Sodium-mediated plateau potentials in an identified decisional neuron contribute to feeding-related motor pattern genesis in .

Motivated behaviors such as feeding depend on the functional properties of decision neurons to provide the flexibility required for behavioral adaptation. Here, we analyzed the ionic basis of the endogenous membrane properties of an identified decision neuron (B63) that drive radula biting cycles underlying food-seeking behavior in . Each spontaneous bite cycle arises from the irregular triggering of a plateau-like potential and resultant bursting by rhythmic subthreshold oscillations in B63's membrane potential.

Altered brain rhythms and behaviour in the accelerated ovarian failure mouse model of human menopause.

To date, potential mechanisms of menopause-related memory and cognitive deficits have not been elucidated. Therefore, we studied brain oscillations, their phase-amplitude coupling, sleep and vigilance state patterns, running wheel use and other behavioural measures in a translationally valid mouse model of menopause, the 4-vinylcyclohexene-diepoxide-induced accelerated ovarian failure. After accelerated ovarian failure, female mice show significant alterations in brain rhythms, including changes in the frequencies of θ (5-12 Hz) and γ (30-120 Hz) oscillations, a reversed phase-amplitude coupling, altered coupling of hippocampal sharp-wave ripples to medial prefrontal cortical sleep spindles and reduced δ oscillation (0.

Organelle calcium-derived voltage oscillations in pacemaker neurons drive the motor program for food-seeking behavior in .

The expression of motivated behaviors depends on both external and internally arising neural stimuli, yet the intrinsic releasing mechanisms for such variably occurring behaviors remain elusive. In isolated nervous system preparations of , we have found that irregularly expressed cycles of motor output underlying food-seeking behavior arise from regular membrane potential oscillations of varying magnitude in an identified pair of interneurons (B63) in the bilateral buccal ganglia. This rhythmic signal, which is specific to the B63 cells, is generated by organelle-derived intracellular calcium fluxes that activate voltage-independent plasma membrane channels.

RNA from Trained Can Induce an Epigenetic Engram for Long-Term Sensitization in Untrained .

The precise nature of the engram, the physical substrate of memory, remains uncertain. Here, it is reported that RNA extracted from the central nervous system of given long-term sensitization (LTS) training induced sensitization when injected into untrained animals; furthermore, the RNA-induced sensitization, like training-induced sensitization, required DNA methylation. In cellular experiments, treatment with RNA extracted from trained animals was found to increase excitability in sensory neurons, but not in motor neurons, dissociated from naïve animals.

Intracellular manganese enhanced MRI signals reflect the frequency of action potentials in Aplysia neurons.

Background: Manganese-enhanced magnetic resonance imaging (MEMRI) is an increasingly popular alternative to standard functional MRI methods in animal studies. The contrast in MEMRI images is based on the accumulation of Mn ions inside neurons, and, since manganese can serve as calcium analogue, this accumulation reflects calcium dynamics providing versatile information about brain neuroarchitecture and functionality. However, despite its use as a functional imaging tool, the exact relationship between the MEMRI signal and neuronal activity remains elusive.

Differential roles of nonsynaptic and synaptic plasticity in operant reward learning-induced compulsive behavior.

Background: Rewarding stimuli in associative learning can transform the irregularly and infrequently generated motor patterns underlying motivated behaviors into output for accelerated and stereotyped repetitive action. This transition to compulsive behavioral expression is associated with modified synaptic and membrane properties of central neurons, but establishing the causal relationships between cellular plasticity and motor adaptation has remained a challenge.

Results: We found previously that changes in the intrinsic excitability and electrical synapses of identified neurons in Aplysia's central pattern-generating network for feeding are correlated with a switch to compulsive-like motor output expression induced by in vivo operant conditioning.

Implication of dopaminergic modulation in operant reward learning and the induction of compulsive-like feeding behavior in Aplysia.

Feeding in Aplysia provides an amenable model system for analyzing the neuronal substrates of motivated behavior and its adaptability by associative reward learning and neuromodulation. Among such learning processes, appetitive operant conditioning that leads to a compulsive-like expression of feeding actions is known to be associated with changes in the membrane properties and electrical coupling of essential action-initiating B63 neurons in the buccal central pattern generator (CPG). Moreover, the food-reward signal for this learning is conveyed in the esophageal nerve (En), an input nerve rich in dopamine-containing fibers.