Classification of odorants across layers in locust olfactory pathway. Sanda P, Kee T, Gupta N, Stopfer M, Bazhenov M. J Neurophysiol. 2016 May 1;115(5):2303-16.

Olfactory processing takes place across multiple layers of neurons from the transduction of odorants in the periphery, to odor quality processing, learning, and decision making in higher olfactory structures. In insects, projection neurons (PNs) in the antennal lobe send odor information to the Kenyon cells (KCs) of the mushroom bodies and lateral horn neurons (LHNs). To examine the odor information content in different structures of the insect brain, antennal lobe, mushroom bodies and lateral horn, ...

Read More →
0

Hippocampal CA1 Ripples as Inhibitory Transients. Malerba P, Krishnan GP, Fellous JM, Bazhenov M. PLoS Comput Biol. 2016 Apr 19;12(4):e1004880.

Memories are stored and consolidated as a result of a dialogue between the hippocampus and cortex during sleep. Neurons active during behavior reactivate in both structures during sleep, in conjunction with characteristic brain oscillations that may form the neural substrate of memory consolidation. In the hippocampus, replay occurs within sharp wave-ripples: short bouts of high-frequency activity in area CA1 caused by excitatory activation from area CA3. In this work, we develop a computational model of ripple generation, motivated ...

Read More →
0

Synaptic Mechanisms of Memory Consolidation during Sleep Slow Oscillations. Wei Y, Krishnan GP, Bazhenov M. J Neurosci. 2016 Apr 13;36(15):4231-47.

Sleep is critical for regulation of synaptic efficacy, memories, and learning. However, the underlying mechanisms of how sleep rhythms contribute to consolidating memories acquired during wakefulness remain unclear. Here we studied the role of slow oscillations, 0.2-1 Hz rhythmic transitions between Up and Down states during stage 3/4 sleep, on dynamics of synaptic connectivity in the thalamocortical network model implementing spike-timing-dependent synaptic plasticity. We found that the spatiotemporal pattern of Up-state propagation ...

Read More →
0

Feed-Forward versus Feedback Inhibition in a Basic Olfactory Circuit. Kee T, Sanda P, Gupta N, Stopfer M, Bazhenov M. PLoS Comput Biol. 2015 Oct 12;11(10):e1004531.

Inhibitory interneurons play critical roles in shaping the firing patterns of principal neurons in many brain systems. Despite difference in the anatomy or functions of neuronal circuits containing inhibition, two basic motifs repeatedly emerge: feed-forward and feedback. In the locust, it was proposed that a subset of lateral horn interneurons (LHNs), provide feed-forward inhibition onto Kenyon cells (KCs) to maintain their sparse firing–a property critical for olfactory learning and memory. But recently it ...

Read More →
0

Learning modifies odor mixture processing to improve detection of relevant components. Chen JY, Marachlian E, Assisi C, Huerta R, Smith BH, Locatelli F, Bazhenov M. J Neurosci. 2015 Jan 7;35(1):179-97.

Honey bees have a rich repertoire of olfactory learning behaviors, and they therefore are an excellent model to study plasticity in olfactory circuits. Recent behavioral, physiological, and molecular evidence suggested that the antennal lobe, the first relay of the olfactory system in insects and analog to the olfactory bulb in vertebrates, is involved in associative and nonassociative olfactory learning. Here we use calcium imaging to reveal how responses across antennal lobe projection neurons change after association of an ...

Read More →
0

Modeling of Age-Dependent Epileptogenesis by Differential Homeostatic Synaptic Scaling. González OC, Krishnan GP, Chauvette S, Timofeev I, Sejnowski T, Bazhenov M. J Neurosci. 2015 Sep 30;35(39):13448-62.

Homeostatic synaptic plasticity (HSP) has been implicated in the development of hyperexcitability and epileptic seizures following traumatic brain injury (TBI). Our in vivo experimental studies in cats revealed that the severity of TBI-mediated epileptogenesis depends on the age of the animal. To characterize mechanisms of these differences, we studied the properties of the TBI-induced epileptogenesis in a biophysically realistic cortical network model with dynamic ion concentrations. After deafferentation, which was induced by dissection of the afferent ...

Read More →
0

Electrogenic properties of the Na+/K+ ATPase controls transitions between normal and pathological brain states. Krishnan GP, Filatov G, Shilnikov A, Bazhenov M. J Neurophysiol. 2015 Jan 14:jn.00460.2014.

Ionic concentrations fluctuate significantly during epileptic seizures. In this study, using a combination of in vitro electrophysiology, computer modeling, and dynamical systems analysis, we demonstrate that changes in the potassium and sodium intra- and extracellular ion concentrations ([K(+)] and [Na(+)], respectively) during seizure affect the neuron dynamics by modulating the outward Na(+)/K(+) pump current. First, we show that an increase of the outward Na(+)/K(+) pump current mediates termination of seizures when there is a progressive increase in the intracellular [Na(+)]. ...

Read More →
0

Coupling of Thalamocortical Sleep Oscillations Are Important for Memory Consolidation in Humans. Niknazar M, Krishnan GP, Bazhenov M, Mednick SC. PLoS One. 2015 Dec 15;10(12):e0144720.

Sleep, specifically non-rapid eye movement (NREM) sleep, is thought to play a critical role in the consolidation of recent memories. Two main oscillatory activities observed during NREM, cortical slow oscillations (SO, 0.5-1.0 Hz) and thalamic spindles (12-15 Hz), have been shown to independently correlate with memory improvement. Yet, it is not known how these thalamocortical events interact, or the significance of this interaction, during the consolidation process. Here, we found that systemic administration ...

Read More →
0
Page 1 of 3 123