scholarly journals Asymmetric, dynamic adaptation in prefrontal cortex during dichotic listening tasks

2019 ◽  
Author(s):  
J. A. N. Fisher ◽  
I. Gumenchuk ◽  
O. Rogovin ◽  
A. G. Yodh ◽  
D. R. Busch
Keyword(s):  
Blood Flow ◽  
Prefrontal Cortex ◽  
Otoacoustic Emissions ◽  
Dichotic Listening ◽  
Right Hemisphere ◽  
Assessment Tool ◽  
Regional Blood Flow ◽  
Speech Comprehension ◽  
Distortion Product ◽  
The Right

AbstractSpeech comprehension relies on highly distributed, dynamically interconnected neuroanatomical loci. Accordingly, performance on complex speech processing tasks such as dichotic listening can be used to assess the integrity and health of many functional and structural aspects of the brain. Despite the potential merits as a clinical assessment tool, however, the neural substrates activated during dichotic listening remain relatively opaque at higher processing levels. Ultimately, this knowledge gap limits diagnostic use of the task. At the level of the prefrontal cortex, dichotic listening induces an asymmetric response wherein regions on the right hemisphere exhibit a higher functional activation than on the left. Superficially, this finding is counterintuitive given the left hemisphere’s dominance for speech and language. To obtain a more in-depth perspective on the potentially distinct roles of the right and left prefrontal cortex, we optically monitored cerebral blood flow in the dorsolateral prefrontal cortex (DLPFC) during dichotic listening tasks in human subjects. The method permitted us to avoid systematic experimental confounds that functional magnetic resonance imaging (fMRI) measurements suffer from, namely the influence of scanner noise. In addition to reproducing the documented larger activation amplitude in the right hemisphere, we also found that repeated listening task blocks were associated with altered kinetics of blood flow in the right, but not the left DLPFC. Interestingly, subjects with the most prominent regional blood flow changes in the right hemisphere also displayed large distortion product otoacoustic emissions (DPOAEs) in the left ear, possibly signaling a correlation between prefrontal activity and top-down listening control infrastructure through medial olivocochlear efferent projections to the inner ear. Overall, our results suggest that the right prefrontal cortical regions play an active role in optimizing task performance.

scholarly journals The role of prefrontal cortex in working memory: examining the contents of consciousness

1998 ◽  
Vol 353 (1377) ◽  
pp. 1819-1828 ◽  
Author(s):  
◽  
S. M. Courtney ◽  
L. Petit ◽  
J. V. Haxby ◽  
L. G. Ungerleider
Keyword(s):  
Working Memory ◽  
Prefrontal Cortex ◽  
Visual Processing ◽  
Right Hemisphere ◽  
Functional Organization ◽  
Spatial Working Memory ◽  
Domain Specificity ◽  
Long Term Memory ◽  
Present Evidence ◽  
The Right

Working memory enables us to hold in our ‘mind's eye’ the contents of our conscious awareness, even in the absence of sensory input, by maintaining an active representation of information for a brief period of time. In this review we consider the functional organization of the prefrontal cortex and its role in this cognitive process. First, we present evidence from brain–imaging studies that prefrontal cortex shows sustained activity during the delay period of visual working memory tasks, indicating that this cortex maintains on–line representations of stimuli after they are removed from view. We then present evidence for domain specificity within frontal cortex based on the type of information, with object working memory mediated by more ventral frontal regions and spatial working memory mediated by more dorsal frontal regions. We also propose that a second dimension for domain specificity within prefrontal cortex might exist for object working memory on the basis of the type of representation, with analytic representations maintained preferentially in the left hemisphere and image–based representations maintained preferentially in the right hemisphere. Furthermore, we discuss the possibility that there are prefrontal areas brought into play during the monitoring and manipulation of information in working memory in addition to those engaged during the maintenance of this information. Finally, we consider the relationship of prefrontal areas important for working memory, both to posterior visual processing areas and to prefrontal areas associated with long–term memory.

scholarly journals Gene expression profiling of the dorsolateral and medial orbitofrontal cortex in schizophrenia

2016 ◽  
Vol 7 (1) ◽  
Author(s):  
Mihovil Mladinov ◽  
Goran Sedmak ◽  
Heidi R. Fuller ◽  
Mirjana Babić Leko ◽  
Davor Mayer ◽  
...  
Keyword(s):  
Gene Expression ◽  
Prefrontal Cortex ◽  
Cognitive Processing ◽  
Orbitofrontal Cortex ◽  
Right Hemisphere ◽  
Transcriptome Profiling ◽  
Differentially Expressed ◽  
Unknown Etiology ◽  
Dorsolateral Prefrontal ◽  
The Right

