Spontaneous activity of auditory cortical neurons of waking cats at rest and during defensive conditioning

1979 ◽  
Vol 10 (3) ◽  
pp. 159-168 ◽  
Author(s):  
V. N. Dumenko ◽  
V. V. Sachenko
Keyword(s):  
Spontaneous Activity ◽  
Cortical Neurons ◽  
Defensive Conditioning

Development, learning and memory in large random networks of cortical neurons: lessons beyond anatomy

2002 ◽  
Vol 35 (1) ◽  
pp. 63-87 ◽  
Author(s):  
Shimon Marom ◽  
Goded Shahaf
Keyword(s):  
Functional Connectivity ◽  
Spontaneous Activity ◽  
Learning And Memory ◽  
Cortical Neurons ◽  
Ex Vivo ◽  
Adaptive Responses ◽  
Cortical Networks ◽  
Neural Learning ◽  
Wide Range ◽  
Activity Dependent

1. Introduction 631.1 Outline 631.2 Universals versus realizations in the study of learning and memory 642. Large random cortical networks developing ex vivo 652.1 Preparation 652.2 Measuring electrical activity 673. Spontaneous development 693.1 Activity 693.2 Connectivity 704. Consequences of spontaneous activity: pharmacological manipulations 724.1 Structural consequences 724.2 Functional consequences 735. Effects of stimulation 745.1 Response to focal stimulation 745.2 Stimulation-induced changes in connectivity 746. Embedding functionality in real neural networks 776.1 Facing the physiological definition of ‘reward’: two classes of theories 786.2 Closing the loop 797. Concluding remarks 848. Acknowledgments 859. References 85The phenomena of learning and memory are inherent to neural systems that differ from each other markedly. The differences, at the molecular, cellular and anatomical levels, reflect the wealth of possible instantiations of two neural learning and memory universals: (i) an extensive functional connectivity that enables a large repertoire of possible responses to stimuli; and (ii) sensitivity of the functional connectivity to activity, allowing for selection of adaptive responses. These universals can now be fully realized in ex-vivo developing neuronal networks due to advances in multi-electrode recording techniques and desktop computing. Applied to the study of ex-vivo networks of neurons, these approaches provide a unique view into learning and memory in networks, over a wide range of spatio-temporal scales. In this review, we summarize experimental data obtained from large random developing ex-vivo cortical networks. We describe how these networks are prepared, their structure, stages of functional development, and the forms of spontaneous activity they exhibit (Sections 2–4). In Section 5 we describe studies that seek to characterize the rules of activity-dependent changes in neural ensembles and their relation to monosynaptic rules. In Section 6, we demonstrate that it is possible to embed functionality into ex-vivo networks, that is, to teach them to perform desired firing patterns in both time and space. This requires ‘closing a loop’ between the network and the environment. Section 7 emphasizes the potential of ex-vivo developing cortical networks in the study of neural learning and memory universals. This may be achieved by combining closed loop experiments and ensemble-defined rules of activity-dependent change.

scholarly journals Spontaneous dynamics of neural networks in deep layers of prefrontal cortex

2017 ◽  
Vol 117 (4) ◽  
pp. 1581-1594 ◽  
Author(s):  
Andrew S. Blaeser ◽  
Barry W. Connors ◽  
Arto V. Nurmikko
Keyword(s):  
Prefrontal Cortex ◽  
Spontaneous Activity ◽  
Calcium Imaging ◽  
Cortical Neurons ◽  
Rhythmic Activity ◽  
Network Activity ◽  
Local Networks ◽  
Spatiotemporal Scale ◽  
Deep Layers ◽  
Delta Oscillations

Cortical systems maintain and process information through the sustained activation of recurrent local networks of neurons. Layer 5 is known to have a major role in generating the recurrent activation associated with these functions, but relatively little is known about its intrinsic dynamics at the mesoscopic level of large numbers of neighboring neurons. Using calcium imaging, we measured the spontaneous activity of networks of deep-layer medial prefrontal cortical neurons in an acute slice model. Inferring the simultaneous activity of tens of neighboring neurons, we found that while the majority showed only sporadic activity, a subset of neurons engaged in sustained delta frequency rhythmic activity. Spontaneous activity under baseline conditions was weakly correlated between pairs of neurons, and rhythmic neurons showed little coherence in their oscillations. However, we consistently observed brief bouts of highly synchronous activity that must be attributed to network activity. NMDA-mediated stimulation enhanced rhythmicity, synchrony, and correlation within these local networks. These results characterize spontaneous prefrontal activity at a previously unexplored spatiotemporal scale and suggest that medial prefrontal cortex can act as an intrinsic generator of delta oscillations. NEW & NOTEWORTHY Using calcium imaging and a novel analytic framework, we characterized the spontaneous and NMDA-evoked activity of layer 5 prefrontal cortex at a largely unexplored spatiotemporal scale. Our results suggest that the mPFC microcircuitry is capable of intrinsically generating delta oscillations and sustaining synchronized network activity that is potentially relevant for understanding its contribution to cognitive processes.

scholarly journals Quantitative differences in developmental profiles of spontaneous activity in cortical and hippocampal cultures

