We examined the relationship between tonic--a correlate of self-regulatory functioning--and phasic cardiac vagal activity (indexed by heart rate variability; HRV) during a selective attentional task with varying levels of load. Participants detected a target letter among letter strings superimposed on either fearful or neutral face distractors. Letter strings consisted of six target letters und...

Unexpected, biologically salient stimuli elicit a short-latency, phasic response in midbrain dopaminergic (DA) neurons. Although this signal is important for reinforcement learning, the information it conveys to forebrain target structures remains uncertain. One way to decode the phasic DA signal would be to determine the perceptual properties of sensory inputs to DA neurons. After local disinh...

Krause, Kristin M., Joanne Pearce, and C. K. Govina. RegenerM E T H O D S ation of phasic motor axons on a crayfish tonic muscle: neuron Crayfish motor neurons have remarkable powers of regeneration, specifies synapses. J. Neurophysiol. 80: 994–997, 1998. Motor not only to their own muscle (Ely and Velez 1982) but when neurons are matched to their target muscles, often forming separate transpla...

Neurons, by virtue of their complex and continuously changing signaling roles in brain, must be able to regulate access to energy in order to maintain their ability to communicate meaningful frequency-encoded information. This is accomplished by release of neurotransmitters to astrocytes that in turn signal the vascular system to increase cerebral blood flow (CBF). This process has been termed ...

Whereas extensor muscles of decerebrate mammalian preparations usually present both phasic and tonic reflex contraction to stretch (Liddell & Sherrington, 1925), flexor muscles present phasic stretch reflexes only (Asayama, 1916). Under anaesthesia or during spinal shock (Creed, Denny-Brown, Eccles, Liddell & Sherrington, 1932, p. 51), tonic stretch reflexes are lost while phasic responses are ...