scholarly journals Revisiting the role of spike afterhyperpolarization and spike threshold in motoneuron current-frequency gain

2012 ◽  
Vol 107 (11) ◽  
pp. 3071-3077 ◽  
Author(s):  
Robert H. Lee ◽  
Cassie S. Mitchell
Keyword(s):  
Firing Rate ◽  
Spinal Motoneurons ◽  
Current Frequency ◽  
Spike Threshold ◽  
Adult Cat ◽  
Threshold Variation ◽  
The Relationship ◽  
Input Level ◽  
Algebraic Summation

The relationship between synaptic or injecting input level and firing rate is an important metric to characterize neuron input-output dynamics. In this study, we examine two long-held, but never validated, assumptions in the “algebraic summation of afterhyperpolarization” theory, which explains how firing rate varies with input (typically referred to as input current-frequency modulation or “F-I gain”). In the theory, the afterhyperpolarizations themselves, along with spike threshold, were assumed constant. That is, whereas they were central concepts in the theory, they were not included in any feedback loops, wherein they could both affect and be affected by firing rate. We performed intracellular recordings from spinal motoneurons in the adult cat to determine whether F-I gain correlates with the afterhyperpolarization and/or spike threshold. We observe that the afterhyperpolarization does indeed appear to be out of the F-I gain mechanism loop, and thus that original assumption holds. However, the presented experimental evidence indicates that the spike threshold appears to be in the loop. That is, spike threshold variation associated with input correlates with F-I gain. We present an extension to the original theory, which explains the F-I gain experimental correlations.

A dynamic role of rubral neurons in contact placing by the adult cat

1986 ◽  
Vol 56 (3) ◽  
pp. 835-856 ◽  
Author(s):  
D. E. Batson ◽  
V. E. Amassian
Keyword(s):  
Firing Rate ◽  
Red Nucleus ◽  
Rubrospinal Tract ◽  
Forelimb Muscles ◽  
The Mean ◽  
Adult Cat ◽  
Withdrawal Phase ◽  
Interspike Interval Distribution ◽  
Interval Distribution

The potential dynamic role of red nucleus in contact placing (CP) was investigated in intact awake cats. The activity of individual rubral neurons was recorded and the timing of their discharges was compared with electrical activity in selected contralateral forelimb muscles and with associated changes in joint angles characteristic of CP of the forelimb or hindlimb. The series included 273 rubral neurons (RN) that were recorded extracellularly in five cats; 62% were identified as rubrospinal tract neurons (RTN). Latencies of antidromic invasion following stimulation in the caudal contralateral medulla ranged from 0.25 to 3.3 ms. In some units, invasion occurred intermittently regardless of the stimulus strength above threshold. Most RN discharged tonically in the absence of obvious movement at, e.g., rates of 5-60 spikes/s. Spike train analyses were performed on 21 RN with stable resting discharge. Although the interspike interval distribution usually resembled that of a gamma process, the discharges were nonrandom. Usually, successive intervals were not independent, long and short intervals tending to be followed by intervals longer and shorter, respectively, than the mean interval. The sequence of intervals often shows episodes of relatively periodic discharge with mean interval differing between episodes. Among 120 RN that altered in firing rate during the first lifting-withdrawal phase of CP, 97 (81%) initially accelerated in rate. Variability in the delay between forepaw contact and the initial RN discharge permitted the distinction between contact-locked responses (53%), which began with a short latency, e.g., 20 ms, after contact and peaked usually within 50 ms. When CP failed to occur to a trial, contact-locked responses were further subdivided into a noncontingent type in which the RN response occurred regardless of whether CP occurred or not (type A) and a contingent type in which the RN response was significantly reduced or even absent when CP failed to occur (type B); delayed movement-locked responses (47%), which could be identified only when CP movements were delayed after contact. Delayed movement-locked responses were either types A or B, according to whether the RN response preceded (e.g., by 40-160 ms), or started during the electromyogram (EMG) response or the movement, respectively. Thus response types 1B and 2A can predict the success or failure of subsequent CP. Among an additional 17 RN initially responding after the paw cleared the top corner of the placing apparatus, the firing rate accelerated.(ABSTRACT TRUNCATED AT 400 WORDS)

