Layer 4 organization and respiration locking in the rodent nose somatosensory cortex

2020 ◽  
Vol 124 (3) ◽  
pp. 822-832 ◽  
Author(s):  
Eduard Maier ◽  
Simon Lauer ◽  
Michael Brecht
Keyword(s):  
Somatosensory Cortex ◽  
Neural Activity ◽  
Field Recordings ◽  
Physiological Properties ◽  
Sensory Modalities ◽  
Layer 4

We characterized the rodent nose somatosensory cortex. The nostril representation appeared as a kind of “hole” (i.e., as a stripe-like recess of layer 4) in tangential cortical sections. Neural activity in nose somatosensory cortex was locked to respiration and simultaneous field recordings indicate that this locking was specific to this region. Our results reveal previously unknown cytoarchitectonic and physiological properties of the rodent nose somatosensory cortex, potentially enabling it to integrate multiple sensory modalities.

scholarly journals Seasonal plasticity in the adult somatosensory cortex

2020 ◽  
Vol 117 (50) ◽  
pp. 32136-32144
Author(s):  
Saikat Ray ◽  
Miao Li ◽  
Stefan Paul Koch ◽  
Susanne Mueller ◽  
Philipp Boehm-Sturm ◽  
...  
Keyword(s):  
Somatosensory Cortex ◽  
Activity Patterns ◽  
Adaptive Plasticity ◽  
Neural Systems ◽  
Mammalian Brain ◽  
Sensory Stimuli ◽  
Seasonal Plasticity ◽  
Layer 4 ◽  
Life On Earth

Seasonal cycles govern life on earth, from setting the time for the mating season to influencing migrations and governing physiological conditions like hibernation. The effect of such changing conditions on behavior is well-appreciated, but their impact on the brain remains virtually unknown. We investigate long-term seasonal changes in the mammalian brain, known as Dehnel’s effect, where animals exhibit plasticity in body and brain sizes to counter metabolic demands in winter. We find large seasonal variation in cellular architecture and neuronal activity in the smallest terrestrial mammal, the Etruscan shrew, Suncus etruscus. Their brain, and specifically their neocortex, shrinks in winter. Shrews are tactile hunters, and information from whiskers first reaches the somatosensory cortex layer 4, which exhibits a reduced width (−28%) in winter. Layer 4 width (+29%) and neuron number (+42%) increase the following summer. Activity patterns in the somatosensory cortex show a prominent reduction of touch-suppressed neurons in layer 4 (−55%), the most metabolically active layer. Loss of inhibitory gating occurs with a reduction in parvalbumin-positive interneurons, one of the most active neuronal subtypes and the main regulators of inhibition in layer 4. Thus, a reduction in neurons in layer 4 and particularly parvalbumin-positive interneurons may incur direct metabolic benefits. However, changes in cortical balance can also affect the threshold for detecting sensory stimuli and impact prey choice, as observed in wild shrews. Thus, seasonal neural adaptation can offer synergistic metabolic and behavioral benefits to the organism and offer insights on how neural systems show adaptive plasticity in response to ecological demands.

scholarly journals Behavioral Choice-related Neuronal Activity in Monkey Primary Somatosensory Cortex in a Haptic Delay Task

2012 ◽  
Vol 24 (7) ◽  
pp. 1634-1644 ◽  
Author(s):  
Liping Wang ◽  
Xianchun Li ◽  
Steven S. Hsiao ◽  
Mark Bodner ◽  
Fred Lenz ◽  
...  
Keyword(s):  
Somatosensory Cortex ◽  
Neuronal Activity ◽  
Neural Activity ◽  
Incorrect Response ◽  
Primary Somatosensory Cortex ◽  
Control Task ◽  
Neural Correlate ◽  
Behavioral Choice ◽  
Delay Task ◽  
Number Of Cells

The neuronal activity in the primary somatosensory cortex was collected when monkeys performed a haptic–haptic DMS task. We found that, in trials with correct task performance, a substantial number of cells showed significant differential neural activity only when the monkeys had to make a choice between two different haptic objects. Such a difference in neural activity was significantly reduced in incorrect response trials. However, very few cells showed the choice-only differential neural activity in monkeys who performed a control task that was identical to the haptic–haptic task but did not require the animal to either actively memorize the sample or make a choice between two objects at the end of a trial. From these results, we infer that the differential activity recorded from cells in the primary somatosensory cortex in correct performance reflects the neural process of behavioral choice, and therefore, it is a neural correlate of decision-making when the animal has to make a haptic choice.

