In “Freedom and Resentment,” P. F. Strawson argues that the “profound opposition” between the objective and reactive stances is quite compatible with our rationally retaining the latter as important elements in a recognizably human life. Unless he can establish this, he has no hope of establishing his version of compatibilism in the free will debate. But, because objectivity is associated so intimately with the rationally conducted explanation of action, it is not clear how the opposition of these stances is compatible (...) with the rationality of the reactive attitudes. More to the point, it is not clear how an intellectual activity like shifting from the reactive to the objective stance can dispel reactive attitudes without thereby also rationally disqualifying them. I solve this puzzle by drawing on the idea that one cognitive component of emotions is the rationally optional “shift of attention.” a feature which in turn helps to explain a lot about the role reactive emotions can play in the fixation of belief. (shrink)

_Abstract_: Rather than seeking a common architecture for cognitive processing, this paper argues that we should recognize that the brain employs multiple information processing structures. Many of these are manifest in brain areas outside the neocortex such as the hypothalamus, brain stem pattern generators, the basal ganglia, and various nuclei releasing neuromodulators. Rather than employing one mode of information processing, the brain employs multiple modes integrated in a heterarchical network. These in turn affect processing within the neocortex and together (...) with the neocortex regulate vertebrate behavior, including human. Cognitive science can better understand human information processing by attending to the plurality of information-processing architectures employed in the brain. _Keywords_: Basal Ganglia; Cognitive Architectures; Heterarchical Networks; Hypothalamus; Pattern Generators; Neuromodulators _Ripensare l’architettura cognitiva: una rete eterarchica di differenti tipi di elaborazione di informazione_ _Riassunto_: Anziché cercare un’architettura comune ai processi cognitivi, in questo lavoro si sosterrà che dovremmo riconoscere come il cervello impieghi molteplici strutture per processare l’informazione. Molte di loro si trovano nelle aree cerebrali esterne alla neocorteccia, come l’ipotalamo, i generatori di pattern del tronco encefalico, i gangli basali e i vari nuclei che rilasciano i neuromodulatori. Anziché impiegare un’unica modalità per l’elaborazione dell’informazione, il cervello usa molteplici modalità integrate in una rete eterarchica. Queste, a loro volta, influenzano i processi all’interno della neocorteccia e, assieme alla neocorteccia, regolano il comportamento dei vertebrati, compreso quello umano. La scienza cognitiva può meglio comprendere l’elaborazione dell’informazione da parte degli esseri umani concentrandosi sulla pluralità delle architetture impiegate nel cervello per realizzare questa elaborazione. _Parole chiave_: Gangli basali; Architetture cognitive; Reti eterarchiche; Ipotalamo; Generatori di pattern; Neuromodulatori. (shrink)

We recently described a novel form of stress‐associated bidirectional plasticity at GABA synapses onto hypothalamic parvocellular neuroendocrine cells (PNCs), the apex of the hypothalamus‐pituitary‐adrenal axis. This plasticity may contribute to neuroendocrine adaptation. However, this GABA synapse plasticity likely does not translate into a simple more and less of inhibition because the ionic driving force for Cl−, the primary charge carrier for GABAA receptors, is dynamic. Specifically, stress impairs a Cl− extrusion mechanism in PNCs. This not only renders the steady‐state (...) GABA response less hyperpolarizing but also makes PNCs susceptible to the activity‐dependent accumulation of Cl−. Accordingly, GABA synapse plasticity impacts both the robustness of GABA voltage response and dynamic Cl− loading, imposing nonlinear influences on PNC excitability during circuit activities. This theoretical consideration predicts roles for GABA transmission far more versatile than canonical inhibition. We propose potential impacts of GABA synapse plasticity on the experience‐dependent fine‐tuning of neuroendocrine stress responses. (shrink)

