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Biomedical subjects

K Hugdahl

Publications and source records attributed to K Hugdahl.

At least 109 records · Page 6Linked to original sources
PubMed1989

Hemispheric differences in recognition of facial expressions: a VHF-study of negative, positive, and neutral emotions.

The present study was concerned with a tachistoscopic investigation of asymmetry of recognition of different facial emotional expressions. Twenty-eight subjects had nine different drawings of facial expressions (either positive, negative, or neutral in emotional content) presented either to the left or right visual half-field. Recognition of the correct face was made for each stimulus-presentation. The results showed overall better recognition for presentations in the left half-field (LVF) (i.e., right hemisphere) compared to right half-field (RVF) (i.e., left hemisphere) presentations. Furthermore, while all three emotional categories were recognized about equally well in the right half-field, positive emotional expressions were significantly better than the neutral and negative categories when presented to the left half-field. The results are discussed in relation to previous findings of cerebral asymmetry in processing of emotional facial expressions.

Adult↗
PubMed1989

Effects of arousal and directed attention on hemispheric asymmetry in a finger-tapping dual-task paradigm.

In the present study we investigated the effects of concurrent verbal (reading) and nonverbal (humming) cognitive tasks on right- and left-hand finger-tapping in relation to hemispheric asymmetry in right- and left-handed females and males. The aim of the study was to investigate effects of attending either to the cognitive or manual task, and effects of differences in arousal attributed to the various tasks. The results revealed decreased finger-tapping frequency in males, and especially in right-handers, during execution of both the reading and humming task. For the reading task, the interference was lateralized, with a greater decrease in tapping frequency in the right hand. No interference was observed in the female groups. Biased attention to the cognitive or manual task did not have any effect on finger-tapping. However, increased arousal was observed during execution of the humming task, thus indicating this to be a mediating factor in finger-tapping interference.

Adult↗
PubMed1988

Psychophysiological aspects of phobic fears: an evaluative review.

The present paper is a review of the use of psychophysiology in diagnosis and treatment of simple phobias. The paper begins with a definition and characterization of phobic fears, together with a description of prevalence rates, age onset, and gender differences. Acquisition is then discussed within a Three-Systems model. Psychophysiological measures are described, and the typical response patterns obtained in phobic reactions are outlined. Special attention is devoted to the paradoxical response seen in blood injury phobias, and the use of beta-blockers and other pharmacological drugs. The paper is ended with a discussion of Lang's emotional imagery as a psychophysiological model for fear reactions and fear therapy.

Adrenergic beta-Antagonists↗
PubMed1988

Bilateral electrodermal asymmetry: past hopes and future prospects.

In the present paper, I have reviewed data and evidence concerning bilateral electrodermal (EDA) recordings and hemispheric asymmetry. Nine papers published between 1982 and 1986 are evaluated together with the 51 papers reviewed in the prior Hugdahl (1984) paper. The overall impression of the data is skepticism concerning what bilateral differences imply. This does, however, not imply that EDA is a less relevant index of hemispheric asymmetry compared to other psychophysiological measures. The important aspect of psychophysiological laterality research is not the use of different dependent measures, but the design and manipulation of the independent variables. Thus, increased responding to a verbal stimulus initially projected only to the left as compared to the right hemisphere may be as instructive concerning conclusions about asymmetry as bilateral differences to a stimulus presented to both hemispheres simultaneously.

Brain↗
PubMed1988

Hemispheric asymmetry and finger-tapping in right-handed females.

The purpose of the present experiment was to investigate effects of concurrent verbal and nonverbal tasks on right- and left-hand finger-tapping in an adult female group. In addition to the verbal versus nonverbal distinction, both motor and sensory tasks were used. Previous experiments have demonstrated lateralized right-hand decrement in finger-tapping in males during a motor verbal task; increases in both hands during a motor nonverbal task; and increase in left-hand tapping frequencies during sensory verbal and sensory nonverbal tasks. In the present study, significant increases in finger-tapping was observed in all the experimental conditions compared to pre- and postbaseline measures. It is concluded that both facilitation and interference may be observed in a finger-tapping paradigm. Thus, a cautious interpretation concerning the relation of finger-tapping and hemispheric asymmetry is encouraged.

Adult↗
PubMed1987

Effects of speed vs. accuracy in vocal reaction time to visual half-field presentations of incongruent (Stroop) color-words.

Incongruent color-words were briefly flashed initially to the left or right hemisphere using the visual half-field (VHF) technique. In half of the trials, subjects were requested to name the word, and in half of the trials they were requested to name the ink the word was written in. Congruent color-words and neutral words served as control-stimuli. Vocal reaction time (VRT) and error-frequency were used as dependent measures. Half of the subjects were instructed to try to be as fast as possible in the task (Speed group), the other half were instructed to try to be as accurate as possible in the task (Accuracy group). All subjects were right handed males. Results showed significantly longer VRTs in the Accuracy group, and more errors in the Speed group to right-field projections (initial left hemisphere input) of the incongruent color-words during the color-naming condition. Thus, the present results have revealed; (a) significant effects of hemispheric asymmetry in an incongruent color-words paradigm; and (b) that the speed vs accuracy dimension interferes with hemisphere differences.

Color↗
PubMed1987

Dichotic listening and reading acquisition in children: a one-year follow-up.

Two dichotic listening experiments on hemispheric asymmetry and reading acquisition in children are reported. In the first experiment, 60 eight-year-old children were divided into three groups with different levels of reading acquisition. In order to separate attentional factors from hemisphere factors, all subjects were requested to attend to and report only the right-ear input in one third of the trials, to attend to the left-ear input in one third, and to be free to divide attention either way in one third. The results showed an expected right-ear advantage (REA) in all groups during the forced-right, and nonforced recall conditions. However, a REA was also found during the forced-left recall condition for subjects less advanced in reading. The same children were followed-up 1 year later in a second experiment. The results showed that the REA during the forced-left condition for the less advanced subjects in Experiment 1 was in essence shifted to a left-ear advantage (LEA) in Experiment 2. The relationships of attentional factors in hemispheric asymmetry and reading acquisition are discussed.

