ABSTRACT
Bone-conducted auditory brainstem responses (ABRs) elicited by monoaural stimulation are very useful for evaluating hearing in children with congenital atresia of both ears. In a previous study of sound lateralization in children with congenital atresia of both ears, using bilateral bone-conducted stimuli, we found that most of the children could sufficiently retain binaural hearing ability in terms of both intensity and time differences. In this study we attempted to record bilateral bone-conducted ABRs in normal subjects in order to explore binaural interaction objectively. The study revealed that binaural interaction exists in bone-conducted ABRs. This can be taken as neurophysiological evidence that sound lateralization can be detected by children with bilateral microtia and atresia.
Subject(s)
Bone Conduction/physiology , Evoked Potentials, Auditory, Brain Stem/physiology , Adult , Ear Diseases/congenital , Ear Diseases/diagnosis , Female , Humans , Male , Mastoid/physiology , Perceptual Masking/physiology , Sound Localization/physiologyABSTRACT
Application of regioselective nucleophilic substitution reactions of 1-hydroxytryptamines to novel and simple syntheses of serotonin (1a), N-methylserotonin (1b), bufotenine (1c), 5-methoxy-N-methyltryptamine (2a), bufobutanoic acid (3a), N-(indol-3-yl)methyl-5-methoxy-N-methyltryptamine (4), and lespedamine (5) are described. Effective syntheses of 5-benzyloxytryptamine and 1-methoxy-2-oxindoles are also reported.
Subject(s)
Alkaloids/chemical synthesis , Indoles/chemistry , Serotonin/chemical synthesis , Tryptamines/chemistry , Alkaloids/chemistry , Molecular Structure , Serotonin/analogs & derivatives , Serotonin/chemistry , Spectrum AnalysisABSTRACT
We measured human evoked magnetic fields to binaural sounds with an interaural time delay as a cue for auditory localization. By analyzing the topography of auditory-evoked magnetic fields in the middle-latency, we demonstrated that particular cortical regions represent the direction of sound localization by their activity level. Upon presenting a binaural sound, the first representations were found in the middle frontal region as well as the superior temporal region of the right hemisphere approximately 19 ms after the stimulation, but their patterns differed. Other cortical regions including the prefrontal and parietal spatial areas were affected within roughly 60 ms. The results showed that the right hemisphere is dominant even in the preattentive stage of auditory spatial processing of sounds from different directions.
Subject(s)
Cerebral Cortex/physiology , Reaction Time/physiology , Sound Localization/physiology , Acoustic Stimulation , Adult , Attention/physiology , Brain Mapping , Dominance, Cerebral/physiology , Electroencephalography , Evoked Potentials, Auditory/physiology , Female , Frontal Lobe/physiology , Humans , Male , Middle Aged , Parietal Lobe/physiology , Prefrontal Cortex/physiology , Temporal Lobe/physiologyABSTRACT
An auditory test battery consisting of pure tone audiometry, the auditory brainstem response (ABR), the nonsense monosyllable perception test, the dichotic listening test and the Token test were administered to three patients with palatal myoclonus. All patients had ABR abnormalities correlated with the location of brainstem lesions, despite relatively normal pure-tone threshold. In two of the three patients, both the nonsense monosyllable test and the dichotic listening test revealed dominance on the side ipsilateral to the lesion, while ABR abnormalities were present on the contralateral side. In one patient who had bilateral ABR abnormalities, both the monosyllable perception and dichotic listening test scores were poor for bilateral ears. These results suggest that brainstem lesions producing palatal myoclonus could have an effect on auditory perception.