Childhood adversity is associated with altered or dysregulated stress reactivity; these altered patterns of physiological functioning persist into adulthood. Evidence from both preclinical animal models and human neuroimaging studies indicates that early life experience differentially influences stressor-evoked activity within central visceral neural circuits proximally involved in the control of stress responses, including the subgenual anterior cingulate cortex (sgACC), paraventricular nucleus of the hypothalamus (PVN), bed nucleus of the stria terminalis (BNST) and amygdala. However, the relationship between childhood adversity and (...) the resting-state connectivity of this central visceral network remains unclear. To this end, we examined relationships between childhood threat and childhood socioeconomic deprivation, the resting-state connectivity between our regions of interest (ROIs), and affective symptom severity and diagnoses. We recruited a transdiagnostic sample of young adult males and females (n= 100; mean age = 27.28,SD= 3.99; 59 females) with a full distribution of maltreatment history and symptom severity across multiple affective disorders. Resting-state data were acquired using a 7.2-min functional magnetic resonance imaging (fMRI) sequence; noted ROIs were applied as masks to determine ROI-to-ROI connectivity. Threat was determined by measures of childhood traumatic events and abuse. Socioeconomic deprivation (SED) was determined by a measure of childhood socioeconomic status (parental education level). Covarying for age, race and sex, greater childhood threat was significantly associated with lower BNST-PVN, amygdala-sgACC and PVN-sgACC connectivity. No significant relationships were found between SED and resting-state connectivity. BNST-PVN connectivity was associated with the number of lifetime affective diagnoses. Exposure to threat during early development may entrain altered patterns of resting-state connectivity between these stress-related ROIs in ways that contribute to dysregulated neural and physiological responses to stress and subsequent affective psychopathology. (shrink)

The hypothalamus is a specialized area in the brain that integrates the control of energy homeostasis. More than 70 years ago, it was proposed that the central nervous system sensed circulating levels of metabolites such as glucose, lipids and amino acids and modified feeding according to the levels of those molecules. This led to the formulation of the Glucostatic, Lipostatic and Aminostatic Hypotheses. It has taken almost that much time to demonstrate that circulating long‐chain fatty acids act as signals (...) of nutrient surplus in the hypothalamus. Moreover, pharmacological and/or genetic inhibition of fatty acid synthase, AMP‐activated protein kinase and carnitine palmitoyltransferase 1 results in profound decrease in feeding and body weight in rodents. The molecular mechanism behind these actions depends on changes in the cellular pool of malonyl‐CoA and fatty acyl‐CoAs. Current evidence also suggests that this pathway may play a major role in the physiological regulation of feeding, by integrating hormonal and nutrient‐derived signals in the hypothalamus. Here, we summarize what is known about hypothalamic fatty acid metabolism and feeding control and provide future directions for research. Understanding these molecular mechanisms could provide new targets for the treatment of obesity and related disorders. BioEssays 29: 248–261, 2007. © 2007 Wiley Periodicals, Inc. (shrink)

Although most aspects of world and self-consciousness are inherently subjective, neuroscience studies in humans and non-human animals provide correlational and causative indices of specific links between brain activity and representation of the self and the world. In this article we review neuroanatomic, neurophysiological and neuropsychological data supporting the hypothesis that different levels of self and world representation in vertebrates rely upon i) a 'basal' subcortical system that includes brainstem, hypothalamus and central thalamic nuclei and that may underpin the primary (...) (or anoetic) consciousness likely present in all vertebrates; and ii) a forebrain system that include the medial and lateral structures of the cerebral hemispheres and may sustain the most sophisticated forms of consciousness (e.g. noetic (knowledge based) and autonoetic, reflective knowledge). We posit a mutual, bidirectional functional influence between these two major brain circuits. We conclude that basic aspects of consciousness like primary self and core self (based on anoetic and noetic consciousness) are present in many species of vertebrates and that, even self-consciousness (autonoetic consciousness) does not seem to be a prerogative of humans and of some non-human primates but may, to a certain extent, be present in some other mammals and birds. (shrink)

