Brain activity in the action observation network is lateralized during action execution, with greater activation in the contralateral hemisphere to the side of the body used to perform the task. However, it is unknown whether the AON is also lateralized when watching another person perform an action. In this study, we use fNIRS to measure brain activity over the left and right cortex while participants completed actions with their left and right hands and watched an actor complete action (...) with their left and right hands. We show that while activation is lateralized when the participants themselves are moving, brain lateralization is not affected by the side of the body when the participant is observing another person’s action. In addition, we demonstrate that individual differences in hand preference and dexterity between the right and left hands are related to brain lateralization patterns. (shrink)

Can we understand brain lateralization in humans by analysis in terms of an evolutionarily stable strategy? The attempt to demonstrate a link between lateralization in humans and that in, for example, fish appears to hinge critically on whether the isomorphism is viewed as a matter of homology or homoplasy. Consideration of human handedness presents a number of challenges to the proposed framework.

Recent evidence in natural and semi-natural settings has revealed a variety of left-right perceptual asymmetries among vertebrates. These include preferential use of the left or right visual hemifield during activities such as searching for food, agonistic responses, or escape from predators in animals as different as fish, amphibians, reptiles, birds, and mammals. There are obvious disadvantages in showing such directional asymmetries because relevant stimuli may be located to the animal's left or right at random; there is no a priori association (...) between the meaning of a stimulus (e.g., its being a predator or a food item) and its being located to the animal's left or right. Moreover, other organisms (e.g., predators) could exploit the predictability of behavior that arises from population-level lateral biases. It might be argued that lateralization of function enhances cognitive capacity and efficiency of the brain, thus counteracting the ecological disadvantages of lateral biases in behavior. However, such an increase in brain efficiency could be obtained by each individual being lateralized without any need to align the direction of the asymmetry in the majority of the individuals of the population. Here we argue that the alignment of the direction of behavioral asymmetries at the population level arises as an “evolutionarily stable strategy” under “social” pressures occurring when individually asymmetrical organisms must coordinate their behavior with the behavior of other asymmetrical organisms of the same or different species. Key Words: asymmetry; brain evolution; brain lateralization; development; hemispheric specialization; laterality; lateralization of behavior; social behavior; theory of games. (shrink)

Dual-Brain Psychology is a theory and its clinical applications that come out of the author's clinical observations and from the Split-brain Studies. The theory posits, based on decades of rigorous, peer-reviewed experiments and clinical reports, that, in most patients, one brain's cerebral hemisphere when stimulated by simple lateral visual field stimulation, or unilateral transcranial photobiomodulation, reveals a dramatic change in personality such that stimulating one hemisphere evokes, as a trait, a personality that is more childlike and more (...) presently affected by childhood maltreatments that are usually not presently appreciated but are the proximal cause of the patient's symptoms. The personality associated with the other hemisphere is much more mature, less affected by the traumas, and less symptomatic. The theory can be applied to in-depth psychotherapy in which the focus is on helping the troubled side to bear and process the traumas with the help of the therapist and the healthier personality. A person's symptoms can be evoked to aid the psychotherapy with hemispheric stimulation and the relationship between the dual personalities can be transformed from conflicted and sabotaging to cooperating toward overall health. Stimulating the positive hemisphere in most therapy patients rapidly relieves symptoms such as anxiety, depression, or substance cravings. Two randomized controlled trials used unilateral transcranial photobiomodulation to the positive hemisphere as a stand-alone treatment for opioid cravings and both revealed high effect sizes. The theory is supported by brain imaging and rTMS studies. It is the first psychological theory and application that comes out of and is supported by rigorous peer-reviewed experimentation. (shrink)

