, each of these tools poses significant technical challenges and faces limitations, which require careful consideration of their underlying anatomical, physiological, and physical specificity. In this review, we focus on emerging methods for measuring spontaneous or evoked activity in the brain. We discuss methods that can measure large-scale brain activity (directly or indirectly) with a relatively high temporal resolution, from milliseconds to seconds. We further focus on methods designed for studying the mammalian brain in preclinical models, specifically in mice and rats. This field has seen a great deal of innovation in recent years, facilitated by concomitant innovation in gene-editing techniques and the possibility of more invasive recordings. This review aims to give an overview of currently available preclinical imaging methods and an outlook on future developments. This information is suitable for educational purposes and for assisting scientists in choosing the appropriate method for their own research question.

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