Animal Brain Research Research Articles

The Importance of Studying Human Brain

Abstract Due to its numerous distinctive functions and unique pathology, the human brain, or rather forebrain has been difficult to study in common animal models. Although many basic molecular and cellular events are conserved across species, human brain connectivity, pertinent especially to the cerebral cortex circuitry, is unique and demands extensive research. Despite a great advancement in functional imaging methods accomplished over the last two decades, many basic features of healthy and diseased human forebrain remain elusive. Here we address difficulties in anatomical studies of developing and adult human brain and indicate the new directions and challenges to be addressed in the future. We pay special attention to possibilities of translating animal brain research to human cases. We consider that, although animal experiments play a vital role in understanding fundamental molecular and cellular mechanisms behind brain function, understanding of higher brain functions (language, intelligence, memory) has to be based on understanding uniqueness of human circuitries. Furthermore, brain is the site of many human-specific diseases, such as multiple sclerosis, schizophrenia, and Alzheimer’s disease, for which only partial animal models exist. To study human brain, thus, remains irreplaceable in the quest for new therapeutic tools, as well as in understanding the essence of our being.

Rewarding and punishing properties of deep brain stimulation: The most promising entry points for constitutive studies of affective experiences in other animals...with profound psychiatric implications for human consciousness and psychiatric therapeutics.

Neither experimental psychology nor neuroscience has made much progress in understanding the constitution (the hard-problem) of consciousness, although affective issues are finally being intensively considered. Miskovic and colleagues provide a penetrating essay into the problem and the conceptual advances being made, without sufficient consideration of the critical role of animal brain research in such enterprises. I will argue that the task will be much easier when we integrate human and animal findings, especially because animal brain research—particularly with regard to the identification of rewarding and punishing brain systems (namely, the affective neuroscience strategy)—will be very useful in informing how primal affective states in humans are created from brain dynamics.

Will better psychiatric treatments emerge from top-down or bottom-up neuroscientific studies of affect?

Will better psychiatric treatments emerge from top-down or bottom-up neuroscientific studies of affect?

What is an emotional feeling? Lessons about affective origins from cross-species neuroscience

Cross-species affective neuroscience aspires to provide an evidence-based foundation for understanding the primary-process emotional networks that concurrently control instinctual emotional actions and affective feelings—direct emotional circuit mediated ‘rewards’ and ‘punishments’. In humans and other mammals, the ancestral subcortical regions of the brain are central to such affective BrainMind functions (a monistic term, here used synonymously with MindBrain, depending on stylistic needs). Although these circuits cannot be ‘identical’ across species (that would be incompatible with evolutionary principles) they are sufficiently similar, anatomically, neurochemically and functionally, to allow animal brain research to illuminate (yield testable predictions) about homologous human mind functions. Primal emotional feelings (affects) are inbuilt value functions of the brain that energize and inform the rest of the mental apparatus about basic survival values, thereby promoting secondary-process learning/memory functions and tertiary-process cognitive thinking-ruminative functions, yielding bottom-up evolutionary controls that ultimately allow top-down regulatory controls. As we envision how such “nested” hierarchies—two-way paths of causality—reflecting both bottom-up and top-down functions—we will need disciplined distinctions between cognitions and emotions at the primary-process level, while also accepting total interpenetrance of cognitions and affects at the tertiary-process level of MindBrain organization. This allows full and synergistic integration of basic and dimensional approaches to emotions. Here the primal emotional networks, so critically important for understanding ‘human-nature’ and psychiatric disorders, are discussed didactically in ways that can minimize dilemmas that non-evolutionary, non-hierarchical perspectives are subject to in modern emotion research.

A robotic assistant for stereotactic neurosurgery on small animals

This work presents the development and performance analysis of a robotic system for stereotactic neurosurgery on small animals. The system is dedicated to the precise placement of probes in the small animal brain, thus providing an improved framework for brain research. Based on an analysis of small animal stereotaxy, the mechanical design of the robotic system is presented. Details of the structure and mechanical components and a kinematic description are outlined. The calibration process of the system for arbitrary probes is described. To analyse the mechanical positioning accuracy of the system, a testbed is presented. Positioning performance results show that the system features a mean mechanical positioning accuracy of 32 microm and a mean positioning repeatability of 11 microm. The system meets the requirements of targeting small functional areas within the brain of small animals and thus offers a new tool for small animal brain research.

