Effects of Long Term Unilateral Hearing Loss on the Lateralization of fMRI Measured Activation in Human Auditory Cortex

Moore, David R.; Devlin, Joseph T.; Raley, Josephine M.; Tunbridge, Elizabeth; Lanary, Katherine; Floyer-Lea, Anna; Narain, Charvy; Cohen, Ian S.; Jezzard, Peter; Burton, Martin J; Matthews, Paul M.

doi:10.1007/0-387-23181-1_34

Cited by 6 publications

(5 citation statements)

References 26 publications

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“…The surprising finding that the ipsilateral AC to noise exposure showed a more dramatic change could be explained by functional asymmetry between two hemispheres of the auditory cortex. In human being, left AC prevails in processing sound information [ 34 , 35 ], and in the left ear noise-exposed gerbil [ 36 ], the primary AC of the left side was more activated than that of the right side. Similarly, if the activity of the left AC is higher than that of the right AC in our experimental rats, the compensatory mechanism would enable more PV activity in the left AC.…”

Section: Discussionmentioning

confidence: 99%

Acoustic Trauma Changes the Parvalbumin-Positive Neurons in Rat Auditory Cortex

Liu

et al. 2018

Neural Plasticity

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Acoustic trauma is being reported to damage the auditory periphery and central system, and the compromised cortical inhibition is involved in auditory disorders, such as hyperacusis and tinnitus. Parvalbumin-containing neurons (PV neurons), a subset of GABAergic neurons, greatly shape and synchronize neural network activities. However, the change of PV neurons following acoustic trauma remains to be elucidated. The present study investigated how auditory cortical PV neurons change following unilateral 1 hour noise exposure (left ear, one octave band noise centered at 16 kHz, 116 dB SPL). Noise exposure elevated the auditory brainstem response threshold of the exposed ear when examined 7 days later. More detectable PV neurons were observed in both sides of the auditory cortex of noise-exposed rats when compared to control. The detectable PV neurons of the left auditory cortex (ipsilateral to the exposed ear) to noise exposure outnumbered those of the right auditory cortex (contralateral to the exposed ear). Quantification of Western blotted bands revealed higher expression level of PV protein in the left cortex. These findings of more active PV neurons in noise-exposed rats suggested that a compensatory mechanism might be initiated to maintain a stable state of the brain.

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Section: Discussionmentioning

confidence: 99%

Acoustic Trauma Changes the Parvalbumin-Positive Neurons in Rat Auditory Cortex

Liu

et al. 2018

Neural Plasticity

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“…The clear finding of asymmetric strengthening of the contralateral pathways from the stimulated ear might be explained by increased excitability of auditory neurons from this side. Early unilateral auditory deprivation leads to a loss of cochlear nucleus neurons and reduced synaptic inhibition in pathways from the affected side [Blumenthal et al, ; Byrne and Byrne, ; Hashisaki and Rubel, ; Sanes and Kotak, ; Takesian et al, ], and enhanced excitatory glutamatergic conductance from the superior olive [Kotak and Sanes, ], to the inferior colliculus [Blumenthal et al, ; Byrne and Byrne, ; Kitzes, ; Lang et al, ; Popescu and Polley, ; Takesian et al, ] and primary auditory cortex of the stimulated pathways [Kotak et al, ; Kral et al, ; Moore et al, ; Popescu and Polley, ]. Importantly, effects are found only when the loss is present in early life [Blumenthal et al, ; Moore and Kowalchuk, ; Nordeen et al, ; Reale et al, ] and when it is unilateral [Moore, ].…”

Section: Discussionmentioning

confidence: 99%

Early unilateral cochlear implantation promotes mature cortical asymmetries in adolescents who are deaf