Attention↗
PubMed1987

Heart-rate indices of hemispheric asymmetry in a discrete-trials Stroop-paradigm.

Heart-rate changes were recorded in a discrete-trials Stroop-paradigm where slides with color-words written in an incongruent color were briefly flashed (200 msec.) either to the left or to the right of a central fixation point. Subjects were required to attend only to the color, ignoring the color-word. The logic behind the paradigm is that a greater conflict should occur for the Stroop-words presented in the right visual half-field due to the relative inability of the left hemisphere to suppress the verbal information. By recording phasic heart-rate it would be possible to elucidate 1982 findings of Walker and Sandman that changes in heart-rate are differentially related to the right and left cerebral hemispheres. The results showed a significant initial deceleration during the first trialblock only to stimuli presented in the left half-field. Asymmetrical effects were demonstrated for heart-rate.

Adult↗
PubMed1986

The "forced-attention paradigm" in dichotic listening to CV-syllables: a comparison between adults and children.

The present study was concerned with the effects of directional attention on the right-ear-advantage (REA) in dichotic listening. It was suggested that if selective attention contributes to the REA during a non-forced, free recall condition, then comparing the unattended left and right ear scores when attention is forced to the right and the left ear, respectively, would yield an "attention-free" estimate of the REA. Each subject participated in a non-forced, free recall, condition; in a forced-right condition; and in a forced-left condition. During the two forced conditions, subjects were instructed to only attend to and report the right and left ear inputs, respectively. The stimuli were the six stop-consonants paired with the vowel a. Four right-handed groups participated (N = 18): Adult males, adult females, boys (8-9 years), girls (8-9 years). The results showed a significant REA in all groups during the non-forced condition. During the forced-right condition, significantly more correct recalls were obtained from the right compared to the left ear in all groups. During the forced-left condition, significantly more correct recalls from the left compared to the right ear was obtained only in the two adult groups, but not in the children groups. Finally, comparing correct recalls from the unattended right ear (during the forced-left condition) with the unattended left ear (during the forced-right condition) revealed a significant REA in all groups except for the adult females.

Adolescent↗
PubMed1986

Visual half-field presentations of incongruent color words: effects of gender and handedness.

Right-handed (dextral) and left-handed (sinistral) males and females (N = 15) were compared for language lateralization in a visual half-field (VHF) incongruent color-words paradigm. The paradigm consists of repeated brief (less than 200 msec) presentations of color-words written in an incongruent color. Presentations are either to the right or to the left of center fixation. The task of the subject is to report the color the word is written in on each trial, ignoring the color-word. Color-bars and congruent color-words were used as control stimuli. Vocal reaction time (VRT) and error frequency were used as dependent measures. The logic behind the paradigm is that incongruent color-words should lead to a greater cognitive conflict when presented in the half-field contralateral to the dominant hemisphere. The results showed significantly longer VRTs in the right half-field for the dextral subjects. Furthermore, significantly more errors were observed in the male dextral group when the incongruent stimuli were presented in the right half-field. There was a similar trend in the data for the sinistral males. No differences between half-fields were observed for the female groups. It is concluded that the present results strengthen previous findings from our laboratory (Hugdahl and Franzon, 1985) that the incongruent color-words paradigm is a useful non-invasive technique for the study of lateralization in the intact brain.

Adolescent↗
PubMed1986

Inhibitory versus facilitory interference for finger-tapping to verbal and nonverbal, motor, and sensory tasks.

The purpose of the present experiment was to investigate lateralized effects of concurrent verbal and nonverbal tasks on right- and left-hand finger-tapping. In addition to the verbal vs. nonverbal dichotomy, both motor and sensory tasks were used. It was predicted that a verbal motor task (reading aloud) would lead to more inhibitory interference for right-hand tappings than would a sensory verbal task (watching and remembering slides with nonsense syllables). Similarly, it was predicted that a motor nonverbal task (humming a tune) would lead to more left-hand inhibitory interference than would a sensory nonverbal task (watching pairs of spatial patterns). Results showed a predicted lateralized right-hand decrement in finger-tapping during the motor verbal task. However, an increase in left-hand tapping frequency above baseline was observed during both sensory tasks, while no significant difference was observed between the hands for the motor nonverbal task.

Adult↗
PubMed1985

Visual half-field presentations of incongruent color-words reveal mirror-reversal of language lateralization in dextral and sinistral subjects.

Two experiments are reported concerning identification of left and right hemisphere dominance for language in dextral and sinistral subjects. A visual half-field (VHF) incongruent color-words paradigm was used. Color-words written in incongruent colors were presented either to the right or left half-field. Subjects were instructed to report the color, ignoring the color-word. Vocal reaction time (VRT) and frequency of errors were measured. Twenty dextral adult males were tested in Experiment 1. Results showed significantly more errors and a trend towards longer VRT:s when the words were presented in the right half-field, i.e. initially to the left hemisphere. No differences between half-fields were observed to color-stripes serving as control-stimuli. The results were followed up in Experiment 2 with a preselected sinistral group. All subjects in the sinistral group had revealed a left-ear-advantage (LEA) in a previous dichotic listening test, i.e. right hemisphere language dominance. The results from the VHF inconguent color-words test showed a reverse pattern of responding compared to the dextral group, i.e. more errors and longer VRTs when the color-words were initially presented to the right hemisphere.

Adult↗