The classification of preserved hypothalamic activity in brain death and brainstem death as functional or non-functional has become a subject of debate. While proponents of the neurological criterion claim that these activities lack functional significance (Shemie et al. 2014), Nair-Collins and Joffe (2023) argue for their functional physiological role. However, the interpretation of the term "function" within the medico-legal framework, where death is characterized by the irreversible cessation of all brain functions, remains unclear. -/- My intention here is not to (...) engage in a debate over the validity of different viewpoints regarding the functional significance of preserved activities in the hypothalamus or the heart. Rather, I aim to highlight the critical importance of exploring and defining the concept of function in medicine, which currently lacks clarity. My point is that, whatever our position in the brain death debate, reaching a consensus on this conceptual matter would minimize misunderstandings and establish a robust foundation for further insightful analysis. (shrink)

The success of deep brain stimulation (DBS) for movement disorders and the improved understanding of the neurobiologic and neuroanatomic bases of psychiatric diseases have led to proposals to expand current DBS applications. Recent preclinical and clinical work with Alzheimer's disease and obsessive-compulsive disorder, for example, supports the safety of stimulating regions in the hypothalamus and nucleus accumbens in humans. These regions are known to be involved in addiction and overeating associated with obesity. However, the use of DBS targeting these (...) areas as a treatment modality raises common ethical considerations, which include informed consent, coercion, enhancement, threat to personhood, and manipulation of the reward center. Pilot studies for both of these conditions are currently investigational. If these studies show promise, then there is a need to address the ethical concerns related to the initiation of clinical trials including the reliability of preclinical evidence, patient selection, study design, compensation for participation and injury, cost-effectiveness, and the need for long-term follow-up. Multidisciplinary teams are necessary for the ethical execution of such studies. In addition to establishing safety and efficacy, the consideration of these ethical issues is vital to the adoption of DBS as a treatment for these conditions. We offer suggestions about the pursuit of future clinical trials of DBS for the treatment of addiction and overeating associated with obesity and provide a framework for addressing ethical concerns related to treatment. (shrink)

Approach–avoidance generally describes appetitive motivation and fear of punishment. In a social context approach motivation is, however, also expressed as social aggression and dominance. We therefore link approach–avoidance to dominance–submissiveness, and provide a neural framework that describes how the steroid hormone testosterone shifts reflexive as well as deliberate behaviors towards dominance and promotion of social status. Testosterone inhibits acute fear at the level of the basolateral amygdala and hypothalamus and promotes reactive dominance through upregulation of vasopressin gene expression in (...) the central-medial amygdala. Finally, the hormone can, depending on social context and prenatal hormone exposure, promote both pro- and antisocial behaviors and decisions through its effects on prefrontal–amygdala interactions. All these effects of testosterone, however, serve to increase and maintain social status. (shrink)

Hypocretin regulates brain reward function and cocaine consumption in rats. The hypocretinergic (Hcrt) system is implicated in energy homeostasis, feeding and sleep regulation. Hypocretinergic cell bodies are located in the lateral hypothalamus (LH) and project throughout the brain. The aim of the present studies was to investigate the role of the Hcrt system in regulating brain reward function and the reinforcing properties of cocaine in rats. Intracranial self-stimulation (ICSS) thresholds provide an accurate measure of brain reward function in rats. (...) Here we show that a single injection of Hcrt-1 (5 µg icv) induced persistent, long-lasting elevations in ICSS thresholds in drug-naïve rats. Indeed, Hrct-1 elevated ICSS thresholds for 36 h, with peak elevations between 6 and 12 hours after injection. Hrct-1-induced threshold elevations were attenuated by an antibody known to neutralize the binding of hcrt-1 to its receptors. Taken together, these observations suggest that Hrct-1 negatively regulates brain reward function in rats. Because Hrct-1 negatively regulates brain reward function, we hypothesized that it may attenuate the increased brain reward function usually observed after cocaine consumption, and thereby alter cocaine self-administration behavior. A daily injection of Hrct-1 (1 µg icv), for 4 consecutive days, slightly increased cocaine self-administration (0.25 mg/infusion) in rats. Overall, these data demonstrate that Hrct-1 negatively regulates brain reward function, and as such may indirectly alter cocaine self-administration. Given the well-established role of hypocretin neurons in regulating feeding behavior and sleep, we hypothesize that hypocretinergic regulation of brain reward function may provide a mechanism by which appropriate and competing behaviors (e.g. sleep or feeding) may be engaged to maintain energy homeostasis. (shrink)

My commentary on mcmahon addresses the fact that only peripheral data have been considered for explaining differential sensibility in somato- and viscerosensory systems. This fails to take it into account that central processing for visceral and somatic inputs is now known to depend on different functional pathways. My commentary on berkley points out that the hypothalamus-pituitary axis is more responsive to stress in females than in males.

