Search results for "Auditory"

Les Réponses évoquées Du Noyau Caudé A La Suite De Modifications De L'Excitabilité De L'Aire Auditive Primaire

1966

A Basis Set of Elementary Operations Captures Recombination of Neocortical Cell Assemblies During Basal Conditions and Learning

2019

Cell assemblies — subgroups within neuronal networks — are believed to serve as functional entities underlying cognitive capabilities such as categorical perception or memory formation and storage. However, little is known about their long-term dynamics. Using chronic in vivo calcium imaging in the mouse auditory cortex, we find that cell assemblies undergo continuous recombination, even under behaviorally stable conditions. We identify a basis set of elementary operations capturing the dynamics of cell assemblies, which involve plasticity of both the stimulus tuning of particular assemblies as well as the cellular composition of an assembly. Auditory fear conditioning introduces biases in …

Electron microscopic localization of nitric oxide I synthase in the organ of Corti of the guinea pig

1997

Nitric oxide synthase (NOS) activity has been detected previously in the mammalian cochlea at a light microscopic level. Here we present results of electron microscopic analysis for post-embedding immunoreactivity of neural-type NOS I in the cochlea of the guinea pig. Strong enzyme immunoreactivity was identified in the cytoplasm of inner and outer hair cells. Gold-labeled NOS I antibodies were mainly located in electron-dense areas of the cytoplasm, whereas electron-lucent regions of the receptor cells were nearly free from any immunoreactivity. In both types of hair cells anti-NOS I antibodies were also visible in the cuticular plates, hair bundles and nuclei. Further ultrastructural anal…

A critical role for the cholesterol-associated proteolipids PLP and M6B in myelination of the central nervous system.

2012

The formation of central nervous system myelin by oligodendrocytes requires sterol synthesis and is associated with a significant enrichment of cholesterol in the myelin membrane. However, it is unknown how oligodendrocytes concentrate cholesterol above the level found in nonmyelin membranes. Here, we demonstrate a critical role for proteolipids in cholesterol accumulation. Mice lacking the most abundant myelin protein, proteolipid protein (PLP), are fully myelinated, but PLP-deficient myelin exhibits a reduced cholesterol content. We therefore hypothesized that "high cholesterol" is not essential in the myelin sheath itself but is required for an earlier step of myelin biogenesis that is f…

Music and Emotions in the Brain: Familiarity Matters

2011

The importance of music in our daily life has given rise to an increased number of studies addressing the brain regions involved in its appreciation. Some of these studies controlled only for the familiarity of the stimuli, while others relied on pleasantness ratings, and others still on musical preferences. With a listening test and a functional magnetic resonance imaging (fMRI) experiment, we wished to clarify the role of familiarity in the brain correlates of music appreciation by controlling, in the same study, for both familiarity and musical preferences. First, we conducted a listening test, in which participants rated the familiarity and liking of song excerpts from the pop/rock repe…

Harmonic priming in an amusic patient: the power of implicit tasks.

2008

Our study investigated with an implicit method (i.e., priming paradigm) whether I.R. - a brain-damaged patient exhibiting severe amusia - processes implicitly musical structures. The task consisted in identifying one of two phonemes (Experiment 1) or timbres (Experiment 2) on the last chord of eight-chord sequences (i.e., target). The targets were harmonically related or less related to the prior chords. I.R. displayed harmonic priming effects: Phoneme and timbre identification was faster for related than for less related targets (Experiments 1 and 2). However, I.R.'s explicit judgements of completion for the same sequences did not differ between related and less related contexts (Experimen…

Auditory cortical and hippocampal-system mismatch responses to duration deviants in urethane-anesthetized rats.

2013

Any change in the invariant aspects of the auditory environment is of potential importance. The human brain preattentively or automatically detects such changes. The mismatch negativity (MMN) of event-related potentials (ERPs) reflects this initial stage of auditory change detection. The origin of MMN is held to be cortical. The hippocampus is associated with a later generated P3a of ERPs reflecting involuntarily attention switches towards auditory changes that are high in magnitude. The evidence for this cortico-hippocampal dichotomy is scarce, however. To shed further light on this issue, auditory cortical and hippocampal-system (CA1, dentate gyrus, subiculum) local-field potentials were …

Rapid categorization of sound objects in anesthetized rats as indexed by the electrophysiological mismatch response

2014

It is not known whether animals can, similarly to humans, categorize auditory objects based on an abstract rule in combining their physical features. We recorded local-field potentials from the dura above the primary auditory cortex in urethane-anesthetized rats presented with sound series occasionally violating a rule (e.g., "the higher the frequency, the weaker the intensity"). In a separate control condition, the same frequency and intensity levels were applied in the sound objects, but they obeyed no rule. Responses found selectively to the violations of the rule suggest that an abstract rule was represented in the rat brain, enabling auditory categorization.

How functional coupling between the auditory cortex and the amygdala induces musical emotion: a single case study.

2013

Music is a sound structure of remarkable acoustical and temporal complexity. Although it cannot denote specific meaning, it is one of the most potent and universal stimuli for inducing mood. How the auditory and limbic systems interact, and whether this interaction is lateralized when feeling emotions related to music, remains unclear. We studied the functional correlation between the auditory cortex (AC) and amygdala (AMY) through intracerebral recordings from both hemispheres in a single patient while she listened attentively to musical excerpts, which we compared to passive listening of a sequence of pure tones. While the left primary and secondary auditory cortices (PAC and SAC) showed …

Musical training facilitates the neural discrimination of major versus minor chords in 13-year-old children

2012

Music practice since childhood affects the development of hearing skills. An important classification in Western music is the chords’ major-minor dichotomy. Its preattentive auditory discrimination was studied here using a mismatch negativity (MMN) paradigm in 13-year-olds with active hobbies, music-related (music group) or other (control group). In a context of root major chords, root minor chords and inverted major chords were presented infrequently. The interval structure of inverted majors differs more from root majors than the interval structure of root minors. However, the identity of the chords is the same in inverted and root majors (major), but different in root minors. The deviant…