Hemispheric asymmetry in event related potentials associated with positive and negative emotions.

Event-related potentials from symmetrical points of the left and right frontal and occipital cortex were recorded while subjects experienced positive and negative emotions. The emotions were elicited by either missing or hitting a target with a photoelectric gun. Twenty three right-handers (10 males and 13 females) were tested.

Hemispheric differences in evoked potentials to pictures of faces in the left and right visual fields.

Fifteen right-handed women evaluated the similarity of two faces presented to them either in the left or in the right visual field. The subjects' task was to decide whether the faces were the same or different and accordingly to press a button or abstain from doing so. Errors made by the subjects and the visual evoked potentials (VEPs) from points O1 and O2 referred to point CZ were recorded.

Cerebral hemispheric differences in visual perception of various types of verbal material.

Hemispheric differences in perception of various verbal material were sought in two groups of Ss: 10 normal adults (a control group) and 10 patients of the Neurosurgery Clinic with focal brain damage either to the left or right hemisphere. The stimuli were letters projected singly, in three-letter nonsense sequences or in three letter Polish words on a screen in the left or right visual half-field. The results obtained from the control groups indicate that the dominance of the left hemisphere is limited only to the meaningful verbal material.

Evoked response correlates of letter recognition.

The positive late wave of the average evoked responses induced by tachistoscopic presentation of single letters had a higher amplitude when the letters were correctly recognized than when they were not. The results suggest that the late positive component of VER is a correlate of complex cognitive processes engaged in object’s identification.

Search for structures involved in integration of letters in pairs.

Two experiments aimed at finding, at what stage of perceptual processing the positive interactions between letters, observed in some previous studies, are established. Single letters and pairs of letters were exposed. The task of the subjects was to recognize letters.

Interactions between two spatially separated letters presented in succession.

The interactions between two letters presented in succession to neighboring regions of retina were investigated. The interstimulus intervals were: 0, 20, 60, 250 ms, 2.5 s.

The effect of distractor on memory for pitch: trace distortion or interference with retrieval?

The effect of the time of presentation of an interpolated stimulus on dynamic memory for pitch of pure tones of 900-2000 Hz was investigated by comparison of successive stimuli. The test tone followed the sample tone after 25, 40, 60, 80, 160 or 320 s. The interpolated stimulus (a pure tone of 220 Hz) was timed either 20 s before the test tone (Experiment I) or 20 s after the sample (Experiment II).

Specific visual disability in relation to ontogeny of brain asymmetry.

Children with retarded development of visual perception were compared with previously tested normal children Verbal and non-verbal patterns were presented either to the left or to the right hemisphere. In both groups of children the results showed a functional equality of the hemispheres during analysis of the non-verbal patterns. Left hemisphere superiority for verbal material in Normal group was not confirmed by the results in Retarded children.

Hemispheric differences in the visual analysis of the verbal and non-verbal material in children.

Five years old children, who could not read, and the same children at the aged of 7, who already knew letters, were used as subjects. A visual procedure involved presentation of single letters or a pair of letters randomly to the left or right of a central fixation point. Reaction time and number of correct identifications, showed by pressing a key, were indicators of the perception of letters.

Interactions between two simple visual patterns.

The interaction of linear and dot elements of simple visual patterns was examined. The following patterns were used: short line-dot, long line-dot, right turned angle-dot, downward angle-dot, circle-dot, and two dots. Except for circle-dot and two dots, perception of either of both elements of the composite stimulus deteriorates as compared to perception of the same elements when presented separately.

Interaction between two letters in visual perception.

Letters were exposed by tachistoscope for 17 ms to adult subjects. In Experiment I, single letters were exposed. The proportion of errors differed strongly for particular letters.

Analysis of perception of complex visual stimulus-patterns.

This paper deals with the analysis of visual perceptions of complex patterns consisting of two simple patterns placed one above the other in one frame (united pattern) or in two separate frames each (divided pattern). The upper pattern consisted of a configuration of lines, the lower one of a configuration of dots. There were one positive pattern which a subject had to recognize in tachistoscopic exposure and a number of negative patterns which a subject had to reject.