Solms and the other authors in this series of BBS target articles accept the findings that the executive control of the REM/NREM cycle is still localized within a narrow region of the pontine brainstem. However, recent findings challenge this notion. We will review the recent data and suggest instead that the hypothalamus is the primary regulator of states of consciousness. If the hypothalamus indeed controls all the fun stuff, such as sex, eating, drinking, sleeping, and so on, then (...) one can more easily accept Solms's argument that dreams are also generated from the forebrain. [Solms]. (shrink)

SummaryIn this synthetic exposition, devoted to the relations which exist between psľchic functions and anatomic structures, Dr Pontes first insists on the difficulties of the subject and of its scientific analysis. Soma, Psyche, and social Milieu form a kind of continuum which is artificiallľ dissociated by our one‐sided approaches. Experimentation cannot be fullľ practised on man, nor can its results on animal be extended to man without serious risks of error. Similar limitations appear if, resorting to the pathological method, we (...) try to apply to the normal conclusions arrived at through the Study of the abnormal. Special reference is made here to psychosurgery, a topic quite familiar to Dr Fontes, who is Dr Egas Moniz’ countryman.The author then summarises our present knowledge concerning the structure, connections and functions of encephalic centers, especially; the thalamus, the hypothalamus and the frontal lobes.Finally, he subscribes, though not without serious reservations, to the hierarchical conception of the Nervous Sľstem as well as of the human mind, first suggested by Jouffroy, after him developed by Baillarger, Janet, Wallon in France, by Hughlings Jackson in Great Britain, and recentlľ revived in Europe by von Mona‐kow and Mourgue, Eľ, and Delaľ. This view enables one to consider nervous or psľchic illnesses as various dissolutions, resulting on the one hand from the suppression of higher centers or powers, on the other hand from the liberation of lower ones. It agrees rather well with the informations gathered by the anatomy and the physiology of the nervous sľstem, and with the conclusions suggested by psychosurgical opérations. To the thalamus and hypothalamus correspond the lower and older manifestations of mind: emotion and instinct, to the cortex the higher and more recent adaptive and intellectual processes. The hypothalamus plays a most important role in the nervous machinery as a regulator of vegetative and instinctive life, of wake and sleep, of consciousness, and of the basic biological rhythms. At the cortical level the frontal lobe appears as the structural basis for such psychical functions as Ego‐control, Will, Personality, and succèssfull action on the milieu. (shrink)

Some patients who have been diagnosed as “dead by neurologic criteria” continue to exhibit certain brain functions, most commonly, neuroendocrine functions. This preservation of neurologic function after the diagnosis of “brain death” or “brainstem death” is an ongoing source of controversy and concern in the medical, bioethics, and legal literatures. Most obviously, if some brain function persists, then it is not the case that all functions of the entire brain have ceased and hence, declaring such a patient to be “dead” (...) would be a false positive, in any nation with so-called “whole brain death” laws. Furthermore, and perhaps more concerning, the preservation of any brain function necessarily entails the preservation of some amount of brain perfusion, thereby raising the concern as to whether additional areas of neural tissue may remain viable, including areas in the brainstem. These and other considerations cast significant doubt on the reliability of diagnosing either “brain death” or “brainstem death.”. (shrink)

