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PS-57-7 Functional differences between the prefrontal cortices of left and right cerebral hemispheres in the monkey
Poster session 57. Higher brain functions and speech
IPS-57-51
Changes of event related potentials in negative and positive decisions during memory-scanning performance
Takao Osanai, Takuhiko Kato, Yoshiaki Seimiya, Tosaku Nikara.
Department of Occupational Therapeutics, School of Ailed Medical Sciences, Hirosaki University Event related potentials were recorded in negative and positive decisions during the memory-scanning performance. Eight normal young adults, aged 18-21 old performed. An alphabet character (conditioning stimulus) was displayed on a TV screen for one second. After the alphabet character disappeared, another or same alphabet character (probe stimulus) was displayed randomly on the screen with 1.5 second's interval. Subject was asked for selecting either one of two buttons abruptly; one used for a positive decision, the other for a negative decision. The positive decision means that the conditioning stimulus and the probe stimulus were same in character. The negative one means that the conditioning stimulus and the probe stimulus were different. The appearing frequency of stimulus of positive decision was 50% in provabilit3,' and vice versa. The incident of correct answer obtained from both cases of positive decision and negative decision was nearly same with occurrence of more than 90%. There was no significant between the two decisions statistically. This result suggested that analyzing process in brain underlying the positive decision was more simple than that underlying the negative decision.
IPS-57-61
Cognitive EPs delayed for late learners of a second language
Mehri Sarfarazi, Michael E. Sedgwick. Clinical Neurological
Sciences, University of Southampton Healthy subjects viewed a series of pictures and English words appearing simultaneously on a V D U for two seconds. They had to respond by button press according to whether the word was congruent or incongruent with the picture. There were three groups of subjects:- 1) N E (Native English speakers). 2) A L (Adult learners) Farsi speakers who learned English after the age of 12 years and were fluent in speech, reading and writing. 3) CL (Childhood learners) Adult Persians brought up bilingually from childhood. Cognitive evoked potentials from 16 scalp channels showed that N 4°0 and P60~ were prolonged by 100 and 70 msec respectively in adult learners (AL) compared with NE and CL. The amplitude of N 4°° is higher and P~0 lower in AL compared with NE and C L The results are consistent with an hypothesis that A L take longer to search and recall their lexical memories. CL are equally quick in both languages.
IPS-57-71
Functional differences between the prefrontal cortices of left and right cerebral hemispheres in the monkey
Hisae G e m b a l.z, Kazuo Sasaki 2. l Department of Physiology, Kansai Medical University, Moriguchi; 2Department of Integrative Brain Science, Faculty of Medicine, Kyoto University, Kyoto, Japan Field potentials were recorded with electrodes chronically implanted on the surface and at 2.0-3.0 mm depth in respective cortical areas in monkeys on self-initiated hand, face and vocalizing movements, and on visually initiated hand movements. Surfacenegative, depth-positive (s-N, d-P) potentials were recorded prior to the movement in the prefrontal cortex only when the movements were performed with intense motivation for reward. Such
$237
a motivation-dependent activity was obtained in the rostral bank of the inferior limb of the arcuate sulcus of the right hemisphere but not in that of the sulcus in the left hemisphere. Three of the monkeys were also tasked with reaction-time hand movements with complex tone. Cortical field potentials were recorded with same electrodes as the above-mentioned movements, being analyzed during learning processes of the movements. In processes of the recognition learning in associating the stimulus with the movementl, s-N, d-P potentials at a latency of about 80 ms after stimulus onset became gradually larger in that rostral bank of the inferior limb of the arcuate sulcus in the left hemisphere, but this did not occur in the bank of the right hemisphere. Further detailed studies on field potentials in the prefrontal cortex during learning processes of the visually initiated movements in two monkeys ascertained that such the finding was obtained independently of sensory modalities of stimuli. These facts suggest functional differences between t h e prefrontal cortices of left and right hemispheres in monkeys. [1] Gemba et al., Neurosci. Lett., in press, 1995.
