scholarly journals State-dependent modulation of activity in distinct layer 6 corticothalamic neurons in barrel cortex of awake mice

2021 ◽  
Author(s):  
Suryadeep Dash ◽  
Dawn M Autio ◽  
Shane R Crandall
Keyword(s):  
Cortical Neurons ◽  
Barrel Cortex ◽  
Related Activity ◽  
Functional Roles ◽  
Firing Rates ◽  
State Dependent ◽  
Rich Diversity ◽  
Response Profiles ◽  
Strategic Position ◽  
Activity Dependent

Layer 6 corticothalamic (L6 CT) neurons are in a strategic position to control sensory input to the neocortex, yet we understand very little about their functions. Apart from studying their anatomical, physiological and synaptic properties, most recent efforts have focused on the activity-dependent influences CT cells can exert on thalamic and cortical neurons through causal optogenetic manipulations. However, few studies have attempted to study them during behavior. In an attempt to address this gap, we performed juxtacellular recordings from optogenetically identified CT neurons in whisker-related primary somatosensory cortex (wS1) of awake, head-fixed mice (of either sex) free to rest quietly or self-initiate bouts of whisking and locomotion. We found a rich diversity of response profiles exhibited by CT cells. Broadly, their spiking patterns were either modulated by whisker-related behavior (~28%) or not (~72%). Whisker-related neurons exhibited both increases as well as decreases in firing rates. We also encountered cells with preceding modulations in firing rate before whisking onset. Overall, whisking better explained these changes in rates than overall changes in arousal. The CT cells that showed no whisker-related activity had low spontaneous firing rates (<0.5 Hz), with many all but silent. Remarkably, this relatively silent population preferentially spiked at the state transition point when pupil diameter constricted and the mouse entered quiet wakefulness. Thus, our results demonstrate that L6 CT neurons in wS1 show diverse spiking patterns, perhaps subserving distinct functional roles related to precisely timed responses during complex behaviors and transitions between discrete waking states.

scholarly journals Activity in the Barrel Cortex During Active Behavior and Sleep

2010 ◽  
Vol 103 (4) ◽  
pp. 2074-2084 ◽  
Author(s):  
Sujith Vijayan ◽  
Greg J. Hale ◽  
Christopher I. Moore ◽  
Emery N. Brown ◽  
Matthew Wilson
Keyword(s):  
Barrel Cortex ◽  
Slow Wave Sleep ◽  
Neural Firing ◽  
Related Activity ◽  
Firing Rates ◽  
Coding Schemes ◽  
Baseline Activity ◽  
Sensory Cue ◽  
The Individual

The rate at which neurons fire has wide-reaching implications for the coding schemes used by neural systems. Despite the extensive use of the barrel cortex as a model system, relatively few studies have examined the rate of sensory activity in single neurons in freely moving animals. We examined the activity of barrel cortex neurons in behaving animals during sensory cue interaction, during non–stimulus-related activity, during various states of sleep, and during the administration of isoflurane. The activity of regular-spiking units (RSUs: predominantly excitatory neurons) and fast spiking units (FSUs: a subtype of inhibitory interneurons) was examined separately. We characterized activity by calculating neural firing rates, because several reports have emphasized the low firing rates in this system, reporting that both baseline activity and stimulus evoked activity is <1 Hz. We report that, during sensory cue interaction or non–stimulus-related activity, the majority of RSUs in rat barrel cortex fired at rates significantly >1 Hz, with 27.4% showing rates above 10 Hz during cue interaction. Even during slow wave sleep, which had the lowest mean and median firing rates of any nonanesthetized state observed, 80.0% of RSUs fired above 1 Hz. During all of the nonanesthetized states observed 100% of the FSUs fired well above 1 Hz. When rats were administered isoflurane and at a depth of anesthesia used in standard in vivo electrophysiological preparations, all of the RSUs fired below 1 Hz. We also found that >80% of RSUs either upmodulated or downmodulated their firing during cue interaction. These data suggest that low firing rates do not typify the output of the barrel cortex during awake activity and during sleep and indicate that sensory coding at both the individual and population levels may be nonsparse.

scholarly journals Self-generated whisker movements drive state-dependent sensory input to developing barrel cortex