Pre-reading language skills develop rapidly in early childhood and are related to brain structure and functional architecture in young children prior to formal education. However, the early neurobiological development that supports these skills is not well understood. Here we acquired anatomical, diffusion tensor imaging and resting state functional MRI from 35 children at 3.5 years of age. Children were assessed for pre-reading abilities using the NEPSY-II subtests 1 year later. We applied a data-driven linked independent component analysis to explore (...) the shared co-variation of gray and white matter measures. Two sources of structural variation at 3.5 years of age demonstrated relationships with Speeded Naming scores at 4.5 years of age. The first imaging component involved volumetric variability in reading-related cortical regions alongside microstructural features of the superior longitudinal fasciculus. The second component was dominated by cortical volumetric variations within the cerebellum and visual association area. In a subset of children with rs-fMRI data, we evaluated the inter-network functional connectivity of the left-lateralized fronto-parietal language network and its relationship with pre-reading measures. Higher functional connectivity between the FPL and the default mode and visual networks at 3.5 years significantly predicted better Phonological Processing scores at 4.5 years. Together, these results suggest that the integration of functional networks, as well as the co-development of white and gray matter brain structures in early childhood, support the emergence of pre-reading measures in preschool children. (shrink)

The aim of this study was to verify whether chimpanzees demonstrate an auditory laterality during the orientation reaction, and which hemisphere is responsible for processing the emotional stimuli and which for the species-specific vocalizations. The study involved nine chimpanzees from the Warsaw Municipal Zoological Garden. They were tested individually in their bedrooms. Chimpanzees approached a tube filled with food, located in the centre of the cage. Randomly selected sounds were played from the speakers when the subject was focused on getting (...) food. Individual reactions were observed and outcomes reported. The four types of sound used: thunderstorm, dog barking, chimpanzee vocalization and a zookeeper’s voice. To test whether chimpanzees demonstrate auditory laterality we used a single sample X2 test. The existence of auditory laterality has been confirmed. The sound of the storm caused the orientation reaction to the left, while chimpanzee vocalization - to the right. On this basis we can conclude that among chimpanzees, arousing stimuli are being processed by the right hemisphere, and species-specific vocalizations by the left. However, the set of stimuli was limited so the study did not unequivocally resolve this issue. (shrink)

This sequel to the widely read Zen and the Brain continues James Austin's explorations into the key interrelationships between Zen Buddhism and brain research. In Zen-Brain Reflections, Austin, a clinical neurologist, researcher, and Zen practitioner, examines the evolving psychological processes and brain changes associated with the path of long-range meditative training. Austin draws not only on the latest neuroscience research and new neuroimaging studies but also on Zen literature and his personal experience with alternate states of (...) consciousness.Zen-Brain Reflections takes up where the earlier book left off. It addresses such questions as: how do placebos and acupuncture change the brain? Can neuroimaging studies localize the sites where our notions of self arise? How can the latest brain imaging methods monitor meditators more effectively? How do long years of meditative training plus brief enlightened states produce pivotal transformations in the physiology of the brain? In many chapters testable hypotheses suggest ways to correlate normal brain functions and meditative training with the phenomena of extraordinary states of consciousness.After briefly introducing the topic of Zen and describing recent research into meditation, Austin reviews the latest studies on the amygdala, frontotemporal interactions, and paralimbic extensions of the limbic system. He then explores different states of consciousness, both the early superficial absorptions and the later, major "peak experiences." This discussion begins with the states called kensho and satori and includes a fresh analysis of their several different expressions of "oneness." He points beyond the still more advanced states toward that rare ongoing stage of enlightenment that is manifest as "sage wisdom."Finally, with reference to a delayed "moonlight" phase of kensho, Austin envisions novel links between migraines and metaphors, moonlight and mysticism. The Zen perspective on the self and consciousness is an ancient one. Readers will discover how relevant Zen is to the neurosciences, and how each field can illuminate the other. (shrink)