Art perception offers action affordances for the self-generated movement of the eyes, the mind, and the emotions; thus some scenes are ’easy to look at', and evoke different kinds of moods depending on what kind of affordances they present for the eyes, the brain, and the action schemas that further the dynamical self-organizing patterns of activity toward which the organism tends, as reflected in its ongoing emotional life. Art can do this only because perception is active rather than passive, and (...) begins with efferent activity in emotional brain areas (e.g. hypothalamus, amygdala, hippocampus and anterior cingulate) which then motivates afferent processing (parietal imaging activity which finally, after a 1/3-second motivational/selective process is complete, resonates with occipital patterns, resulting in perceptual consciousness). The limbic system ’categories’ that motivate the ’looking-for’ of selective attention are categories of utility, to be understood in terms of emotional affordances and whole-organism affective meanings. Art plays with this looking-for, using it to make us engage in different afforded actions that relate to different limbic (emotional) categories. The drawings of children and of the artistically untutored reveal this structure when we fail to ’draw what we see’, drawing instead what we conceptualize that we ought to be seeing. Art teaches us to get beyond this almost complete dominance of habitual categories, and to see things more freshly -- both in the perceptual and in the emotive sphere. Rather than reinforcing our preconceptions, it forces us to see how they affect our view of reality. -/- Because neither perceptions nor emotional responses are really passive ’responses’ at all, art does not cause us to feel a certain way. Instead, we ’use’ art for the purpose of symbolizing our emotions. Our most important feelings are not directly ’about’ the perceptual objects that trigger them. The object in conscious attention during the feeling of an emotion is normally not the intentional object of the emotion, i.e., it is not the object in relation to which our actions could serve the purpose of the emotion. Emotions are not even triggered by simple ’stimuli’, but rather by the meaning for us of a stimulus in a total context determined by ongoing and dynamical organismic purposes. Emotions arise from the total life process, which is a dynamical system -- not as an isolated chemical event or a causal result of a simple stimulus. For this reason, emotions call not just for satiation or pleasure, but for explication; this is why art is different from entertainment or pretty decoration. Visual art affords not only a meaningful, self-directed dance of the eyes, but also a meaningful dance of this emotional explicating process. (shrink)

One of the positive arguments for the type-identity theory of mental states is an inference-to-the-best-explanation (IBE) argument, which purports to show that type-identity theory is likely true since it is the best explanation for the correlations between mental states and brain states that we find in the neurosciences. But given the methods of neuroscience, there are other relations besides identity that can explain such correlations. I illustrate some of these relations by examining the literature on the function of the (...) class='Hi'>hypothalamus and its correlation with sensations of thirst. Given that there are relations besides identity that can explain such correlations, the type-identity theorist is left with a dilemma: either the correlations we consider are weak, in which case we do not have an IBE to an identity claim, or else the correlations we look at are maximally strong, in which case there are too few cases for the inductive part of the strategy to work. (shrink)

This article examines the neurobiological basis of the healing power attributed to shamanic practices in the Andes and Brazil in light of the pharmacology of neurotransmitters and the new technological explorations of brain functioning. The psychotropic plants used in shamanic psychiatric cures interfere selectively with the intrinsic neuromediators of the brain. Mainly they may alter: (1) the neuroendocrine functioning through the adrenergic system by controlling stressful conditions, (2) the dopaminergic system in incentive learning and emotions incorporation, (3) the serotoninergic system (...) in modulating behaviors, and mood, and (4) basic functions implied in anxiety or depression. PET scans and functional magnetic resonance imaging studies of hypnotic trance and altered states of consciousness may provide a useful model for the neurophysiological phenomena of shamanic drum-and-dance trance. The reorganization of cortical areas and the direct interconnections between the prefrontal cortex and the dopaminergic reward centers in the limbic system are of particular significance for human social judgment and symbolic processing. Those centers—including the hypothalamus and the amygdala (associated with psychosomatic equilibrium, memory, and emotion) are enhanced. This arousal may be amplified in order to induce a cathartic crisis—the shamanic trance. It is suggested that through this holistic approach the shaman empirically interferes in neurobiological dysfunctions. (shrink)

