Motor Program Disinhibition

Cross references:     
Behavioral Disinhibition   GABA/Glycine Inhibition  
Inhibition of Locomotion in Lampreys              
Excitation      Glutamate    
     


Searching PubMed for "behavioral disinhibition motor programs"  found 7 references:     


2010  3<7  What roles do tonic inhibition and disinhibition play in the control of motor programs?   
    Abstract     
Animals show periods of quiescence interspersed with periods of motor activity. In a number of invertebrate and vertebrate systems, quiescence is achieved by active suppression of motor behavior due to tonic inhibition induced by sensory input or changes in internal state. Removal of this inhibition (disinhibition) has the converse effect tending to increase the level of motor activity.  
    We show that tonic inhibition and disinhibition can have a variety of roles. It can simply switch off specific unwanted motor behaviors, or modulate the occurrence of a motor response, a type of 'threshold' controlling function, or be involved in the selection of a particular motor program by inhibiting 'competing' motor mechanisms that would otherwise interfere with the carrying out of a desired movement.  
    A suggested general function for tonic inhibition is to prevent unnecessary non-goal directed motor activity that would be energetically expensive. The reason why basic motor programs might be a particular target for tonic inhibition is that many of them involve central pattern generator circuits that are often spontaneously active and need to be actively suppressed for energy saving.  
    Based on this hypothesis, tonic inhibition represents the default state for energy saving and motor programs are switched-on when required by removal of this inhibition.     Free PMC Article   


Searching PubMed for "gaba tonic inhibition" yielded 1206 references:   

    Note:  During the course of the review of these references, the number of them rose from 1206 to 1240.


1985  1162<1206  (1196<1240)
Disinhibition as a basic process in the expression of striatal functions. I. The striato-nigral influence on tecto-spinal/tecto-diencephalic neurons. 
http://www.ncbi.nlm.nih.gov/pubmed/2859912   
    "The ... striatum exerts a facilitatory influence on
tecto-spinal/tecto-diencephalic (TSD) cells by releasing these neurons from the tonic inhibitory nigral influence." 
    See:  Substantia Nigra  for  Related citations and Cited by's.   
   
The motor programs which are  referred to  tecto-spinal/tecto-diencephalic   
    Abstract
    "The striato-nigro-collicular pathway is one of the neuronal circuits through which basal ganglia can influence ocular and cephalic motricity. Through this pathway striatal signals are conveyed to a major collicular efferent system i.e. the tecto-spinal/tecto-diencephalic neurons (TSD). A striking particularity of the striato-nigro-collicular connection is to present an assemblage of two successive GABAergic inhibitory links.  

    To analyze how striatal information is expressed through this double inhibitory system we made use of concomitant unitary recordings of substantia nigra pars reticulata (SNR) and TSD activity while nigral and/or striatal activity was changed by local applications of pharmacological agents. We observed  
    (1) that an intranigral application of GABA which transiently abolishes the tonic discharge of SNR cells, causes the TSD cells to discharge vigorously. During this period of increased excitability the responsiveness of TSD cells to somatosensory input is significantly enhanced;  
    (2) that an intrastriatal injection of glutamate which silences the nigro-collicular cells, causes the TSD cells to discharge.  
    This striatally induced tectal firing being sensitive to intranigral application of a GABA antagonist (bicuculline), led us to the conclusion that striatum exerts a facilitatory influence on TSD cells by releasing these neurons from the tonic inhibitory nigral influence. The functional implication of such a mechanism is discussed in the light of the current knowledge on the involvement of basal ganglia in eye/head orienting movements. 


2016  Competitive Disinhibition Mediates Behavioral Choice and Sequences in Drosophila 
    My comment    
Good diagrams, but no suggestion of what determines the outcome of the competition between the various disinhibitions.  
   SUMMARY  
"Even a simple sensory stimulus can elicit distinct innate behaviors and sequences. During sensori- motor decisions, competitive interactions among neurons that promote distinct behaviors must ensure the selection and maintenance of one behavior, while suppressing others. The circuit implementation of these competitive interactions is still an open question.  
    By combining comprehensive electron microscopy reconstruction of inhibitory interneuron networks, modeling, electrophysiology, and behavioral studies, we determined the circuit mechanisms that contribute to the Drosophila larval sensorimotor decision to startle, explore, or perform a sequence of the two in response to a mechanosensory stimulus. Together, these studies reveal that, early in sensory processing,  
    (1) reciprocally connected feedforward inhibitory interneurons implement behavioral choice,  
    (2) local feedback disinhibition provides positive feedback that consolidates and maintains the chosen behavior, and  
    (3) lateral disinhibition promotes sequence transitions.  
The combination of these interconnected circuit motifs can implement both behavior selection and the serial organization of behaviors into a sequence."
    My comment
    What is a "feedforward inhibitory interneuron"?     







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