TEACHING BRAIN—BEHAVIOR RELATIONS ECONOMICALLY WITH STIMULUS EQUIVALENCE TECHNOLOGY

Instructional interventions based on stimulus equivalence provide learners with the opportunity to acquire skills that are not directly taught, thereby improving the efficiency of instructional efforts. The present report describes a study in which equivalence‐based instruction was used to teach college students facts regarding brain anatomy and function. The instruction involved creating two classes of stimuli that students understood as being related. Because the two classes shared a common member, they spontaneously merged, thereby increasing the yield of emergent relations. Overall, students mastered more than twice as many facts as were explicitly taught, thus demonstrating the potential of equivalence‐based instruction to reduce the amount of student investment that is required to master advanced academic topics.     

Functional neuroimaging studies of syntactic processing

This paper reviews studies of the functional neuroanatomy of syntactic processing using positron emission tomography (PET) and functional magnetic resonance imaging (fMRI), focusing on interpretability of studies and the model of functional neuroanatomy that emerges from existing work. It is argued that existing studies suggest a specialization for one aspect of syntactic processing in the left inferior frontal cortex in proficient language users, with variability in this localization across the entire population.     

Aggressive behavior induced by electrical stimulation in the midbrain central gray of male rats

Electrical stimulation via electrodes implanted in the lateral hypothalamus may induce intraspecific aggressive behavior. Small electrolytic lesions placed via these electrodes resulted in a five– to tenfold increase in the current threshold for aggression. Degenerating fibers were stained by means of the Fink-Heimer method and could be followed caudally to the dorsal midbrain central gray and to the mammillary bodies. A few axons could be traced rostrally to the medial septum. Aggression could be induced from 10 of 112 electrodes implanted in the central gray; the other electrodes elicited either locomotion, vocalization, jump, or “alarm-like reactions.” The morphology of the induced aggression was similar to the morphology of the hypothalamically induced aggression, though it was often accompanied with motor disturbances and was less intense. Hypothalamic stimulation was combined with simultaneous central gray stimulation in rats with electrodes both in the hypothalamus and in the central gray. Hypothalamic thresholds for aggression could be lowered by this stimulation of the central gray, even when no aggressive responses were observed during central gray stimulation alone. This suggests that, although aggression is not manifest, electrical stimulation may activate neural tissue involved in aggressive behavior. It is concluded that in rats central gray and hypothalamus are part of the same neural network mediating intraspecific aggression.     

"Miles within Millimeters" and Other Awe–Inspiring Facts about Our "Mortarboard" Human Cortex

Consideration of the amazing organized intricacy of human cortical anatomy entails a deeper appreciation of nature that is fully consistent with a mature religious spirit. A brain seems at first glance to be a mere lump of grayish claylike stuff, but facts of basic neuroanatomy compel us to consider that this particular kind of stuff may really contain all the richly tangible and richly ghostly inner essences of emotion, thought, and behavior. Humans are the "college graduates" of evolution. The human cortex is 3,400 times the volume of, yet only slightly thicker (about 3 millimeters) than, that of the mouse. This remarkable sheet is as thin as a graduation-day "mortarboard" cap, but its 2,600 square centimeter area is four times as large (about 20 × 20 inches if a square; both metric and English units used deliberately). Zooming in, there are about 50 billion cortical neurons; though named after "pyramids," they are more like tiny "magic trees," with branches and roots so long and fine that there are 1 or 2 miles of these electrically scintillating fibers within each cubic millimeter of cortex. Cortical neurons communicate intimately: viewed from above, beneath a single square millimeter 100,000 nerve cells intertwine; each such neuron makes 5,000 or more connections with others. These and many additional amazing facts about brain tissue, together with some conjectures about dense connectedness in the mathematics of graph theory, help to bear out the groundwork prepared by such pioneers as Ralph Wendell Burhoe that the spirit and knowledge of science might rejoin that of religion. If it takes enchanted matter to contain consciousness, this is a kind of enchantment that science may well be able to penetrate for eventual thoroughgoing understanding. Inevitable by-products will be greater reverence for nature and greater awe at the mystery of nature's origin.     

