PubMed Health⌕ Search

SEARCH · PubMed Health

Results for “Visual Perception”

Explore indexed PubMed citations for clinical trials, systematic reviews and public health research. Read source abstracts and follow each citation to its original PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 217 records · Page 12Linked to original sources
PubMed1978

Lateral asymmetries in visual perception with and without eye movements.

A signal detection analysis was made of single letter recognition in the right and left visual fields. When letters were presented 2 degrees 3' to the right or left of a central fixation there were no significant differences between the fields in perceptual accuracy independent of bias when the subject maintained a central fixation point. However, when subjects were free to move their eyes a right field advantage was found. The results were discussed in terms of attentional bias theories and hemispheric specialization theories.

Cerebral Cortex↗
PubMedDate not supplied

[Ontogenetic characteristics of the development of slow negative and positive potentials during the performance of a visual perceptive task].

In age aspect, topography and parameters were studied of late EPs and slow negative components (CNV) to successively presented visual stimuli: the preliminary signal and two compared contour images. Age characteristics of development of the frontal negativity N450 and the late positive complex (LPC) were revealed. in children 7 and 10 years old, the component N450 was present in response both to the preliminary and the first stimulus in the compared pair; LPC was recorded to all three presented visual stimuli. In 17 years old subjects and in adults, selectivity of N450 formation in the EP to the first of the compared stimuli and LPC to the second (imperative) stimulus correlates with involvement of rostral brain areas--central in youths, central and frontal ones in adults--both in the process of waiting (CNV) and evaluation of coming information (LPC).

Adolescent↗
PubMed1983

Visual perception fields in the superficial layers of the opossum's superior colliculus: representation of the ipsi and contralateral hemifields by each eye.

Visual receptive fields of single units in the superior colliculus of the opossums were analysed in regions representing the ipsilateral (rostral pole - RP) and the contralateral hemifields (direct binocular region - DBR) close to and including the representation of the horizontal meridian. Of 242 units half had receptive field centres of the contralateral eye at the ipsilateral hemifield and the other half at the contralateral hemifield. The proportion of units driven by the ipsilateral eye was considerably smaller at the RP than at the DBR and the frequency of unit response to this eye diminished within the ipsilateral hemifield with progressively more rostral penetrations in the RP. The midline was unequally represented by the two eyes in RP units: while 24 out of 26 receptive fields of the ipsilateral eye straddled the vertical meridian, only 50 out of 120 of the contralateral eye did so. Furthermore, at the RP receptive fields of units responsive to the contralateral eye extended up to 46.8 degrees into the ipsilateral visual field while those mapped for the ipsilateral eye extended only up to 26 degrees. As a result of this tendency for the receptive fields of the ipsilateral, but not the contralateral eye, to overlap the vertical meridian, progressively more rostral recordings yielded an increase in the binocular convergent disparity as a function of the eccentricity for the receptive field of the contralateral eye. Since the disparity didn't vary with the eccentricity in the DBR units, we suggest that stimuli at the midline and close to the animal might be the natural ones to drive large disparity units present in the RP.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