A PRC Description of How Inhibitory Feedback Promotes Oscillation Stability

Seeking of attention appears to be intimately bound up with certain principles of motivation, especially the seeking of observable results of action and of optimum levels of stimulation, variety and challenge, and the relationship between results and the cost of achieving them—a high cost will tend to inhibit action but enhance the value subsequently placed upon what is achieved. These principles can be applied to personal relationships: thus friendship can be regarded as a situation involving facilitative feedback between persons, hostility as involving inhibitory feedback and loneliness as occurring when there is no feedback. Which of these situations occurs appears to depend upon the relationships between the costs and benefits of interaction between the persons concerned. The care of psychiatric or senile patients in the community appears likely to impose demands for attention which are unreasonably severe (“costly”). Any attempt to change community attitudes in the hope of securing greater acceptance of such demands appears to be unrealistic. Substantial benefits could probably be attained in many cases from training in skills, especially social skills, which would enable patients to cope more effectively with the world as it is.

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Correlated Firing Improves Stimulus Discrimination in a Retinal Model

Neural Computation ◽

10.1162/0899766041941916 ◽

2004 ◽

Vol 16 (11) ◽

pp. 2261-2291 ◽

Cited By ~ 16

Author(s):

Garrett T. Kenyon ◽

James Theiler ◽

John S. George ◽

Bryan J. Travis ◽

David W. Marshak

Keyword(s):

Stimulus Intensity ◽

Ganglion Cells ◽

Fano Factor ◽

Spike Trains ◽

Dependent Manner ◽

Common Input ◽

Threshold Detector ◽

Synchronous Firing ◽

Inhibitory Feedback ◽

Synchronous Oscillations

Synchronous firing limits the amount of information that can be extracted by averaging the firing rates of similarly tuned neurons. Here, we show that the loss of such rate-coded information due to synchronous oscillations between retinal ganglion cells can be overcome by exploiting the information encoded by the correlations themselves. Two very different models, one based on axon-mediated inhibitory feedback and the other on oscillatory common input, were used to generate artificial spike trains whose synchronous oscillations were similar to those measured experimentally. Pooled spike trains were summed into a threshold detector whose output was classified using Bayesian discrimination. For a threshold detector with short summation times, realistic oscillatory input yielded superior discrimination of stimulus intensity compared to rate-matched Poisson controls. Even for summation times too long to resolve synchronous inputs, gamma band oscillations still contributed to improved discrimination by reducing the total spike count variability, or Fano factor. In separate experiments in which neurons were synchronized in a stimulus-dependent manner without attendant oscillations, the Fano factor increased markedly with stimulus intensity, implying that stimulus-dependent oscillations can offset the increased variability due to synchrony alone.

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Corticosterone regulates behavioral effects of lipopolysaccharide and interleukin-1 beta in mice

AJP Regulatory Integrative and Comparative Physiology ◽

10.1152/ajpregu.1995.269.1.r154 ◽

1995 ◽

Vol 269 (1) ◽

pp. R154-R159 ◽

Cited By ~ 6

Author(s):

E. Goujon ◽

P. Parnet ◽

A. Aubert ◽

G. Goodall ◽

R. Dantzer

Keyword(s):

Interleukin 1 ◽

Behavioral Effects ◽

Protective Effects ◽

Interleukin 1 Beta ◽

Social Exploration ◽

Inhibitory Feedback ◽

Adrenal Response ◽

Acute Injection ◽

Progesterone Antagonist

The modulatory role of endogenous corticoids in the behavioral effects of lipopolysaccharide (LPS) and recombinant human interleukin-1 beta (IL-1 beta) was studied in mice. Adrenalectomy enhanced the depression of social exploration induced by subcutaneous injection of 200 ng of IL-1 beta or 2 micrograms of LPS. This effect was mimicked by an acute injection of the progesterone antagonist RU-38486 (0.25-1 mg). Chronic replacement with a 15-mg corticosterone pellet abrogated the enhanced susceptibility of adrenalectomized animals to 200 ng of IL-1 beta but had only partial protective effects on their response to 400 ng of IL-1 beta and LPS. These results suggest that the pituitary-adrenal response to cytokines exerts an inhibitory feedback on the cell targets that mediate the behavioral effects of LPS and IL-1 beta.

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Long-latency, inhibitory spinal pathway to ankle flexors activated by homonymous group 1 afferents

Journal of Neurophysiology ◽

10.1152/jn.00673.2013 ◽

2014 ◽

Vol 111 (12) ◽

pp. 2544-2553 ◽

Cited By ~ 5

Author(s):

Ephrem T. Zewdie ◽

Francois D. Roy ◽

Yoshino Okuma ◽

Jaynie F. Yang ◽

Monica A. Gorassini

Keyword(s):