2015

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Unilateral cochlear implant (CI) stimulation establishes hearing to children who are deaf but compromises bilateral auditory development if a second implant is not provided within ∼ 1.5 years. In this study we asked: 1) What are the cortical consequences of missing this early sensitive period once children reach adolescence? 2) What are the effects of unilateral deprivation on the pathways from the opposite ear? Cortical responses were recorded from 64-cephalic electrodes within the first week of bilateral CI activation in 34 adolescents who had over 10 years of unilateral right CI experience and in 16 normal hearing peers. Cortical activation underlying the evoked peaks was localized to areas of the brain using beamformer imaging. The first CI evoked activity which was more strongly lateralized to the contralateral left hemisphere than normal, with abnormal recruitment of the left prefrontal cortex (involved in cognition/attention), left temporo-parietal-occipital junction (multi-modal integration), and right precuneus (visual processing) region. CI stimulation in the opposite deprived ear evoked atypical cortical responses with abnormally large and widespread dipole activity across the cortex. Thus, using a unilateral CI to hear beyond the period of cortical maturation causes lasting asymmetries in the auditory system, requires recruitment of additional cortical areas to support hearing, and does little to protect the unstimulated pathways from effects of auditory deprivation. The persistence of this reorganization into maturity could signal a closing of a sensitive period for promoting auditory development on the deprived side.

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“…For instance, the left primary auditory cortex (PAC) was found to be significantly more dominant than the right PAC in long-term unilateral hearing loss. 30 The link between hearing acuity and hemispheric lateralisation requires further investigation in future studies.…”

Section: Discussionmentioning

confidence: 98%

White-matter integrity and hearing acuity decline in healthy subjects: Magnetic resonance tractography

Alhazmi

2020

Neuroradiol J

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Aim The association between hearing acuity and white-matter (WM) microstructure integrity was evaluated in a normal healthy population with a variety of hearing acuity using an automated tractography technique known as TRACULA (TRActs Constrained by UnderLying Anatomy) in order to investigate whether hearing acuity decline is correlated with brain structural connectivity. Methods Forty healthy controls were recruited to this study, which used a Siemens 3T Trio with a standard eight-channel head coil. Hearing acuity was assessed using pure-tone air conduction audiometry (Amplivox 2160, with Audiocups to eliminate noise and allow accurate pure-tone audiometry). Handedness and anxiety and depression were assessed for all participants in this study using the Edinburgh Handedness Inventory and the Hospital Anxiety and Depression Scale, respectively. Results This study showed a significant reduction in WM volume of the left cingulum angular bundle (CAB; t = 2.32, p = 0.02) in the mild to moderate hearing-loss group (238 ± 223 mm2) compared to the group with normal hearing (105 ± 121 mm2). The WM integrity of the left CAB was found to be significantly different ( t = 2.06, p = 0.04) in the mild to moderate hearing-loss group (0.18 ± 0.06 mm2/s) compared to the group with normal hearing (0.22 ± 0.05 mm2/s). The WM integrity of the left anterior thalamic radiation (ATR) was found to be significantly different ( t = 2.58, p = 0.014) in the mild to moderate hearing-loss group (0.33 ± 0.05 mm2/s) compared to the group with normal hearing (0.37 ± 0.03 mm2/s). A significant negative correlation was found between age and the WM integrity of the right ATR ( r = −0.33, p = 0.038), and between hearing acuity and the WM integrity of the right ATR ( r = −0.38, p = 0.013) and left CAB ( r = −0.36, p = 0.019). Discussion and conclusion: An important finding in this study is that brain structural connectivity changes in the left hemisphere seem to be associated with age-related hearing loss found mainly in the ATR and CAB tracts.

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Effects of Long Term Unilateral Hearing Loss on the Lateralization of fMRI Measured Activation in Human Auditory Cortex

Cited by 6 publications

References 26 publications

Acoustic Trauma Changes the Parvalbumin-Positive Neurons in Rat Auditory Cortex

Acoustic Trauma Changes the Parvalbumin-Positive Neurons in Rat Auditory Cortex

Early unilateral cochlear implantation promotes mature cortical asymmetries in adolescents who are deaf

White-matter integrity and hearing acuity decline in healthy subjects: Magnetic resonance tractography

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