Low-frequency BOLD fluctuations demonstrate altered thalamocortical connectivity in diabetic neuropathic pain

Background  

In this paper we explored thalamocortical functional connectivity in a group of eight patients suffering from peripheral neuropathic pain (diabetic pain), and compared it with that of a group of healthy subjects. We hypothesized that functional interconnections between the thalamus and cortex can be altered after years of ongoing chronic neuropathic pain.     

The effect of long-term unilateral deafness on the activation pattern in the auditory cortices of French-native speakers: influence of deafness side

Background  

In normal-hearing subjects, monaural stimulation produces a normal pattern of asynchrony and asymmetry over the auditory cortices in favour of the contralateral temporal lobe. While late onset unilateral deafness has been reported to change this pattern, the exact influence of the side of deafness on central auditory plasticity still remains unclear. The present study aimed at assessing whether left-sided and right-sided deafness had differential effects on the characteristics of neurophysiological responses over auditory areas. Eighteen unilaterally deaf and 16 normal hearing right-handed subjects participated. All unilaterally deaf subjects had post-lingual deafness. Long latency auditory evoked potentials (late-AEPs) were elicited by two types of stimuli, non-speech (1 kHz tone-burst) and speech-sounds (voiceless syllable/pa/) delivered to the intact ear at 50 dB SL. The latencies and amplitudes of the early exogenous components (N100 and P150) were measured using temporal scalp electrodes.     

Abnormal auditory mismatch response in tinnitus sufferers with high-frequency hearing loss is associated with subjective distress level

Background  

Tinnitus is an auditory sensation frequently following hearing loss. After cochlear injury, deafferented neurons become sensitive to neighbouring intact edge-frequencies, guiding an enhanced central representation of these frequencies. As psychoacoustical data [1–3] indicate enhanced frequency discrimination ability for edge-frequencies that may be related to a reorganization within the auditory cortex, the aim of the present study was twofold: 1) to search for abnormal auditory mismatch responses in tinnitus sufferers and 2) relate these to subjective indicators of tinnitus.     

Auditory temporal processing in healthy aging: a magnetoencephalographic study

Background  

Impaired speech perception is one of the major sequelae of aging. In addition to peripheral hearing loss, central deficits of auditory processing are supposed to contribute to the deterioration of speech perception in older individuals. To test the hypothesis that auditory temporal processing is compromised in aging, auditory evoked magnetic fields were recorded during stimulation with sequences of 4 rapidly recurring speech sounds in 28 healthy individuals aged 20 – 78 years.     

Transgenic mouse model for the formation of Hirano bodies

Background

The present study compared the neural correlates of an intramodally and a crossmodally acquired second language (L2). Deaf people who had learned their L1, German Sign Language (DGS), and their L2, German, through the visual modality were compared with hearing L2 learners of German and German native speakers. Correct and incorrect German sentences were presented word by word on a computer screen while the electroencephalogram was recorded. At the end of each sentence, the participants judged whether or not the sentence was correct. Two types of violations were realized: Either a semantically implausible noun or a violation of subject-verb number agreement was embedded at a sentence medial position.

Results

Semantic errors elicited an N400, followed by a late positivity in all groups. In native speakers of German, verb-agreement violations were followed by a left lateralized negativity, which has been associated with an automatic parsing process. We observed a syntax related negativity in both high performing hearing and deaf L2 learners as well. Finally, this negativity was followed by a posteriorly distributed positivity in all three groups.

Conclusions

Although deaf learners have learned German as an L2 mainly via the visual modality they seem to engage comparable processing mechanisms as hearing L2 learners. Thus, the data underscore the modality transcendence of language.     

The auditory cortex of the bat <Emphasis Type="Italic">Phyllostomus discolor</Emphasis>: Localization and organization of basic response properties

Background  

The mammalian auditory cortex can be subdivided into various fields characterized by neurophysiological and neuroarchitectural properties and by connections with different nuclei of the thalamus. Besides the primary auditory cortex, echolocating bats have cortical fields for the processing of temporal and spectral features of the echolocation pulses. This paper reports on location, neuroarchitecture and basic functional organization of the auditory cortex of the microchiropteran bat Phyllostomus discolor (family: Phyllostomidae).     

Fingersomatotopy in area 3b: an fMRI-study

Background  

The primary sensory cortex (S1) in the postcentral gyrus is comprised of four areas that each contain a body map, where the representation of the hand is located with the thumb most laterally, anteriorly and inferiorly and the little finger most medially, posteriorly and superiorly. Previous studies on somatotopy using functional MRI have either used low field strength, have included a small number of subjects or failed to attribute activations to any area within S1. In the present study we included twenty subjects, who were investigated at 3 Tesla (T). We focused specifically on Brodmann area 3b, which neurons have discrete receptive fields with a potentially more clearcut somatotopic organisation. The spatial distribution for all fingers' peak activation was determined and group as well as individual analysis was performed.     

Downstream targets of methyl CpG binding protein 2 and their abnormal expression in the frontal cortex of the human Rett syndrome brain

Background  

The Rett Syndrome (RTT) brain displays regional histopathology and volumetric reduction, with frontal cortex showing such abnormalities, whereas the occipital cortex is relatively less affected.     

Fast reproducible identification and large-scale databasing of individual functional cognitive networks

Background  

Although cognitive processes such as reading and calculation are associated with reproducible cerebral networks, inter-individual variability is considerable. Understanding the origins of this variability will require the elaboration of large multimodal databases compiling behavioral, anatomical, genetic and functional neuroimaging data over hundreds of subjects. With this goal in mind, we designed a simple and fast acquisition procedure based on a 5-minute functional magnetic resonance imaging (fMRI) sequence that can be run as easily and as systematically as an anatomical scan, and is therefore used in every subject undergoing fMRI in our laboratory. This protocol captures the cerebral bases of auditory and visual perception, motor actions, reading, language comprehension and mental calculation at an individual level.     

