Electrophysiological evidence for interhemispheric transmission of visual information in man.

Berardi, Nicoletta; Bódis-Wollner, Iván; Fiorentini, Adriana; Giuffrè, Giuseppe; Morelli, Maria Sole

doi:10.1113/jphysiol.1989.sp017569

Cited by 17 publications

(11 citation statements)

References 28 publications

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“…A recent psychophysical investigation in humans (Berardi and Fiorentini, 1987), combined with VEP recordings (Berardi et al, 1989), suggests that in humans the interhemispheric transfer also takes place only for stimuli of high contrast and low spatial frequency, a result consistent with the properties of callosal transfer reported in ASCC.…”

Section: Discussionsupporting

confidence: 67%

Neonatal Section of the Optic Chiasm Changes the Interhemispheric Transfer of Visual Information in Cats

Bisti

Biral

Trimarchi

1990

Eur J of Neuroscience

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Recent studies in adult split-chiasm cats show that the contrast gain of the visual callosal pathway is considerably lower than the gain of the direct geniculocortical system and that high spatial and temporal frequencies are strongly attenuated in the process of callosal transfer. We recorded visual evoked potentials (VEPs) and single unit activities from visual cortical areas 17 and 18 in cats which had the optic chiasm sectioned at 3 weeks of age. Our results show that, unlike the animals sectioned as adults, the contrast gain and the spatial and temporal acuities of the callosal pathway of young split-chiasm cats were as good as the direct retinogeniculocortical pathway. Thus, under the present experimental conditions all the spatial and temporal information processed in areas 17 and 18 of one hemicortex is transferred to the other hemicortex via the callosal connections. These animals have also been tested behaviourally for the interocular (interhemispheric) transfer of learning of patterns of high spatial frequency and low contrast. In agreement with the electrophysiological results, we find a complete interocular transfer for this behavioural task. We conclude that the functional development of the interhemispheric connections can be modified by an early section of the optic chiasm and therefore the loss in binocular convergence can be partially compensated.

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Section: Discussionsupporting

confidence: 67%

Neonatal Section of the Optic Chiasm Changes the Interhemispheric Transfer of Visual Information in Cats

Bisti

Biral

Trimarchi

1990

Eur J of Neuroscience

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“…In particular, the interhemispheric transfer of learning in the visual discrimination task occurred only for gratings with the fundamental SF not higher than 2 cpd (Berardi and Fiorentini 1987). These interactions were accompanied by the VEP changes that disappeared at SF beyond 4 cpd (Berardi et al 1989).…”

Section: Interhemispheric Synchronization At Various Spatial Frequenciesmentioning

confidence: 88%

Interhemispheric Integration at Different Spatial Scales: The Evidence From EEG Coherence and fMRI

Knyazeva

Fornari²,

Meuli³

et al. 2006

Journal of Neurophysiology

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The early visual system processes different spatial frequencies (SFs) separately. To examine where in the brain the scale-specific information is integrated, we mapped the neural assemblies engaged in interhemispheric coupling with electroencephalographic (EEG) coherence and blood-oxygen-level dependent (BOLD) signal. During similar EEG and functional magnetic resonance imaging (fMRI) experiments, our subjects viewed centrally presented bilateral gratings of different SF (0.25-8.0 cpd), which either obeyed Gestalt grouping rules (iso-oriented, IG) or violated them (orthogonally oriented, OG). The IG stimuli (0.5-4.0 cpd) synchronized EEG at discrete beta frequencies (beta1, beta2) and increased BOLD (0.5 and 2.0 cpd tested) in ventral (around collateral sulcus) and dorsal (parieto-occipital fissure) regions compared with OG. At both SF, the beta1 coherence correlated with the ventral activations, whereas the beta2 coherence correlated with the dorsal ones. Thus distributed neural substrates mediated interhemispheric integration at single SF. The relative impact of the ventral versus dorsal networks was modulated by the SF of the stimulus.

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“…In SCs, the pattern of functional connectivity within visual cortex has been extensively investigated in neuroimaging studies (35,36). Interhemispheric synchronization of the primary visual cortex during visual stimuli was detected by the EEG method (37–39). The interhemispheric connections of the visual cortex are important features of the integration of visual information and might be involved in visual fusion and visual recognition (40–42).…”

Section: Discussionmentioning

confidence: 99%

Impaired interhemispheric synchrony in late blindness

et al. 2019

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Background Several neuroimaging studies demonstrated that visual deprivation led to significant cross-modal plasticity in the brain’s functional and anatomical architecture. Purpose To investigate the pattern of the interhemispheric functional connectivity in individuals with late blindness using the voxel-mirrored homotopic connectivity (VMHC) and seed-based functional connectivity (FC) methods. Material and Methods Forty-four individuals with late blindness (22 men, 22 women; mean age = 39.88 ± 12.84 years) and 55 sighted control individuals (35 men, 20 women; mean age = 43.13 ± 13.98 years)—closely matched for age, sex, and education—underwent resting-state magnetic resonance imaging scans. The VMHC and seed-based FC methods were applied to assess interhemispheric coordination in a voxel-wise manner. Results Compared with the sighted control groups, the late blindness groups showed decreased VMHC values in the bilateral cuneus/calcarine/lingual gyrus (CUN/CAL/LING) (BA 17/18/19) (voxel level: P < 0.001, Gaussian random field [GRF] correction, cluster level: P < 0.005). Meanwhile, for seed-based FC analysis, compared with the sighted control group, the late blindness group showed a decreased FC between the right lower VMHC regions and the bilateral CUN/LING/CAL/precuneus (PreCUN)/left middle occipital gyrus (MOG) (BA 18/19/30/31) and left precentral gyrus (PreCG) and postcentral gyrus (PostCG) (BA 2/3/4/6). The late blindness group showed a decreased FC between the left lower VMHC regions and the bilateral CUN/LING/CAL/PreCUN (BA 18/19/31) and left PreCG and PostCG (BA 2/3/4/6) relative to the sighted control group (voxel level: P < 0.001, GRF correction, cluster level: P < 0.005). Moreover, a negative correlation was observed between the duration of blindness and VMHC values in the bilateral CUN/CAL/LING (r = −0.393, P = 0.008) in individuals with late blindness. Conclusion Our results indicated that late blindness induced substantial impairment of interhemispheric coordination in the visual cortex. This might reflect impaired visual fusion, visual recognition function, and top-down modulations in individuals with late blindness.

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Electrophysiological evidence for interhemispheric transmission of visual information in man.

Cited by 17 publications

References 28 publications

Neonatal Section of the Optic Chiasm Changes the Interhemispheric Transfer of Visual Information in Cats

Neonatal Section of the Optic Chiasm Changes the Interhemispheric Transfer of Visual Information in Cats

Interhemispheric Integration at Different Spatial Scales: The Evidence From EEG Coherence and fMRI

Impaired interhemispheric synchrony in late blindness

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