Bicuculline-induced enhancement of sensory responses and cross-correlations between reticular formation and cortical neurons

1983 ◽  
Vol 55 (3) ◽  
pp. 301-313 ◽  
Author(s):  
C.L Faingold ◽  
W.E Hoffmann ◽  
D.M Caspary
Keyword(s):  
Reticular Formation ◽  
Cortical Neurons ◽  
Cross Correlations ◽  
Sensory Responses

scholarly journals Altered cortical processing of sensory input in Huntington disease mouse models

2021 ◽  
Author(s):  
Marja D Sepers ◽  
James P Mackay ◽  
Ellen Koch ◽  
Dongsheng Xiao ◽  
Majid H Mohajerani ◽  
...  
Keyword(s):  
Huntington Disease ◽  
Cortical Neurons ◽  
Neurodegenerative Disorder ◽  
Ex Vivo ◽  
Sensory Stimulation ◽  
In Vivo Studies ◽  
Field Potentials ◽  
Sensory Responses ◽  
Voltage Sensitive Dyes

Huntington disease (HD), a hereditary neurodegenerative disorder, manifests as progressively impaired movement and cognition. Although early abnormalities of neuronal activity in striatum are well established in HD models, there are fewer in vivo studies of the cortex. Here, we record local field potentials (LFPs) in YAC128 HD model mice versus wild-type mice. In multiple cortical areas, limb sensory stimulation evokes a greater change in LFP power in YAC128 mice. Mesoscopic imaging using voltage-sensitive dyes reveal more extensive spread of evoked sensory signals across the cortical surface in YAC128 mice. YAC128 layer 2/3 sensory cortical neurons ex vivo show increased excitatory events, which could contribute to enhanced sensory responses in vivo. Cortical LFP responses to limb stimulation, visual and auditory input are also significantly increased in zQ175 HD mice. Results presented here extend knowledge of HD beyond ex vivo studies of individual neurons to the intact cortical network.

scholarly journals Effects of Task Difficulty and Target Likelihood in Area V4 of Macaque Monkeys

2006 ◽  
Vol 96 (5) ◽  
pp. 2377-2387 ◽  
Author(s):  
C. Elizabeth Boudreau ◽  
Tori H. Williford ◽  
John H. R. Maunsell
Keyword(s):  
Spatial Attention ◽  
Cortical Neurons ◽  
Task Difficulty ◽  
Focus Of Attention ◽  
Behavioral Performance ◽  
Neuronal Responses ◽  
Fixed Amount ◽  
Processing Resource ◽  
Area V4 ◽  
Sensory Responses

Spatial attention improves performance at attended locations and correspondingly modulates firing rates of cortical neurons. The size of these behavioral and neuronal effects depends on the difficulty of the task performed at the attended location. Psychological theorists have attributed this to a tighter focus of a fixed amount of processing resource at the attended location, but the effects of task difficulty on the distribution of neuronal effects of attention across the visual field have not been fully explored. We trained rhesus monkeys to do a detection task in which difficulty and spatial attention were manipulated independently. Probe stimuli were used to measure behavioral performance in different conditions of attention and difficulty. Animals performed better at attended locations and this advantage increased with difficulty, consistent with data from human psychophysics. Neuronal modulation by spatial attention was larger with greater difficulty. In two animals, increasing difficulty caused a modest increase in neuronal responses to visual stimuli regardless of the locus of spatial attention. In a third animal, which was previously trained to ignore multiple distracting stimuli, increasing task difficulty increased responses at the focus of attention and suppressed responses away from the focus of attention. The results show that difficulty can modulate effects of spatial attention in V4; it can alter the distribution of sensory responses across the visual scene in ways that may depend on the subject's behavioral strategy.

Spike-Wave Complexes and Fast Components of Cortically Generated Seizures. III. Synchronizing Mechanisms

1998 ◽  
Vol 80 (3) ◽  
pp. 1480-1494 ◽  
Author(s):  
Dag Neckelmann ◽  
Florin Amzica ◽  
Mircea Steriade
Keyword(s):  
Cortical Neurons ◽  
Time Delays ◽  
Slow Oscillation ◽  
Time Lags ◽  
Intracellular Recordings ◽  
Field Potentials ◽  
Thalamic Nuclei ◽  
Dorsal Thalamus ◽  
Cross Correlations ◽  
Spike Wave

