Graphical AbstractThe SRY gene, which is located on the Y chromosome and directs male development, may promote aggression and other traditionally male behavioural traits, resulting in the fight-or-flight reaction to stress.

This paper proposes that mammals exhibit three primary emotion categories for mating and reproduction: (1) the sex drive, or lust, characterized by the craving for sexual gratification; (2) attraction, characterized by increased energy and focused attention on one or more potential mates, accompanied in humans by feelings of exhilaration, “intrusive thinking” about a mate, and the craving for emotional union with this mate or potential mate; and (3) attachment, characterized by the maintenance of close social contact in mammals, accompanied in (...) humans by feelings of calm, comfort, and emotional union with a mate. Each emotion category is associated with a discrete constellation of neural correlates, and each evolved to direct a specific aspect of reproduction. The sex drive is associated primarily with the estrogens and androgens; it evolved to motivate individuals to seek sexual union. The attraction system is associated primarily with the catecholamines; it evolved to facilitate mate choice, enabling individuals to focus their mating effort on preferred partners. The attachment system is associated primarily with the peptides, vasopressin, and oxytocin; it evolved to motivate individuals to engage in positive social behaviors and assume species-specific parental duties.During the evolution of the genus Homo, these emotion systems became increasingly independent of one another, a phenomenon that contributes to human mating flexibility and the wide range of contemporary human mating and reproductive strategies. (shrink)

Attention-deficit/hyperactivity disorder (ADHD) is currently defined as a cognitive/behavioral developmental disorder where all clinical criteria are behavioral. Inattentiveness, overactivity, and impulsiveness are presently regarded as the main clinical symptoms. The dynamic developmental behavioral theory is based on the hypothesis that altered dopaminergic function plays a pivotal role by failing to modulate nondopaminergic (primarily glutamate and GABA) signal transmission appropriately. A hypofunctioning mesolimbic dopamine branch produces altered reinforcement of behavior and deficient extinction of previously reinforced behavior. This gives rise to delay (...) aversion, development of hyperactivity in novel situations, impulsiveness, deficient sustained attention, increased behavioral variability, and failure to “inhibit” responses (“disinhibition”). A hypofunctioning mesocortical dopamine branch will cause attention response deficiencies (deficient orienting responses, impaired saccadic eye movements, and poorer attention responses toward a target) and poor behavioral planning (poor executive functions). A hypofunctioning nigrostriatal dopamine branch will cause impaired modulation of motor functions and deficient nondeclarative habit learning and memory. These impairments will give rise to apparent developmental delay, clumsiness, neurological “soft signs,” and a “failure to inhibit” responses when quick reactions are required. Hypofunctioning dopamine branches represent the main individual predispositions in the present theory. The theory predicts that behavior and symptoms in ADHD result from the interplay between individual predispositions and the surroundings. The exact ADHD symptoms at a particular time in life will vary and be influenced by factors having positive or negative effects on symptom development. Altered or deficient learning and motor functions will produce special needs for optimal parenting and societal styles. Medication will to some degree normalize the underlying dopamine dysfunction and reduce the special needs of these children. The theory describes how individual predispositions interact with these conditions to produce behavioral, emotional, and cognitive effects that can turn into relatively stable behavioral patterns. Key Words: catecholamine; clumsiness; dopamine; hyperkinesis; hyperkinetic disorder; impulsivity; monoamine; neuromodulator; overactivity; pollutants; reinforcement; reward; verbally governed behavior; soft signs; variability. (shrink)

A comparative method of studying the biological bases of personality compares human trait dimensions with likely animal models in terms of genetic determination and common biological correlates. The approach is applied to the trait of sensation seeking, which is defined on the human level by a questionnaire, reports of experience, and observations of behavior, and on the animal level by general activity, behavior in novel situations, and certain types of naturalistic behavior in animal colonies. Moderately high genetic determination has been (...) found for human sensation seeking, and marked strain differences in rodents have been found in open-field behavior that may be related to basic differences in brain neurochemistry. Agonistic and sociable behaviors in both animals and humans and the trait measure of sensation seeking in humans have been related to certain common biological correlates such as gonadal hormones, monoamine oxidase (MAO), and augmenting of the cortical evoked potential.The monoamine systems in the rodent brain are involved in general activity, exploratory behavior, emotionality, socialization, dominance, sexual and consummately behaviors, and intracranial self-stimulation. Preliminary studies have related norepinephrine and enzymes involved in its production and degradation to human sensation seeking. A model is suggested that relates mood, behavioral activity, sociability, and clinical states to activity of the central catecholamine neurotransmitters and to neuroregulators and other transmitters that act in opposite ways on behavior or stabilize activity in the arousal systems. Stimulation and behavioral activity act on the catecholamine systems in a brain–behavior feedback loop. At optimal levels of catecholamine systems activity (CSA) mood is positive and activity and sociability are adaptive. At very low or very high levels of CSA mood is dysphoric, activity is restricted or stereotyped, and the organism is unsocial or aggressively antisocial. Novelty, in the absence of threat, may be rewarding through activation of noradrenergic neurons. (shrink)

