Glomeruli, the initial sites of synaptic processing in the olfactory system, contain at least three types of neurons collectively referred to as juxtaglomerular (JG) neurons. The role of JG neurons in odor processing is poorly understood. We investigated the morphology, spontaneous, and sensory-evoked activity of one class of JG neurons, external tufted (ET) cells, using whole-cell patch-clamp ...

Coherent oscillatory electrical activity and apical-basal wave propagation have been described previously in the procerebral (PC) lobe, an olfactory center of the terrestrial slug Limax maximus. In this study, we investigate the physiological basis of oscillatory activity and wave propagation in the PC lobe. Calcium green dextran was locally deposited in the PC lobe; this led to cellular uptake...

We examine the role of structural autapses, when a neuron synapses onto itself, in driving network-wide bursting behavior. Using a simple spiking model of neuronal activity, we study how autaptic connections affect activity patterns, and evaluate if controllability significantly affects changes in bursting from autaptic connections. Adding more autaptic connections to excitatory neurons increas...

BACKGROUND During development, spinal networks undergo an intense period of maturation in which immature forms of motor behavior are observed. Such behaviors are transient, giving way to more mature activity as development proceeds. The processes governing age-specific transitions in motor behavior are not fully understood. RESULTS Using in vivo patch clamp electrophysiology, we have characte...

We present a qualitative analysis of a generic model structure that can simulate the bursting and spiking dynamics of many biological cells. Four different scenarios for the emergence of bursting are described. In this connection a number of theorems are stated concerning the relation between the phase portraits of the fast subsystem and the global behavior of the full model. It is emphasized t...

We investigate the emergence of bursting oscillations and their relation to (quasi-) periodic behaviour in two different model systems, a pH oscillator and a calcium oscillator. Both systems are described by 3-dimensional ODE systems and follow different ‘routes’ to bursting oscillations as parameters are varied. In the first part, we exploit the slow-fast structure of the 3-dimensional ODE sys...

Electrophysiological recordings were conducted to determine the control of spermathecal contractions during oviposition of interrupted egg-laying locusts, Locusta migratoria. Following transection of the central nervous system below the metathoracic ganglion, rhythmic patterned bursting was detected by extracellular recordings of the nerve N2B2 that innervates the muscles of the spermatheca. Su...

Kainic acid-induced status epilepticus (KA-SE) in mature rats results in the development of spontaneous recurrent seizures and a pattern of cell death resembling hippocampal sclerosis in patients with temporal lobe epilepsy. In contrast, KA-SE in young animals before postnatal day (P) 18 is less likely to cause cell death or epilepsy. To investigate whether changes in neuronal excitability occu...

Somatostatin-14 (SRIF) co-localizes with gamma-aminobutyric acid (GABA) in the hippocampus and regulates neuronal excitability. A role of SRIF in the control of seizures has been proposed, although its exact contribution requires some clarification. In particular, SRIF knockout (KO) mice do not exhibit spontaneous seizures, indicating that compensatory changes may occur in KO. In the KO hippoca...

We recorded action potential activity from the isolated brain of the nudibranch seaslug Tritonia diomedea during fictive swimming. Candidate central pattern generator (CPG) interneurons were identified by their bursting patterns and positions in the brain. Previously identifed populations of interneurons were imaged, including the dorsal swim interneurons (DSI), C2, and ventral swim interneuron...