Self-injurious behavior is associated with diverse psychiatric conditions. Sometimes, SIB is the most dominant symptom, severely restricting the psychosocial functioning and quality of life of the patients and inhibiting appropriate patient care. In severe cases, it can lead to permanent physical injuries or even death. Primary therapy consists of medical treatment and if implementable, behavioral therapy. For patients with severe SIB refractory to conventional therapy, neuromodulation can be considered as a last recourse. In scientific literature, several successful lesioning and deep (...) brain stimulation targets have been described that can indicate a common underlying neuronal pathway. The objectives of this study were to evaluate the short- and long-term clinical outcome of patients with severe, therapy refractory SIB who underwent DBS with diverse underlying psychiatric disorders and to correlate these outcomes with the activated connectivity networks. We retrospectively analyzed 10 patients with SIB who underwent DBS surgery with diverse psychiatric conditions including autism spectrum disorder, organic personality disorder after hypoxic or traumatic brain injury or Tourette syndrome. DBS targets were chosen according to the underlying disorder, patients were either stimulated in the nucleus accumbens, amygdala, posterior hypothalamus, medial thalamus or ventrolateral thalamus. Clinical outcome was measured 6 months after surgery and at long-term follow-up after 10 or more years using the Early Rehabilitation Barthel index and time of restraint. Connectivity patterns were analyzed using normative connectome. Based on previous literature the orbitofrontal cortex, superior frontal gyrus, the anterior cingulate cortex, the amygdala and the hippocampus were chosen as regions of interest. This analysis showed a significant improvement in the functionality of the patients with DBS in the short- and long-term follow-up. Good clinical outcome correlated with higher connectivity to the amygdala and hippocampus. These findings may suggest a common pathway, which can be relevant when planning a surgical procedure in patients with SIB. (shrink)

The Western diet pattern characterized by high daily intake of saturated fats and refined carbohydrates often leads to obesity and overweight, and it has been linked to cognitive impairment and emotional disorders in both animal models and humans. This dietary pattern alters the composition of gut microbiota, influencing brain function by different mechanisms involving the gut–brain axis. In addition, long-term exposure to highly palatable foods typical of WD could induce addictive-like eating behaviors and hypothalamic-pituitary-adrenal axis dysregulation associated with chronic stress, (...) anxiety, and depression. In turn, chronic stress modulates eating behavior, and it could have detrimental effects on different brain regions such as the hippocampus, hypothalamus, amygdala, and several cortical regions. Moreover, obesity and overweight induce neuroinflammation, causing neuronal dysfunction. In this review, we summarize the current scientific evidence about the mechanisms and factors relating WD consumption with altered brain function and behavior. Possible therapeutic interventions and limitations are also discussed, aiming to tackle and prevent this current pandemic. (shrink)

IT sounds like something out of the satirical journal Annals of Improbable Research: a team of Swedish neuroscientists scanned people's brains as they smelled a testosterone derivative found in men's sweat and an estrogen-like compound found in women's urine. In heterosexual men, a part of the hypothalamus (the seat of physical drives) responded to the female compound but not the male one; in heterosexual women and homosexual men, it was the other way around. But the discovery is more than (...) just a shoo-in for that journal's annual Ig Nobel Prize - it raises provocative questions about the science and ethics of human sexuality. (shrink)

It has been shown that various types of stress initiate different physiological and neuroendocrine disorders. Oxytocin is mainly produced in the supraoptic nucleus and paraventricular nucleus of the hypothalamus. Hypothalamic OT has antistress effects and attenuates the hypothalamic–pituitary–adrenal axis. One mechanism behind the antistress effects of OT is mediated through the inhibition from GABAA receptors on corticotropin-releasing factor expression at the PVN. Various manual therapies such as acupuncture, transcutaneous electrical nerve stimulation, and massage initiate the stimulation of somatosensory neurons (...) of the body. It is well-known that TENS simulates OT expression, while it inhibits CRF expression at the PVN following chronic stress loading in rodents. Upregulation of OT expression at the hypothalamus is activated by the somatosensory stimulation, which is mediated via the spinothalamic pathway. Thus, somatosensory stimulation is beneficial in treating stress-associated symptoms. Hypothalamic OT is associated with the social behaviors, including maternal care and affiliation. Childhood neglect and/or child abuse are severely responsible for deleterious long-term effects on the cognitive/social activity and behavioral development. At parturition, a profound amount of OT is released into the systemic circulation in response to vaginal and cervical stimulation caused by the body of fetus, which induces the onset of maternal behavior. Peridural anesthesia effectively impairs the sensitivity to vaginal and cervical stimulation at parturition. OT levels in cerebrospinal fluid is significantly reduced following peridural anesthesia. The vaginal delivery mothers had significantly more OT pulses than the caesarian section mothers. Due to low levels of endogenous OT, maternal behavior could be interrupted by epidural anesthesia and CS at parturition because of the reduction of the usual sensory input from the genitalia. (shrink)