Role of monkey midbrain near-response neurons in phoria adaptation

1992 ◽  
Vol 67 (6) ◽  
pp. 1475-1492 ◽  
Author(s):  
J. W. Morley ◽  
S. J. Judge ◽  
J. W. Lindsey
Keyword(s):  
Firing Rate ◽  
Binocular Viewing ◽  
The Other ◽  
Oculomotor Nucleus ◽  
Before And After ◽  
Tightly Coupled ◽  
Phoria Adaptation ◽  
The Relationship ◽  
Real Target

1. One striking characteristic of the way in which accommodation and convergence of the eyes are organized is that although the two responses are usually tightly coupled, a brief period of binocular viewing through prisms that require extra convergence brings about a persistent, adaptive alteration in the relationship between the two responses: the vergence during monocular viewing of a target at a given distance is biased in a convergent direction. We sought to discover the role of the near-response neurons we have previously described in the monkey midbrain in such phoria adaptation. 2. Phoria adaptation was produced in two monkeys by having them view binocularly stereoscopic targets under conditions that mimicked prism viewing, i.e., the mirrors of the stereoscope were set so as to require more convergence than that associated with a real target at the same distance as the images seen in the stereoscope. The activity of 57 near-response neurons located dorsally and dorsolaterally to the oculomotor nucleus was recorded before and after adaptation while the monkeys monocularly viewed targets at a range of distances. 3. Comparison of a neuron's response in normal binocular viewing with the response when the accommodation and vergence stimuli were in conflict allowed us to distinguish 24 neurons that behaved as though they were related exclusively to the vergence response. 5 neurons that behaved as though they were exclusively related to the accommodation response, and 12 neurons whose firing was not so simply related to either response. We were unable to classify the remaining 16 near-response cells by this method. 4. In accommodation-related neurons, the relationship between firing rate and accommodation did not alter, or only altered slightly, when the animal's phoria was adapted. 5. The relationship between firing rate and vergence was unaltered by phoria adaptation in only a small proportion of vergence-related neurons, showing that most neurons do not carry the entire signal responsible for phoria adaptation. On the other hand, in the majority of vergence-related neurons the relationship between firing rate and accommodation was altered by phoria adaptation, showing that most neurons do carry part of the phoria adaptation signal. 6. The implication is that the increase in vergence observed after adaptation is mediated at more than one site. A proportion of the phoria adaptation signal is present at the level of the midbrain vergence-related neurons, with the remainder of the signal being added later, presumably at the motoneurons.

Choosing a Markov blanket

2020 ◽  
Vol 43 ◽  
Author(s):  
Thomas Parr
Keyword(s):  
Markov Blanket ◽  
Target Article ◽  
The Relationship

Abstract This commentary focuses upon the relationship between two themes in the target article: the ways in which a Markov blanket may be defined and the role of precision and salience in mediating the interactions between what is internal and external to a system. These each rest upon the different perspectives we might take while “choosing” a Markov blanket.

Staring Down Death

Crisis ◽  
2016 ◽  
Vol 37 (3) ◽  
pp. 212-217 ◽  
Author(s):  
Thomas E. Joiner ◽  
Melanie A. Hom ◽  
Megan L. Rogers ◽  
Carol Chu ◽  
Ian H. Stanley ◽  
...  
Keyword(s):  
Suicide Risk ◽  
Clinical Utility ◽  
Blink Rate ◽  
Specific Task ◽  
Careful Planning ◽  
Eye Blink ◽  
Eye Blinks ◽  
Potential Clinical Utility ◽  
The Relationship

Abstract. Background: Lowered eye blink rate may be a clinically useful indicator of acute, imminent, and severe suicide risk. Diminished eye blink rates are often seen among individuals engaged in heightened concentration on a specific task that requires careful planning and attention. Indeed, overcoming one’s biological instinct for survival through suicide necessitates premeditation and concentration; thus, a diminished eye blink rate may signal imminent suicidality. Aims: This article aims to spur research and clinical inquiry into the role of eye blinks as an indicator of acute suicide risk. Method: Literature relevant to the potential connection between eye blink rate and suicidality was reviewed and synthesized. Results: Anecdotal, cognitive, neurological, and conceptual support for the relationship between decreased blink rate and suicide risk is outlined. Conclusion: Given that eye blinks are a highly observable behavior, the potential clinical utility of using eye blink rate as a marker of suicide risk is immense. Research is warranted to explore the association between eye blink rate and acute suicide risk.

