The development of functional lateralization in visual hemifield attention

1985 ◽  
Vol 1 (1) ◽  
pp. 67-80 ◽  
Author(s):  
Michael S. Shapiro ◽  
George W. Hynd
Keyword(s):  
Visual Hemifield ◽  
Functional Lateralization

Right-Hemisphere Specialization for Contour Grouping

2014 ◽  
Vol 61 (5) ◽  
pp. 331-339 ◽  
Author(s):  
Gregor Volberg
Keyword(s):  
Right Hemisphere ◽  
Contour Detection ◽  
Global Processing ◽  
Detection Accuracy ◽  
Frequency Spectra ◽  
Visual Hemifield ◽  
Spatial Frequencies ◽  
A Chain ◽  
The Right ◽  
Hemisphere Specialization

Previous studies often revealed a right-hemisphere specialization for processing the global level of compound visual stimuli. Here we explore whether a similar specialization exists for the detection of intersected contours defined by a chain of local elements. Subjects were presented with arrays of randomly oriented Gabor patches that could contain a global path of collinearly arranged elements in the left or in the right visual hemifield. As expected, the detection accuracy was higher for contours presented to the left visual field/right hemisphere. This difference was absent in two control conditions where the smoothness of the contour was decreased. The results demonstrate that the contour detection, often considered to be driven by lateral coactivation in primary visual cortex, relies on higher-level visual representations that differ between the hemispheres. Furthermore, because contour and non-contour stimuli had the same spatial frequency spectra, the results challenge the view that the right-hemisphere advantage in global processing depends on a specialization for processing low spatial frequencies.

scholarly journals Lateralization in monogamous pairs: wild geese prefer to keep their partner in the left hemifield except when disturbed

2020 ◽  
Author(s):  
Elmira Zaynagutdinova ◽  
Karina Karenina ◽  
Andrey Giljov
Keyword(s):  
Social Interactions ◽  
Right Hemisphere ◽  
Natural Setting ◽  
Intraspecific Interactions ◽  
Brain Hemispheres ◽  
Emergency Situations ◽  
Anser Albifrons ◽  
Significant Bias ◽  
Visual Hemifield ◽  
The Right

Abstract Behavioural lateralization, which reflects the functional specializations of the two brain hemispheres, is assumed to play an important role in cooperative intraspecific interactions. However, there are few studies focused on the lateralization in cooperative behaviours of individuals, especially in a natural setting. In the present study, we investigated lateralized spatial interactions between the partners in life-long monogamous pairs. The male-female pairs of two geese species (barnacle, Branta leucopsis, and white-fronted, Anser albifrons geese), were observed during different stages of the annual cycle in a variety of conditions. In geese flocks, we recorded which visual hemifield (left/right) the following partner used to monitor the leading partner relevant to the type of behaviour and the disturbance factors. In a significant majority of pairs, the following bird viewed the leading partner with the left eye during routine behaviours such as resting and feeding in undisturbed conditions. This behavioural lateralization, implicating the right hemisphere processing, was consistent across the different aggregation sites and years of the study. In contrast, no significant bias was found in a variety of geese behaviours associated with enhanced disturbance (when alert on water, flying or fleeing away when disturbed, feeding during the hunting period, in urban area feeding and during moulting). We hypothesize that the increased demands for right hemisphere processing to deal with stressful and emergency situations may interfere with the manifestation of lateralization in social interactions.

scholarly journals White Matter Pathway Asymmetry Underlies Functional Lateralization

2006 ◽  
Vol 17 (3) ◽  
pp. 591-598 ◽  
Author(s):  
T. R. Barrick ◽  
I. N. Lawes ◽  
C. E. Mackay ◽  
C. A. Clark
Keyword(s):  
White Matter ◽  
Functional Lateralization

Lateralization of lexical processing in monolinguals and bilinguals

2021 ◽  
pp. 136700692110188
Author(s):  
Filiz Mergen ◽  
Gulmira Kuruoglu
Keyword(s):  
Lexical Processing ◽  
Response Times ◽  
Visual Fields ◽  
Decision Task ◽  
Bilingual Speakers ◽  
Visual Hemifield ◽  
Significant Difference ◽  
Brain Correlates ◽  
Orthographic Neighbors

