Abstract Under the realm of neurocultures the concept of the cerebral subject emerges as the central category to define the self, socio-cultural interaction and behaviour. The brain is the reference for explaining cognitive processes and behaviour but at the same time the plastic brain is situated in current paradigms of (self)optimization on the market of meritocracy by means of neurotechnologies. This paper explores whether neurotechnological apparatuses may—due to their hybridity and malleability—bear potentials for a change in gender based attributions (...) that have been historically legitimized by apparently natural differences between women and men. Or, in contrast, which gendered ascriptions are (again) produced in theories and applications according to the normative demands for the bio-techno-social cerebral subject situated in neoliberal power relations. An exploration of three main fields of current developments, the neurotechnological apparatus of brain-computer-interfaces, the technologies for brain tuning and the discourses in neuroeconomics, reveals first insights on these gender aspects in reliance with the ethical/political debate. Moreover, this paper concretizes questions for further research on gender and ethical aspects in the field of neurotechnologies. Content Type Journal Article Category Original Paper Pages 1-14 DOI 10.1007/s12152-011-9129-1 Authors Sigrid Schmitz, Faculty of Social Sciences, Institute of Cultural and Social Anthropology, University of Vienna, Alserstraße 23/22, 1080 Vienna, Austria Journal Neuroethics Online ISSN 1874-5504 Print ISSN 1874-5490. (shrink)
Taking children with Cerebral Palsy (CP) as an example, the article seeks an understanding of children with disabilities that connects neuropsychological theories of neural development with the situated cognition perspective and the child as an active participant in its social practices. The early brain lesion of CP is reconceptualised as a neurobiological constraint that exists in the relations between the neural, cognitive and social levels. Through a multi-method study of two children with CP, it is analysed how neurobiological constraints (...) arise, evolve and sometimes are resolved through local matches between the child and its social practices. The result is discussed as support of a developmental science approach that includes processes at the social practice level along with knowledge of biological processes. (shrink)
Concepts and experimental results taken frombehavioral pharmacology, functional brain imaging,brain physiology, and behavioral neuroscience, wereused to develop the hypothesis that behavioraltolerance can, in part, be attributed to cellulartolerance. It is argued that task specific activationof circumscribed neuronal populations gives rise tocorresponding increases in regional cerebral bloodflow such that neurons related to task performance areexposed to higher effective doses of blood-borne drugthan neuronal groups not highly activated by thebehavioral task. Through this cerebral hemodynamicregulatory mechanism cellular tolerance phenomena canat least (...) partially account for behavioral tolerance(i.e., tolerance conferred through drugged practice). (shrink)
The ability to predict is the most importantability of the brain. Somehow, the cortex isable to extract regularities from theenvironment and use those regularities as abasis for prediction. This is a most remarkableskill, considering that behaviourallysignificant environmental regularities are noteasy to discern: they operate not only betweenpairs of simple environmental conditions, astraditional associationism has assumed, butamong complex functions of conditions that areorders of complexity removed from raw sensoryinputs. We propose that the brain's basicmechanism for discovering such complexregularities is implemented in (...) the dendritictrees of individual pyramidal cells in thecerebral cortex. Pyramidal cells have 5–8principal dendrites, each of which is capableof learning nonlinear input-to-outputtransfer functions. We propose that eachdendrite is trained, in learning its transferfunction, by all the other principal dendritesof the same cell. These dendrites teach eachother to respond to their separate inputs with matching outputs. Exposed to differentbut related information about the sensoryenvironment, principal dendrites of the samecell tune to functions over environmentalconditions that, while different, are correlated . As a result, the cell as awhole tunes to the source of the regularitiesdiscovered by the cooperating dendrites,creating a new representation. When organizedinto feed-forward/feedback layers, pyramidalcells can build their discoveries on thediscoveries of other cells, graduallyuncovering nature's hidden order. Theresulting associative network is powerfulenough to meet a troubling traditionalobjection to associationism: that it is toosimple an architecture to implement rationalprocesses. (shrink)