This sequel to the widely read Zen and the Brain continues James Austin's explorations into the key interrelationships between Zen Buddhism and brain research. In Zen-Brain Reflections, Austin, a clinical neurologist, researcher, and Zen practitioner, examines the evolving psychological processes and brain changes associated with the path of long-range meditative training. Austin draws not only on the latest neuroscience research and new neuroimaging studies but also on Zen literature and his personal experience with alternate states of (...) consciousness.Zen-Brain Reflections takes up where the earlier book left off. It addresses such questions as: how do placebos and acupuncture change the brain? Can neuroimaging studies localize the sites where our notions of self arise? How can the latest brain imaging methods monitor meditators more effectively? How do long years of meditative training plus brief enlightened states produce pivotal transformations in the physiology of the brain? In many chapters testable hypotheses suggest ways to correlate normal brain functions and meditative training with the phenomena of extraordinary states of consciousness.After briefly introducing the topic of Zen and describing recent research into meditation, Austin reviews the latest studies on the amygdala, frontotemporal interactions, and paralimbic extensions of the limbic system. He then explores different states of consciousness, both the early superficial absorptions and the later, major "peak experiences." This discussion begins with the states called kensho and satori and includes a fresh analysis of their several different expressions of "oneness." He points beyond the still more advanced states toward that rare ongoing stage of enlightenment that is manifest as "sage wisdom."Finally, with reference to a delayed "moonlight" phase of kensho, Austin envisions novel links between migraines and metaphors, moonlight and mysticism. The Zen perspective on the self and consciousness is an ancient one. Readers will discover how relevant Zen is to the neurosciences, and how each field can illuminate the other. (shrink)

An evolutionarily stable strategy (ESS) may apply to characters expressed across species for predation and feeding, because these characters are conservative. However, the evolution of complex, polymorphic behaviors is more difficult to define as an ESS. Lateralization may be selective for certain simple traits, but lateralization of complex traits is likely the result of coadaptation of otherwise non-lateralized features.

In 1968, the Harvard criteria equated irreversible coma and apnea with human death and later, the Uniform Determination of Death Act was enacted permitting organ procurement from heart-beating donors. Since then, clinical studies have defined a spectrum of states of impaired consciousness in human beings: coma, akinetic mutism, minimally conscious state, vegetative state and brain death. In this article, we argue against the validity of the Harvard criteria for equating brain death with human death. Brain death does (...) not disrupt somatic integrative unity and coordinated biological functioning of a living organism. Neurological criteria of human death fail to determine the precise moment of an organism’s death when death is established by circulatory criterion in other states of impaired consciousness for organ procurement with non-heart-beating donation protocols. The criterion of circulatory arrest 75 s to 5 min is too short for irreversible cessation of whole brain functions and respiration controlled by the brain stem. Brain -based criteria for determining death with a beating heart exclude relevant anthropologic, psychosocial, cultural, and religious aspects of death and dying in society. Clinical guidelines for determining brain death are not consistently validated by the presence of irreversible brain stem ischemic injury or necrosis on autopsy; therefore, they do not completely exclude reversible loss of integrated neurological functions in donors. The questionable reliability and varying compliance with these guidelines among institutions amplify the risk of determining reversible states of impaired consciousness as irreversible brain death. The scientific uncertainty of defining and determining states of impaired consciousness including brain death have been neither disclosed to the general public nor broadly debated by the medical community or by legal and religious scholars. Heart-beating or non-heart-beating organ procurement from patients with impaired consciousness is de facto a concealed practice of physician-assisted death, and therefore, violates both criminal law and the central tenet of medicine not to do harm to patients. Society must decide if physician-assisted death is permissible and desirable to resolve the conflict about procuring organs from patients with impaired consciousness within the context of the perceived need to enhance the supply of transplantable organs. (shrink)

After the first callosotomy surgeries were performed, the general consensus among the medical community was that severing the corpus callosum had relatively little, if any, effect on an individual's behavior. Nearly twenty years later, researchers discovered that, under experimental conditions, the two hemispheres could simultaneously maintain very different interpretations of the same stimulus. These findings immediately called into question the unity of subjective experience, a fundamental characteristic of human consciousness. How could the split‐brain patient not experience any disruption in (...) his experience as a unified self when the two hemispheres are physically and functionally disconnected? In this chapter, we review the research that has led to a conceptualization of the split brain as two minds within one body and the implications of this research for the scientific study of consciousness. We argue that consciousness is a neural function that emerges from the integration of information across available functional modules. (shrink)