Aims and objectives: This study aims to investigate how lexical processing (LP) is organized in early Turkish–English bilinguals and Turkish monolinguals. Methodology: We used a visual hemifield paradigm where bilingual ( n = 48) and monolingual ( n = 53) participants performed a lexical decision task. Bilingual participants performed the task in both their languages. Data and analysis: We recorded response times (RTs) and the accuracy rates (ARs) of the participants. An analysis of variance and t-test were run to analyze the bilingual and monolingual data, respectively. Findings: The results obtained from the analysis of the RTs and ARs for the Turkish and English words showed a balanced hemispheric organization in LP in bilingual speakers. The RTs for Turkish words in the monolingual group provided supportive evidence for the predominant role of the left hemisphere in LP. However, no significant difference was found in the accuracy of their answers, suggesting that the monolingual participants’ performance was not influenced by visual field of presentation of the words. Finally, the comparison of the two groups revealed that bilingual participants’ performance was inferior to monolinguals’ in speed and accuracy of processing of words presented in both visual fields. This result gives further support for the differential representation of LP in monolinguals and bilinguals. Originality: The psycholinguistic literature abounds with studies of LP in bilinguals and monolinguals from a variety of language backgrounds; however, there is much less data regarding the brain correlates of LP in Turkish–English bilinguals and Turkish monolinguals. Implications: Since Turkish–English bilinguals and Turkish monolinguals are underrepresented in the literature as compared to the population who speak other languages with alphabetic writing, this study provides preliminary data for future studies. Limitations: We did not control for gender or lexical factors such as orthographic neighbors when designing the word sets used as stimuli.

scholarly journals Sustained Splits of Attention within versus across Visual Hemifields Produce Distinct Spatial Gain Profiles

2016 ◽  
Vol 28 (1) ◽  
pp. 111-124 ◽  
Author(s):  
Sabrina Walter ◽  
Christian Keitel ◽  
Matthias M. Müller
Keyword(s):  
Visual Attention ◽  
Visual Processing ◽  
Behavioral Performance ◽  
Lower Visual Field ◽  
Light Emitting ◽  
Visual Hemifield ◽  
Attention Tasks ◽  
Visual Cortices ◽  
Cortical Visual Processing ◽  
Visual Hemifields

Visual attention can be focused concurrently on two stimuli at noncontiguous locations while intermediate stimuli remain ignored. Nevertheless, behavioral performance in multifocal attention tasks falters when attended stimuli fall within one visual hemifield as opposed to when they are distributed across left and right hemifields. This “different-hemifield advantage” has been ascribed to largely independent processing capacities of each cerebral hemisphere in early visual cortices. Here, we investigated how this advantage influences the sustained division of spatial attention. We presented six isoeccentric light-emitting diodes (LEDs) in the lower visual field, each flickering at a different frequency. Participants attended to two LEDs that were spatially separated by an intermediate LED and responded to synchronous events at to-be-attended LEDs. Task-relevant pairs of LEDs were either located in the same hemifield (“within-hemifield” conditions) or separated by the vertical meridian (“across-hemifield” conditions). Flicker-driven brain oscillations, steady-state visual evoked potentials (SSVEPs), indexed the allocation of attention to individual LEDs. Both behavioral performance and SSVEPs indicated enhanced processing of attended LED pairs during “across-hemifield” relative to “within-hemifield” conditions. Moreover, SSVEPs demonstrated effective filtering of intermediate stimuli in “across-hemifield” condition only. Thus, despite identical physical distances between LEDs of attended pairs, the spatial profiles of gain effects differed profoundly between “across-hemifield” and “within-hemifield” conditions. These findings corroborate that early cortical visual processing stages rely on hemisphere-specific processing capacities and highlight their limiting role in the concurrent allocation of visual attention to multiple locations.

Polysensory properties of neurons in the anterior bank of the caudal superior temporal sulcus of the macaque monkey

1988 ◽  
Vol 60 (5) ◽  
pp. 1615-1637 ◽  
Author(s):  
K. Hikosaka ◽  
E. Iwai ◽  
H. Saito ◽  
K. Tanaka
Keyword(s):  
Visual Stimuli ◽  
Three Dimensional ◽  
Superior Temporal Gyrus ◽  
Superior Temporal Sulcus ◽  
Sensory Properties ◽  
Temporal Region ◽  
Directional Selectivity ◽  
Temporal Area ◽  
Response Properties ◽  
Visual Hemifield

