Postnatal development of the human primary motor cortex: a quantitative cytoarchitectonic analysis

1995 ◽  
Vol 192 (6) ◽  
Author(s):  
Katrin Amunts ◽  
Vadim Istomin ◽  
Axel Schleicher ◽  
Karl Zilles
Keyword(s):  
Motor Cortex ◽  
Postnatal Development ◽  
Primary Motor Cortex

scholarly journals Structural and Functional Maturation of Rat Primary Motor Cortex Layer V Neurons

2020 ◽  
Vol 21 (17) ◽  
pp. 6101
Author(s):  
Bruno Benedetti ◽  
Dominik Dannehl ◽  
Jan Maximilian Janssen ◽  
Corinna Corcelli ◽  
Sébastien Couillard-Després ◽  
...  
Keyword(s):  
Cell Growth ◽  
Motor Cortex ◽  
Postnatal Development ◽  
Primary Motor Cortex ◽  
Continuous Process ◽  
Network Activity ◽  
Functional Maturation ◽  
Sensory Cortices ◽  
Layer V ◽  
Functional Output

Rodent neocortical neurons undergo prominent postnatal development and maturation. The process is associated with structural and functional maturation of the axon initial segment (AIS), the site of action potential initiation. In this regard, cell size and optimal AIS length are interconnected. In sensory cortices, developmental onset of sensory input and consequent changes in network activity cause phasic AIS plasticity that can also control functional output. In non-sensory cortices, network input driving phasic events should be less prominent. We, therefore, explored the relationship between postnatal functional maturation and AIS maturation in principal neurons of the primary motor cortex layer V (M1LV), a non-sensory area of the rat brain. We hypothesized that a rather continuous process of AIS maturation and elongation would reflect cell growth, accompanied by progressive refinement of functional output properties. We found that, in the first two postnatal weeks, cell growth prompted substantial decline of neuronal input resistance, such that older neurons needed larger input current to reach rheobase and fire action potentials. In the same period, we observed the most prominent AIS elongation and significant maturation of functional output properties. Alternating phases of AIS plasticity did not occur, and changes in functional output properties were largely justified by AIS elongation. From the third postnatal week up to five months of age, cell growth, AIS elongation, and functional output maturation were marginal. Thus, AIS maturation in M1LV is a continuous process that attunes the functional output of pyramidal neurons and associates with early postnatal development to counterbalance increasing electrical leakage due to cell growth.

Effect of Forelimb Use on Postnatal Development of the Forelimb Motor Representation in Primary Motor Cortex of the Cat

2005 ◽  
Vol 93 (5) ◽  
pp. 2822-2831 ◽  
Author(s):  
John H. Martin ◽  
Daniel Engber ◽  
Zhuo Meng
Keyword(s):  
Botulinum Toxin ◽  
Motor Cortex ◽  
Postnatal Development ◽  
Primary Motor Cortex ◽  
Botulinum Toxin Injection ◽  
Intracortical Microstimulation ◽  
Behavioral Repertoire ◽  
Concomitant Increase ◽  
Motor Representation ◽  
Forelimb Movements

In the cat, the motor representation in motor cortex develops between wk 8 and wk 13. Motor map development is accompanied by a decrease in the current thresholds for evoking movements with a concomitant increase in the number of effective sites, an increase in the distal representation, and the representation of multijoint synergies. In this study we used intracortical microstimulation in anesthetized cats to examine how forelimb motor experiences influence development of map characteristics. To promote skilled movements during wks 8–13, animals were engaged in daily performance of a prehension task. Forelimb movements were prevented by intramuscular botulinum toxin injection or restraint. To determine whether experience-dependent changes were permanent, we examined the map in different animals between 1 wk and 1 yr after cessation of testing. Promoting forelimb use resulted in an increase in the number of sites from which multiple joint effects were produced by stimulation and the number of joints represented at those sites. The effect was maximal at 1 wk after cessation of testing, and became progressively less at 1 mo and at 4 mo. Preventing limb use resulted in a decreased number of effective sites, an increase in current thresholds for evoking responses, and a decreased representation of joints at multijoint sites. Our findings show that the motor map can respond to novel motor demands as it is forming during development but that it reverts back to one with the properties of a map in a control animal if those demands are not maintained in the animal's behavioral repertoire.

scholarly journals Refinement of Active and Passive Membrane Properties of Layer V Pyramidal Neurons in Rat Primary Motor Cortex During Postnatal Development

2021 ◽  
Vol 14 ◽  
Author(s):  
Patricia Perez-García ◽  
Ricardo Pardillo-Díaz ◽  
Noelia Geribaldi-Doldán ◽  
Ricardo Gómez-Oliva ◽  
Samuel Domínguez-García ◽  
...  
Keyword(s):  
Motor Cortex ◽  
Postnatal Development ◽  
Primary Motor Cortex ◽  
Neuronal Excitability ◽  
Pyramidal Neurons ◽  
Membrane Properties ◽  
Neuronal Membrane ◽  
Maturation Process ◽  
Postnatal Maturation ◽  
Layer V

Achieving the distinctive complex behaviors of adult mammals requires the development of a great variety of specialized neural circuits. Although the development of these circuits begins during the embryonic stage, they remain immature at birth, requiring a postnatal maturation process to achieve these complex tasks. Understanding how the neuronal membrane properties and circuits change during development is the first step to understand their transition into efficient ones. Thus, using whole cell patch clamp recordings, we have studied the changes in the electrophysiological properties of layer V pyramidal neurons of the rat primary motor cortex during postnatal development. Among all the parameters studied, only the voltage threshold was established at birth and, although some of the changes occurred mainly during the second postnatal week, other properties such as membrane potential, capacitance, duration of the post-hyperpolarization phase or the maximum firing rate were not defined until the beginning of adulthood. Those modifications lead to a decrease in neuronal excitability and to an increase in the working range in young adult neurons, allowing more sensitive and accurate responses. This maturation process, that involves an increase in neuronal size and changes in ionic conductances, seems to be influenced by the neuronal type and by the task that neurons perform as inferred from the comparison with other pyramidal and motor neuron populations.

Location of Primary Motor Cortex Function in Cerebral Migration Disorder

1998 ◽  
Vol 38 (5) ◽  
pp. 769
Author(s):  
Ho Kyu Lee ◽  
Jin Suh Kim ◽  
Youn Mee Hwang ◽  
Myung Joon Lee ◽  
Soo Mee Lim ◽  
...  
Keyword(s):  
Motor Cortex ◽  
Primary Motor Cortex ◽  
Migration Disorder
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