On the use of isoflurane versus halothane in the study of visual response properties of single cells in the primary visual cortex

Halothane is a widely used anesthetic in research. It produces several alterations in organs, especially in the brain. Recently, isoflurane emerged in neuroscience laboratories. For many reasons it appears to be better than halothane for animal brain research (e.g. isoflurane induces lower intracranial pressure, and is less detrimental on the cardiovascular system). However, no one is in a position to recommend it in electrophysiology research because its effects on specific brain functions are relatively unknown. Given that both anesthetics yield different actions on gross brain activity (EEG, VEP), it is likely that they differentially affect single neuron activity. The goal of this study is to determine whether halothane or isoflurane use is best suited to study the receptive field properties of neurons in the cat's primary visual cortex. Extra-cellular recordings were made for both anesthetics in area 17 of adult cats under different levels of anesthesia. Results indicate that various cell parameters differ under halothane anesthesia when compared with isoflurane. The main difference between the two anesthetics is the greater depression of the cell optimal visual response amplitude induced by isoflurane at equipotent concentration. Due to its stronger depressive effects, isoflurane may not be the ideal anesthetic for single-cell recordings in the primary visual cortex.

“Laughing” rats and the evolutionary antecedents of human joy?

Paul MacLean's concept of epistemics—the neuroscientific study of subjective experience—requires animal brain research that can be related to predictions concerning the internal experiences of humans. Especially robust relationships come from studies of the emotional/affective processes that arise from subcortical brain systems shared by all mammals. Recent affective neuroscience research has yielded the discovery of play- and tickle-induced ultrasonic vocalization patterns (∼50-kHz chirps) in rats may have more than a passing resemblance to primitive human laughter. In this paper, we summarize a dozen reasons for the working hypothesis that such rat vocalizations reflect a type of positive affect that may have evolutionary relations to the joyfulness of human childhood laughter commonly accompanying social play. The neurobiological nature of human laughter is discussed, and the relevance of such ludic processes for understanding clinical disorders such as attention deficit hyperactivity disorders (ADHD), addictive urges and mood imbalances are discussed.

An Algorithm for Rapid Calculation of a Probabilistic Functional Atlas of Subcortical Structures from Electrophysiological Data Collected during Functional Neurosurgery Procedures

The paper introduces an optimal algorithm for rapid calculation of a probabilistic functional atlas (PFA) of subcortical structures from data collected during functional neurosurgery procedures. The PFA is calculated based on combined intraoperative electrophysiology, pre- and intraoperative neuroimaging, and postoperative neurological verification. The algorithm converts the coordinates of the neurologically most effective contacts into probabilistic functional maps taking into account the geometry of a stimulating electrode. The PFA calculation comprises the reconstruction of the contact coordinates from two orthogonal projections, normalizing (warping) the contacts modeled as cylinders, voxelizing the contact models, calculating the atlas, and computing probability. In addition, an analytical representation of the PFA is formulated based on Gaussian modeling. The initial PFA has been calculated from the data collected during the treatment of 274 Parkinson's disease patients, most of them operated bilaterally (487 operated hemispheres). It contains the most popular stereotactic targets, the subthalamic nucleus, globus pallidus internus, and ventral intermedius nucleus. The key application of the algorithm is targeting in stereotactic and functional neurosurgery, and it also can be employed in human and animal brain research.

Medial temporal lobe structures and autism: A review of clinical and experimental findings

Although substantive understanding of brain dysfunction in autism remains meager, clinical evidence as well as animal brain research on the effects of early damage to selective brain system have now yielded enough knowledge that some provisional hypotheses concerning the etiology of autism can be generated. Basically, the underlying premise of this review is that a major dysfunction of the autistic brain resides in neural mechanisms of the structures in the medial temporal lobe, and, perhaps, more specifically the amygdaloid complex. This review begins with a summary of clinical evidence of the involvement of the medial temporal lobe structures in autism. The major behavioral disturbances seen in monkeys that had received neonatal lesions of the medial temporal lobe structures are then described. From this survey it can be seen that distinct patterns of memory losses and socioemotional abnormalities emerge as a result of extent of damage to the medial temporal lobe structures. The potential value of the experimental findings for an understanding of neural dysfunction in autism as well as directions of future research are discussed in the final section of the review.

Toward a general psychobiological theory of emotions

AbstractEmotions seem to arise ultimately from hard-wired neural circuits in the visceral-limbic brain that facilitate diverse and adaptive behavioral and physiological responses to major classes of environmental challenges. Presumably these circuits developed early in mammalian brain evolution, and the underlying control mechanisms remain similar in humans and “lower” mammals. This would suggest that theoretically guided studies of the animal brain can reveal how primitive emotions are organized in the human brain. Conversely, granted this cross-species heritage, it is arguable that human introspective access to emotional states may provide direct information concerning operations of emotive circuits and thus be a primary source of hypotheses for animal brain research. In this article the possibility that emotions are elaborated by transhypothalamic executive (command) circuits that concurrently activate related behavior patterns is assessed. Current neurobehavioral evidence indicates that there are at least four executive circuits of this type – those which elaborate central states of expectancy, rage, fear, and panic. The manner in which learning and psychiatric disorders may arise from activities of such circuits is also discussed.