Don M. Tucker

Sex differences and lateral specialization of hemispheric functioning

Abstract The study was designed to explore whether male-female differences in the EEG ratio of the left hemisphere to the right hemisphere could be found with general tasks which more closely approximate normal activities. Six males and six females performed tasks chosen to utilize one hemisphere of the brain more than the other. In all, there were four right hemispheric tasks and four left hemispheric tasks. The ratios of EEG power measured from the temporal lobes were statistically significant for the males between these tasks but not for the females. The results suggest that males and females process the same environmental event with different patterns of brain activity as reflected by EEG.

Right hemisphere activation during stress.

Abstract To examine the effects of psychological stress upon hemisphere activation, subjects lateral eye movements to reflective questions were observed under conditions of neutral instructions and instructions designed to be stressful. An increased frequency of left eye movements during the stress condition suggested greater right than left hemisphere activation with emotional arousal.

Verbal versus imaginal cognitive strategies in the inhibition of emotional arousal

A substantial body of evidence indicates that psychiatric disorders are accompanied by altered lateral brain function. The left hemisphere appears to become highly activated and dysfunctional in schizophrenia (FlorHenry, 1974; Gruzelier & Hammond, 1976; Gur, 1978), while a specific right-hemisphere performance decrement has been found in affective disorders (Flor-Henry, 1974; Kronfol, Hamsher, Digre, & Waziri, 1978). These findings raise the issue of whether a particular alteration of hemispheric function is related to a predictable alteration of cognitive processes. The right hemispheres documented importance to the understanding and expression of emotion (Heilman, Scholes, & Watson, 1975; Sackeim, Gur, & Saucy, 1978; Schwartz, Davidson, & Maer, 1975; Wechsler, 1973) seems to be facilitated by its capacity for global conceptual intregration of sensory with visceral cues (Safer & Leventhal, 1977; Semmes, 1968). Smokler and Shevrin (1979) contrasted college students who showed a hysteric cognitive style, wherein ongoing cognition is infused with emotion, with those who showed an obsessive-compulsive style, wherein the intellectualized ideation is isolated from affective significance (Shapiro, 1965); a high frequency of left lateral eye movements observed for the hystericstyle persons suggested the importance of the right hemispheres contribution to their naturalistic ideation. A possible role for the left hemispheres verbal and analytic ideation in modulating the fight hemispheres emotional responsivity has been suggested by Tucker, Antes, Stenslie, and Barnhardt (1978). Characteristically anxious college students were observed to show a pattern of left-hemisphere activation and left-hemisphere performance impairment that may suggest a parallel in normal individuals to the pattern of left-hemisphere involvement in schizophrenia. Observing further that this apparent overactivation of the left hemisphere was accompanied by a decreased frequency of left lateral eye movements, 197

Asymmetry of Facial Expression in Spontaneous Emotion

The observation that emotional expressions are more intense on the left side of the face is consistent with other evidence of the importance of the right hemisphere in emotional communication. However, the question has been raised whether it is truly spontaneous emotional expressions or only posed facial displays that show a left-sided asymmetry. We surreptitiously examined facial asymmetry during spontaneous emotional expressions as subjects remembered happy or sad experiences. These were contrasted with the subjects posed expressions of happy or sad emotions. Both of these procedures resulted in more intense expressions on the left side of the face. The left-sided advantage was stronger during the spontaneous than the posed displays, and was observed for both happy and sad emotions.

Asymmetric Cognitive Function in Anorexia Nervosa

Three anorexics, one at normal weight, were examined, with a neuropsychological battery including the Halstead-Reitan tests. Their data were contrasted with that of 24 psychiatric controls matched for age, sex and IQ. Individually and as a group the anorexics showed above average verbal/academic scores and impaired spatial skills, whereas visual-motor and problem solving skills were equivalent to controls. Somatosensory recognition was impaired bilaterally in all three patients, and motor skills were low in the two emaciated patients. Other sensory tests and intermanual comparisons of sensory and motor skills were not impaired relative to controls. The findings suggest that a spatial reasoning deficit may be a predisposing or maintaining factor in this disorder. High verbal skills, in contrast, may reflect substantial left hemisphere contributions to the anorexics cognitive style.

Differential cognitive contributions of the cerebral hemispheres in the modulation of emotional arousal

To examine the differential roles of the two cerebral hemispheres in emotional processes, college students viewed sexual or aversive slides under instructions to either facilitate or inhibit their emotional responses. An auditory attentional bias measure suggested that reported aversive emosional arousal was associated with relatively greater activation of the right hemisphere. Analysis of the subjects naturalistic cognitive strategies suggested that analytic and verbal ideation was most often used to inhibit arousal, while global and imaginal thinking was used to facilitate emotion.

Lateralized Cognitive Style and Self-Description

A scale of hemispheric preference in cognitive style was related to self-report measures of emotional functioning, with the hypothesis that persons who rely on cognition characteristic of one hemisphere may also manifest emotional characteristics of that hemisphere. In two studies, university students characterizing themselves as preferring a cognitive style representative of right hemisphere processes endorsed more positive emotional orientations. This finding may suggest a more optimistic attitude, but may also reflect a tendency to deny negative traits; a right hemispheric cognitive style was associated with a positive self-report bias. These observations in normals have interesting parallels to the changes in emotional orientation and self-description bias that follow lateralized brain lesions or temporal lobe epilepsy.

Hemispheric specialization and cognitive behavior therapy

Some cognitive behavior therapy methods focus upon verbal cognition, others place more emphasis upon imagery. These two modes of cognition are represented differently in the brain: In most individuals imagery is a function of the right cerebral hemisphere and verbal cognition is processed in the left hemisphere. Two cognitive behavioral methods, one emphasizing imagery, the other verbalizations, were used by speech-anxious subjects, half of whom showed greater right hemisphere usage, half greater left hemisphere usage as indicated by their lateral eye movements in response to reflective questions. Although only approaching significance, the results suggested that treatment was most effective if it employed cognition of the subjects nonpreferred hemisphere. This may suggest that clients with clear imagery may benefit more from a verbal strategy, while clients with frequent self-verbalization may benefit more by using coping imagery.

Evolutionary approaches to understanding the hypnotic experience.

Using Tinbergen’s 4 why questions of causation, development, evolution, and function, the authors examine hypnosis from a larger, evolutionary perspective. Reasoning by analogy, they seek to view hypnosis in terms of an action pattern that represents a self-contained behavioral program although not as rigid as seen in lower organisms. In humans, such a program develops within the context of a long developmental sequence emphasizing social connections, imitation of significant figures, and the use of linguistic symbols to regulate both internal and external processes and actions. In terms of a mechanism, the authors speculate on the involvement of the cingulate cortex in achieving in hypnosis the experience of autonomous actions or analgesic sensory processes. Finally, they point to the fact that hypnotizability is associated with an ability to reduce the experience of pain, modulate the immune system, and achieve greater benefits of psychosocial therapies as a functional significance of the hypnotic experience.

Personality correlates of EEG change during meditation.

15 seminary students who regularly practiced a form of Christian meditation were given the Minnesota Multiphasic Personality Inventory (MMPI). Electroencephalographic (EEG) signals were recorded and analyzed for percent time alpha during performance of a series of mental arithmetic tasks and also during a period of meditation. Higher scores on the Hypochondriasis scale of the MMPI were associated with increase in alpha as the subject proceeded from the mental arithmetic tasks to the meditation period. This result is discussed in terms of previous research, the pre-meditation level of alpha, and the implications for the use of meditation as a therapeutic procedure.