AbstractSchizophrenia is a complex polygenic disorder of unknown etiology. Over 3,000 candidate genes associated with schizophrenia have been reported, most of which being mentioned only once. Alterations in cognitive processing - working memory, metacognition and mentalization - represent a core feature of schizophrenia, which indicates the involvement of the prefrontal cortex in the pathophysiology of this disorder. Hence we compared the gene expression in postmortem tissue from the left and right dorsolateral prefrontal cortex (DLPFC, Brodmann's area 46), and the medial part of the orbitofrontal cortex (MOFC, Brodmann's area 11/12), in six patients with schizophrenia and six control brains. Although in the past decade several studies performed transcriptome profiling in schizophrenia, this is the first study to investigate both hemispheres, providing new knowledge about possible brain asymmetry at the level of gene expression and its relation to schizophrenia. We found that in the left hemisphere, twelve genes from the DLPFC and eight genes from the MOFC were differentially expressed in patients with schizophrenia compared to controls. In the right hemisphere there was only one gene differentially expressed in the MOFC. We reproduce the involvement of previously reported genes TARDBP and HNRNPC in the pathogenesis of schizophrenia, and report seven novel genes:

scholarly journals Steep head-down tilt has persisting effects on the distribution of pulmonary blood flow

2006 ◽  
Vol 101 (2) ◽  
pp. 583-589 ◽  
Author(s):  
A. Cortney Henderson ◽  
David L. Levin ◽  
Susan R. Hopkins ◽  
I. Mark Olfert ◽  
Richard B. Buxton ◽  
...  
Keyword(s):  
Blood Flow ◽  
Pulmonary Blood Flow ◽  
Regional Blood Flow ◽  
Flow Distribution ◽  
Normal Subjects ◽  
Relative Dispersion ◽  
Lung Water ◽  
Before And After ◽  
Capillary Pressures ◽  
The Right

Head-down tilt has been shown to increase lung water content in animals and alter the distribution of ventilation in humans; however, its effects on the distribution of pulmonary blood flow in humans are unknown. We hypothesized that head-down tilt would increase the heterogeneity of pulmonary blood flow in humans, an effect analogous to the changes seen in the distribution of ventilation, by increasing capillary hydrostatic pressure and fluid efflux in the lung. To test this, we evaluated changes in the distribution of pulmonary blood flow in seven normal subjects before and after 1 h of 30° head-down tilt using the magnetic resonance imaging technique of arterial spin labeling. Data were acquired in triplicate before tilt and at 10-min intervals for 1 h after tilt. Pulmonary blood flow heterogeneity was quantified by the relative dispersion (standard deviation/mean) of signal intensity for all voxels within the right lung. Relative dispersion was significantly increased by 29% after tilt and remained elevated during the 1 h of measurements after tilt (0.84 ± 0.06 pretilt, 1.09 ± 0.09 calculated for all time points posttilt, P < 0.05). We speculate that the mechanism most likely responsible for our findings is that increased pulmonary capillary pressures and fluid efflux in the lung resulting from head-down tilt alters regional blood flow distribution.

scholarly journals Morphology of Pyramidal Neurons in the Rat Prefrontal Cortex: Lateralized Dendritic Remodeling by Chronic Stress

2007 ◽  
Vol 2007 ◽  
pp. 1-14 ◽  
Author(s):  
Claudia Perez-Cruz ◽  
Jeanine I. H. Müller-Keuker ◽  
Urs Heilbronner ◽  
Eberhard Fuchs ◽  
Gabriele Flügge
Keyword(s):  
Prefrontal Cortex ◽  
Pyramidal Neurons ◽  
Right Hemisphere ◽  
Anterior Cingulate ◽  
Chronic Restraint Stress ◽  
Hemispheric Difference ◽  
Infralimbic Cortex ◽  
Dendritic Length ◽  
The Right ◽  
Apical Dendrites

The prefrontal cortex (PFC) plays an important role in the stress response. We filled pyramidal neurons in PFC layer III with neurobiotin and analyzed dendrites in rats submitted to chronic restraint stress and in controls. In the right prelimbic cortex (PL) of controls, apical and distal dendrites were longer than in the left PL. Stress reduced the total length of apical dendrites in right PL and abolished the hemispheric difference. In right infralimbic cortex (IL) of controls, proximal apical dendrites were longer than in left IL, and stress eliminated this hemispheric difference. No hemispheric difference was detected in anterior cingulate cortex (ACx) of controls, but stress reduced apical dendritic length in left ACx. These data demonstrate interhemispheric differences in the morphology of pyramidal neurons in PL and IL of control rats and selective effects of stress on the right hemisphere. In contrast, stress reduced dendritic length in the left ACx.