Neuropsychological aspects of facial asymmetry during emotional expression: A review of the normal adult literature

This review focuses on facial asymmetries during emotional expression. Facial asymmetry is defined as the expression intensity or muscular involvement on one side of the face (“hemiface”) relative to the other side and has been used as a behavioral index of hemispheric specialization for facial emotional expression. This paper presents a history of the neuropsychological study of facial asymmetry, originating with Darwin. Both quantitative and qualitative aspects of asymmetry are addressed. Next, neuroanatomical bases for facial expression are elucidated, separately for posed/voluntary and spontaneous/involuntary elicitation conditions. This is followed by a comprehensive review of 49 experiments of facial asymmetry in the adult literature, oriented around emotional valence (pleasantness/unpleasantness), elicitation condition, facial part, social display rules, and demographic factors. Results of this review indicate that the left hemiface is more involved than the right hemiface in the expression of facial emotion. From a neuropsychological perspective, these findings implicate the right cerebral hemisphere as dominant for the facial expression of emotion. In spite of the compelling evidence for right-hemispheric specialization, some data point to the possibility of differential hemispheric involvement as a function of emotional valence. An earlier version of this paper by the first author was presented at the XV Annual Symposium of the Society of Craniofacial Genetics, July 12, 1992, Stanford University, Palo Alto, CA.     

WOMEN: A MORE BALANCED BRAIN?

Abstract. On the basis of knowledge prior to 1988, Ashbrook pointed out that whereas most men are primarily dependent on the left cerebral hemisphere (“dominant hemisphere”) for verbally related functions, women show a greater hemispheric balance in this respect. For men, he argues, their possession of a “speaking” and a “non-speaking hemisphere” results in a positive-negative, bipolar way of thinking that may be characterized as dualistic and dialectically hierarchical. In contrast, the greater balance of hemispheric function in women appears to promote greater generalization and synthesis in their thinking. In this article I cite more recent neuroanatomical and brain imaging studies that provide further evidence of disparities in structure and function of the brains of men and women. As background for an attempt to explain these differences, I give a brief review of the triune evolution of the mammalian brain leading up to the human cerebrum. It is of major significance that the female has played a central role in mammalian evolution for more than 180 million years and that the evolutionary transition from reptilian therapsids to mammals is characterized by the develoment of (1) nursing conjoined with maternal care; (2) audiovocal communication or aiding mother-offspring contact; and (3) play. In human beings, the infant-carrying hypothesis suggests one means by which, over generations, certain parts of a woman's right hemisphere could undergo functional and eventual anatomical expansion. The mother-infant communication of basic mammalian sounds with vowel and consonant components suggests a basis for the origination of speech. Finally, in an expansion of Ashbrook's original thesis, we arrive at the rovocative consideration that, unlike men, with their dialectical reasoning, women, with their more balanced brain, are provided with a trialectial ladder for climbing to achieve knowledge. In terms of quantum mechanics, the particle and wave would correspond to the substance and strength of the sides of the ladder, and the derived psychic information (which is neither matter nor energy) would compare to the rungs in between.     

BRAIN, SYMBOL, & EXPERIENCE: A PSYCHIATRIC AND THEOLOGICAL DIALOGUE

Abstract. Brain, Symbol & Experience attempts to solidify the authors' work in the fields of neurophenomenology and consciousness. The interdisciplinary nature of the work dictates less than extensive discussions of individual academic topics, but it does facilitate the identification of mutual points of interest for future pluralistic dialogues. This paper explores the implications of Laughlin, McManus, and d'Aquili for the neurosciences, psycho-pathology, psychotherapy, contemporary literature, theology, and faith development theory. Suggestions for specific interdisciplinary conversations are offered.