The discovery that hypocretins are involved in narcolepsy, a disorder associated with excessive daytime sleepiness, cataplexy and unusually rapid transitions to rapid‐eye‐movement sleep, opens a new field of investigation in the area of sleep control physiology. Hypocretin‐1 and ‐2 (also called orexin‐A and ‐B) are newly discovered neuropeptides processed from a common precursor, preprohypocretin. Hypocretin‐containing cells are located exclusively in the lateral hypothalamus, with widespread projections to the entire neuroaxis. Two known receptors, Hcrtr1 and Hcrtr2, have been reported. The (...) functional significance of the hypocretin system is rapidly emerging in both animals and humans. Hypocretin abnormalities cause narcolepsy in dogs, human and mice. The role of the hypocretin system in normal sleep regulation is more uncertain. We believe hypocretin cells drive cholinergic and monoaminergic activity across the sleep cycle. Input from the suprachiasmatic nucleus to hypocretin‐containing neurons may explain the occurrence of clock‐dependent alertness. Other functions are suggested by pharmacological and neurochemical experiments. These include regulation of food intake, neuroendocrine function, autonomic nervous system activity and energy balance. BioEssays 23:397–408, 2001. © 2001 John Wiley & Sons, Inc. (shrink)

A vast network of cellular circadian clocks regulates 24‐hour rhythms of behavior and physiology in mammals. Complex environments are characterized by multiple, and often conflicting time signals demanding flexible mechanisms of adaptation of endogenous rhythms to external time. Traditionally this process of circadian entrainment has been conceptualized in a hierarchical scheme with a light‐reset master pacemaker residing in the hypothalamus that subsequently aligns subordinate peripheral clocks with each other and with external time. Here we review new experiments using conditional (...) mouse genetics suggesting that resetting of the circadian system occurs in a more “federated” and tissue‐specific fashion, which allows for increased noise resistance and plasticity of circadian timekeeping under natural conditions. (shrink)

Philosophers of biology usually distinguish historical and systemic accounts of functions. In many areas of experimental biology the "systemic" account is often the most relevant. Yet there are problems this account does admittedly not face up to very well. My contention is that, though two minor problems are irredeemably unsolvable for the systemic account of function, the major ones can be solved by assuming that 'function' denotes (directly) a causal role in a model and (indirectly) the corresponding process in nature. (...) I try to show this through the analysis of the hypothalamus-pituitary-adrenal axis of stress. (shrink)

Developmental coordination is vital in the temporally coordinated appearance of cell types within the precise spatial architecture of the vertebrate brain and this, combined with the rich interplay between the developing brain and its target organs, is a biological problem of monumental complexity. An example is the genesis and subsequent integration of the neuroendocrine hypothalamus and the pituitary. Two recent papers(1,2) use the developing hypothalamo‐pituitary axis in order to gather a deeper understanding of these integrative mechanisms. In addition, they (...) show that a sub‐family of homeodomain factors, the POU‐domain proteins, play a critical role in coordinating the respective ontogenies of the hypothalamus and the pituitary. (shrink)