j PS-57-81 Disorders understanding concepts in dyslexic children
Rosana Brakus 1, Slavica Golubovic 2, Z o r k a Kasic z. 1 Children Nursery "Stankom Bajka', 2 Faculty of Defectology, University of Belgrade, Yugoslavia The paper present the results of understanding concepts in dyslexic children. We have examined 70 children, 35 being with dyslexia and 35 without it. The children were 8-11 years old, 25 of which were boys and 10 were girls in each group. They were of the same social status and the same IQ. In the examination the threedimensional reading tests, Harris's test of the lateral domination, and the Bender-Gestalt test were used. The result obtained indicate that understanding, i.e., the number of the concepts understood is influenced only by the visual lateralization, and that there exists an interaction (p = 0.016). By comparing the concepts understood between the visual righthanded, left-handed and ambidextrous children in both "E" and "C" groups a high statistically significant difference has been found. The results also show that the dyslexic children have sensomotoric difficulties which affects the discrimination abilities.
[ PS-57-91 Disorders in phonemic heaving in dyslexic children
1, Rosana Brakus z. 2 Children Nursery "Stankom Bajka " 1Faculty of Defectology, University of Belgrade, Yugoslavia Slavica Golubovic
The investigation have shown that the sound recognition speed is a critical process in development of speech and phonetic reading abilities, which are disturbed in dyslexic children. We have examined 70 children, 35 being with dyslexia and 35 without it. The children were 8-11 years old, 25 of which were boys and 10 were girls in each group. They were of the same social status and the same IQ. The aim of the present investigation has been to establish the possibility of the phonetic perception and synthesis in dyslexic children, as well as to determine the ear advantage (REA, LEA, NA), and thereby to determine the superiority of the hemisphere of the dichotic listening, by presenting verbal stimuli of various complexity degrees: vowels-vowels, vowels-consonants. The results have shown that the mistakes in the phonemic hearing are statistically highly significantly (p < 0.01) influenced by the
IPS-57-51
Changes of event related potentials in negative and positive decisions during memory-scanning performance
Takao Osanai, Takuhiko Kato, Yoshiaki Seimiya, Tosaku Nikara.
Department of Occupational Therapeutics, School of Ailed Medical Sciences, Hirosaki University Event related potentials were recorded in negative and positive decisions during the memory-scanning performance. Eight normal young adults, aged 18-21 old performed. An alphabet character (conditioning stimulus) was displayed on a TV screen for one second. After the alphabet character disappeared, another or same alphabet character (probe stimulus) was displayed randomly on the screen with 1.5 second's interval. Subject was asked for selecting either one of two buttons abruptly; one used for a positive decision, the other for a negative decision. The positive decision means that the conditioning stimulus and the probe stimulus were same in character. The negative one means that the conditioning stimulus and the probe stimulus were different. The appearing frequency of stimulus of positive decision was 50% in provabilit3,' and vice versa. The incident of correct answer obtained from both cases of positive decision and negative decision was nearly same with occurrence of more than 90%. There was no significant between the two decisions statistically. This result suggested that analyzing process in brain underlying the positive decision was more simple than that underlying the negative decision.
IPS-57-61
Cognitive EPs delayed for late learners of a second language
Mehri Sarfarazi, Michael E. Sedgwick. Clinical Neurological
Sciences, University of Southampton Healthy subjects viewed a series of pictures and English words appearing simultaneously on a V D U for two seconds. They had to respond by button press according to whether the word was congruent or incongruent with the picture. There were three groups of subjects:- 1) N E (Native English speakers). 2) A L (Adult learners) Farsi speakers who learned English after the age of 12 years and were fluent in speech, reading and writing. 3) CL (Childhood learners) Adult Persians brought up bilingually from childhood. Cognitive evoked potentials from 16 scalp channels showed that N 4°0 and P60~ were prolonged by 100 and 70 msec respectively in adult learners (AL) compared with NE and CL. The amplitude of N 4°° is higher and P~0 lower in AL compared with NE and C L The results are consistent with an hypothesis that A L take longer to search and recall their lexical memories. CL are equally quick in both languages.