2020 ◽  
Author(s):  
James C. Dooley ◽  
Ryan M. Glanz ◽  
Greta Sokoloff ◽  
Mark S. Blumberg
Keyword(s):  
Somatosensory Cortex ◽  
Sensory Feedback ◽  
Barrel Cortex ◽  
Cortical Activity ◽  
Behavioral State ◽  
State Dependent ◽  
Field Activity ◽  
Drive State ◽  
Old Rats ◽  
Activity Dependent

SummaryCortical development is an activity-dependent process [1–3]. Regarding the role of activity in developing somatosensory cortex, one persistent debate concerns the importance of sensory feedback from self-generated movements. Specifically, recent studies claim that cortical activity is generated intrinsically, independent of movement [3, 4]. However, other studies claim that behavioral state moderates the relationship between movement and cortical activity [5–7]. Thus, perhaps inattention to behavioral state leads to failures to detect movement-driven activity [8]. Here, we resolve this issue by associating local field activity (i.e., spindle bursts) and unit activity in the barrel cortex of 5-day-old rats with whisker movements during wake and myoclonic twitches of the whiskers during active (REM) sleep. Barrel activity increased significantly within 500 ms of whisker movements, especially after twitches. Also, higher-amplitude movements were more likely to trigger barrel activity; when we controlled for movement amplitude, barrel activity was again greater after a twitch than a wake movement. We then inverted the analysis to assess the likelihood that increases in barrel activity were preceded within 500 ms by whisker movements: At least 55% of barrel activity was attributable to sensory feedback from whisker movements. Finally, when periods with and without movement were compared, 70–75% of barrel activity was movement-related. These results confirm the importance of sensory feedback from movements in driving activity in sensorimotor cortex and underscore the necessity of monitoring sleep-wake states to ensure accurate assessments of the contributions of the sensory periphery to activity in developing somatosensory cortex.

Role of Voltage-Gated K+ Currents in Mediating the Regular-Spiking Phenotype of Callosal-Projecting Rat Visual Cortical Neurons

1997 ◽  
Vol 78 (5) ◽  
pp. 2321-2335 ◽  
Author(s):  
Rachel E. Locke ◽  
Jeanne M. Nerbonne
Keyword(s):  
Action Potential ◽  
Cortical Neurons ◽  
Action Potentials ◽  
Repetitive Firing ◽  
Functional Roles ◽  
Firing Rates ◽  
Voltage Gated ◽  
Firing Properties ◽  
Visual Cortical

Locke, Rachel E. and Jeanne M. Nerbonne. Role of voltage-gated K+ currents in mediating the regular-spiking phenotype of callosal-projecting rat visual cortical neurons. J. Neurophysiol. 78: 2321–2335, 1997. Whole cell current- and voltage-clamp recordings were combined to examine action potential waveforms, repetitive firing patterns, and the functional roles of voltage-gated K+ currents ( I A, I D, and I K) in identified callosal-projecting (CP) neurons from postnatal (day 7–13) rat primary visual cortex. Brief (1 ms) depolarizing current injections evoke single action potentials in CP neurons with mean ± SD ( n = 60) durations at 50 and 90% repolarization of 1.9 ± 0.5 and 5.5 ± 2.0 ms, respectively; action potential durations in individual cells are correlated inversely with peak outward current density. During prolonged threshold depolarizing current injections, CP neurons fire repetitively, and two distinct, noninterconverting “regular-spiking” firing patterns are evident: weakly adapting CP cells fire continuously, whereas strongly adapting CP cells cease firing during maintained depolarizing current injections. Action potential repolarization is faster and afterhyperpolarizations are more pronounced in strongly than in weakly adapting CP cells. In addition, input resistances are lower and plateau K+ current densities are higher in strongly than in weakly adapting CP cells. Functional studies reveal that blockade of I D reduces the latency to firing an action potential, and increases action potential durations at 50 and 90% repolarization. Blockade of I D also increases firing rates in weakly adapting cells and results in continuous firing of strongly adapting cells. After applications of millimolar concentrations of 4-aminopyridine to suppress I A (as well as block I D), action potential durations at 50 and 90% repolarization are further increased, and firing rates are accelerated over those observed when only I D is blocked. Using VClamp/CClamp and the voltage-clamp data in the preceding paper, mathematical descriptions of I A, I D, and I K are generated and a model of the electrophysiological properties of rat visual cortical CP neurons is developed. The model is used to simulate the firing properties of strongly adapting and weakly adapting CP cells and to explore the functional roles of I A, I D, and I K in shaping the waveforms of individual action potentials and controlling the repetitive firing properties of these cells.