Dual functional brain asymmetry refers to the notion that in most individuals the left cerebral hemisphere is specialized for language functions, whereas the right cerebral hemisphere is more important than the left for the perception, construction, and recall of stimuli that are difficult to verbalize. In the last twenty years there have been scattered reports of sex differences in degree of hemispheric specialization. This review provides a critical framework within which two related topics are discussed: Do meaningful sex differences (...) in verbal or spatial cerebral lateralization exist? and, if so, Is the brain of one sex more symmetrically organized than the other? Data gathered on right-handed adults are examined from clinical studies of patients with unilateral brain lesions; from dichotic listening, tachistoscopic, and sensorimotor studies of functional asymmetries in non-brain-damaged subjects; from anatomical and electrophysiological investigations, as well as from the developmental literature. Retrospective and descriptive findings predominate over prospective and experimental methodologies. Nevertheless, there is an impressive accummulation of evidence suggesting that the male brain may be more asymmetrically organized than the female brain, both for verbal and nonverbal functions. These trends are rarely found in childhood but are often significant in the mature organism. (shrink)

The planninnjg of this Study Week at the Pontifical Academy of Science from September 28 to October 4, 1964, began just two years before when the President, Professor Lemaitre, asked me if 1 would be responsible for a Study Week relating Psychology to what we may call the Neurosciences. 1 accepted this responsibility on the understanding that 1 could have as sistance from two colleagues in the Academy, Professors Heymans and Chagas. Besides participating in the Study Week they gave me (...) much needed assistance and advice in the arduous and, at times, perplexing task that 1 had undertaken, and 1 gratefully acknowledge my indebtedness to them. Though there have been in recent years many symposia concerned with the so-called higher functions of the brain, for example witbh percep tion, learning and conditioning, and with the processing of information in the brain, there has to my knowledge been no symposium specifically with brain functions and consciousness since the memorable treating Laurentian Conference of 1953, which was later published in 1954 as the book, "Brain Mechanisms and Consciousness. (shrink)

At its inception, “brain death” was proposed not as a coherent concept but as a useful one. The 1968 Ad Hoc Committee of the Harvard Medical School to Examine the Definition of Brain Death gave no reason that “irreversible coma” should be death itself, but simply asserted that the time had come for it to be declared so. Subsequent writings by chairman Henry Beecher made clear that, to him at least, death was essentially a social construct, and society (...) could define it however it pleased. The first widely endorsed attempt at a philosophical justification appeared thirteen years later, with a report from the President's Commission for the Study of Ethical Problems in Medicine and Biomedical and Behavioral Research and a seminal paper by James Bernat, Charles Culver, and Bernard Gert, which introduced the insightful tripartite scheme of concept, criterion, and tests for death. Their paper proposed that the correct concept of death is the “permanent cessation of functioning of the organism as a whole,” which tenuously remains the mainstream concept to this day. In this essay, I focus on this mainstream concept, arguing that equating brain death with death involves several levels of incoherence: between concept and criterion, between criterion and tests, between tests and concept, and between all of these and actual brain death praxis. (shrink)

One important way in which neuroscience, particularly neuroanatomy, contributes to cognitive science is by providing a model of the brain's architecture, which, in turn, can be utilized as a guide to the architecture of cognition. This project assumes commitment to a view, now well established, that different mental processes, such as perceiving and remembering, employ different parts of the brain (where part is loosely construed so as not to exclude entities which may themselves be composite). These parts may (...) differ according to their internal organizational structure, information processing capacities, and degree of informational connectivity with other parts. Later I will present an example of research in visual processing where researchers are currently attempting to realize the heuristic potential of the brain's architecture in order to understand cognitive organization. Of prior importance, however, is an understanding of how neuroscientists decipher the architecture of the brain itself. This task of mapping the brain, of carving it up into distinct areas, is not as straightforward as one might think. There are, for example, several different criteria by which one might fix a given boundary between brain regions. Below, I not only highlight some of the more interesting facets of brain mapping research but also elaborate on why such research is of interest to cognitive scientists. (shrink)

