Brain activity during motor performance becomes more widespread and less lateralized with advancing age in response to ongoing degenerative processes. In this study, we were interested in the mechanism by which this change in the pattern of activity supports motor performance with advancing age. We used both transcranial magnetic stimulation (TMS) and functional magnetic resonance imaging (fMRI...

Group I fibers from muscle spindles and Golgi tendon organs modulate motoneuron excitabilities to coordinate smooth movements. In this study, to elucidate the effects of group I fibers of the median nerve (MN) on the excitabilities of the brachioradialis (BR), we evaluated the changes in the firing probability of a BR motor unit after electrical conditioning stimulation (CS) to MN with a post-s...

We studied roles of inhibition on temporally sensitive facilitation in combination-sensitive neurons from the mustached bat's inferior colliculus (IC). In these integrative neurons, excitatory responses to best frequency (BF) tones are enhanced by much lower frequency signals presented in a specific temporal relationship. Most facilitated neurons (76%) showed inhibition at delays earlier than o...

The behavioral effects of Transcranial Magnetic Stimulation (TMS) are often nonlinear; factors such as stimulation intensity and brain state can modulate the impact of TMS on observable behavior in qualitatively different manner. Here we propose a theoretical framework to account for these effects. In this model, there are distinct intensity ranges for facilitatory and suppressive effects of TM...

The Chronic Constriction Injury of the Infraorbital Nerve (CCI-ION) is a well-established model to study facial sensory changes related to trigeminal neuropathic pain. CCI-ION induces heat hypersensitivity that resolves within 2-3 weeks and a delayed mechanical hypersensitivity that emerges during the second week post-injury. The role of descending facilitatory pain pathways from the rostro ven...

Neurotransmitter release going through synaptic vesicle cycle is one key step how signal is transported in our brains. The mechanism on molecular level has been under development and debated for decades. Many milestones have been made including, the identification of SNARE as core assembly machinery, the clarification of synaptotagmin as calcium sensor, the recognition of NSF and SNAP as disass...

Tail shock-induced modulation of the siphon withdrawal reflex of Aplysia has recently been shown to have a transient inhibitory component, as well as a facilitatory component. This transient behavioral inhibition is also seen in a reduced preparation in which a cellular reflection of the inhibitory process, tail shock-induced inhibition of complex EPSPs in siphon motor neurons, is observed. The...

If a peripheral, behaviorally irrelevant cue is followed by a target at the same position, response time for the target is either facilitated or inhibited relative to the response at an uncued position, depending on the delay between target and cue (Posner, 1980; Posner & Cohen, 1984). A few studies have suggested that this spatial cueing effect (termed reflexive spatial attention) is affected ...

In an environment that is temporal as well as spatial in nature, the nervous system of agents needs to deal with various forms of delay, internal or external. Neural (or internal) delay can cause serious problems because by the time the central nervous system receives an input from the periphery, the environmental state is already updated. To be in touch with reality in the present rather than ...