scholarly journals Activity of motor cortex neurons during backward locomotion

2011 ◽  
Vol 105 (6) ◽  
pp. 2698-2714 ◽  
Author(s):  
P. V. Zelenin ◽  
T. G. Deliagina ◽  
G. N. Orlovsky ◽  
A. Karayannidou ◽  
E. E. Stout ◽  
...  
Keyword(s):  
Motor Cortex ◽  
Cortical Neurons ◽  
Cortical Activity ◽  
The Other ◽  
Bipedal Locomotion ◽  
Related Activity ◽  
Quadrupedal Locomotion ◽  
Functional Roles ◽  
Recorded Activity ◽  
Almost All

Forward walking (FW) and backward walking (BW) are two important forms of locomotion in quadrupeds. Participation of the motor cortex in the control of FW has been intensively studied, whereas cortical activity during BW has never been investigated. The aim of this study was to analyze locomotion-related activity of the motor cortex during BW and compare it with that during FW. For this purpose, we recorded activity of individual neurons in the cat during BW and FW. We found that the discharge frequency in almost all neurons was modulated in the rhythm of stepping during both FW and BW. However, the modulation patterns during BW and FW were different in 80% of neurons. To determine the source of modulating influences (forelimb controllers vs. hindlimb controllers), the neurons were recorded not only during quadrupedal locomotion but also during bipedal locomotion (with either forelimbs or hindlimbs walking), and their modulation patterns were compared. We found that during BW (like during FW), modulation in some neurons was determined by inputs from limb controllers of only one girdle, whereas the other neurons received inputs from both girdles. The combinations of inputs could depend on the direction of locomotion. Most often (in 51% of forelimb-related neurons and in 34% of the hindlimb-related neurons), the neurons received inputs only from their own girdle when this girdle was leading and from both girdles when this girdle was trailing. This reconfiguration of inputs suggests flexibility of the functional roles of individual cortical neurons during different forms of locomotion.

scholarly journals Self-organization of modular network architecture by activity-dependent neuronal migration and outgrowth

eLife ◽  
2019 ◽  
Vol 8 ◽  
Author(s):  
Samora Okujeni ◽  
Ulrich Egert
Keyword(s):  
Neurite Outgrowth ◽  
Cortical Neurons ◽  
Network Architecture ◽  
Activity Levels ◽  
Range Interaction ◽  
Firing Rates ◽  
Rat Cortical Neurons ◽  
Average Activity ◽  
Highly Correlated ◽  
Activity Dependent

The spatial distribution of neurons and activity-dependent neurite outgrowth shape long-range interaction, recurrent local connectivity and the modularity in neuronal networks. We investigated how this mesoscale architecture develops by interaction of neurite outgrowth, cell migration and activity in cultured networks of rat cortical neurons and show that simple rules can explain variations of network modularity. In contrast to theoretical studies on activity-dependent outgrowth but consistent with predictions for modular networks, spontaneous activity and the rate of synchronized bursts increased with clustering, whereas peak firing rates in bursts increased in highly interconnected homogeneous networks. As Ca2+ influx increased exponentially with increasing network recruitment during bursts, its modulation was highly correlated to peak firing rates. During network maturation, long-term estimates of Ca2+ influx showed convergence, even for highly different mesoscale architectures, neurite extent, connectivity, modularity and average activity levels, indicating homeostatic regulation towards a common set-point of Ca2+ influx.

Gustatory neural coding in the monkey cortex: stimulus quality

1991 ◽  
Vol 66 (4) ◽  
pp. 1156-1165 ◽  
Author(s):  
V. L. Smith-Swintosky ◽  
C. R. Plata-Salaman ◽  
T. R. Scott
Keyword(s):  
Cortical Neurons ◽  
Neural Coding ◽  
Monosodium Glutamate ◽  
Stimulus Array ◽  
Cortical Region ◽  
Stimulus Similarity ◽  
Somatosensory Stimulation ◽  
Wide Range ◽  
Response Profiles ◽  
Stimulation Of