Neuroscientific studies have shown that brain activity correlated with a decision to move can be observed before a person reports being consciously aware of having made that decision . Given that a later event cannot cause an earlier one , such results have been interpreted as evidence that decisions are made unconsciously . We argue that this interpretation depends upon an all-or-none view of consciousness, and we offer an alternative interpretation of the early decision-related brain activity based on (...) models in which conscious awareness of the decision to move develops gradually up to the level of a reporting criterion. Under this interpretation, the early brain activity reflects sub-criterion levels of awareness rather than complete absence of awareness and thus does not suggest that decisions are made unconsciously. (shrink)

The question of what determines brain laterality for auditory cognitive processing is unresolved. Here, we demonstrate a swap of hemisphere dominance from right to left during semantic interpretation of Chinese lexical tones in native speakers using simultaneously recorded mismatch negativity response and behavioral reaction time during dichotic listening judgment. The mismatch negativity, which is a brain wave response and indexes auditory processing at an early stage, indicated right hemisphere dominance. In contrast, the behavioral reaction time, which reflects auditory (...) processing at a later stage, indicated a right ear listening advantage, or left hemisphere dominance. The observed swap of hemisphere dominance would not occur when the lexical tone was substituted with a meaningless pure tone. This swap reveals dependence of hemisphere labor division initially on acoustic and then on functional cues of auditory inputs in the processing from sound to meaning. (shrink)

Two meta-analyses of 66 behavioral studies examined variables influencing functional cerebral lateralization of each language of brain-intact bilingual adults. Functional lateralization was found to be primarily influenced by age of onset of bilingualism: bilinguals who acquired both languages by 6 years of age showed bilateral hemispheric involvement for both languages, whereas those who acquired their second language after age 6 showed left hemisphere dominance for both languages. Moreover, among late bilinguals, left hemisphere involvement was found to be (...) greater for those less proficient in their second language, those whose second language was English, and for studies involving dichotic listening paradigms; early bilinguals instead showed bilateral involvement in every condition. Implications of the observed differences in lateralization between early and late bilinguals are explored for existing theories of bilingualism and for neurocognitive models of brain functional organization of language. (shrink)

Many vertebrate animals approximate, to various degrees, the “split‐brain” condition that results from surgery done in humans to treat severe epilepsy, with very limited connection between the left and right sides of the upper parts of the brain. The split‐brain condition has been the topic of extensive philosophical discussion, because it appears, in some circumstances, to give rise to two minds within one body. Is the same true of these animals? This article attempts to make progress on (...) two difficult topics—animal experience, and the consequences of the human split‐brain condition—by considering both at once. (shrink)

[opening paragraph]: Nicholas Humphrey argues persuasively that consciousness results from active and efferent rather than passive and afferent functions. These arguments contribute to the mounting recent evidence that consciousness is inseparable from the motivated action planning of creatures that in some sense are organismic and agent-like rather than passively mechanical and reactive in the way that digital computers are. Newton calls this new approach the ‘action theory of understanding'; Varela et al. dubbed it the ‘enactive’ view of consciousness. It was (...) endorsed in passing by the early Dennett , although he never followed up on it in his later work. According to Dennett, ‘No afferent can be said to have a significance ‘A’ until it is ‘taken’ to have the significance ‘A’ by the efferent side of the brain’ . Luria also stressed the neurophysiology of efferent processes as correlated with consciousness . Further elaborations of the enactive approach are defended by Ellis , Newton , Ellis and Newton , Watt , Thelen and Smith , Jarvilehto and Gendlin . According to this view, conscious information processing can arise only as the self-regulated action of a self-organizing process that confronts the world as a system of action affordances. While information can be passively absorbed in the form of afferent input, only efferent nervous activity in the interest of a living organism's homeostatic balance can create consciousness of any information, whether perceptual, imagistic, emotional or intellectual. (shrink)

_Figure 1. Dendrites and cell bodies of schematic neurons connected by dendritic-dendritic gap junctions form a laterally connected input_ _layer (“dendritic web”) within a neurocomputational architecture. Dendritic web dynamics are temporally coupled to gamma synchrony_ _EEG, and correspond with integration phases of “integrate and fire” cycles. Axonal firings provide input to, and output from, integration_ _phases (only one input, and three output axons are shown). Cell bodies/soma contain nuclei shown as black circles; microtubule networks_ _pervade the cytoplasm. According to the (...) Orch OR theory, gamma EEG-synchronized integration phases include quantum computations in_ _microtubule networks which culminate with conscious moments. Insert closeup shows a gap junction through which microtubule quantum_ _states entangle among different neurons, enabling macroscopic quantum states in dendritic webs extending throughout cortex and other_ _brain regions._. (shrink)