scholarly journals Effect of Astrocytic Energy Metabolism Depressant on 14C-Acetate Uptake in Intact Rat Brain

2004 ◽  
Vol 24 (2) ◽  
pp. 188-190 ◽  
Author(s):  
Rie Hosoi ◽  
Maki Okada ◽  
Jun Hatazawa ◽  
Antony Gee ◽  
Osamu Inoue
Keyword(s):  
Blood Flow ◽  
Energy Metabolism ◽  
Rat Brain ◽  
Regional Blood Flow ◽  
Regional Distribution ◽  
Acetate Uptake ◽  
Minute Period ◽  
Intact Brain ◽  
The Right

Fluorocitrate, a selective astrocytic toxin, was microinjected into the right striatum of rat brain, and the regional distribution of 14C-acetate was measured using autoradiography. A significant reduction (more than 80%) in 14C-acetate uptake over a 5-minute period was observed in the right striatum, compared with that in the left striatum (saline infused), 4 hours after fluorocitrate (1 nmol/μL) infusion. This effect was transient, and 14C-acetate uptake had almost returned to normal at 24 hours after the fluorocitrate infusion. In contrast, the regional blood flow in the striatum, as determined using 14C-iodoamphetamine, was significantly increased by the fluorocitrate infusion. The present observations indicate that 14C-acetate uptake might be a useful characteristic for examining astrocytic energy metabolism in the intact brain.

scholarly journals Optical Mapping of Brain Activity Underlying Directionality and Its Modulation by Expertise in Mandarin/English Interpreting

2021 ◽  
Vol 15 ◽  
Author(s):  
Yan He ◽  
Yinying Hu ◽  
Yaxi Yang ◽  
Defeng Li ◽  
Yi Hu
Keyword(s):  
Prefrontal Cortex ◽  
Cognitive Skills ◽  
Near Infrared ◽  
Right Hemisphere ◽  
Brain Activity ◽  
Brain Regions ◽  
Broca’S Area ◽  
Broca's Area ◽  
Functional Near Infrared Spectroscopy ◽  
The Right

Recent neuroimaging research has suggested that unequal cognitive efforts exist between interpreting from language 1 (L1) to language 2 (L2) compared with interpreting from L2 to L1. However, the neural substrates that underlie this directionality effect are not yet well understood. Whether directionality is modulated by interpreting expertise also remains unknown. In this study, we recruited two groups of Mandarin (L1)/English (L2) bilingual speakers with varying levels of interpreting expertise and asked them to perform interpreting and reading tasks. Functional near-infrared spectroscopy (fNIRS) was used to collect cortical brain data for participants during each task, using 68 channels that covered the prefrontal cortex and the bilateral perisylvian regions. The interpreting-related neuroimaging data was normalized by using both L1 and L2 reading tasks, to control the function of reading and vocalization respectively. Our findings revealed the directionality effect in both groups, with forward interpreting (from L1 to L2) produced more pronounced brain activity, when normalized for reading. We also found that directionality was modulated by interpreting expertise in both normalizations. For the group with relatively high expertise, the activated brain regions included the right Broca’s area and the left premotor and supplementary motor cortex; whereas for the group with relatively low expertise, the activated brain areas covered the superior temporal gyrus, the dorsolateral prefrontal cortex (DLPFC), the Broca’s area, and visual area 3 in the right hemisphere. These findings indicated that interpreting expertise modulated brain activation, possibly because of more developed cognitive skills associated with executive functions in experienced interpreters.

scholarly journals Effectiveness of transcranial magnetic stimulation of the prefrontal cortex for the correction of autonomic disorders in miners with polyneuropathy

2021 ◽  
Vol 100 (7) ◽  
pp. 679-682
Author(s):  
Margarita O. Gidayatova ◽  
Ilya D. Martynov ◽  
Anastasia V. Yamshchikova ◽  
Arnold N. Fleishman
Keyword(s):  
Heart Rate ◽  
Prefrontal Cortex ◽  
Transcranial Magnetic Stimulation ◽  
Magnetic Stimulation ◽  
Right Hemisphere ◽  
Spectral Indices ◽  
Adaptive Capabilities ◽  
Autonomic Disorders ◽  
The Right ◽  
Stimulation Of