Daily rhythms are a ubiquitous feature of living systems. Generally, these rhythms are not just passive consequences of cyclic fluctuations in the environment, but instead originate within the organism. In mammals, including humans, the master pacemaker controlling 24‐hour rhythms is localized in the suprachiasmatic nuclei of the hypothalamus. This circadian clock is responsible for the temporal organization of a wide variety of functions, ranging from sleep and food intake, to physiological measures such as body temperature, heart rate and hormone (...) release. The retinal circadian clock was the first extra‐SCN circadian oscillator to be discovered in mammals and several studies have now demonstrated that many of the physiological, cellular and molecular rhythms that are present within the retina are under the control of a retinal circadian clock, or more likely a network of hierarchically organized circadian clocks that are present within this tissue. BioEssays 30:624–633, 2008. © 2008 Wiley Periodicals, Inc. (shrink)

This article joins with others in the same issue to celebrate the career of Robert B. Zajonc who was a broad, as well as a deeply talented, psychologist. Beyond his well-known focus in social psychology, the work of Zajonc also involved, at one time or another, forays into nearly every other subfield of psychology. This article focuses specifically on his studies that extended into biopsychology, which deserve special highlighting in order to be recognized alongside his many major achievements in emotion (...) and related social topics. The biopsychological focus is offered here in the hope that all his diverse contributions be savored together when celebrating the complete psychology of Robert Zajonc. (shrink)

Expression of sexually dimorphic behaviors critical for reproduction depends on the organizational actions of steroid hormones on the developing brain. We offer the new hypothesis that transcriptional activities in brain regions executing these sexually dimorphic behaviors are modulated by estrogen‐induced modifications of histone proteins. Specifically, in preoptic nerve cells responsible for facilitating male sexual behavior in rodents, gene expression is fostered by increased histone acetylation and reduced methylation (Me), and, that the opposite set of histone modifications will be found in (...) females. Conversely, in ventromedial hypothalamic neurons that are responsible for coordinating female sexual behavior, transcriptional activities in genetic females are fostered by increased histone acetylation and reduced Me, and, further, that the opposite set of histone modifications will be found in males. Thus, these epigenetic events will guarantee that effects of sex hormone exposure during the neonatal critical period will be translated into lasting sex differences in adult reproductive behaviors. (shrink)

This article develops a theory for how caringbehavior fits into the makeup of humans andother mammals. Biochemical evidence for threemajor patterns of response to stressful orotherwise complex situations is reviewed. There is the classic fight-or-flight response;the dissociative response, involving emotionalwithdrawal and disengagement; and the bondingresponse, a variant of which Taylor et al. (2000) called tend-and-befriend. All three ofthese responses can be explained as adaptationsthat have been selected for in evolution andare shared between humans and other mammals. Yet each of us (...) contains varying tendenciestoward all of these responses. How doesdevelopment interact with genes to influencethese tendencies? How do individuals,societies, and institutions make choicesbetween these types of responses?We review the evidence, based on behavioral,lesion, single-cell, and brain imaging studies,for cortical-subcortical interactions involvedin all three of these response types, andpropose partial neural network models for someof these interactions. We propose that theorbitomedial prefrontal cortex mediates thischoice process. This area of prefrontal cortexperforms this mediation through its connectionswith areas of sensory and association cortexthat represent social contexts or stimuli, andwith areas of the hypothalamus, limbic system,and autonomic nervous system that representemotional states or classes of response patterns.The article concludes with implications of ourtheory for social interactions andinstitutions. We argue that despite the wideprevalence of fight-or-flight responses, thebonding, caring responses remain available. Weshow with historical and contemporary exampleshow social settings – whether in education,work places, families, politics, and informalsocial customs – can be designed to supportand enhance the natural caring responses of thebrain. (shrink)

Social interactions are essential for animals to reproduce, defend their territory, and raise their young. The conserved nature of social behaviors across animal species suggests that the neural pathways underlying the motivation for, and the execution of, specific social responses are also maintained. Modern tools of neuroscience have offered new opportunities for dissecting the molecular and neural mechanisms controlling specific social responses. We will review here recent insights into the neural circuits underlying a particularly fascinating and important form of social (...) interaction, that of parental care. We will discuss how these findings open new avenues to deconstruct infant‐directed behavioral control in males and females, and to help understand the neural basis of parenting in a variety of animal species, including humans. (shrink)