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International audience; Gut bacteria influence brain functions and metabolism. We investigated whether this influence can be mediated by direct sensing of bacterial cell wall components by brain neurons. In mice, we found that bacterial peptidoglycan plays a major role in mediating gut-brain communication via the Nod2 receptor. Peptidoglycan-derived muropeptides reach the brain and alter the activity of a subset of brain neurons that express Nod2. Activation of Nod2 in hypothalamic inhibitory neurons is essential for proper appetite and body temperature control, primarily in females. This study identifies a microbe-sensing mechanism that regulates feeding behavior and host metabolism.

In sensory systems, cortical areas send excitatory projections back to subcortical areas to dynamically adjust sensory processing. Here, we uncover for the first time the existence of a cortical inhibitory feedback to subcortical sensory areas. Investigating the olfactory system, we reveal that a subpopulation of GABAergic neurons in the anterior olfactory cortex target the olfactory bulb. Analogous inhibitory cortico-thalamic projections were also present in the somatosensory system. Long-range inhibitory inputs synapsed with both local and output neurons of the olfactory bulb. At the functional level, optogenetic activation of cortical GABAergic projections caused a net subtractive inhibition of both spontaneous and odor-evoked activity in local as well as output projection neurons, mitral and tufted cells. In tufted cells, but not mitral cells, this resulted in an enhanced separation of population odor responses. Furthermore, GABAergic corticofugal projections entrained network oscillations in the communication band between the cortex and the olfactory bulb. Targeted pharmacogenetic silencing of the cortical GABAergic outputs in the olfactory bulb impaired discrimination of similar odor mixtures. Thus, cortical GABAergic feedback represents a new circuit motif in sensory systems involved in refining sensory processing and perception.

Comment in Sensory systems: the hungry sense. [Nat Rev Neurosci. 2014] Inhaling: endocannabinoids and food intake. [Nat Neurosci. 2014]; International audience; Hunger arouses sensory perception, eventually leading to an increase in food intake, but the underlying mechanisms remain poorly understood. We found that cannabinoid type-1 (CB1) receptors promote food intake in fasted mice by increasing odor detection. CB1 receptors were abundantly expressed on axon terminals of centrifugal cortical glutamatergic neurons that project to inhibitory granule cells of the main olfactory bulb (MOB). Local pharmacological and genetic manipulations revealed that endocannabinoids and exogenous cannabinoids increased odor detection and food intake in fasted mice by decreasing excitatory drive from olfactory cortex areas to the MOB. Consistently, cannabinoid agonists dampened in vivo optogenetically stimulated excitatory transmission in the same circuit. Our data indicate that cortical feedback projections to the MOB crucially regulate food intake via CB1 receptor signaling, linking the feeling of hunger to stronger odor processing. Thus, CB1 receptor-dependent control of cortical feedback projections in olfactory circuits couples internal states to perception and behavior.

ClC-K2 is present on the basolateral membrane of kidney epithelial cells, but little is known about its single channel properties. Pinelli et al. record unitary ClC-K2 currents from intercalated cells of mouse connecting tubules and investigate their regulation by voltage, pH, Cl−, and Ca2+., ClC-K2, a member of the ClC family of Cl− channels and transporters, forms the major basolateral Cl− conductance in distal nephron epithelial cells and therefore plays a central role in renal Cl− absorption. However, its regulation remains largely unknown because of the fact that recombinant ClC-K2 has not yet been studied at the single-channel level. In the present study, we investigate the effects of voltage, pH, Cl−, and Ca2+ on native ClC-K2 in the basolateral membrane of intercalated cells from the mouse connecting tubule. The ∼10-pS channel shows a steep voltage dependence such that channel activity increases with membrane depolarization. Intracellular pH (pHi) and extracellular pH (pHo) differentially modulate the voltage dependence curve: alkaline pHi flattens the curve by causing an increase in activity at negative voltages, whereas alkaline pHo shifts the curve toward negative voltages. In addition, pHi, pHo, and extracellular Ca2+ strongly increase activity, mainly because of an increase in the number of active channels with a comparatively minor effect on channel open probability. Furthermore, voltage alters both the number of active channels and their open probability, whereas intracellular Cl− has little influence. We propose that changes in the number of active channels correspond to them entering or leaving an inactivated state, whereas modulation of open probability corresponds to common gating by these channels. We suggest that pH, through the combined effects of pHi and pHo on ClC-K2, might be a key regulator of NaCl absorption and Cl−/HCO3− exchange in type B intercalated cells.