Introduction. Polyneuropathy is the most common occupational neurological pathology. Violation of the activity of the central links of autonomic regulation due to excessive afferent impulses from the receptors of the skin and other tissues of the extremities leads to sympathetic activation and angiospasm, the progression of polyneuropathy. A decrease in the parasympathetic influence is the cause of systemic trophic disturbances. The possibility of transcranial magnetic stimulation of the prefrontal cortex opens up new therapeutic opportunities to correct the autonomic disorders in occupationally caused polyneuropathy. The aim of the study was to evaluate the effect of transcranial magnetic stimulation of the dorsolateral zone in the prefrontal cortex of the right hemisphere for the correction of neuroautonomic disorders in miners with polyneuropathy. Material and methods. Forty-two miners of the Kuzbass coal mines with a proven diagnosis of upper extremity polyneuropathy were examined. To identify autonomic dysregulation, the “Questionnaire for revealing the signs of autonomic changes”, spectral and nonlinear indices of cardio rhythm were used. Low-frequency (1 Hz) transcranial magnetic stimulation of the dorsolateral zone of the prefrontal cortex of the right hemisphere was performed in the course of 5 procedures according to a specially elaborated methodology. Results. In the examined miners, a decrease in the nonlinear and spectral indices of heart rate variability was initially determined, which indicated reducing adaptive capabilities, an increase in sympathetic influence. After the magnetic stimulation course, there was an improvement in general well-being and normalization of autonomous regulation according to the questionnaire. An increase in the spectral indices of the heart rate variability, more pronounced in the range of very low frequencies, indicated the activation of suprasegmental autonomic centers and an increase in parasympathetic influence. Conclusions. Transcranial magnetic stimulation of the prefrontal cortex effectively corrects autonomic disorders in miners with polyneuropathy and promotes an increase in adaptive capabilities due to the activation of suprasegmental autonomic centres.

Systemic Absorption of Gentamicin Nasal Irrigations

2006 ◽  
Vol 20 (3) ◽  
pp. 251-254 ◽  
Author(s):  
W. Stites Whatley ◽  
Rakesh K. Chandra ◽  
C. Bruce MacDonald
Keyword(s):  
Otoacoustic Emissions ◽  
Pure Tone Audiometry ◽  
Sinus Surgery ◽  
Systemic Absorption ◽  
Normal Range ◽  
Nasal Irrigation ◽  
Distortion Product ◽  
Patient Reported ◽  
Before And After ◽  
The Right

Objective To determine if gentamicin nasal irrigation is systemically absorbed, and to identify any ototoxic side effects related to its use. Design Retrospective review of 12 patients treated with gentamicin nasal irrigations (30 cc of 80 mg/L solution used bilaterally twice daily). Methods Serum gentamicin levels were assayed after the course treatment. Pure tone audiometry (250–8000 Hz) and distortion product otoacoustic emissions (DP-OAEs) at 7280, 5133, 3640 and 2560 Hz were obtained before and after therapy. Results Twelve patients (age 4 to 74, mean 43) with chronic rhinosinusitis were treated for 3–15 weeks (mean 7 weeks). All patients had undergone previous endoscopic sinus surgery. Ten patients had pretreatment cultures that grew organisms sensitive to gentamicin (Pseudomonas, Proteus, or methacillin resistant Staphylococcus aureus), and three patients had cystic fibrosis. Ten of 12 patients (83%) had detectable posttreatment levels of gentamicin, with a mean serum level of 0.42 mcg/mL (range 0.3 to 0.7 mcg/mL). Four of 12 patients (33%) had serum gentamicin levels within the normal range for gentamicin trough (0.5 to 2 mcg/mL). Comparison of pre- and posttreatment audiologic data revealed no significant change in PTA or DP-OAE, except for the right ear at 8000 Hz on PTA (p = 0.035) where a mean of 7 dB loss was observed. No patient reported hearing loss or vertigo during treatment. Conclusion Gentamicin nasal irrigation may be systemically absorbed. Although the otologic consequences of this finding are questionable, patients receiving gentamicin nasal irrigations should be counseled regarding this hypothetical possibility.

Handedness and Dichotic Listening to Nonverbal Features of Speech

1978 ◽  
Vol 47 (3_suppl) ◽  
pp. 1111-1114 ◽  
Author(s):  
Israel Nachshon
Keyword(s):  
Dichotic Listening ◽  
Right Hemisphere ◽  
Pure Tones ◽  
The Right

The assumption that pitch and loudness are processed in the right hemisphere was tested by comparing left-handers' with right-handers' performance on pitch and loudness discrimination tasks. Four groups of left-handers (20 subjects in each group) were dichotically presented either with digits varying in pitch or loudness or with pure tones varying in pitch. The subjects identified the digits, or the pitch and loudness variations, from both ears. Confirming the assumption, the data showed that the left-handers, who had no ear preference on any of these tasks, differed significantly from the right-handers, who, preferring the right ear for digit identification, preferred the left ear for the discrimination of the nonverbal features (pitch and loudness) of these digits.

Sign in / Sign up

Export Citation Format

Share Document