Search results for "Vibrissae"
showing 7 items of 17 documents
Laminar and Columnar Structure of Sensory-Evoked Multineuronal Spike Sequences in Adult Rat Barrel Cortex In Vivo
2014
One of the most relevant questions regarding the function of the nervous system is how sensory information is represented in populations of cortical neurons. Despite its importance, the manner in which sensory-evoked activity propagates across neocortical layers and columns has yet not been fully characterized. In this study, we took advantage of the distinct organization of the rodent barrel cortex and recorded with multielectrode arrays simultaneously from up to 74 neurons localized in several functionally identified layers and columns of anesthetized adult Wistar rats in vivo. The flow of activity within neuronal populations was characterized by temporally precise spike sequences, which …
A Scanning Technique to Measure Regional Cerebral Blood Flow and Oxyhemoglobin Level
2001
OBJECTIVE: The application of a laser scanning technique to measure regional cerebral blood flow (CBF) and tissue hemoglobin oxygenation (HbO 2 ) using the rat closed cranial window preparation is described. METHODS: Twenty-nine male Wistar rats were used to consecutively measure local CBF by laser Doppler flowmetry and tissue HbO 2 by a microspectrophotometric method at multiple corresponding cortical locations. The scanning technique used a computer-controlled micromanipulator. Data from three experimental models are presented: the whisker stimulation model, the ischemia-reperfusion model, and the sinus-vein thrombosis model. Sequential changes in local CBF and HbO 2 data before, during, …
Long-range intralaminar noise correlations in the barrel cortex
2015
Identifying the properties of correlations in the firing of neocortical neurons is central to our understanding of cortical information processing. It has been generally assumed, by virtue of the columnar organization of the neocortex, that the firing of neurons residing in a certain vertical domain is highly correlated. On the other hand, firing correlations between neurons steeply decline with horizontal distance. Technical difficulties in sampling neurons with sufficient spatial information have precluded the critical evaluation of these notions. We used 128-channel “silicon probes” to examine the spike-count noise correlations during spontaneous activity between multiple neurons with i…
Contralateral increase in thigmotactic scanning following unilateral barrel-cortex lesion in mice.
2005
Adult C57BL/6 mice received uni- or bilateral cryogenic or sham-lesions over the barrel field and their exploratory behaviour was assessed in an open field between 1 and 7 days post-lesion. Bilateral cortical lesions produced a short-lasting increase in thigmotactic scanning with both sides of the face on the first day of testing. Mice with a unilateral barrel-cortex lesion showed more contralateral wall scanning with a recovery to behavioural symmetry after 5-7 days. Furthermore, the increase in contralateral thigmotaxis was most pronounced in animals with damage to the left barrel field, indicative of a lateralization of the lesion-induced behavioural changes. The cortical lesions did not…
Temporal refinement of sensory-evoked activity across layers in developing mouse barrel cortex.
2019
Rhythmic whisking behavior in rodents fully develops during a critical period about 2 weeks after birth, in parallel with the maturation of other sensory modalities and the onset of exploratory locomotion. How whisker-related sensory processing develops during this period in the primary somatosensory cortex (S1) remains poorly understood. Here, we characterized neuronal activity evoked by single- or dual-whisker stimulation patterns in developing S1, before, during and after the occurrence of active whisking. Employing multi-electrode recordings in all layers of barrel cortex in urethane-anesthetized mice, we find layer-specific changes in multi-unit activity for principal and neighboring b…
Three Patterns of Oscillatory Activity Differentially Synchronize Developing Neocortical Networks In Vivo
2009
Coordinated patterns of electrical activity are important for the early development of sensory systems. The spatiotemporal dynamics of these early activity patterns and the role of the peripheral sensory input for their generation are essentially unknown. We performed extracellular multielectrode recordings in the somatosensory cortex of postnatal day 0 to 7 rats in vivo and observed three distinct patterns of synchronized oscillatory activity. (1) Spontaneous and periphery-driven spindle bursts of 1-2 s in duration and approximately 10 Hz in frequency occurred approximately every 10 s. (2) Spontaneous and sensory-driven gamma oscillations of 150-300 ms duration and 30-40 Hz in frequency oc…
Long-Term Potentiation in the Neonatal Rat Barrel Cortex In Vivo
2012
Long-term potentiation (LTP) is important for the activity-dependent formation of early cortical circuits. In the neonatal rodent barrel cortex, LTP has been studied only in vitro . We combined voltage-sensitive dye imaging with extracellular multielectrode recordings to study whisker stimulation-induced LTP in the whisker-to-barrel cortex pathway of the neonatal rat barrel cortex in vivo . Single whisker stimulation at 2 Hz for 10 min induced an age-dependent expression of LTP in postnatal day (P) 0 to P14 rats, with the strongest expression of LTP at P3–P5. The magnitude of LTP was largest in the activated barrel-related column, smaller in the surrounding septal region, and no LTP could b…