Neckelmann, Dag, Florin Amzica, and Mircea Steriade. Spike-wave complexes and fast components of cortically generated seizures. III. Synchronizing mechanisms. J. Neurophysiol. 80: 1480–1494, 1998. The intracortical and thalamocortical synchronization of spontaneously occurring or bicuculline-induced seizures, consisting of spike-wave (SW) or polyspike-wave (PSW) complexes at 2–3 Hz and fast runs at 10–15 Hz, was investigated in cats under ketamine-xylazine anesthesia. We used single and dual simultaneous intracellular recordings from cortical areas 5 and 7, and extracellular recordings of unit firing and field potentials from neocortical areas 5, 7, 17, 18, as well as related thalamic nuclei. The evolution of time delays between paroxysmal depolarizing events in single neurons or neuronal pools recorded from adjacent and distant sites was analyzed by using 1) sequential cross-correlations between field potentials, 2) averaged activities triggered by the spiky component of cortical SW/PSW complexes, and 3) time histograms between neuronal discharges. In all instances, the paroxysmal activities recorded from the dorsal thalamus lagged the onset of seizures in neocortex. The time lags between simultaneously impaled cortical neurons were significantly smaller during SW complexes than during the prior epochs of slow oscillation. During seizures, as during the slow oscillation, the intracortical synchrony was reduced with increased distance between different cortical sites. Dual intracellular recordings showed that, during the same seizure, time lags were not constant and, instead, reflected alternating precession of the recorded foci. After transection between areas 5 and 7, the intracortical synchrony was lost, but corticothalamocortical volleys could partially restore seizure synchrony. These data show that the neocortex leads the thalamus during SW/PSW seizures, that time lags between cortical foci are not static, and that thalamus may assist synchronization of SW/PSW seizures after disconnection of intracortical synaptic linkages.

Time-Dependent, Layer-Specific Modulation of Sensory Responses Mediated by Neocortical Layer 1

2006 ◽  
Vol 96 (6) ◽  
pp. 3170-3182 ◽  
Author(s):  
Dan Shlosberg ◽  
Yael Amitai ◽  
Rony Azouz
Keyword(s):  
Somatosensory Cortex ◽  
Cortical Neurons ◽  
Sensory Information ◽  
Time Dependent ◽  
Inhibitory Influence ◽  
Sensory Responses ◽  
Specific Regulation ◽  
Sensory Evoked

An essential component of feedback and top-down information in the cortical column arrives at layer 1 (L1) where it contacts distal dendrites of pyramidal neurons. Although much is known about the anatomical organization of L1 fibers, their contribution to sensory information processing remains to be determined. We assessed the physiological significance of L1 inputs by performing extracellular recordings in vivo from neurons in the primary somatosensory cortex of rodents. We found that blocking activity in L1 increases whisker-evoked response magnitude and variance, suggesting that L1 exerts an inhibitory influence on whisker responses. However, when pairing L1 stimulation with whisker deflection, the interval between the stimuli determined the outcome of the interaction, with facilitation of sensory responses dominating the short intervals (≤10 ms) and suppression prevailing at longer intervals (>10 ms). These temporal interactions resulted in a time-dependent regulation of direction tuning of cortical neurons. The synaptic mechanisms underlying L1 inputs’ influences were examined using whole cell recordings in vitro while pairing L1 and white-matter stimulations. We found time-dependent, layer-specific differences in synaptic summation of the two inputs, with supralinearity at shorter intervals and sublinearity at longer intervals that resulted mainly from shunting inhibition. Taken together, our results demonstrate that L1 inputs impose a time- and layer-specific regulation on sensory-evoked responses. This in turn may lead to a dynamic transmission of sensory information in the somatosensory cortex.

scholarly journals Multimodal Sensory Responses of Nucleus Reticularis Gigantocellularis and the Responses' Relation to Cortical and Motor Activation

2010 ◽  
Vol 103 (5) ◽  
pp. 2326-2338 ◽  
Author(s):  
Eugene M. Martin ◽  
Constantine Pavlides ◽  
Donald Pfaff
Keyword(s):  
Reticular Formation ◽  
Neck Muscle ◽  
Medullary Reticular Formation ◽  
Nucleus Reticularis ◽  
Nucleus Reticularis Gigantocellularis ◽  
Arousal Mechanism ◽  
Sensory Responses ◽  
Excitatory Responses ◽  
Fast Oscillations ◽  
Large Neurons

The connectivity of large neurons of the nucleus reticularis gigantocellularis (NRGc) in the medullary reticular formation potentially allows both for the integration of stimuli, in several modalities, that would demand immediate action, and for coordinated activation of cortical and motoric activity. We have simultaneously recorded cortical local field potentials, neck muscle electromyograph (EMG), and the neural activity of medullary NRGc neurons in unrestrained, unanesthetized rats to determine whether the activity of the NRGc is consistent with the modulation of general arousal. We observed excitatory responses of individual NRGc neurons to all modalities tested: tactile, visual, auditory, vestibular, and olfactory. Excitation was directly linked to increases in neck muscle EMG amplitude and corresponded with increases in the power of fast oscillations (30 to 80 Hz) of cortical activity and decreases in the power of slow oscillations (2 to 8 Hz). Because these reticular formation neurons can respond to broad ranges of stimuli with increased firing rates associated with the initiation of behavioral responses, we infer that they are part of an elementary “first responder” CNS arousal mechanism.

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