Angiotensin II attenuates functional hyperemia in the mouse somatosensory cortex

2003 ◽  
Vol 285 (5) ◽  
pp. H1890-H1899 ◽  
Author(s):  
Ken Kazama ◽  
Gang Wang ◽  
Kelly Frys ◽  
Josef Anrather ◽  
Costantino Iadecola
Keyword(s):  
Angiotensin Ii ◽  
Somatosensory Cortex ◽  
Neural Activity ◽  
Brain Regions ◽  
Synaptic Activity ◽  
Nitric Oxide Donor ◽  
Ang Ii ◽  
Functional Hyperemia ◽  
Doppler Flowmetry ◽  
Whisker Stimulation

We investigated whether angiotensin II (ANG II), a peptide that plays a central role in the genesis of hypertension, alters the coupling between synaptic activity and cerebral blood flow (CBF), a critical homeostatic mechanism that assures adequate cerebral perfusion to active brain regions. The somatosensory cortex was activated by stroking the facial whiskers in anesthetized C57BL/6J mice while local CBF was recorded by laser-Doppler flowmetry. Intravenous ANG II infusion (0.25 μg·kg–1·min–1) increased mean arterial pressure (MAP) from 82 ± 2 to 102 ± 3 mmHg ( P < 0.05) without affecting resting CBF ( P > 0.05). ANG II attenuated the CBF increase produced by whisker stimulation by 65% ( P < 0.05) but did not affect the response to hypercapnia or to neocortical application of the nitric oxide donor S-nitroso- N-acetyl penicillamine ( P > 0.05). The effect of ANG II on functional hyperemia persisted if the elevation in MAP was offset by controlled hemorrhage or prevented by topical application of the peptide to the activated cortex. ANG II did not reduce the amplitude of the P1 wave of the field potentials evoked by whisker stimulation ( P > 0.05). Infusion of phenylephrine increased MAP ( P > 0.05 from ANG II) but did not alter the functional hyperemic response ( P > 0.05). The data suggest that ANG II alters the coupling between CBF and neural activity. The mechanisms of the effect are not related to the elevation in MAP and/or to inhibition of the synaptic activity evoked by whisker stimulation. The imbalance between CBF and neural activity induced by ANG II may alter the homeostasis of the neuronal microenvironment and contribute to brain dysfunction during ANG II-induced hypertension.

scholarly journals Steady-state dynamics and experience-dependent plasticity of dendritic spines of layer 4/5a pyramidal neurons in somatosensory cortex

2014 ◽  
Vol 8 ◽  
Author(s):  
Miquelajauregui Amaya ◽  
Kribakaran Sahana ◽  
Mostany Ricardo ◽  
Badaloni Aurora ◽  
Consalez Giacomo ◽  
...  
Keyword(s):  
Steady State ◽  
Somatosensory Cortex ◽  
Dendritic Spines ◽  
Pyramidal Neurons ◽  
Dependent Plasticity ◽  
Layer 4

scholarly journals Rhythmic modulation of visual perception by continuous rhythmic auditory stimulation

2020 ◽  
Author(s):  
Anna-Katharina R. Bauer ◽  
Freek van Ede ◽  
Andrew J. Quinn ◽  
Anna C. Nobre
Keyword(s):  
Visual Perception ◽  
Neural Activity ◽  
Sensory Modality ◽  
Auditory Stimulation ◽  
Visual Performance ◽  
List Type ◽  
Sensory Modalities ◽  
Visual Areas ◽  
Visual Cortical

AbstractAt any given moment our sensory systems receive multiple, often rhythmic, inputs from the environment. Processing of temporally structured events in one sensory modality can guide both behavioural and neural processing of events in other sensory modalities, but how this occurs remains unclear. Here, we used human electroencephalography (EEG) to test the cross-modal influences of a continuous auditory frequency-modulated (FM) sound on visual perception and visual cortical activity. We report systematic fluctuations in perceptual discrimination of brief visual stimuli in line with the phase of the FM sound. We further show that this rhythmic modulation in visual perception is related to an accompanying rhythmic modulation of neural activity recorded over visual areas. Importantly, in our task, perceptual and neural visual modulations occurred without any abrupt and salient onsets in the energy of the auditory stimulation and without any rhythmic structure in the visual stimulus. As such, the results provide a critical validation for the existence and functional role of cross-modal entrainment and demonstrates its utility for organising the perception of multisensory stimulation in the natural environment.Highlightscross-modal influences are mediated by the synchronisation of neural oscillationsvisual performance fluctuates in line with the phase of a frequency-modulated soundcross-modal entrainment of neural activity predicts fluctuation in visual performancecross-modal entrainment organises perception of multisensory stimuli

scholarly journals The non-linear mixed representations in somatosensory cortex support simple and complex tasks