1. We examined the sensory properties of cells in the anterior bank of the caudal part of the superior temporal sulcus (caudal STS) in anesthetized, paralyzed monkeys to visual, auditory, and somesthetic stimuli. 2. In the anterior bank of the caudal STS, there were three regions distinguishable from each other and also from the middle temporal area (MT) in the floor of the STS and area Tpt in the superior temporal gyrus. The three regions were located approximately in the respective inner, middle, and outer thirds of the anterior bank of the caudal STS. These three regions are referred to, from the inner to the outer, as the medial superior temporal region (MST), the mostly unresponsive region, and the caudal STS polysensory region (cSTP), respectively. 3. The extent of MST and its response properties agreed with previous studies. Cells in MST responded exclusively to visual stimuli, had large visual receptive fields (RFs), and nearly all (91%) showed directional selectivity. 4. In the mostly unresponsive region, three quarters of cells were unresponsive to any stimulus used in this study. A quarter of the cells responded to only visual stimuli and most did not show directional selectivity for moving stimuli. Several directionally selective cells responded to movements of three-dimensional objects, but not of projected stimuli. 5. The response properties of cells in the superficial cortex of the caudal superior temporal gyrus, a part of area Tpt, external to cSTP were different from those of cells in the three regions in the anterior bank of the STS. Cells in Tpt were exclusively auditory, and had much larger auditory RFs (mean = 271 degrees) than those of acoustically-driven cSTP cells (mean = 138 degrees). 6. The cSTP contained unimodal visual, auditory, and somesthetic cells as well as multimodal cells of two or all three modalities. The sensory properties of cSTP cells were as follows. 1) Out of 200 cells recorded, 102 (51%) cells were unimodal (59 visual, 33 auditory, and 10 somesthetic), 36 (18%) cells were bimodal (21 visual+auditory, 7 visual+somesthetic, and 8 auditory+somesthetic), and four (2%) cells were trimodal. Visual and auditory responses were more frequent than somesthetic responses: the ratio of the population of cells driven by visual: auditory: somesthetic stimuli was 3:2:1. 2) Visual RFs were large (mean diameter, 59 degrees), but two-thirds were limited to the contralateral visual hemifield. About half the cells showed directional selectivity for moving visual stimuli. None showed selectivity for particular visual shapes.(ABSTRACT TRUNCATED AT 400 WORDS)

Area 17 lesions deactivate area MT in owl monkeys

1992 ◽  
Vol 9 (3-4) ◽  
pp. 399-407 ◽  
Author(s):  
Jon H. Kaas ◽  
Leah A. Krubitzer
Keyword(s):  
Visual Stimuli ◽  
Receptive Fields ◽  
Area 17 ◽  
Area Mt ◽  
Mt Neurons ◽  
Visual Hemifield ◽  
Cortex Area ◽  
Owl Monkeys ◽  
Evoked Activity ◽  
Visual Area Mt

AbstractThe middle temporal visual area, MT, is one of three major targets of the primary visual cortex, area 17, in primates. We assessed the contribution of area 17 connections to the responsiveness of area MT neurons to visual stimuli by first mapping the representation of the visual hemifield in MT of anesthetized owl monkeys with microelectrodes, ablating an electrophysiologically mapped part of area 17, and then immediately remapping MT. Before the lesions, neurons at recording sites throughout MT responded vigorously to moving slits of light and other visual stimuli. In addition, the relationship of receptive fields to recording sites revealed a systematic representation of the contralateral visual hemifield in MT, as reported previously for owl monkeys and other primates. The immediate effect of removing part of the retinotopic map in area 17 by gentle aspiration was to selectively deactivate the corresponding part of the visuotopic map in MT. Lesions of dorsomedial area 17 representing central and paracentral vision of the lower visual quadrant deactivated neurons in caudomedial MT formerly having receptive fields in the central and paracentral lower visual quadrant. Most neurons at recording sites throughout other parts of MT had normal levels of responsiveness to visual stimuli, and receptive-field locations that closely matched those before the lesion. However, neurons at a few sites along the margin of the deactivated zone of cortex had receptive fields that were slightly displaced from the region of vision affected by the lesion into other parts of the visual field, suggesting some degree of plasticity in the visual hemifield representation in MT. Subsequent histological examination of cortex confirmed that the lesions were confined to area 17 and the recordings were in MT. The results indicate that the visually evoked activity of neurons in MT of owl monkeys is highly dependent on inputs relayed directly or indirectly from area 17.

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