I hypothesize that people engage in religious practices, in part, because such practices activate the frontal lobes. Activation of the frontal lobes is both intrinsically rewarding and necessary for acquisition of many of the behaviors that religions seek to foster, including self‐responsibility, impulse and emotion modulation, empathy, moral insight, hope, and optimism. Although direct tests of the hypothesis are as yet nonexistent, there is reasonably strong circumstantial evidence (reviewed herein) for it. Recent brain‐imaging studies indicate greater anterior activation values and (...) increased blood flow to frontal sites during prayer and meditation. Regular prayer is positively correlated with better overall mental health. Religiosity is correlated with higher levels of self‐monitoring, empathy, and moral insight and other positive behaviors and negatively correlated with depression and impulsive and risky behaviors. Independent data show that self‐monitoring, empathy, hope, and moral insight are all selectively associated with intact frontal function, whereas depression, impulsiveness, and drug and alcohol abuse are associated selectively with frontal dysfunction. If religious practices do indeed preferentially activate and stimulate development of the frontal lobes, (a) religious practices should be considered as possible adjuncts for some patients in treatment for mental health disorders, and (b) the frontal lobes (rather than the temporal lobes) should be considered the major brain site that supports the core components of religious experience. (shrink)

Recent years have witnessed an intensification of historical and philosophical research on the link between psychotropic drugs and psychiatric theories. For example, Kendler and Schaffner detailed how the dopamine hypothesis of schizophrenia was intimately linked to the dopamine theory of antipsychotic drug action. Here, a related case is explored: the use of antidepressants' neurochemical effects to speculate about the pathophysiology of depression.This rationale was central to American psychiatrist Schildkraut's landmark article on the catecholamine hypothesis of affective disorders. Accordingly, the paper's (...) hypothesis—that depressions may relate to decreased... (shrink)

The target articles on sleep and dreaming are discussed in terms of the concept of search activity integrating different types of behavior, body resistance, REM sleep/dream functions, and the brain catecholamine system. REM sleep may be functionally sufficient or insufficient, depending on the dream scenario, the latter being more important than the physiological manifestation of REM sleep. REM sleep contributes to memory consolidation in the indirect way. [Nielsen; Revonsuo; Solms; Vertes & Eastman].

Amine acetylation is a diverse topic with importance to the regulation of several physiological processes as well as the metabolism of drugs and environmental chemicals. Arylalkylamine N‐acetyltransferase is widely distributed in several species, where this enzyme plays an important role in the seasonal regulation of reproduction and photoperiodism in vertebrates through the pathway of melatonin formation. In insects, this enzyme is involved in monoamine neurotransmitter inactivation and the formation of catecholamine intermediates necessary for sclerotization of the insect cuticle.

Cognitive dysfunction in Alzheimer’s disease is caused by disturbances in neuronal circuits of the brain underpinned by synapse loss, neuronal dysfunction and neuronal death. Amyloid beta and tau protein cause these pathological changes and enhance neuroinflammation, which in turn modifies disease progression and severity. Vagal nerve stimulation, via activation of the locus coeruleus, results in the release of catecholamines in the hippocampus and neocortex, which can enhance synaptic plasticity and reduce inflammatory signalling. Vagal nerve stimulation has shown promise to (...) enhance cognitive ability in animal models. Research in rodents has shown that VNS can have positive effects on basal synaptic function and synaptic plasticity, tune inflammatory signalling, and limit the accumulation of amyloid plaques. Research in humans with invasive and non-invasive VNS devices has shown promise for the modulation of cognition. However, the direct stimulation of the vagus nerve afforded with the invasive procedure carries surgical risks. In contrast, non-invasive VNS has the potential to be a broadly available therapy to manage cognitive symptoms in early AD, however, the magnitude and specificity of its effects remains to be elucidated, and the non-inferiority of the effects of non-invasive VNS as compared with invasive VNS still needs to be established. Ongoing clinical trials with healthy individuals and patients with early AD will provide valuable information to clarify the potential benefits of non-invasive VNS in cognition and AD. Whether invasive or non-invasive VNS can produce a significant improvement on memory function and whether its effects can modify the progression of AD will require further investigation. (shrink)

This article reviews the effects of malnutrition on early brain development using data generated from animal experiments and human clinical studies. Three related processes, each with their own functional consequences, are implicated in the alteration of brain development. (1) Maternal undernutrition at the start of pregnancy results in reduced transfer of nutrients across the placenta, allowing the conservation of effort for future reproductive episodes. (2) Differential allocation to growing organs by the fetus in response to nutritional stress spares the brain (...) to a large though still limited degree, reflecting the organ’s relative contribution to survival and reproductive success. (3) Prenatal malnutrition disrupts developing neurotransmitter systems, which results in the expression of specific cognitive and affective traits. It is argued that the increasing size and therefore cost of the brain, in conjunction with increasing ecological instability and marginality, reinforced selection for maternally controlled growth suppression of offspring, reallocation of organ growth rates by offspring, and behavioral changes related to development of neurotransmitter systems. (shrink)