The Efferent Control of Afferent Signals Entering the Central Nervous System

Abstract

The centrifugal control of afferent transmission in central sensory stations, long suspected by the perceptive neuroanatomists Cajal,5 Brouwer,3 and Wallenberg,42 is now firmly established as the result of numerous experiments carried out during the last six years.Early as well as recent anatomical studies,2,3'5.6'33,34,4n,41 *42 have shown in the central nervous system the presence of efferent or centrifugal fibers projecting down to sensory synapses as low as those of the spinal cord, of the spinal fifth sensory nucleus, of the dorsal column nuclei, of the cochlear nucleus, of the retina, and of the olfactory bulb. It has also been demonstrated in acute experiments that electrical stimulation of these fibers elicits inhibitory" ,32~1n or facilitatoryll~ZfiJIJo interactions with the ascending afferent impulses in all the above mentioned sensory centers (see the reviews on this subject by Hagbarth13 and by Hern&ndez-Pe6nlG).Furthermore, some descending influences that control synaptic afferent transmission act tonically during wakefulness. It has been shown that synchronized afferent volleys recorded from the lowest levels of the somatic, auditory, and olfactory central pathways are enhanced by anesthetics and by brain stem lesions, which impair c o n s c i o u~n e s s .~~~~~~~~~~~ These experimental observations are consistent with older observations in which larger cortical sensoryevoked potentials were recorded during deep rather than during light anesthesia.* Therefore the conclusion is warranted that the reticular activity related to wakefulness normally regulates the passage of a great number of sensory impulses to the central nervous system. Undoubtedly this new neurophysiological concept can account, at least in part, for the well-known psychological phenomenon concerning the constantly limited span of perception.Since perception is invariably associated with the process of attention, it occurred to one of us (R.H.-P.) that sensory impulses generated by stimuli outside of the span of attention would be prevented from entering the brain by descending inhibitory influences such as those mentioned above. Correlated behavioral and electrophysiological studies carried out in unanesthetized cats with electrodes permanently implanted in the lowest subcortical sensory relays have substantiated this hypothesis. By recording synchronized afferent volleys evoked by brief sensory stimuli, HernSndez-Pebn and his co-workers17 have demonstrated that the corresponding evoked potentials are reduced or abolished when the animal attends to stimuli more significant than the test stimulus. This phenomenon has been observed in the dorsal cochlear nucleus,28 in the axons of the retinal ganglion cells along the optic tract,22,233J7 in the spinal fifth sensory nucleus,7 in the lateral columns of the spinal cord: and in the olfactory bulb.I9 A similar reduction of sensory-evoked potentials at those lower stations of the mentioned sensory pathways has also been observed by Hernindez-PeQ and his co-~orkers'~ consecutive to monotonou...

Cerebral mechanisms underlying the effects of music during a fatiguing isometric ankle‐dorsiflexion task

“…The authors suggest that subcortical regions of the brain might be responsible for controlling the execution of motor tasks and the processing of music; in this case, little processing would need to take place for music to have its beneficial effects on affective responses. Furthermore, it has been indicated that music could not only activate one sensory region, but also reduce the activity in other sensory regions (Hernández‐Peón, Brust‐Carmona, Peñaloza‐Rojas, & Bach‐Y‐Rita, ), and these combined responses could be responsible for the positive effects of music on fatigue‐related symptoms and affective responses (Karageorghis & Priest, ). The present results are noticeably similar to those found by Jones et al () and Hutchinson et al (), and support the notion that music‐related interventions are facilitative strategies that modulate affective valence, attentional focus, and task performance during the execution of exhaustive or fatiguing motor tasks.…”

La influencia de la música y el ejercicio físico en la preparación física y psicológica

“…Por otro lado, el carácter de esfuerzo en las semanas con canciones de tempo musical elevado (>100 bpm) fue menor que en las semanas con canciones de tempo bajo (<100 bpm). En línea con las teorías de "percepción selectiva" de Broadbent (1958) y de "atención focalizada" de Hernández-Peon (1961), parace que el sistema nervioso centra la atención en la música como único estímulo, inhibiendo los demás envolventes durante la práctica deportiva y atenuando la sensación de cansancio (Copeland y Franks, 1991;Nideffer, 1976;Guillén y Ruiz-Alfonso, 2013;Hernández-Peon, 1961;Ju-Han y Jing-Horng Lu, 2013;Pennebaker y Lightner, 1980;Rejeski, 1985). Por lo tanto, aunque la música no cambia la fatiga producida al realizar los ejercicios, sí cambia la percepción del sujeto acerca de ésta.…”

“…Este posible efecto parece poder explicarse según las teorías de "percepción selectiva" (Broadbent, 1958) y de "atención focalizada" (Hernández-Peon, 1961), según las cuales el sistema nervioso puede atender únicamente a un estímulo (musical, en este caso) a expensas de discriminar el resto de estímulos envolventes (Copeland y Franks, 1991;Nideffer, 1976) atenuando la sensación de cansancio en el individuo (Guillén y Ruiz-Alfonso, 2013;Hernández-Peon, 1961;Ju-Han y Jing-Horng Lu, 2013;Pennebaker y Lightner, 1980). Rejeski (1985) también señala que la capacidad del sistema nervioso central es limitada y que solo es capaz de atender a un estímulo, por lo que, cuando una actividad física es acompañada por música, los estímulos que produce ésta pueden evitar las señales de retroalimentación relacionadas con el esfuerzo físico (Karageorghis y Priest, 2012).…”

Efeitos da música eletrônica nos sistemas neuromuscular, cardiovascular e parâmetros psicofisiológicos durante teste incremental exaustivo

“…Primeiramente os dados foram submetidos à estatística descritiva. -Peon et al (1961), o cérebro possui uma quantidade limitada de informações que podem ser processadas ao mesmo tempo e, a música, acabaria por inibir sensações "desagradáveis" resultante do exercício físico, atenuando a sensação de esforço do indivíduo. Essa teoria tem sido utilizada para explicar os efeitos da música durante o exercício físico (Karageorghis & Terry, 1997;Szmedra & Bacharach, 1998).…”