Neuronal precursors are continuously integrated into the adult olfactory bulb (OB). The vast majority of these precursor cells originates from the subventricular zone and migrates along the rostral migratory stream (RMS) en route to the OB. This process, called postnatal neurogenesis, results from intricate pathways depending both on cell-autonomous factors and extrinsic regulation provided by the local environment. Using electroporation in postnatal mice to label neuronal precursors with green fluorescent protein (GFP) and to reduce the expression levels of doublecortin (DCX) with short-hairpin (Sh) RNA, we investigated the consequences of impairing migration on the fate of postnatal-formed neurons. First, we showed that electroporation of Dcx ShRNA plasmid efficiently knocks down the expression of DCX and disrupts cells migration along the RMS. Second, we found misplaced anomalous migrating cells that displayed defects in polarity and directionality. Third, patch-clamp recordings performed at 5–7 days post-electroporation (dpe) revealed increased density of voltage-dependent Na+channels and enhanced responsiveness to GABAAreceptor agonist. At later time points (i.e., 12 and 30 dpe), most of the Dcx ShRNA+cells developed in the core of the OB and displayed aberrant dendritic length and branching. Additional analysis revealed the formation of GABAergic and glutamatergic synaptic inputs on the mispositioned neurons. Finally, quantifying fate determination by numbering the proportion of GFP+/calretinin+newborn neurons revealed that Dcx ShRNA+cells acquire mature phenotype despite their immature location. We conclude that altering the pace of migration at early stages of postnatal neurogenesis profoundly modifies the tightly orchestrated steps of neuronal maturation, and unveils the influence of microenvironment on controlling neuronal development in the postnatal forebrain.

In adult mammals, thousands of new neurons integrate in the olfactory bulb (OB) each day. This process of adult neurogenesis has received a great deal of scientific attention aimed at understanding how mature neural networks withstand neuronal replacement, and medical interest to explore the promise that these cells may be manipulated for brain repair therapies. In the present review, we focus on the mechanisms and consequences of the functional integration of newborn interneurons in the OB network. We first describe the steps of synaptic integration and functional maturation of adult-born interneurons in the OB. We then examine the physiological control of cell maturation and survival. Finally, we explore the potential impact of adult neurogenesis on the function of the OB.

In the olfactory bulb (OB), odorants induce oscillations in the γ range (20–80 Hz) that play an important role in the processing of sensory information. Synaptic transmission between dendrites is a major contributor to this processing. Glutamate released from mitral cell dendrites excites the dendrites of granule cells, which in turn mediate GABAergic inhibition back onto mitral cells. Although this reciprocal synapse is thought to be a key element supporting oscillatory activity, the mechanisms by which dendrodendritic inhibition induces and maintains γ oscillations remain unknown. Here, we assessed the role of the dendrodendritic inhibition, using mice lacking the GABA A receptor α1-subunit, which is specifically expressed in mitral cells but not in granule cells. The spontaneous inhibitory postsynaptic current frequency in these mutants was low and was consistent with the reduction of GABA A receptor clusters detected by immunohistochemistry. The remaining GABA A receptors in mitral cells contained the α3-subunit and supported slower decaying currents of unchanged amplitude. Overall, inhibitory-mediated interactions between mitral cells were smaller and slower in mutant than in WT mice, although the strength of sensory afferent inputs remained unchanged. Consequently, both experimental and theoretical approaches revealed slower γ oscillations in the OB network of mutant mice. We conclude, therefore, that fast oscillations in the OB circuit are strongly constrained by the precise location, subunit composition and kinetics of GABA A receptors expressed in mitral cells.