Muscle Activity ◽

Corticospinal Tract ◽

Inhibitory Pathway ◽

Thoracic Spinal Cord ◽

Thoracic Spinal ◽

Long Latency ◽

Inhibitory Feedback ◽

Spinal Pathway ◽

Low Threshold ◽

Pulse Stimulation

Inhibitory feedback from sensory pathways is important for controlling movement. Here, we characterize, for the first time, a long-latency, inhibitory spinal pathway to ankle flexors that is activated by low-threshold homonymous afferents. To examine this inhibitory pathway in uninjured, healthy participants, we suppressed motor-evoked potentials (MEPs), produced in the tibialis anterior (TA), by a prior stimulation to the homonymous common peroneal nerve (CPN). The TA MEP was suppressed by a triple-pulse stimulation to the CPN, applied 40, 50, and 60 ms earlier and at intensities of 0.5–0.7 times motor threshold (average suppression of test MEP was 33%). Whereas the triple-pulse stimulation was below M-wave and H-reflex threshold, it produced a long-latency inhibition of background muscle activity, approximately 65–115 ms after the CPN stimulation, a time period that overlapped with the test MEP. However, not all of the MEP suppression could be accounted for by this decrease in background muscle activity. Evoked responses from direct activation of the corticospinal tract, at the level of the brain stem or thoracic spinal cord, were also suppressed by low-threshold CPN stimulation. Our findings suggest that low-threshold muscle and cutaneous afferents from the CPN activate a long-latency, homonymous spinal inhibitory pathway to TA motoneurons. We propose that inhibitory feedback from spinal networks, activated by low-threshold homonymous afferents, helps regulate the activation of flexor motoneurons by the corticospinal tract.

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Reflex Inhibition of Normal Cramp Following Electrical Stimulation of the Muscle Tendon

Journal of Neurophysiology ◽

10.1152/jn.00371.2007 ◽

2007 ◽

Vol 98 (3) ◽

pp. 1102-1107 ◽

Cited By ~ 31

Author(s):

Serajul I. Khan ◽

John A. Burne

Keyword(s):

Electrical Stimulation ◽

Maximum Voluntary Contraction ◽

Voluntary Contraction ◽

Muscle Cramp ◽

Emg Activity ◽

Reflex Inhibition ◽

Experimental Conditions ◽

Inhibitory Feedback ◽

Two Phases ◽

Stimulation Of

Muscle cramp was induced in one head of the gastrocnemius muscle (GA) in eight of thirteen subjects using maximum voluntary contraction when the muscle was in the shortened position. Cramp in GA was painful, involuntary, and localized. Induction of cramp was indicated by the presence of electromyographic (EMG) activity in one head of GA while the other head remained silent. In all cramping subjects, reflex inhibition of cramp electrical activity was observed following Achilles tendon electrical stimulation and they all reported subjective relief of cramp. Thus muscle cramp can be inhibited by stimulation of tendon afferents in the cramped muscle. When the inhibition of cramp-generated EMG and voluntary EMG was compared at similar mean EMG levels, the area and timing of the two phases of inhibition (I1, I2) did not differ significantly. This strongly suggests that the same reflex pathway was the source of the inhibition in both cases. Thus the cramp-generated EMG is also likely to be driven by spinal synaptic input to the motorneurons. We have found that the muscle conditions that appear necessary to facilitate cramp, a near to maximal contraction of the shortened muscle, are also the conditions that render the inhibition generated by tendon afferents ineffective. When the strength of tendon inhibition in cramping subjects was compared with that in subjects that failed to cramp, it was found to be significantly weaker under the same experimental conditions. It is likely that reduced inhibitory feedback from tendon afferents has an important role in generating cramp.

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Effects of melanin-concentrating hormone on licking microstructure and brief-access taste responses

AJP Regulatory Integrative and Comparative Physiology ◽

10.1152/ajpregu.00143.2006 ◽

2006 ◽

Vol 291 (5) ◽

pp. R1265-R1274 ◽

Cited By ~ 15

Author(s):

John-Paul Baird ◽

Catalina Rios ◽

Nora Elizabeth Gray ◽

Caroline Elizabeth Walsh ◽

Shannon Glenora Fischer ◽

...

Keyword(s):

Third Ventricle ◽

Taste Stimulus ◽

Water Solutions ◽

The Third ◽

Sucrose Solutions ◽

Quinine Hydrochloride ◽

Inhibitory Feedback ◽

Melanin Concentrating Hormone ◽

Taste Evaluation ◽

The Mean

The effects of intracerebroventricular application of melanin-concentrating hormone (MCH) on licking for sucrose, quinine hydrochloride (QHCl), and water solutions were evaluated in two experiments. In experiment 1, rats received 90-min access to sucrose and water solutions after MCH or vehicle microinjection to the third ventricle (3V). MCH increased intake largely through increases in the rate of licking early in the meal and in the mean duration of lick bursts, suggesting an effect on gustatory evaluation. Therefore, in experiment 2, brief access tests were used with a series of sucrose and QHCl concentrations to behaviorally isolate the effects of intracerebroventricular MCH on gustatory evaluation. MCH uniformly increased licking for all sucrose solutions, water, and weak concentrations of QHCl; however, it had no effect on licking for the strongest concentrations of QHCl, which were generally avoided under control conditions. Thus MCH did not produce nonspecific increases in oromotor activity, nor did it change the perceived intensity of the tastants. We conclude that MCH enhanced the gain of responses to normally accepted stimuli at a phase of processing after initial gustatory detection and after the decision to accept or reject the taste stimulus. A comparison of 3V NPY and MCH effects on licking microstructure indicated that these two peptides increased intake via dichotomous behavioral processes; although NPY suppressed measures associated with inhibitory feedback from the gut, MCH appeared instead to enhance measures associated with hedonic taste evaluation.

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