Objective Vocal Quality in Children Using Cochlear Implants: A Multiparameter Approach

Objectives

The purpose of this study was to determine the objective vocal quality in 36 prelingually deaf children using cochlear implant (CI) with a mean age of 9 years. An additional purpose was to compare the objective vocal quality of these 36 CI users with 25 age-matched children with prelingual severe hearing loss using conventional hearing aids (HAs) and 25 normal hearing (NH) children.

Study Design

The design for this cross-sectional study was a multigroup posttest-only design.

Methods

The objective vocal quality was measured by means of the dysphonia severity index (DSI). Moreover, perceptual voice assessment using the GRBASI scale was performed.

Results

CI children have a vocal quality by means of the DSI of +1.8, corresponding with a DSI% of 68%, indicating a borderline vocal quality situated 2% above the limit of normality. The voice was perceptually characterized by the presence of a very slight grade of hoarseness, roughness, strained phonation, and higher pitch and intensity levels. No significant objective vocal quality differences were measured between the voices of the CI children, HA users, and NH children.

Conclusions

According to the results, one aspect of the vocal approach in children with CI and using HAs must be focused on the improvement of the strained vocal characteristic and the use of a lower pitch and intensity level.     

Response of SI cortex to ipsilateral,contralateral and bilateral flutter stimulation in the cat

Background  

While SII cortex is considered to be the first cortical stage of the pathway that integrates tactile information arising from both sides of the body, SI cortex is generally not considered as a region in which neuronal response is modulated by simultaneous stimulation of bilateral (and mirror-image) skin sites.     

ERP evidence for different strategies in the processing of case markers in native speakers and non-native learners

Background  

The present experiments were designed to test how the linguistic feature of case is processed in Japanese by native and non-native listeners. We used a miniature version of Japanese as a model to compare sentence comprehension mechanisms in native speakers and non-native learners who had received training until they had mastered the system. In the first experiment we auditorily presented native Japanese speakers with sentences containing incorrect double nominatives and incorrect double accusatives, and with correct sentences. In the second experiment we tested trained non-natives with the same material. Based on previous research in German we expected an N400-P600 biphasic ERP response with specific modulations depending on the violated case and whether the listeners were native or non-native.     

Aging is associated with increased collagen type IV accumulation in the basal lamina of human cerebral microvessels

Background  

Microvascular alterations contribute to the development of stroke and vascular dementia. The goal of this study was to evaluate age and hypertension related changes of the basal lamina in cerebral microvessels of individuals, who died from non-cerebral causes.     

Genetic analysis of the GRIK2 modifier effect in Huntington's disease

Background  

In Huntington's disease (HD), age at neurological onset is inversely correlated with the length of the CAG trinucleotide repeat mutation, but can be modified by genetic factors beyond the HD gene. Association of a relatively infrequent 16 TAA allele of a trinucleotide repeat polymorphism in the GRIK2 3'UTR with earlier than expected age at neurological onset has been suggested to reflect linkage disequilibrium with a functional polymorphism in GRIK2 or an adjacent gene.     

Functional evaluation of auditory system in patients with cochlear implant using electrically evoked auditory brainstem responses

Aim  

The objective of this study is to evaluate the recovery of hearing function of auditory pathway after cochlear implantation by extracting the characterizations of electrically evoked auditory brainstem responses (EABR). The purpose of this study was to explore a reality and possible EABR test mode in clinical applications, rather than strict animal research.     

Dysfunctional GABAergic inhibition in the prefrontal cortex leading to "psychotic" hyperactivation

Background  

The GABAergic system in the brain seems to be dysfunctional in various psychiatric disorders. Many studies have suggested so far that, in schizophrenia patients, GABAergic inhibition is selectively but consistently reduced in the prefrontal cortex (PFC).     

Speech target modulates speaking induced suppression in auditory cortex

Background  

Previous magnetoencephalography (MEG) studies have demonstrated speaking-induced suppression (SIS) in the auditory cortex during vocalization tasks wherein the M100 response to a subject's own speaking is reduced compared to the response when they hear playback of their speech.     

Electrical neuroimaging evidence that spatial frequency-based selective attention affects V1 activity as early as 40-60 ms in humans

Background  

Karns and Knight (2009) [1] demonstrated by using ERP and gamma band oscillatory responses that intermodal attention modulates visual processing at the latency of the early phase of the C1 response (62-72 ms) thought to be generated in the primary visual cortex. However, the timing of attentional modulation of visual cortex during object-based attention remains a controversial issue.     

Perisylvian white matter connectivity in the human right hemisphere

Background  

By using diffusion tensor magnetic resonance imaging (DTI) and subsequent tractography, a perisylvian language network in the human left hemisphere recently has been identified connecting Brocas's and Wernicke's areas directly (arcuate fasciculus) and indirectly by a pathway through the inferior parietal cortex.     

Hippocampal activity during the transverse patterning task declines with cognitive competence but not with age

Background  

The hippocampus is a brain region that is particularly affected by age-related morphological changes. It is generally assumed that a loss in hippocampal volume results in functional deficits that contribute to age-related cognitive decline. In a combined cross-sectional behavioural and magnetoencephalography (MEG) study we investigated whether hippocampal-associated neural current flow during a transverse patterning task - which requires learning relational associations between stimuli - correlates with age and whether it is modulated by cognitive competence.