Sensory perception emerges from the confluence of sensory inputs that encode the composition of external environment and top-down feedback that conveys information from higher brain centers. In olfaction, sensory input activity is initially processed in the olfactory bulb (OB), serving as the first central relay before being transferred to the olfactory cortex. In addition, the OB receives dense connectivity from feedback projections, so the OB has the capacity to implement a wide array of sensory neuronal computation. However, little is known about the impact and the regulation of this cortical feedback. Here, we describe a novel mechanism to gate glutamatergic feedback selectively from the anterior olfactory cortex (AOC) to the OB. Combining in vitro and in vivo electrophysiological recordings, optogenetics, and fiber-photometry-based calcium imaging applied to wild-type and conditional transgenic mice, we explore the functional consequences of circuit-specific GABA type-B receptor (GABA(B)R) manipulation. We found that activation of presynaptic GABA(B)Rs specifically depresses synaptic transmission from the AOC to OB inhibitory interneurons, but spares direct excitation to principal neurons. As a consequence, feedforward inhibition of spontaneous and odor-evoked activity of principal neurons is diminished. We also show that tunable cortico-bulbar feedback is critical for generating beta, but not gamma, OB oscillations. Together, these results show that GABA(B)Rs on cortico-bulbar afferents gate excitatory transmission in a target-specific manner and thus shape how the OB integrates sensory inputs and top-down information. SIGNIFICANCE STATEMENT The olfactory bulb (OB) receives top-down inputs from the olfactory cortex that produce direct excitation and feedforward inhibition onto mitral and tufted cells, the principal neurons. The functional role of this feedback and the mechanisms regulating the balance of feedback excitation and inhibition remain unknown. We found that GABA(B) receptors are expressed in cortico-bulbar axons that synapse on granule cells and receptor activation reduces the feedforward inhibition of spontaneous and odor-driven mitral and tufted cells' firing activity. In contrast, direct excitatory inputs to these principal neurons remain unchanged. This study demonstrates that activation of GABA(B) receptors biases the excitation/inhibition balance provided by cortical inputs to the OB, leading to profound effects on early stages of sensory information processing.

International audience; For a long time, the mammalian brain has been perceived to be a static organ. However, the discovery of adult neurogenesis in most mammalian species, including humans, monkeys, and rodents, has disrupted this view. As this continuous regeneration has an effect on established behavioral patterns, it holds promising therapeutic potential. However, before harnessing this potential regenerative power, we must understand what effects new neurons have on existing brain circuits. Ongoing research contributes to several important steps toward bridging the gap between adult-born neurons, circuits, and behavior. The study of adult neurogenesis in different neurogenic regions from a systems neuroscience perspective will pave the way to understanding how it supports adaptive behavior and why its dysfunction correlates with some human brain disorders.

The distal convoluted tubule (DCT) is a heterogeneous segment subdivided into early (DCT1) and late (DCT2) parts, depending on the distribution of various transport systems. We do not have an exhaustive picture of the Cl−channels on the basolateral side: the presence of ClC-K2 channels is generally accepted, whereas that of ClC-K1 remains controversial. We used here single-cell RT-PCR and patch clamp to probe Cl−channel heterogeneity in microdissected mouse DCT at the molecular and functional levels. Our findings show that 63% of the DCT cells express ClC-K2 mRNA, either alone (type 1 cells: 47 and 23% in DCT1 and DCT2, respectively), or combined with ClC-K1, mostly in DCT2 (type 2 cells: 33%), but 37% of DCT1 and DCT2 cells do not express any ClC-K. Patch-clamp experiments revealed that a Cl−channel, with 9-pS conductance and Cl−> NO3−= Br−anion selectivity sequence, is present in the DCT1 and DCT2 basolateral membranes (87 and 71% of the patches, respectively). This dominant channel is likely to be ClC-K2 in type 1 cells. In type 2 cells, it could be ClC-K2 and/or ClC-K1 homodimers, but also ClC-K1/ClC-K2 heterodimers, or a mixture of all combinations. A second, distinct Cl−channel (13% of DCT1 patches, 29% of DCT2 patches) also displayed 9-pS conductance but had a completely different anion selectivity (I−> NO3−> Br−> Cl−), which was not compatible with that of the ClC-Ks. This indicates that a Cl−channel that is unlikely to belong to the ClC family may also be involved in Cl−absorption in the DCT2.