Reading in the Brain (Les neurones de la lecture, 2007) examined the origins of human reading abilities in the light of contemporary cognitive neuroscience. It argued that reading acquisition, in all cultures, recycles preexisting cortical circuits dedicated to invariant visual recognition, and that the organization of these circuits imposes strong constraints on the invention and cultural evolution of writing systems. In this article, seven years later, I briefly review new experimental evidence, particularly from brain imaging studies of illiterate (...) adults, which indicates that reading acquisition invades culturally universal cortical circuits and competes with their prior function, including mirror-invariant visual recognition and face processing. In response to my critics, I emphasize how brain plasticity and brain constraints can be reconciled within the Bayesian perspective on learning. I also discuss the importance of a newly discovered gesture system in reading and writing. Finally, I argue that there is consistent evidence for deep cross-cultural universals in writing systems, as well as for the multiple subtypes of dyslexia that are expected given the broad set of areas recruited by the reading task. (shrink)

To assess the ability of the disconnected cerebral hemispheres to recognize images of the self, a split-brain patient was tested using morphed self-face images presented to one visual hemifield at a time while making “self/other” judgments. The performance of the right and left hemispheres of this patient as assessed by a signal detection method was not significantly different, though a measure of bias did reveal hemispheric differences. The right and left hemispheres of this patient independently and equally possessed the (...) ability to self-recognize, but only the right hemisphere could successfully recognize familiar others. This supports a modular concept of self-recognition and other-recognition, separately present in each cerebral hemisphere. (shrink)

''As a text in developmental psychology the book is excellent, and this lower-priced paperback version will be snapped up by psychology students.'' -European NeurologyOne of the most dramatic areas of development in early human life is that of vision. Whereas vision plays a relatively minor role in the world of the newborn infant, by 6 months it has assumed the position as a dominant sense and forms the basis of later perceptual, cognitive, and social development. From a world leader in (...) the study of visual development in human infants comes a major new work, condensing a lifetime of work in this area - The developing visual brain. Drawing on over 20 years of cutting edge research in the Visual Develoment Units in Cambridge and University College London, the book provides the definitive account of what we know about the developing visual system, and the problems that can occur during development. The book reviews, evaluates, and sets in context the exciting progress being made in this area, and additionally suggests new areas for research. Written to be accessible for advanced undergraduates, graduate students, and researchers in psychology, the neurosciences, optometry, and visual science, The developing visual brain represents an important new addition to the literature on vision. (shrink)

This article argues for the gestural origins of speech and language based on the available evidence gathered in humans and nonhuman primates and especially from ape studies. The strong link between motor functions and speech in humans is reviewed. The presence of asymmetrical cerebral organization in nonhuman primates along with functional asymmetries in the perception and production of vocalizations and in intentional referential gestural communication is then emphasized. The nature of primate communicatory systems is presented, and the similarities and differences (...) between these systems and human speech are discussed. It is argued that recent findings concerning neuroanatomical asymmetries in the chimpanzee brain and the existence of both mirror neurons and lateralized use of hands and vocalizations in communication necessitate a reconsideration of the phylogenic emergence of the cerebral and behavioral prerequisites for human speech. (shrink)

