Franco-British relations in Neurophysiology in Edgar Adrian's Era

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L'Institut Marey (1947-1978)

Au sein de la communauté française des Neurosciences, l'Institut Marey demeure pour les plus jeunes un mythe difficilement accessible, tellement l'histoire de ce petit pavillon 1900, détruit pendant l'hiver 1978, reste encore entourée de mystère. Depuis quelques années, historiens et anciens de l'Institut recherchent dans leurs archives et souvenirs ce qui a déterminé, depuis l'Institut de E. J. Marey des années 1900, l'émergence dès 1947 d'un Institut du CNRS qui a contribué à former après guerre plusieurs générations de chercheurs qui ont essaimé par la suite dans la France entière

The Fessard's School of Physiology after war in France: globalization and diversity in neurophysiological research on Torpedo fish (1938-1955)

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Les heures sombres de la Neurophysiologie à Paris (1909-1939)

Louis Lapicque (1866-1952) n'a pas fini de faire parler de lui. Ses travaux, dont ceux relevant des débuts français de la cybernétique et son célèbre paramètre, la chronaxie, retrouvent quelques échos dans la littérature actuelle. En 1941, selon le compte rendu des sciences biologiques de Maurice Caullery, « Louis Lapicque poursuit encore présentement l'étude de l'influx nerveux, où il a établi et développé avec une rare persévérance la notion de chronaxie. » C'est en 1909 que Lapicque dérive ce paramètre de la courbe d'excitabilité des nerfs. Pendant plus de trente années, la neurophysiologie française sera marquée, sinon dominée par l'hégémonie d'un seul indice empirique d'excitation, pris comme base de positions théoriques générales, s'adaptant curieusement aux débats sur les modes de transmission nerveuse. Or, Lapicque s'isole progressivement, en refusant de voir les progrès de la neurophysiologie et les réfutations de l'école de Cambridge, au point qu'il finit par perdre son crédit, tant à l'étranger qu'en France, où le poids de son dogmatisme paralyse la recherche et freine les débuts de talentueux physiologistes, tel Alfred Fessard, soucieux de prendre part aux progrès réalisés outre-manche et outre-atlantique

Monoaminergic modulation of photoreception in ascidian:evidence for a proto-hypothalamo-retinal territory

Background : The retina of craniates/vertebrates has been proposed to derive from a photoreceptor prosencephalic territory in ancestral chordates, but the evolutionary origin of the different cell types making the retina is disputed. Except for photoreceptors, the existence of homologs of retinal cells remains uncertain outside vertebrates. Methods : The expression of genes expressed in the sensory vesicle of the ascidian Ciona intestinalis including those encoding components of the monoaminergic neurotransmission systems, was analyzed by in situ hybridization or in vivo transfection of the corresponding regulatory elements driving fluorescent reporters. Modulation of photic responses by monoamines was studied by electrophysiology combined with pharmacological treatments. Results : We show that many molecular characteristics of dopamine-synthesizing cells located in the vicinity of photoreceptors in the sensory vesicle of the ascidian Ciona intestinalis are similar to those of amacrine dopamine cells of the vertebrate retina. The ascidian dopamine cells share with vertebrate amacrine cells the expression of the key-transcription factor Ptf1a, as well as that of dopamine-synthesizing enzymes. Surprisingly, the ascidian dopamine cells accumulate serotonin via a functional serotonin transporter, as some amacrine cells also do. Moreover, dopamine cells located in the vicinity of the photoreceptors modulate the light-off induced swimming behavior of ascidian larvae by acting on alpha2-like receptors, instead of dopamine receptors, supporting a role in the modulation of the photic response. These cells are located in a territory of the ascidian sensory vesicle expressing genes found both in the retina and the hypothalamus of vertebrates (six3/6, Rx, meis, pax6, visual cycle proteins). Conclusion : We propose that the dopamine cells of the ascidian larva derive from an ancestral multifunctional cell population located in the periventricular, photoreceptive field of the anterior neural tube of chordates, which also gives rise to both anterior hypothalamus and the retina in craniates/vertebrates. It also shows that the existence of multiple cell types associated with photic responses predates the formation of the vertebrate retina

Physiology in Europe and the birth of European Neuroscience

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Sensing with the Motor Cortex

The primary motor cortex is a critical node in the network of brain regions responsible for voluntary motor behavior. It has been less appreciated, however, that the motor cortex exhibits sensory responses in a variety of modalities including vision and somatosensation. We review current work that emphasizes the heterogeneity in sensorimotor responses in the motor cortex and focus on its implications for cortical control of movement as well as for brain-machine interface development