Formation and computational implications of assemblies in neural circuits

The Journal of Physiology, Год журнала: 2022, Номер 601(15), С. 3071 - 3090

Опубликована: Сен. 7, 2022

Abstract In the brain, patterns of neural activity represent sensory information and store it in non‐random synaptic connectivity. A prominent theoretical hypothesis states that assemblies, groups neurons are strongly connected to each other, key computational units underlying perception memory formation. Compatible with these hypothesised experiments have revealed display synchronous activity, either spontaneously or upon stimulus presentation, exhibit behavioural relevance. While remains unclear how assemblies form work has vastly contributed understanding various interacting mechanisms this process. Here, we review recent literature on assembly formation by categorising involved into four components: plasticity, symmetry breaking, competition stability. We highlight different approaches assumptions behind discuss ideas as unit brain. image

Язык: Английский

---

Contributions of cortical neuron firing patterns, synaptic connectivity, and plasticity to task performance

Nature Communications, Год журнала: 2024, Номер 15(1)

Опубликована: Июль 17, 2024

Abstract Neuronal responses during behavior are diverse, ranging from highly reliable ‘classical’ to irregular ‘non-classically responsive’ firing. While a continuum of response properties is observed across neural systems, little known about the synaptic origins and contributions diverse network function, perception, behavior. To capture heterogeneous measured auditory cortex rodents performing frequency recognition task, we use novel task-performing spiking recurrent incorporating spike-timing-dependent plasticity. Reliable units contribute differentially task performance via output connections, respectively. Excitatory plasticity shifts distribution while inhibition constrains its diversity. Together both improve with full engagement. The same local patterns inputs predict cortical neurons in vivo whole-cell recordings Thus, function emerge rules.

Язык: Английский

---

Autonomous emergence of connectivity assemblies via spike triplet interactions

PLoS Computational Biology, Год журнала: 2020, Номер 16(5), С. e1007835 - e1007835

Опубликована: Май 8, 2020

Non-random connectivity can emerge without structured external input driven by activity-dependent mechanisms of synaptic plasticity based on precise spiking patterns. Here we analyze the emergence global structures in recurrent networks a triplet model spike timing dependent (STDP), which depends interactions three precisely-timed spikes, and describe experiments with varying frequency better than classical pair-based STDP rule. We derive changes arising from correlations up to third-order them as sum structural motifs, determine how any network influences given connection through possible paths. This motif expansion framework reveals novel motifs under rule, support formation bidirectional connections ultimately spontaneous structure form self-connected groups neurons, or assemblies. propose that assembly need for externally patterned inputs assuming symmetric rule common previous studies. The non-random occurs internally-generated higher-order correlations, are ubiquitous natural stimuli neuronal activity, important coding. further demonstrate neuromodulatory modulate shape transmission function differentially promote underlying assemblies, quantify differences using graph theoretic measures.

Язык: Английский

---

Activity-Dependent Gene Expression in Neurons

The Neuroscientist, Год журнала: 2020, Номер 27(4), С. 355 - 366

Опубликована: Июль 30, 2020

The function of the nervous system in conveying and processing information necessary to interact with environment confers unique aspects on how expression genes neurons is regulated. Three salient factors are that (1) largest among most morphologically complex all cells, strict polarity, subcellular compartmentation, long-distant transport gene products, signaling molecules, other materials; (2) coded temporal firing pattern membrane depolarization; (3) must maintain a stable homeostatic level activation so stimuli do not normally drive intracellular steady state. Each these can require special methods analysis differing from approaches used non-neuronal cells. This review considers three neuronal current being analyze features transcriptome modulated by action potential firing.

Язык: Английский

---

Network control through coordinated inhibition

Current Opinion in Neurobiology, Год журнала: 2020, Номер 67, С. 34 - 41

Опубликована: Авг. 24, 2020

Coordinated excitatory and inhibitory activity is required for proper brain functioning. Recent computational experimental studies have demonstrated that patterns in recurrent cortical networks are dominated by inhibition. Whereas previous suggested plasticity important homeostatic control, this new framework puts inhibition the driver's seat. Complex neuronal comprise many configurations parallel, controlled external internal 'switches'. Context-dependent modulation of connections play a key role memory learning. It therefore to realize synaptic often multisynaptic balance between excitation not fixed, but depends on context level.