In adult mammals, thousands of new neurons integrate in the olfactory bulb (OB) each day. This process of adult neurogenesis has received a great deal of scientific attention aimed at understanding how mature neural networks withstand neuronal replacement, and medical interest to explore the promise that these cells may be manipulated for brain repair therapies. In the present review, we focus on the mechanisms and consequences of the functional integration of newborn interneurons in the OB network. We first describe the steps of synaptic integration and functional maturation of adult-born interneurons in the OB. We then examine the physiological control of cell maturation and survival. Finally, we explore the potential impact of adult neurogenesis on the function of the OB.

The fragile X mental retardation protein (FMRP) is an RNA-binding protein essential for multiple aspects of neuronal mRNA metabolism. Its absence leads to the fragile X syndrome, the most prevalent genetic form of mental retardation. The anatomical landmark of the disease, also present in theFmr1knock-out (KO) mice, is the hyperabundance of immature-looking lengthened dendritic spines. We used the well known continuous production of adult-born granule cells (GCs) in the mouse olfactory bulb (OB) to analyze the consequences of Fmrp loss on the differentiation of GCs. Morphological analysis of GCs in theFmr1KO mice showed an increase in spine density without a change in spine length. We developed an RNA interference strategy to cell-autonomously mutateFmr1in a wild-type OB network. Mutated GCs displayed an increase in spine density and spine length. Detailed analysis of the spines through immunohistochemistry, electron microscopy, and electrophysiology surprisingly showed that, despite these abnormalities, spines receive normal glutamatergic synapses, and thus that mutated adult-born neurons are synaptically integrated into the OB circuitry. Time-course analysis of the spine defects showed that Fmrp cell-autonomously downregulates the level and rate of spine production and limits their overgrowth. Finally, we report that Fmrp does not regulate dendritogenesis in standard conditions but is necessary for activity-dependent dendritic remodeling. Overall, our study of Fmrp in the context of adult neurogenesis has enabled us to carry out a precise dissection of the role of Fmrp in neuronal differentiation and underscores its pleiotropic involvement in both spinogenesis and dendritogenesis.

The olfactory bulb (OB) receives and integrates newborn interneurons throughout life. This process is important for the proper functioning of the OB circuit and consequently, for the sense of smell. Although we know how these new interneurons are produced, the way in which they integrate into the pre-existing ongoing circuits remains poorly documented. Bearing in mind that glutamatergic inputs onto local OB interneurons are crucial for adjusting the level of bulbar inhibition, it is important to characterize when and how these inputs from excitatory synapses develop on newborn OB interneurons. We studied early synaptic events that lead to the formation and maturation of the first glutamatergic synapses on adult-born granule cells (GCs), the most abundant subtype of OB interneuron. Patch-clamp recordings and electron microscopy (EM) analysis were performed on adult-born interneurons shortly after their arrival in the adult OB circuits. We found that both the ratio of N-methyl-D-aspartate receptor (NMDAR) to α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid receptor (AMPAR), and the number of functional release sites at proximal inputs reached a maximum during the critical period for the sensory-dependent survival of newborn cells, well before the completion of dendritic arborization. EM analysis showed an accompanying change in postsynaptic density shape during the same period of time. Interestingly, the latter morphological changes disappeared in more mature newly-formed neurons, when the NMDAR to AMPAR ratio had decreased and functional presynaptic terminals expressed only single release sites. Together, these findings show that the first glutamatergic inputs to adult-generated OB interneurons undergo a unique sequence of maturation stages.

International audience; The first synapse in olfaction undergoes considerable anatomical plasticity in both early postnatal development and adult neurogenesis, yet we know very little concerning its functional maturation at these times. Here, we used whole-cell recordings in olfactory bulb slices to describe olfactory nerve inputs to developing postnatal neurons and to maturing adult-born cells labeled with a GFP-encoding lentivirus. In both postnatal development and adult neurogenesis, the maturation of olfactory nerve synapses involved an increase in the relative contribution of AMPA over NMDA receptors, and a decrease in the contribution of NMDA receptors containing the NR2B subunit. These postsynaptic transformations, however, were not mirrored by presynaptic changes: in all cell groups, paired-pulse depression remained constant as olfactory nerve synapses matured. Although maturing cells may therefore offer, transiently, a functionally distinct connection for inputs from the nose, presynaptic function at the first olfactory connection remains remarkably constant in the face of considerable anatomical plasticity.

