The Spinal Neurons Exhibit an ON-OFF and OFF-ON Firing Activity Around the Onset of Fictive Scratching Episodes in the Cat

Cuellar, Carlos A.; Valdovinos, Braniff De la Torre; Huidobro, Nayeli; Delgado‐Lezama, Rodolfo; Ornelas-Kobayashi, Rafael; Manjarrez, Elı́as

doi:10.3389/fncel.2018.00068

Cited by 4 publications

(4 citation statements)

References 39 publications

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“…In other studies, it was found that previous to the alternating flexor-extensor activity during scratching, a positive DC shift occurs in the hind limb enlargement of decerebrate cats (Bayev and Kostyuk, 1981). Such DC shift is correlated to the tonic activity of interneurons from the deep dorsal horn and to the postural stage that precedes scratching (Cuellar et al, 2018). As stated in our ''Results'' section, we recorded a similar positive DC shift correlated to interneuron activity from the deep dorsal horn.…”

Section: Slow DC Potentialsupporting

confidence: 84%

Afterdischarges of Spinal Interneurons Following a Brief High-Frequency Stimulation of Ia Afferents in the Cat

Méndez-Fernández

Moreno-Castillo

Huidobro

et al. 2020

Front. Integr. Neurosci.

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Spinal motoneurons exhibit sustained afterdischarges and plateau potentials following a brief high-frequency stimulation of Ia afferents. Also, there is evidence that spinal cord interneurons exhibit plateau potentials. However, to our knowledge, there are no reports about the possible afterdischarge behavior of lumbar spinal interneurons activated by Ia afferents. Given that there are spinal interneurons receiving monosynaptic inputs from Ia afferents, these cells could then be activated in parallel to motoneurons after repetitive muscle stretch. We explored this possibility in cats with a precollicularpostmammillary decerebration. We found that a brief high-frequency stimulation of Ia afferents produces afterdischarges that are highly correlated to a DC slow potential recorded at the cord dorsum. We conclude that in the cat spinal cord, not only the motoneurons but also the interneurons from the superficial and deep dorsal horn produce sustained afterdischarges, thus highlighting the importance of interneurons in the spinal neuronal circuitry. The significance of our finding is that it opens the possibility that the spinal cord interneurons activated by Ia afferents could also exhibit bistability, a relevant phenomenon well-characterized in the motoneurons.

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Section: Slow DC Potentialsupporting

confidence: 84%

Afterdischarges of Spinal Interneurons Following a Brief High-Frequency Stimulation of Ia Afferents in the Cat

Méndez-Fernández

Moreno-Castillo

Huidobro

et al. 2020

Front. Integr. Neurosci.

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“…Our survey of the literature provides two observations: First, a distribution of firing rates across neuronal population has rarely been reported (Petersen and Berg, 2016;Cuellar et al, 2018). Second, those experimental reports that do provide the firing rate distribution, they seem in impressive agreement.…”

Section: Experimentally Observed Firing Rate Distributionsmentioning

confidence: 53%

Why Firing Rate Distributions Are Important for Understanding Spinal Central Pattern Generators

Lindén

Berg

2021

Front. Hum. Neurosci.

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Networks in the spinal cord, which are responsible for the generation of rhythmic movements, commonly known as central pattern generators (CPGs), have remained elusive for decades. Although it is well-known that many spinal neurons are rhythmically active, little attention has been given to the distribution of firing rates across the population. Here, we argue that firing rate distributions can provide an important clue to the organization of the CPGs. The data that can be gleaned from the sparse literature indicate a firing rate distribution, which is skewed toward zero with a long tail, akin to a normal distribution on a log-scale, i.e., a “log-normal” distribution. Importantly, such a shape is difficult to unite with the widespread assumption of modules composed of recurrently connected excitatory neurons. Spinal modules with recurrent excitation has the propensity to quickly escalate their firing rate and reach the maximum, hence equalizing the spiking activity across the population. The population distribution of firing rates hence would consist of a narrow peak near the maximum. This is incompatible with experiments, that show wide distributions and a peak close to zero. A way to resolve this puzzle is to include recurrent inhibition internally in each CPG modules. Hence, we investigate the impact of recurrent inhibition in a model and find that the firing rate distributions are closer to the experimentally observed. We therefore propose that recurrent inhibition is a crucial element in motor circuits, and suggest that future models of motor circuits should include recurrent inhibition as a mandatory element.

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“…We performed experiments in four adult cats (2.3–3.7 kg, two males and two females). We followed similar experimental procedures as in previous reports from our group (Cuellar et al, 2009, 2018; Pérez et al, 2009; Tapia et al, 2013). During surgery, we induced and maintained deep anesthesia with isoflurane at 2%.…”

Section: Methodsmentioning

confidence: 99%

Resetting the Respiratory Rhythm with a Spinal Central Pattern Generator

Meza

Huidobro

Moreno-Castillo

et al. 2019

eNeuro

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There is evidence that a variety of central and afferent stimuli, including swallowing, can produce phase resetting in the respiratory rhythmicity. Also, there are reports about the intrinsic linkage between locomotion and respiration. However, little is known about the interaction between the central pattern generators (CPGs) for scratching and respiration. The present study aims to examine whether the activation of scratching CPG produces phase resetting of the respiratory rhythm. We employed decerebrate cats to apply brief tactile stimuli to the pinna during the inspiratory-expiratory transition. We observed that those stimuli to the pinna not eliciting fictive scratching did not reset the respiratory rhythm. However, when the pinna stimuli elicited fictive scratching, then the respiratory rhythm exhibited a significant phase resetting. We also found interneurons in the medulla oblongata exhibiting phase resetting related to scratching-CPG episodes. This second finding suggests that this type of resetting involves brainstem components of the respiratory CPG. These results shed new light on the resetting action from a spinal CPG on the respiratory rhythm.

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The Spinal Neurons Exhibit an ON-OFF and OFF-ON Firing Activity Around the Onset of Fictive Scratching Episodes in the Cat

Cited by 4 publications

References 39 publications

Afterdischarges of Spinal Interneurons Following a Brief High-Frequency Stimulation of Ia Afferents in the Cat

Afterdischarges of Spinal Interneurons Following a Brief High-Frequency Stimulation of Ia Afferents in the Cat

Why Firing Rate Distributions Are Important for Understanding Spinal Central Pattern Generators

Resetting the Respiratory Rhythm with a Spinal Central Pattern Generator

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