2014 ◽  
Author(s):  
Paul Charlesworth ◽  
Ellese Cotterill ◽  
Andrew Morton ◽  
Seth Grant ◽  
Stephen Eglen
Keyword(s):  
Spontaneous Activity ◽  
Cortical Neurons ◽  
Activity Patterns ◽  
Machine Learning Techniques ◽  
Multielectrode Arrays ◽  
Cortical Networks ◽  
Hippocampal Cultures ◽  
Hippocampal Networks ◽  
Cultured Networks

Background: Neural circuits can spontaneously generate complex spatiotemporal firing patterns during development. This spontaneous activity is thought to help guide development of the nervous system. In this study, we had two aims. First, to characterise the changes in spontaneous activity in cultures of developing networks of either hippocampal or cortical neurons dissociated from mouse. Second, to assess whether there are any functional differences in the patterns of activity in hippocampal and cortical networks. Results: We used multielectrode arrays to record the development of spontaneous activity in cultured networks of either hippocampal or cortical neurons every two or three days for the first month after plating. Within a few days of culturing, networks exhibited spontaneous activity. This activity strengthened and then stabilised typically around 21 days in vitro. We quantified the activity patterns in hippocampal and cortical networks using eleven features. Three out of eleven features showed striking differences in activity between hippocampal and cortical networks. 1: Interburst intervals are less variable in spike trains from hippocampal cultures. 2: Hippocampal networks have higher correlations. 3: Hippocampal networks generate more robust theta bursting patterns. Machine learning techniques confirmed that these differences in patterning are sufficient to reliably classify recordings at any given age as either hippocampal or cortical networks. Conclusions: Although cultured networks of hippocampal and cortical networks both generate spontaneous activity that changes over time, at any given time we can reliably detect differences in the activity patterns. We anticipate that this quantitative framework could have applications in many areas, including neurotoxicity testing and for characterising phenotype of different mutant mice. All code and data relating to this report are freely available for others to use.

Spontaneous Activity of Cortical Neurons in Vitro and Its Regulation by Acetylcholine

2010 ◽  
Vol 40 (9) ◽  
pp. 986-992 ◽  
Author(s):  
Yu. S. Mednikova ◽  
F. V. Kopytova ◽  
M. N. Zhadin
Keyword(s):  
Spontaneous Activity ◽  
Cortical Neurons

scholarly journals Local Application of Dopamine Inhibits Pyramidal Tract Neuron Activity in the Rodent Motor Cortex

2002 ◽  
Vol 88 (6) ◽  
pp. 3439-3451 ◽  
Author(s):  
Patrick W. Awenowicz ◽  
Linda L. Porter
Keyword(s):  
Motor Cortex ◽  
Dopamine Receptors ◽  
Spontaneous Activity ◽  
Cortical Neurons ◽  
Pyramidal Tract ◽  
D2 Receptor ◽  
Simultaneous Recording ◽  
Neuron Activity ◽  
Receptor Subtypes ◽  
Baseline Levels

Cortical neurons respond in a variety of ways to locally applied dopamine, perhaps because of the activation of different receptors within or among subpopulations of cells. This study was conducted to assess the effects of dopamine and the receptor subtypes that mediate the responses of a specific population of neurons, the pyramidal tract neurons (PTNs) in the rodent motor cortex. The specific subfamilies of dopamine receptors expressed by PTNs also were determined. PTNs were identified by antidromic stimulation in intact animals. Extracellular recordings of their spontaneous activity and glutamate-induced excitation were performed with multi-barrel pipettes to allow simultaneous recording and iontophoresis of several drugs. Prolonged (30 s) application of dopamine caused a progressive, nonlinear decrease in spontaneous firing rates for nearly all PTNs, with significant reductions from baseline spontaneous activity (71% of baseline levels) occurring between 20 and 30 s of iontophoresis. The D1 selective (SCH23390) and the D2 selective (eticlopride) antagonists were both effective in blocking dopamine-induced inhibition in nearly all PTNs. Mean firing levels were maintained within 3% of baseline levels during co-application of the D1 antagonist with dopamine and within 11% of baseline levels during co-application of the D2 antagonist and dopamine. SCH23390 was ineffective however, in 2 of 16 PTNs, and eticlopride was ineffective in 3 PTNs. The dopamine blockade by both antagonists in most neurons, along with the selective blockade by one, but not the other antagonist in a few neurons indicate that the overall population of PTNs exhibits a heterogeneous expression of dopamine receptors. The firing rate of PTNs was significantly enhanced by iontophoresis of glutamate (mean = 141% of baseline levels). These increases were attenuated significantly (mean= 98% of baseline) by co-application with dopamine in all PTNs, indicating dopaminergic interactions with glutamate transmission. The expression of dopamine receptors was studied with dual-labeling techniques. PTNs were identified by retrograde labeling with fast blue and the D1a, D2, or D5 receptor proteins were stained immunohistochemically. Some, but not all PTNs, showed labeling for D1a, D2, or D5 receptors. The D1a and D2 receptor immunoreactivity was observed primarily in the somata of PTNs, whereas D5 immunoreactivity extended well into the apical dendrites of PTNs. In accordance with findings of D1 and D2 receptor antagonism of dopamine's actions, the identification of three DA receptor subtypes on PTNs suggests that dopamine can directly modulate PTN activity through one or more receptor subtypes.

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