Using the patch-clamp technique, we investigated Cl−channels on the basolateral membrane of the connecting tubule (CNT) and cortical collecting duct (CCD). We found a ∼10-pS channel in CNT cell-attached patches. Substitution of sodium gluconate for NaCl in the pipette shifted the reversal potential by +25 mV, whereas N-methyl-d-gluconate chloride had no effect, indicating anion selectivity. On inside-out patches, we determined a selectivity sequence of Cl−> Br−∼ NO3−> F−, which is compatible with that of ClC-K2, a Cl−channel in the distal nephron. In addition, the number of open channels ( NPo) measured in cell-attached patches was significantly increased when Ca2+concentration or pH in the pipette was increased, which is another characteristic of ClC-K. These findings suggest that the basis for this channel is ClC-K2. A similar Cl−channel was found in CCD patches. Because CNT and CCD are heterogeneous tissues, we studied the cellular distribution of the Cl−channel using recording conditions (KCl-rich solution in the pipette) that allowed us to detect simultaneously Cl−channels and inwardly rectifying K+channels. We detected Cl−channels alone in 45% and 42% and K+channels alone in 51% and 58% of CNT and CCD patches, respectively. Cl−and K+channels were recorded simultaneously from two patches (4% of patches) in the CNT and from none of the patches in the CCD. This indicates that Cl−and K+channels are located in different cell types, which we suggest may be the intercalated cells and principal cells, respectively.

International audience; Edema and ascites in nephrotic syndrome mainly result from increased Na+ reabsorption along connecting tubules and cortical collecting ducts (CCD). In puromycin aminonucleoside (PAN)-induced nephrosis, increased Na+ reabsorption is associated with increased activity of the epithelial sodium channel (ENaC) and Na+,K+-ATPase, two targets of aldosterone. Because plasma aldosterone increases in PAN-nephrotic rats, the aldosterone dependence of ENaC activation in PAN nephrosis was investigated. For this purpose, (1) the mechanism of ENaC activation was compared in nephrotic and sodium-depleted rats, and (2) ENaC activity in PAN-nephrotic rats was evaluated in the absence of hyperaldosteronemia. The mechanism of ENaC activation was similar in CCD from nephrotic and sodium-depleted rats, as demonstrated by (1) increased number of active ENaC evaluated by patch clamp, (2) recruitment of ENaC to the apical membrane determined by immunohistochemistry, (3) shift in the electrophoretic profile of gamma-ENaC, and (4) increased abundance of beta-ENaC mRNA. Corticosteroid clamp fully prevented all PAN-induced changes in ENaC but did not alter the development of a full-blown nephrotic syndrome with massive albuminuria, amiloride-sensitive sodium retention, induction of CCD Na+,K+-ATPase, and ascites. It is concluded that in PAN-nephrosis, (1) ENaC activation in CCD is secondary to hyperaldosteronemia, (2) sodium retention and induction of Na+,K+-ATPase in CCD are independent of hyperaldosteronemia, and (3) ENaC is not necessarily limiting for sodium reabsorption in the distal nephron.

International audience; Chloride channels located on the basolateral membrane are known to be involved in chloride absorption in several parts of the renal tubule, and particularly in the thick ascending limb and distal convoluted tubule. The data available suggest that the ClC-K channels play the major role in this process. We provide here a description of the electrophysiological properties of these channels, still very incomplete at this stage, and we attempt to compare ClC-Ks to three chloride channels that we have identified in the basolateral membrane of microdissected fragments of the mouse renal tubule using the patch-clamp technique. Based on anion selectivity and dependence on external pH and calcium shown by the ClC-Ks, we propose candidate ClC-K1 and ClC-K2 in native tissue. We also discuss the possibility that chloride channels that do not belong to the ClC family may also be involved in the absorption of chloride across the cortical thick ascending limb.