IPS-57-71
Functional differences between the prefrontal cortices of left and right cerebral hemispheres in the monkey
Hisae G e m b a l.z, Kazuo Sasaki 2. l Department of Physiology, Kansai Medical University, Moriguchi; 2Department of Integrative Brain Science, Faculty of Medicine, Kyoto University, Kyoto, Japan Field potentials were recorded with electrodes chronically implanted on the surface and at 2.0-3.0 mm depth in respective cortical areas in monkeys on self-initiated hand, face and vocalizing movements, and on visually initiated hand movements. Surfacenegative, depth-positive (s-N, d-P) potentials were recorded prior to the movement in the prefrontal cortex only when the movements were performed with intense motivation for reward. Such
$237
a motivation-dependent activity was obtained in the rostral bank of the inferior limb of the arcuate sulcus of the right hemisphere but not in that of the sulcus in the left hemisphere. Three of the monkeys were also tasked with reaction-time hand movements with complex tone. Cortical field potentials were recorded with same electrodes as the above-mentioned movements, being analyzed during learning processes of the movements. In processes of the recognition learning in associating the stimulus with the movementl, s-N, d-P potentials at a latency of about 80 ms after stimulus onset became gradually larger in that rostral bank of the inferior limb of the arcuate sulcus in the left hemisphere, but this did not occur in the bank of the right hemisphere. Further detailed studies on field potentials in the prefrontal cortex during learning processes of the visually initiated movements in two monkeys ascertained that such the finding was obtained independently of sensory modalities of stimuli. These facts suggest functional differences between t h e prefrontal cortices of left and right hemispheres in monkeys. [1] Gemba et al., Neurosci. Lett., in press, 1995.
j PS-57-81 Disorders understanding concepts in dyslexic children
Rosana Brakus 1, Slavica Golubovic 2, Z o r k a Kasic z. 1 Children Nursery "Stankom Bajka', 2 Faculty of Defectology, University of Belgrade, Yugoslavia The paper present the results of understanding concepts in dyslexic children. We have examined 70 children, 35 being with dyslexia and 35 without it. The children were 8-11 years old, 25 of which were boys and 10 were girls in each group. They were of the same social status and the same IQ. In the examination the threedimensional reading tests, Harris's test of the lateral domination, and the Bender-Gestalt test were used. The result obtained indicate that understanding, i.e., the number of the concepts understood is influenced only by the visual lateralization, and that there exists an interaction (p = 0.016). By comparing the concepts understood between the visual righthanded, left-handed and ambidextrous children in both "E" and "C" groups a high statistically significant difference has been found. The results also show that the dyslexic children have sensomotoric difficulties which affects the discrimination abilities.
[ PS-57-91 Disorders in phonemic heaving in dyslexic children
1, Rosana Brakus z. 2 Children Nursery "Stankom Bajka " 1Faculty of Defectology, University of Belgrade, Yugoslavia Slavica Golubovic
The investigation have shown that the sound recognition speed is a critical process in development of speech and phonetic reading abilities, which are disturbed in dyslexic children. We have examined 70 children, 35 being with dyslexia and 35 without it. The children were 8-11 years old, 25 of which were boys and 10 were girls in each group. They were of the same social status and the same IQ. The aim of the present investigation has been to establish the possibility of the phonetic perception and synthesis in dyslexic children, as well as to determine the ear advantage (REA, LEA, NA), and thereby to determine the superiority of the hemisphere of the dichotic listening, by presenting verbal stimuli of various complexity degrees: vowels-vowels, vowels-consonants. The results have shown that the mistakes in the phonemic hearing are statistically highly significantly (p < 0.01) influenced by the