Part two of this three-part series commences with anomalous dominance and special talents. Part one appears in a previous issue of theArchives. 1 ANOMALOUS DOMINANCE AND SPECIAL TALENTS According to our hypothesis, slowed growth within certain zones of the left hemisphere is likely to result in enlargement of other cortical regions, in particular, the homologous contralateral area, but also adjacent unfaffected regions. The influences that favor anomalous dominance may thus favor talents associated with superior development of certain regions either in the right hemisphere or in adjacent parts of the left hemisphere. Even with excessive retardation of growth and the resultant migration abnormalities and learning disorders (LD), high talents may exist as a result of compensatory enlargement of other cortical regions. Several types of data are in concordance with these conclusions. Several studies have claimed that the average level of spatial talents is higher in male subiects. 2 Hier

https://jamanetwork.com/journals/jamaneurology/articlepdf/584161/archneur_42_5_008.pdf

Cerebral lateralization. Biological mechanisms, associations, and pathology: II. A hypothesis and a program for research.

The ability to modify mice genetically has been one of the major breakthroughs in modern medical science affecting every discipline including psychiatry. It is hoped that the application of such technologies will result in the identification of novel targets for the treatment of diseases such as depression and to gain a better understanding of the molecular pathophysiological mechanisms that are regulated by current clinically effective antidepressant medications. The advent of these tools has resulted in the need to adopt, refine and develop mouse-specific models for analyses of depression-like behavior or behavioral patterns modulated by antidepressants. In this review, we will focus on the utility of current models (eg forced swim test, tail suspension test, olfactory bulbectomy, learned helplessness, chronic mild stress, drug-withdrawal-induced anhedonia) and research strategies aimed at investigating novel targets relevant to depression in the mouse. We will focus on key questions that are considered relevant for examining the utility of such models. Further, we describe other avenues of research that may give clues as to whether indeed a genetically modified animal has alterations relevant to clinical depression. We suggest that it is prudent and most appropriate to use convergent tests that draw on different antidepressant-related endophenotypes, and complimentary physiological analyses in order to provide a program of information concerning whether a given phenotype is functionally relevant to depression-related pathology.

In search of a depressed mouse: utility of models for studying depression-related behavior in genetically modified mice.

Introduction * Hormonal and Nonhormonal Basis of Maternal Behavior * Experiential Factors Influencing Maternal Behavior * Motivational Models of the Onset and Maintenance of Maternal Behavior and Maternal Agression * Neuroanatomy of Maternal Behavior * Neurochemistry and Molecular Biology of Maternal Behavior * Paternal Behavior * Neural Basis of Parental Behavior Revisited * Human Implications

The Neurobiology of Parental Behavior

A review of research with chicks, songbirds, rodents, and nonhuman primates indicates that the brain is lateralized for a number of behavioral functions. These findings can be understood in terms of three hypothetical brain processes derived from a brain model based on general systems theory: hemispheric activation, interhemispheric inhibition, and interhemispheric coupling.Left-hemisphere activation occurs in songbirds and nonhuman primates in response to salient auditory or visual input, or when a communicative output is required. The right hemisphere is activated in rats when spatial performance is required, and in chicks when they are placed in an emotion-provoking situation. In rats and chicks interhemispheric activation and inhibition occur when there is an affective component in the environment (novelty, aversive conditioning) or when an emotional response is emitted (copulation, attack, killing). An interhemispheric coupling (correlation) found in rats and rabbits implies that the hemispheres are two major components in a control system with a negative feedback loop. Early-experience variables in rats can induce laterality in a symmetric brain or facilitate its development in an already biased brain.It is predicted that functional lateralization, when present, will be similar across species: the left hemisphere will tend to be involved in communicative functions while the right hemisphere will respond to spatial and affective information; both hemispheres will often interact via activation-inhibition mechanisms when affective or emotional processes are involved. Homologous brain areas and their connecting callosal fibers must be intact at birth and must remain intact throughout development for lateralization to reach its maximum level. Injury to any portion of this unit will result in hemispheric redundancy rather than specialization. One major function of early experience is to provide stimulation during development, which acts to enhance the growth and development of the corpus callosum, thereby giving rise to a more specialized brain.

Hemispheric laterality in animals and the effects of early experience

This review focuses on prenatal stress as a risk factor for psychopathology. Evidence from animal studies is summarized, and the relevance of prenatal stress models in animals for human studies is discussed. In the offspring of prenatally stressed animals, overactivity and impaired negative feedback regulation of the hypothalamic-pituitary-adrenal axis are consistent findings and may reflect a pathophysiological mechanism involved in the development of psychopathology. Reduced activity of the opioid GABA/benzodiazepine, serotonin, and dopamine systems and increased activity of the sympathico-adrenal system have been found as well. These alterations have been linked to a diverse spectrum of psychopathology. Therefore, the evidence supports the view that exposure to prenatal stress may result in a general susceptibility to psychopathology, rather than exerting a direct effect on a specific form of psychopathology.

Prenatal stress and risk for psychopathology: specific effects or induction of general susceptibility?

Olfactory bulb removal eliminated maternal behavior in lactating and in virgin mice. The results are in contrast to the generally accepted concept of multisensory control of mammalian maternal behavior.

https://science.sciencemag.org/content/sci/171/3967/210.full.pdf

Olfactory bulb removal eliminates maternal behavior in the mouse.

Prolactin: Is it an essential hormone for maternal behavior in the mammal?

The development of standard stimulus animals for mouse (Mus musculus) aggression testing by means of olfactory bulbectomy

Effects of handling in infancy upon adult behavior and adrenocortical activity: suggestions for a neuroendocrine mechanism1

Retrieval in lactating females, sensitized virgin females, and sensitized adult male rats was compared in a T-maze extension of the home cage. The percent of lactating females that retrieved was significantly greater than in either the sensitized virgin of sensitized male groups. No difference was found between the two sensitized groups. The data are discussed in terms of the hormonal involvement in maternal behavior.

M.X. Zarrow

Papers

Olfactory bulb removal eliminates maternal behavior in the mouse.

Prolactin: Is it an essential hormone for maternal behavior in the mammal?

The development of standard stimulus animals for mouse (Mus musculus) aggression testing by means of olfactory bulbectomy

Effects of handling in infancy upon adult behavior and adrenocortical activity: suggestions for a neuroendocrine mechanism1

Differences in maternal responsiveness between lactating and sensitized rats.