A milestone is marked in our understanding of the brain with the recent acceptance, contrary to early dogma, that the adult nervous system can generate new neurons. One could wonder how this dogma originally came about, particularly because all organisms have some cells that continue to divide, adding to the size of the organism and repairing damage. All mammals have replicating cells in many organs and in some cases, notably the blood, skin, and gut, stem cells have been shown to exist throughout life, contributing to rapid cell replacement. Furthermore, insects, fish, and amphibia can replicate neural cells throughout life. An exception to this rule of self-repair and continued growth was thought to be the mammalian brain and spinal cord. In fact, because we knew that microglia, astrocytes, and oligodendrocytes all normally divide in the adult and respond to injury by dividing, it was only neurons that were considered to be refractory to replication. Now we know that this long accepted limitation is not completely true, because there are two rather discrete areas of the brain, the dentate gyrus of the hippocampal formation and the subventricular zone and its projection through the rostral migratory stream to the olfactory bulb, which can generate new neurons. https://www.jneurosci.org/content/22/3/612

Plasticity is the ability of the brain to change and adapt to new information. Synaptic plasticity is change that occurs at synapses, the junctions between neurons that allow them to communicate.

The idea that synapses could change, and that this change depended on how active or inactive they were, was first proposed in the 1949 by Canadian psychologist Donald Hebb. Because of synaptic plasticity’s probable contribution to memory storage, it has since become one of the most intensively researched topics in all of neuroscience.

What is the function of synaptic plasticity?

Synaptic plasticity controls how effectively two neurons communicate with each other. The strength of communication between two synapses can be likened to the volume of a conversation. When neurons talk, they do so at different volumes – some neurons whisper to each other while others shout. The volume setting of the synapse, or the synaptic strength, is not static, but rather can change in both the short term and long term. Synaptic plasticity refers to these changes in synaptic strength. https://qbi.uq.edu.au/brain-basics/brain/brain-physiology/what-synaptic-plasticity

A milestone is marked in our understanding of the brain with the recent acceptance, contrary to early dogma, that the adult nervous system can generate new neurons. One could wonder how this dogma originally came about, particularly because all organisms have some cells that continue to divide, adding to the size of the organism and repairing damage. All mammals have replicating cells in many organs and in some cases, notably the blood, skin, and gut, stem cells have been shown to exist throughout life, contributing to rapid cell replacement. Furthermore, insects, fish, and amphibia can replicate neural cells throughout life. An exception to this rule of self-repair and continued growth was thought to be the mammalian brain and spinal cord. In fact, because we knew that microglia, astrocytes, and oligodendrocytes all normally divide in the adult and respond to injury by dividing, it was only neurons that were considered to be refractory to replication. Now we know that this long accepted limitation is not completely true, because there are two rather discrete areas of the brain, the dentate gyrus of the hippocampal formation and the subventricular zone and its projection through the rostral migratory stream to the olfactory bulb, which can generate new neurons. https://www.jneurosci.org/content/22/3/612

Se marca un hito en nuestra comprensión del cerebro con la aceptación reciente, contrariamente al dogma inicial, de que el sistema nervioso adulto puede generar nuevas neuronas. Uno podría preguntarse cómo surgió originalmente este dogma, particularmente porque todos los organismos tienen algunas células que continúan dividiéndose, aumentando el tamaño del organismo y reparando el daño. Todos los mamíferos tienen células que se replican en muchos órganos y, en algunos casos, especialmente en la sangre, la piel y el intestino, se ha demostrado que las células madre existen durante toda la vida, lo que contribuye a un reemplazo celular rápido. Además, los insectos, los peces y los anfibios pueden replicar las células neurales durante toda la vida. Se pensaba que una excepción a esta regla de autorreparación y crecimiento continuo era el cerebro y la médula espinal de los mamíferos. De hecho, debido a que sabíamos que la microglía, los astrocitos y los oligodendrocitos normalmente se dividen en el adulto y responden a la lesión dividiéndose, solo las neuronas se consideraban refractarias a la replicación. Ahora sabemos que esta limitación aceptada durante mucho tiempo no es del todo cierta, porque hay dos áreas bastante discretas del cerebro, la circunvolución dentada de la formación del hipocampo y la zona subventricular y su proyección a través de la corriente migratoria rostral al bulbo olfatorio, que puede generar nuevas neuronas. https://www.jneurosci.org/content/22/3/612

La plasticidad es la capacidad del cerebro para cambiar y adaptarse a nueva información. La plasticidad sináptica es el cambio que ocurre en las sinapsis, las uniones entre las neuronas que les permiten comunicarse.

La idea de que las sinapsis pueden cambiar, y que este cambio depende de cuán activas o inactivas estén, fue propuesta por primera vez en 1949 por el psicólogo canadiense Donald Hebb. Debido a la probable contribución de la plasticidad sináptica al almacenamiento de la memoria, desde entonces se ha convertido en uno de los temas más intensamente investigados en toda la neurociencia.

¿Cuál es la función de la plasticidad sináptica?

La plasticidad sináptica controla la eficacia con la que dos neuronas se comunican entre sí. La fuerza de la comunicación entre dos sinapsis se puede comparar con el volumen de una conversación. Cuando las neuronas hablan, lo hacen en diferentes volúmenes: algunas neuronas susurran entre sí mientras que otras gritan. La configuración del volumen de la sinapsis, o la fuerza sináptica, no es estática, sino que puede cambiar tanto a corto como a largo plazo. La plasticidad sináptica se refiere a estos cambios en la fuerza sináptica. https://qbi.uq.edu.au/brain-basics/brain/brain-physiology/what-synaptic-plasticity