2021 ◽  
Author(s):  
Ramon Nogueira ◽  
Chris C. Rodgers ◽  
Randy M. Bruno ◽  
Stefano Fusi
Keyword(s):  
Somatosensory Cortex ◽  
Neural Activity ◽  
High Speed ◽  
Barrel Cortex ◽  
Broad Class ◽  
High Dimensional ◽  
Complex Tasks ◽  
Sensory Inputs ◽  
Neural Representations ◽  
Non Linear

Adaptive behavior in humans, rodents, and other animals often requires the integration over time of multiple sensory inputs. Here we studied the behavior and the neural activity of mice trained to actively integrate information from different whiskers to report the curvature of an object. The analysis of high speed videos of the whiskers revealed that the task could be solved by integrating linearly the whisker contacts on the object. However, recordings from the mouse barrel cortex revealed that the neural representations are high dimensional as the inputs from multiple whiskers are mixed non-linearly to produce the observed neural activity. The observed representation enables the animal to perform a broad class of significantly more complex tasks, with minimal disruption of the ability to generalize to novel situations in simpler tasks. Simulated recurrent neural networks trained to perform similar tasks reproduced both the behavioral and neuronal experimental observations. Our work suggests that the somatosensory cortex operates in a regime that represents an efficient compromise between generalization, which typically requires pure and linear mixed selectivity representations, and the ability to perform complex discrimination tasks, which is granted by non-linear mixed representations.

The Influence of Single VB Thalamocortical Impulses on Barrel Columns of Rabbit Somatosensory Cortex

2000 ◽  
Vol 83 (5) ◽  
pp. 2802-2813 ◽  
Author(s):  
Harvey A. Swadlow ◽  
Alexander G. Gusev
Keyword(s):  
Somatosensory Cortex ◽  
Rise Time ◽  
Action Potentials ◽  
Field Potentials ◽  
Cortical Layers ◽  
Axon Terminals ◽  
Inhibitory Mechanisms ◽  
Layer 4 ◽  
Slow Rise ◽  
A Minor

Extracellular recordings were obtained from single neurons in ventrobasal (VB) thalamus of awake rabbits while field potentials were recorded at various depths within topographically aligned and nonaligned barrel columns of somatosensory cortex (S1). Spike-triggered averages of cortical field potentials were obtained following action potentials in thalamic neurons. Action potentials in a VB neuron elicited a cortical response within layer 4 with three distinct components. 1) A biphasic, initially positive response (latency <1 ms) was interpreted to reflect activation of the VB axon terminals (the AxTP). This response was not affected by infusion of an α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid (AMPA)/kainate receptor antagonist within the barrel. In contrast, later components of the response were completely eliminated and were interpreted to reflect focal synaptic potentials. 2) A negative potential [focal synaptic negativity (FSN)] occurred at a mean latency of 1.65 ms and lasted ∼4 ms. This response had a rapid rise time (∼0.7 ms) and was interpreted to reflect monosynaptic excitation. 3) The third component was a positive potential (the FSP), with a slow rise time and a half-amplitude duration of ∼30 ms. The FSP showed a weak reversal in superficial cortical layers and was interpreted to reflect di/polysynaptic inhibition. The amplitudes of the AxTP, the FSN, and the FSP reached a peak near layer 4 and were highly attenuated in both superficial and deep cortical layers. All components were attenuated or absent when the cortical electrode was missaligned from the thalamic electrode by a single cortical barrel. Deconvolution procedures revealed that the autocorrelogram of the presynaptic VB neuron had very little influence on either the amplitude or duration of the AxTP or the FSN, and only a minor influence (mean, 11%) on the amplitude of the FSP. We conclude that individual VB thalamic impulses entering a cortical barrel engage both monosynaptic excitatory and di/polysynaptic inhibitory mechanisms. Putative inhibitory interneurons of an S1 barrel receive a highly divergent/convergent monosynaptic input from the topographically aligned VB barreloid, and this results in sharp synchrony among these interneurons. We suggest that single-fiber access to disynaptic inhibition is facilitated by this sharp synchrony, and that the FSP reflects a consequent synchronous wave of feed-forward inhibition within the S1 barrel.

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