Papers by Marisa Pedemonte
Archives italiennes de biologie, 1995
Intracellular recordings of identified inferior colliculus (ICc) auditory neurons, were analyzed ... more Intracellular recordings of identified inferior colliculus (ICc) auditory neurons, were analyzed in in vivo awake, chronically implanted guinea-pigs. The passive membrane characteristics as well as the spontaneous and click evoked synaptic potentials and spike activity, were studied. The injection of current pulses revealed little, if any, adaptation and membrane voltage shifts that outlasted the electrical stimuli. The spontaneous action potentials, observed in all the units studied, were of the short-duration type. During wakefulness, spontaneous synaptic potentials of higher amplitude were observed in comparison to the anesthetized preparation as well as an enhanced firing rate. The click evoked synaptic potentials far outlasted the sound (click, 0.1 ms) duration. The binaural, contralateral and ipsilateral sound stimulation evoked different sequences of synaptic potentials and firing. This was mostly in agreement with studies of extracellular recordings from the ICc, in anesthet...
Sleep and Biological Rhythms, 2005
Synopsis of Sleep Medicine, 2016
The present review analyzes sensory processing during sleep and wakefulness from a single neurona... more The present review analyzes sensory processing during sleep and wakefulness from a single neuronal viewpoint. Our premises are that processing changes throughout the sleep– wakefulness cycle may be at least partially evidenced in single neurons by (a) changes in the discharge rate and firing pattern of the response to sound, (b) changes in the phase locking of the response to the hippocampal theta rhythm, and (c) changes in the effects of the neurotransmitters involved in the afferent and efferent pathways. 1. The concept that the neural network organization during sleep versus wakefulness is different and can be modulated by sensory signals and vice versa, and that the sensory input may be influenced by the CNS state, i.e., asleep or awake, is introduced. During sleep the evoked firing of auditory units increases, decreases, or remains similar to that
Journal of Clinical Sleep Medicine
Advances in Cognitive Neurodynamics (VII)
The Auditory System in Sleep
Loquens
It is known that auditory information is continuously processed both during wakefulness and sleep... more It is known that auditory information is continuously processed both during wakefulness and sleep. Consistently, it has been shown that sound stimulation mimicking tinnitus during sleep decreases the intensity of tinnitus and improves the patients’ quality of life. The mechanisms underlying this effect are not known. To begin to address this question, eleven patients suffering from tinnitus were stimulated with sound mimicking tinnitus at different sleep stages; 4 were stimulated in N2, 4 in stage N3 (slow waves sleep) and 3 in REM sleep (stage with Rapid Eyes Movements). Patients’ sleep stage was monitored through polysomnography, for sound stimulation application. Tinnitus level reported by subjects were compared the days before and after stimulation and statistically analyzed (paired Student t test). All patients stimulated at stage N2 reported significantly lower tinnitus intensity the day after stimulation, while none stimulated during stage N3 and only one out of three stimula...
Hearing Research, Jun 30, 2002
The contribution of N-methyl-D-aspartate to the response to sound of guinea pig inferior collicul... more The contribution of N-methyl-D-aspartate to the response to sound of guinea pig inferior colliculus neurons was analyzed by recording single-unit activity before and after iontophoretic injection of a receptor specific antagonist, 2-amino-5-phosphonovaleric acid (AP5), during the sleep^waking cycle. The AP5 produced a significant firing decrease in most of the units recorded, while some neurons exhibited a particular decrease in the later part of the response. A latency reduction in one out of three units in paradoxical sleep was observed. A low proportion of them exhibited a significant firing increase. These actions were observed in wakefulness (W) as well as during sleep phases. We compared the action of kynurenic acid (Kyn) and the electrical stimulation of the auditory cortex on the same inferior colliculus neuron in anesthetized animals and during W. Both Kyn iontophoresis and cortical stimulation evoked similar changes, decreased firing rate in most inferior colliculus units, whereas a low proportion of them increased their discharge, in anesthetized guinea pigs and in W. Ascending as well as descending^efferent^glutamatergic fibers impinging on inferior colliculus neurons contribute to sound-evoked responses. The enhanced unitary activity observed in some neurons with after glutamatergic receptor blocking may indicate that polysynaptic pathways involving inhibitory neurons decreased their activity. These effects were observed in anesthetized and in behaving animals.