Язык: Английский

---

Heterosynaptic Plasticity and the Experience-Dependent Refinement of Developing Neuronal Circuits

Frontiers in Neural Circuits, Год журнала: 2021, Номер 15

Опубликована: Дек. 7, 2021

Neurons remodel the structure and strength of their synapses during critical periods development in order to optimize both perception cognition. Many these developmental synaptic changes are thought occur through synapse-specific homosynaptic forms experience-dependent plasticity. However, plasticity can also induce or contribute neighboring heterosynaptic interactions. Decades research vitro have uncovered many molecular mechanisms that mediate local compensation for plasticity, facilitation further bouts nearby synapses, cooperative induction by acting concert. These discoveries greatly benefited from new tools technologies permitted single synapse imaging manipulation structure, function, protein dynamics living neurons. With recent advent application similar vivo research, it is now feasible explore how neuronal circuits. In this review, we will first define take describe our current understanding mechanisms. Then, outline may lead meaningful refinement responses observations suggest such indeed at work . Finally, use a well-studied model cortical plasticity—ocular dominance period visual cortex development—to highlight overlap between potential avenues future research.

Язык: Английский

---

A circuit mechanism for independent modulation of excitatory and inhibitory firing rates after sensory deprivation

Proceedings of the National Academy of Sciences, Год журнала: 2022, Номер 119(32)

Опубликована: Авг. 4, 2022

Diverse interneuron subtypes shape sensory processing in mature cortical circuits. During development, deprivation evokes powerful synaptic plasticity that alters circuitry, but how different inhibitory modulate circuit dynamics response to this remains unclear. We investigate deprivation-induced changes affect excitatory and firing rates a microcircuit model of the cortex with multiple subtypes. find single subtype (parvalbumin-expressing [PV]), can only be comodulated—increased or decreased together. To explain experimentally observed independent modulation, whereby one rate increases other decreases, requires strong feedback from second (somatostatin-expressing [SST]). Our applies visual somatosensory cortex, suggesting general mechanism across cortices. Therefore, we provide mechanistic explanation for differential role regulating rates, contributing already diverse roles they serve cortex.

Язык: Английский

---

Memory recall involves a transient break in excitatory-inhibitory balance

eLife, Год журнала: 2021, Номер 10

Опубликована: Окт. 8, 2021

The brain has a remarkable capacity to acquire and store memories that can later be selectively recalled. These processes are supported by the hippocampus which is thought index memory recall reinstating information stored across distributed neocortical circuits. However, mechanism supports this interaction remains unclear. Here, in humans, we show of visual cue from paired associate accompanied transient increase ratio between glutamate GABA cortex. Moreover, these excitatory-inhibitory fluctuations predicted activity hippocampus. data suggest gates indexing circuits using disinhibitory mechanism.

Язык: Английский

---

Brain is modulated by neuronal plasticity during postnatal development

The Journal of Physiological Sciences, Год журнала: 2021, Номер 71(1)

Опубликована: Ноя. 17, 2021

Abstract Neuroplasticity is referred to the ability of nervous system change its structure or functions as a result former stimuli. It plausible mechanism underlying dynamic brain through adaptation processes neural and activity patterns. Nevertheless, it still unclear how plastic systems achieve maintain their equilibrium. Additionally, alterations balanced dynamics under different plasticity rules have not been explored either. Therefore, present article primarily aims review recent research studies regarding homosynaptic heterosynaptic neuroplasticity characterized by manipulation excitatory inhibitory synaptic inputs. Moreover, attempts understand mechanisms related main forms at synapses during development processes. Hence, this study comprised surveying those articles published since 1988 available PubMed, Google Scholar science direct databases on keyword-based search paradigm. All in all, results presented extensive corroborative pieces evidence for types plasticity, including long-term potentiation (LTP) depression (LTD) postsynaptic potentials (EPSPs IPSPs).

Язык: Английский

---

Stability and learning in excitatory synapses by nonlinear inhibitory plasticity

PLoS Computational Biology, Год журнала: 2022, Номер 18(12), С. e1010682 - e1010682

Опубликована: Дек. 2, 2022

Synaptic changes are hypothesized to underlie learning and memory formation in the brain. But Hebbian synaptic plasticity of excitatory synapses on its own is unstable, leading either unlimited growth strengths or silencing neuronal activity without additional homeostatic mechanisms. To control strengths, we propose a novel form at inhibitory synapses. Using computational modeling, suggest two key features plasticity, dominance inhibition over excitation nonlinear dependence firing rate postsynaptic neurons whereby change with same sign (potentiate depress) as strengths. We demonstrate that stable realized by this model affects excitatory/inhibitory weight ratios agreement experimental results. Applying disinhibitory signal can gate lead generation receptive fields strong bidirectional connectivity recurrent network. Hence, simultaneously stabilize enable upon disinhibition.

Язык: Английский

---