Parenting Behaviors and Anxiety in Young Adults

2015 ◽  
Vol 36 (3) ◽  
pp. 170-176 ◽  
Author(s):  
Erin N. Stevens ◽  
Joseph R. Bardeen ◽  
Kyle W. Murdock
Keyword(s):  
Effortful Control ◽  
Parenting Behaviors ◽  
Protective Role ◽  
Anxiety Symptoms ◽  
Interactive Effects ◽  
Parental Overprotection ◽  
High Control ◽  
Development Of Anxiety ◽  
The Relationship

Parenting behaviors – specifically behaviors characterized by high control, intrusiveness, rejection, and overprotection – and effortful control have each been implicated in the development of anxiety pathology. However, little research has examined the protective role of effortful control in the relation between parenting and anxiety symptoms, specifically among adults. Thus, we sought to explore the unique and interactive effects of parenting and effortful control on anxiety among adults (N = 162). Results suggest that effortful control uniquely contributes to anxiety symptoms above and beyond that of any parenting behavior. Furthermore, effortful control acted as a moderator of the relationship between parental overprotection and anxiety, such that overprotection is associated with anxiety only in individuals with lower levels of effortful control. Implications for potential prevention and intervention efforts which specifically target effortful control are discussed. These findings underscore the importance of considering individual differences in self-regulatory abilities when examining associations between putative early-life risk factors, such as parenting, and anxiety symptoms.

Social Support, Emotional Intelligence, and Posttraumatic Stress Disorder Symptoms

2016 ◽  
Vol 37 (1) ◽  
pp. 31-39 ◽  
Author(s):  
Nicole L. Hofman ◽  
Austin M. Hahn ◽  
Christine K. Tirabassi ◽  
Raluca M. Gaher
Keyword(s):  
Social Support ◽  
Posttraumatic Stress Disorder ◽  
Emotional Intelligence ◽  
Protective Factors ◽  
Posttraumatic Stress ◽  
Stress Disorder ◽  
Traumatic Events ◽  
Ptsd Symptoms ◽  
The Relationship

Abstract. Exposure to traumatic events and the associated risk of developing Posttraumatic stress disorder (PTSD) symptoms is a significant and overlooked concern in the college population. It is important for current research to identify potential protective factors associated with the development and maintenance of PTSD symptoms unique to this population. Emotional intelligence and perceived social support are two identified protective factors that influence the association between exposure to traumatic events and PTSD symptomology. The current study examined the mediating role of social support in the relationship between emotional intelligence and PTSD symptoms. Participants included 443 trauma-exposed university students who completed online questionnaires. The results of this study indicated that social support mediates the relationship between emotional intelligence and reported PTSD symptoms. Thus, emotional intelligence is significantly associated with PTSD symptoms and social support may play an integral role in the relationship between emotional intelligence and PTSD. The current study is the first to investigate the role of social support in the relationship between emotional intelligence and PTSD symptoms. These findings have important treatment and prevention implications with regard to PTSD.

Coping Humor as a Mediator Between Emotional Intelligence and Job Satisfaction

2017 ◽  
Vol 16 (3) ◽  
pp. 155-159 ◽  
Author(s):  
Peizhen Sun ◽  
Jennifer J. Chen ◽  
Hongyan Jiang
Keyword(s):  
Job Satisfaction ◽  
Emotional Intelligence ◽  
Future Research ◽  
Satisfaction Scale ◽  
Primary School Teachers ◽  
Mediating Role ◽  
Regulation Of Emotion ◽  
The Relationship ◽  
Overall Job Satisfaction

Abstract. This study investigated the mediating role of coping humor in the relationship between emotional intelligence (EI) and job satisfaction. Participants were 398 primary school teachers in China, who completed the Wong Law Emotional Intelligence Scale, Coping Humor Scale, and Overall Job Satisfaction Scale. Results showed that coping humor was a significant mediator between EI and job satisfaction. A further examination revealed, however, that coping humor only mediated two sub-dimensions of EI (use of emotion and regulation of emotion) and job satisfaction. Implications for future research and limitations of the study are discussed.

Sign in / Sign up

Export Citation Format

Share Document