1. Extracellular action potentials were recorded from 50 single neurons in the insular-opercular cortex of two alert cynomolgus monkeys during gustatory stimulation of the tongue and palate. 2. Sixteen stimuli, including salts, sugars, acids, alkaloids, monosodium glutamate, and aspartame, were chosen to represent a wide range of taste qualities. Concentrations were selected to elicit a moderate gustatory response, as determined by reference to previous electrophysiological data or to the human psychophysical literature. 3. The cortical region over which taste-evoked activity could be recorded included the frontal operculum and anterior insula, an area of approximately 75 mm3. Taste-responsive cells constituted 50 (2.7%) of the 1,863 neurons tested. Nongustatory cells responded to mouth movement (20.7%), somatosensory stimulation of the tongue (9.6%), stimulus approach or anticipation (1.7%), and tongue extension (0.6%). The sensitivities of 64.6% of these cortical neurons could not be identified by our stimulation techniques. 4. Taste cells had low spontaneous activity levels (3.7 +/- 3.0 spikes/s, mean +/- SD) and showed little inhibition. They were moderately broadly tuned, with a mean entropy coefficient of 0.76 +/- 0.17. Excitatory responses were typically not robust. 5. Hierarchical cluster analysis was used to determine whether neurons could be divided into discrete types, as defined by their response profiles to the entire stimulus array. There was an apparent division of response profiles into four general categories, with primary sensitivities to sodium (n = 18), glucose (n = 15), quinine (n = 12), and acid (n = 5). However, these categories were not statistically independent. Therefore the notion of functionally distinct neuron types was not supported by an analysis of the distribution of response profiles. It was the case, however, that neurons in the sodium category could be distinguished from other neurons by their relative specificity. 6. The similarity among the taste qualities represented by this stimulus array was assessed by calculating correlations between the activity profiles they elicited from these 50 neurons. The results generally confirmed expectations derived from human psychophysical studies. In a multidimensional representation of stimulus similarity, there were groups that contained acids, sodium salts, and chemicals that humans label bitter and sweet. 7. The small proportion of insular-opercular neurons that are taste sensitive and the low discharge rates that taste stimuli are able to evoke from them suggest a wider role for this cortical area than just gustatory coding.(ABSTRACT TRUNCATED AT 400 WORDS)

Visually Related Activity in Human Temporal Cortical Neurons

1993 ◽  
pp. 279-289 ◽  
Author(s):  
GEORGE A. OJEMANN ◽  
JEFFREY G. OJEMANN ◽  
MICHAEL HAGLUND ◽  
MARK HOLMES ◽  
ETTORE LETTICH
Keyword(s):  
Cortical Neurons ◽  
Related Activity

scholarly journals Self-Generated Whisker Movements Drive State-Dependent Sensory Input to Developing Barrel Cortex

2020 ◽  
Vol 30 (12) ◽  
pp. 2404-2410.e4 ◽  
Author(s):  
James C. Dooley ◽  
Ryan M. Glanz ◽  
Greta Sokoloff ◽  
Mark S. Blumberg
Keyword(s):  
Sensory Input ◽  
Barrel Cortex ◽  
State Dependent ◽  
Drive State

scholarly journals Neurons and neuronal activity control gene expression in astrocytes to regulate their development and metabolism

2017 ◽  
Vol 8 (1) ◽  
Author(s):  
Philip Hasel ◽  
Owen Dando ◽  
Zoeb Jiwaji ◽  
Paul Baxter ◽  
Alison C. Todd ◽  
...  
Keyword(s):  
Gene Expression ◽  
Neuronal Activity ◽  
Cortical Neurons ◽  
Synaptic Activity ◽  
Rna Seq ◽  
Metabolic Cooperation ◽  
Closely Related Species ◽  
Lactate Shuttle ◽  
Activity Dependent ◽  
Elevated Lactate

Abstract The influence that neurons exert on astrocytic function is poorly understood. To investigate this, we first developed a system combining cortical neurons and astrocytes from closely related species, followed by RNA-seq and in silico species separation. This approach uncovers a wide programme of neuron-induced astrocytic gene expression, involving Notch signalling, which drives and maintains astrocytic maturity and neurotransmitter uptake function, is conserved in human development, and is disrupted by neurodegeneration. Separately, hundreds of astrocytic genes are acutely regulated by synaptic activity via mechanisms involving cAMP/PKA-dependent CREB activation. This includes the coordinated activity-dependent upregulation of major astrocytic components of the astrocyte–neuron lactate shuttle, leading to a CREB-dependent increase in astrocytic glucose metabolism and elevated lactate export. Moreover, the groups of astrocytic genes induced by neurons or neuronal activity both show age-dependent decline in humans. Thus, neurons and neuronal activity regulate the astrocytic transcriptome with the potential to shape astrocyte–neuron metabolic cooperation.

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