International audience; The distal-convoluted tubule (DCT) of the kidney absorbs NaCl mainly via an Na+-Cl- cotransporter located at the apical membrane, and Na+, K+ ATPase at the basolateral side. Cl- transport across the basolateral membrane is thought to be conductive, but the corresponding channels have not yet been characterized. In the present study, we investigated Cl- channels on microdissected mouse DCTs using the patch-clamp technique. A channel of approximately 9 pS was found in 50% of cell-attached patches showing anionic selectivity. The NPo in cell-attached patches was not modified when tubules were preincubated in the presence of 10-5 M forskolin, but the channel was inhibited by phorbol ester (10-6 M). In addition, NPo was significantly elevated when the calcium in the pipette was increased from 0 to 5 mM (NPo increased threefold), or pH increased from 6.4 to 8.0 (NPo increased 15-fold). Selectivity experiments conducted on inside-out patches showed that the Na+ to Cl- relative permeability was 0.09, and the anion selectivity sequence Cl(-)--I(-) > Br(-)--NO3(-) > F(-). Intracellular NPPB (10-4 M) and DPC (10-3 M) blocked the channel by 65% and 80%, respectively. The channel was inhibited at acid intracellular pH, but intracellular ATP and PKA had no effect. ClC-K Cl- channels are characterized by their sensitivity to the external calcium and to pH. Since immunohistochemical data indicates that ClC-K2, and perhaps ClC-K1, are present on the DCT basolateral membrane, we suggest that the channel detected in this study may belong to this subfamily of the ClC channel family.

To explore the functional consequences of adult neurogenesis in the mouse olfactory bulb, we investigated plasticity at glutamatergic synapses onto GABAergic interneurons. We found that one subset of excitatory synapses onto adult-born granule cells showed long-term potentiation shortly after their arrival in the bulb. This property faded as the newborn neurons matured. These results indicate that recently generated adult-born olfactory interneurons undergo different experience-dependent synaptic modifications compared with their pre-existing mature neighbors and provide a possible substrate for adult neurogenesis-dependent olfactory learning.

New olfactory bulb granule cells (GCs) are GABAergic interneurons continuously arising from neuronal progenitors and integrating into preexisting bulbar circuits. They receive both GABAergic and glutamatergic synaptic inputs from olfactory bulb intrinsic neurons and centrifugal afferents. Here, we investigated the spatiotemporal dynamic of newborn GC synaptogenesis in adult mouse olfactory bulb. First, we established that GABAergic synapses onto mature GC dendrites contain the GABAAreceptor α2 subunit along with the postsynaptic scaffolding protein gephyrin. Next, we characterized morphologically and electrophysiologically the development of GABAergic and glutamatergic inputs onto newborn GCs labeled with eGFP (enhanced green fluorescent protein) using lentiviral vectors. Already when reaching the GC layer (GCL), at 3 d post-vector injection (dpi), newborn GCs exhibited tiny voltage-dependent sodium currents and received functional GABAergic and glutamatergic synapses, recognized immunohistochemically by apposition of specific presynaptic and postsynaptic markers. Thereafter, GABAergic and glutamatergic synaptic contacts increased differentially in the GCL, and at 7 dpi, PSD-95 clusters outnumbered gephyrin clusters. Thus, the weight of GABAergic input was predominant at early stages of GC maturation, but not later. Newborn GC dendrites first reached the external plexiform layer at 4 dpi, where they received functional GABAergic contacts at 5 dpi. Reciprocal synapses initially were formed on GC dendritic shafts, where they might contribute to spine formation. Their presence was confirmed ultrastructurally at 7 dpi. Together, our findings unravel rapid synaptic integration of newborn GCs in adult mouse olfactory bulb, with GABAergic and glutamatergic influences being established proximally before formation of output synapses by apical GC dendrites onto mitral/tufted cells.