Brain-Computer Interface is a set of technologies that are of increasing interest to researchers. BCI has been proposed as assistive technology for individuals who are non-communicative or paralyzed, such as those with amyotrophic lateral sclerosis or spinal cord injury. The technology has also been suggested for enhancement and entertainment uses, and there are companies currently marketing BCI devices for those purposes as well as health-related purposes. The unprecedented direct connection created by BCI between human brains and computer hardware raises (...) various ethical, social, and legal challenges that merit further examination and discussion. To identify and characterize the key issues associated with BCI use, we performed a scoping review of biomedical ethics literature, analyzing the ethics concerns cited across multiple disciplines, including philosophy and medicine. Based on this investigation, we report that BCI research and its potential translation to therapeutic intervention generate significant ethical, legal, and social concerns, notably with regards to personhood, stigma, autonomy, privacy, research ethics, safety, responsibility, and justice. Our review of the literature determined, furthermore, that while these issues have been enumerated extensively, few concrete recommendations have been expressed. We conclude that future research should focus on remedying a lack of practical solutions to the ethical challenges of BCI, alongside the collection of empirical data on the perspectives of the public, BCI users, and BCI researchers. (shrink)

Introduction As deep brain stimulation (DBS) has shifted to being used earlier during Parkinson’s disease (PD), data is lacking regarding patient specific attitudes, preferences, and factors which may influence the timing of and decision to proceed with DBS in the United States. This study aims to identify and compare attitudes and preferences regarding the earlier use of DBS in Parkinson’s patients who have and have not undergone DBS. Methods We developed an online survey concerning attitudes about DBS and its (...) timing in PD. The survey was distributed nationally in the United States via the Michael J. Fox Foundation Trial Finder, the American Parkinson Disease Association flyers, and as a link on the Parkinson Alliance website. Differences in responses between PD DBS and non-DBS patients were assessed. Results A total of 445 patients with PD met eligibility criteria for the survey of which 160 self-identified as having undergone DBS. Fifty-five percent (n = 124) of non-DBS patients believed that DBS for PD should only be considered after all medication options have been tried. Patients favoring early DBS had fewer concerns regarding the surgery than those favoring later DBS. Conclusion Our findings highlight a variety of important considerations and concerns patients have regarding DBS and its timing. These viewpoints are important aspects of shared decision-making, as they help to identify patients’ preferences, values, and goals, which should enable providers to better navigate, with their patients, the decision path for therapeutic options to consider. (shrink)

If the cortex is an associative memory, strongly connected cell assemblies will form when neurons in different cortical areas are frequently active at the same time. The cortical distributions of these assemblies must be a consequence of where in the cortex correlated neuronal activity occurred during learning. An assembly can be considered a functional unit exhibiting activity states such as full activation (“ignition”) after appropriate sensory stimulation (possibly related to perception) and continuous reverberation of excitation within the assembly (a putative (...) memory process). This has implications for cortical topographies and activity dynamics of cell assemblies forming during language acquisition, in particular for those representing words. Cortical topographies of assemblies should be related to aspects of the meaning of the words they represent, and physiological signs of cell assembly ignition should be followed by possible indicators of reverberation. The following postulates are discussed in detail: (1) assemblies representing phonological word forms are strongly lateralized and distributed over perisylvian cortices; (2) assemblies representing highly abstract words such as grammatical function words are also strongly lateralized and restricted to these perisylvian regions; (3) assemblies representing concrete content words include additional neurons in both hemispheres; (4) assemblies representing words referring to visual stimuli include neurons in visual cortices; and (5) assemblies representing words referring to actions include neurons in motor cortices. Two main sources of evidence are used to evaluate these proposals: (a) imaging studies focusing on localizing word processing in the brain, based on stimulus-triggered event-related potentials (ERPs), positron emission tomography (PET), and functional magnetic resonance imaging (fMRI), and (b) studies of the temporal dynamics of fast activity changes in the brain, as revealed by high-frequency responses recorded in the electroencephalogram (EEG) and magnetoencephalogram (MEG). These data provide evidence for processing differences between words and matched meaningless pseudowords, and between word classes, such as concrete content and abstract function words, and words evoking visual or motor associations. There is evidence for early word class-specific spreading of neuronal activity and for equally specific high-frequency responses occurring later. These results support a neurobiological model of language in the Hebbian tradition. Competing large-scale neuronal theories of language are discussed in light of the data summarized. Neurobiological perspectives on the problem of serial order of words in syntactic strings are considered in closing. Key Words: associative learning; cell assembly; cognition; cortex; ERP; EEG; fMRI; language; lexicon; MEG; PET; word category. (shrink)