Supraspinal Control of Recurrent Inhibition during Anisometric Contractions

A fundamental feature of neural circuitry in the primary visual cortex (V1) is the existence of recurrent excitatory connections between spiny neurons, recurrent inhibitory connections between smooth neurons, and local connections between excitatory and inhibitory neurons. We modeled the dynamic behavior of intermixed excitatory and inhibitory populations of cells in V1 that receive input from the classical receptive field (the receptive field center) through feedforward thalamocortical afferents, as well as input from outside the classical receptive field (the receptive field surround) via long-range intracortical connections. A counterintuitive result is that the response of oriented cells can be facilitated beyond optimal levels when the surround stimulus is cross-oriented with respect to the center and suppressed when the surround stimulus is iso-oriented. This effect is primarily due to changes in recurrent inhibition within a local circuit. Cross-oriented surround stimulation leads to a reduction of presynaptic inhibition and a supraoptimal response, whereas iso-oriented surround stimulation has the opposite effect. This mechanism is used to explain the orientation and contrast dependence of contextual interactions in primary visual cortex: responses to a center stimulus can be both strongly suppressed and supraoptimally facilitated as a function of surround orientation, and these effects diminish as stimulus contrast decreases.

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Recurrence quantification analysis of surface EMG detects changes in motor unit synchronization induced by recurrent inhibition

Experimental Brain Research ◽

10.1007/s00221-006-0734-x ◽

2006 ◽

Vol 178 (3) ◽

pp. 308-315 ◽

Cited By ~ 17

Author(s):

F. Del Santo ◽

F. Gelli ◽

R. Mazzocchio ◽

A. Rossi

Keyword(s):

Motor Unit ◽

Surface Emg ◽

Recurrence Quantification Analysis ◽

Recurrent Inhibition ◽

Recurrence Quantification ◽

Quantification Analysis ◽

Motor Unit Synchronization

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Effects of diazepines and barbiturates on hippocampal recurrent inhibition

Naunyn-Schmiedeberg s Archives of Pharmacology ◽

10.1007/bf00500313 ◽

1977 ◽

Vol 299 (3) ◽

pp. 211-218 ◽

Cited By ~ 57

Author(s):

P. Wolf ◽

H. L. Haas

Keyword(s):

Recurrent Inhibition

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Recurrent inhibition to and from motoneurons innervating the flexor digitorum and flexor hallucis longus muscles of the cat

Journal of Neurophysiology ◽

10.1152/jn.1990.63.3.395 ◽

1990 ◽

Vol 63 (3) ◽

pp. 395-403 ◽

Cited By ~ 26

Author(s):

T. M. Hamm

Keyword(s):

Tibialis Anterior ◽

Recurrent Inhibition ◽

Medial Gastrocnemius ◽

Flexor Hallucis Longus ◽

Flexor Digitorum Longus ◽

Lateral Gastrocnemius ◽

Hindlimb Muscles ◽

Inhibitory Postsynaptic Potentials ◽

Flexor Digitorum ◽

Stimulation Of

1. Recurrent inhibitory postsynaptic potentials (IPSPs) to and from motoneurons innervating the flexor digitorum longus (FDL) and flexor hallucis longus (FHL) muscles of the cat were investigated to determine whether recurrent inhibitory projections involving these motoneurons are similar--as would be consistent with the Ia and anatomic synergism of FDL and FHL--or are dissimilar, as are the activities of these muscles during locomotion (O'Donovan et al. 1982). 2. Composite recurrent IPSPs were recorded in several species of motoneurons innervating hindlimb muscles in response to stimulation of a number of muscle nerves in cats allowed to become unanesthetized after ischemic decapitation. 3. No recurrent IPSPs from stimulation of the FDL nerve were observed in motoneurons innervating FDL, FHL, lateral gastrocnemius-soleus (LG-S), medial gastrocnemius (MG), plantaris (Pl), tibialis anterior (TA), or extensor digitorum longus (EDL). 4. The recurrent IPSPs produced by stimulation of FHL were larger and found more frequently in LG-S than in FDL motoneurons. Recurrent inhibition from FHL was also greater in Pl than in FDL motoneurons. 5. The recurrent IPSPs produced by stimulation of LG-S, PL, and MG were larger in FHL than in FDL motoneurons, and those from LG-S and MG were found more frequently in FHL than in FDL motoneurons. 6. Stimulation of the TA nerve produces recurrent IPSPs in FDL but not in FHL motoneurons. A few FDL and FHL cells (6 of 23 and 9 of 34, respectively) received small (less than 0.5 mV) recurrent IPSPs from stimulation of the EDL nerve.(ABSTRACT TRUNCATED AT 250 WORDS)

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