Traduction française de l’article paru dans « Frontiers in Psychology, auditory cognitive neurosciences » sous le titre original :Strategies used by musicians to identify notes’ pitch: Cognitive bricks and mental representationsFront. Psychol. 11:1480. doi: 10.3389/fpsyg.2020.01480; À ce jour, l'étude de la texture de la pensée et de ses mécanismes implicites est rarement abordée directement. Les approches systémiques basées sur des méthodologies introspectives ne sont actuellement plus à la mode et se trouvent souvent négligées ou ignorées. Le plus souvent, des approches réductionnistes sont réalisées pour déchiffrer les circuits neuronaux fonctionnellement associés aux processus cognitifs. Toutefois, nous soutenons que des études systémiques de la pensée individuelle peuvent encore contribuer à une description utile et complémentaire de la nature multimodale de la perception, car elles sont en mesure de prendre en compte la diversité individuelle tout en identifiant les caractéristiques communes des processus perceptifs. Nous proposons d'aborder cette question en examinant la tâche de reconnaissance d'un "son signifiant" comme exemple de saisie conceptuelle d'une réponse perceptive. En adoptant une approche mixte, combinant des analyses qualitatives d'entretiens basées sur l'introspection avec des analyses statistiques quantitatives réalisées sur la catégorisation qui en résulte, cette étude décrit une variété de stratégies mentales utilisées par les musiciens pour identifier la hauteur des notes. Soixante-sept musiciens (étudiants en musique et professionnels) ont été interrogés, révélant que les musiciens utilisent des étapes intermédiaires lors de l'identification des notes en sélectionnant ou en activant des briques cognitives qui aident à construire et à obtenir la bonne réponse. Nous avons nommé ces éléments "appuis mentaux". Bien que les appuis mentaux ne soient pas universels et diffèrent selon les individus, ils peuvent être regroupés en catégories liées à trois modalités sensorielles principales : auditive, visuelle et kinesthésique. Cette catégorisation nous a permis de caractériser les représentations mentales qui permettent aux musiciens de nommer des notes en fonction de onze typologies de base d'appuis mentaux. Nous proposons un cadre conceptuel qui résume le processus d'identification des notes en cinq étapes, partant de la détection sensorielle et se terminant par la verbalisation de la hauteur de la note, en passant par le rôle pivot des appuis mentaux et des représentations mentales. Nous avons constaté que les musiciens utilisent de multiples stratégies et sélectionnent des combinaisons individuelles d'appuis mentaux appartenant à ces trois différentes modalités sensorielles, à la fois isolément et en combinaison.

Une version traduite de cet article est disponible sur HAL sous le titre : Stratégies utilisées par les musiciens pour identifier la hauteur des notes : briques cognitives et représentations mentales. docid: pasteur-02901456; International audience; To this day, the study of the substratum of thought and its implied mechanisms is rarely directly addressed. Nowadays, systemic approaches based on introspective methodologies are no longer fashionable and are often overlooked or ignored. Most frequently, reductionist approaches are followed for deciphering the neuronal circuits functionally associated with cognitive processes. However, we argue that systemic studies of individual thought may still contribute to a useful and complementary description of the multimodal nature of perception, because they can take into account individual diversity while still identifying the common features of perceptual processes. We propose to address this question by looking at one possible task for recognition of a “signifying sound”, as an example of conceptual grasping of a perceptual response. By adopting a mixed approach combining qualitative analyses of interviews based on introspection with quantitative statistical analyses carried out on the resulting categorization, this study describes a variety of mental strategies used by musicians to identify notes’ pitch. Sixty-seven musicians (music students and professionals) were interviewed, revealing that musicians utilize intermediate steps during note identification by selecting or activating cognitive bricks that help construct and reach the correct decision. We named these elements “mental anchorpoints” (MA). Although the anchorpoints are not universal, and differ between individuals, they can be grouped into categories related to three main sensory modalities – auditory, visual and kinesthetic. Such categorization enabled us to characterize the mental representations (MR) that allow musicians to name notes in relationship to eleven basic typologies of anchorpoints. We propose a conceptual framework which summarizes the process of note identification in five steps, starting from sensory detection and ending with the verbalization of the note pitch, passing through the pivotal role of MAs and MRs. We found that musicians use multiple strategies and select individual combinations of MAs belonging to these three different sensory modalities, both in isolation and in combination.