Revista De Neurologia, 2005
The sensory information that the central nervous system receives represents an enormous amount of... more The sensory information that the central nervous system receives represents an enormous amount of data coming from the outer world and from the body itself. This constitutes a set of influences that affects the general brain developing as well as on the sleep-waking organization. We have proposed changes in the auditory information processing throughout the sleep-wakefulness cycle may be at least partially evidenced by single neurons extracellular recordings. We introduce the concept that the neural network organization during sleep vs that of wakefulness is different and can be modulated by sensory signals, and vice versa, the sensory input may be influenced by the central nervous system asleep or awake. During sleep the evoked firing of auditory units increases, decreases or remains similar to that observed during quiet wakefulness. There has been no auditory unit yet that stopped firing as the guinea pig enters sleep. Approximately half of the cortical neurons studied did not change firing rate when passing into sleep while others increased or decreased. Thus, the system is continuously aware of the environment. We postulate that those neurons that changed their evoked firing during sleep, increasing or decreasing, are part of active sleep processes. Thus, the continuous sensory information input to the brain during sleep may serve to 'sculpt', modulate, the brain by activity-dependent mechanisms of neural development as has been postulated for wakefulness.
ABSTRACT The main concepts presented in this review are that sleep is not a function but a state ... more ABSTRACT The main concepts presented in this review are that sleep is not a function but a state diverse from the waking one. A lot of phy-siologic functions are carried out during sleep, cardiovascular, res-piratory, endocrine, sensory, etc., although in a different way. This state occurs because there is a shifts in all/some cell assemblies -neuronal networks passing from a waking mode into a sleeping mode, perhaps organized by some unknown hub neurons. Since Bremer (1935) postulated a passive sleep theory i.e., the lack of sensory input would be the sleep cause, many active processes have being described. Moreover, since the nineteen sixties, several sensory approaches began to emphasize the role of the sensory input re-garding sleep. We are proposing that at least a percentage of sleep generation is due to shifts in the sensory input to the brain deter-mining changes in the cell assemblies-neuronal networks shift into a different mode the sleeping one. Many experimental data, from unitary recordings to every sensory system evoked potentials in hu-man and animals as well as more recent magnetic evoked responses and brain imaging, support the notion of a sensory participation on sleep. The auditory, olfactory, vestibular and somesthetic system, developed introducing more sensory data which progressively sha-ped a brain that began to reach its completion, leading to a dynamic end: the genetically established sleep-waking cycle features. A pro-portion of "passive" effects must be associated with active func-tions for entering and maintaining normal sleep. Sleep generation, maintenance and every related event, are part of central processes that involve the whole brain.
Achyrocline satureioides and sleep quality Achyrocline satureioides (LAM) D.C. would improve slee... more Achyrocline satureioides and sleep quality Achyrocline satureioides (LAM) D.C. would improve sleep quality in patients with Obstructive Sleep Apnea Syndrome: a pilot study ORIGINAL ARTICLE Achyroclinesatureioides (LAM) D.C. pode melhorar a qualidade do sono em pacientes com apneia obstrutiva do sono: um estudo piloto
International Journal of Bifurcation and Chaos, Feb 1, 2010
Auditory system neuronal networks may change on passing from wakefulness to sleep stages, therefo... more Auditory system neuronal networks may change on passing from wakefulness to sleep stages, therefore, the sleeping brain can process information in a different fashion that includes networks shifts. The auditory unit phase/locking to hippocampus theta rhythm and the firing shifts on passing to the sleep stages, are the processing representative examples shown. Although still receptive to sensory incoming data, new sets of neuronal networks are reorganized on passing from wakefulness to a different functional state, i.e. sleep.
Sleep Science, 2014
Based on the knowledge that sensory processing continues during sleep and that a relationship exi... more Based on the knowledge that sensory processing continues during sleep and that a relationship exists between sleep and learning, a new strategy for treatment of idiopathic subjective tinnitus, consisted of customized sound stimulation presented during sleep, was tested. It has been previously shown that this treatment induces a sustained decrease in tinnitus intensity; however, its effect on brain activity has not yet been studied. In this work, we compared the impact of sound stimulation in tinnitus patients in the different sleep stages. Ten patients with idiopathic tinnitus were treated with sound stimulation mimicking tinnitus during sleep. Power spectra and intra-and inter-hemispheric coherence of electroencephalographic waves from frontal and temporal electrodes were measured with and without sound stimulation for each sleep stage (stages N2 with sleep spindles; N3 with slow wave sleep and REM sleep with Rapid Eye Movements). The main results found were that the largest number of changes, considering both the power spectrum and wave's coherence, occurred in stages N2 and N3. The delta and theta bands were the most changed, with important changes also in coherence of spindles during N2. All changes were more frequent in temporal areas. The differences between the two hemispheres do not depend, at least exclusively, on the side where the tinnitus is perceived and, hence, of the stimulated side. These results demonstrate that sound stimulation during sleep in tinnitus patients' influences brain activity and open an avenue for investigating the mechanism underlying tinnitus and its treatment.
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Papers by Marisa Pedemonte