I dispute that consciousness is generated by core circuitry in the forebrain, with predominance of motor areas, as Cotterillproposes in Enchanted Looms and other theorists do also. Ipropose instead that conscious contents are the momentary modeof action of the integrated cortical field, expressed as a point vector ( dominant focus ), to which, in varying degree, allsectors of the network contribute. Consciousness is the brain''saccess to its own activity space, and is identical with the moment''sdominant mode of activity. The dominant (...) focus is generally weightedtoward enactively encoded percepts. Anticipation and preparation,perception and action, inextricably interdigitate. I also dispute the view of Cotterill and others that consciousnesshas unique agency, which bestowed adaptive advantage when the brain evolved. Being identical with the activity of the network,consciousness can have no additional agency, and it can offerno adaptive advantages beyond those that characterize the network. (shrink)
The current fMRI study investigated cortical processing of electrically induced painful tooth stimulation of both maxillary canines and central incisors in 21 healthy, right handed volunteers. A constant current, 150% above tooth specific pain-perception thresholds was applied and corresponding online ratings of perceived pain intensity were recorded with a computerized visual analog scale during fMRI measurements. Lateralization of cortical activations was investigated by a region of interest analysis. A wide cortical network distributed over several areas, typically described as the pain (...) or nociceptive matrix, was activated on a conservative significance level. Distinct lateralization patterns of analyzed structures allow functional classification of the dental pain processing system. Namely, certain parts are activated independent of the stimulation site, and hence are interpreted to reflect cognitive emotional aspects. Other parts represent somatotopic processing and therefore reflect discriminative perceptive analysis. Of particular interest is the observed amygdala activity depending on the stimulated tooth that might indicate a role in somatotopic encoding. (shrink)
Background: We like to think about sexual activity as something fixed, basic and primal. However, this does not seem to fully capture reality. Even when we relish sex, we may be capable of mentalizing, talking, voluntarily postponing orgasm, and much more. This might indicate that the central control mechanisms of sexual activity are quite flexible and susceptible to learning mechanisms, and that cortical brain areas play a critical part. Objective: This study aimed to identify those cortical areas and mechanisms most (...) consistently implicated in sexual activity. Design: A comprehensive review of the human functional neuroimaging literature on sexual activity, i.e. genital stimulation and orgasm, is made. Results: Genital stimulation recruits the classical somatosensory matrix, but also areas far beyond that. The posterior insula may be particularly important for processing input from the engorged penis and coordinating penile responses. Extrastriate visual cortex tracks sexual arousal and responds to genital stimulation even when subjects have their eyes closed. The ventromedial prefrontal cortex is also tightly coupled to sexual arousal, but low activity in this area predicts high sexual arousal. Conclusion: This review has indicated cortical sites where activity is moderated by tactile genital inflow and high sexual arousal. Behavioral implications are discussed and where possible the relevance for learning mechanisms is indicated. Overall, it is clear that the cerebral cortex has something to say about sexual activity. Keywords: functional neuroimaging; insula; ventromedial prefrontal cortex; extrastriate visual cortex; penis; clitoris; orgasm (Published: 15 March 2012) Citation: Socioaffective Neuroscience & Psychology 2012, 2 : 17337 - DOI: 10.3402/snp.v2i0.17337. (shrink)
The notion of cerebral death is examined in relation to those of cardiopulmonary and whole-brain death. It is argued that rather than being a new concept of death, it is merely a new criterion that leaves the old concept — death as loss of personhood — intact. The argument begins on a theoretical level with the distinction between criteria and concepts, places both into context with the notion of a conceptual framework in its relation to empirical reality, and then (...) particularizes the result to criteria for the determination of death. It is argued that the suggestion of the cerebral criterion is nothing more than an attempt to realign the concept of death with the empirical data with which it has come out of step due to new developments in the empirical field. The paper considers tutioristic objections to the criterion, and shows its compatibility with dualistic religio-metaphysical positions by considering an actual example. It also addresses briefly the ethical impact of the criterion on medical practice. (shrink)
The claim of consistent hemispheric specialisations across classes of chordates is undermined by the absence of population-based directional asymmetry of paw/hand use in rodents and primates. No homologue of the cerebral torque from right frontal to left occipital has been established in a nonhuman species. The null hypothesis that the torque is the sapiens-specific neural basis of language has not been disproved.
Stiff Person Syndrome (SPS) is a rare autoimmune disorder associated with antibodies against glutamic acid decarboxylase (GAD-Ab), the key enzyme in γ -aminobutyric acid synthesis (GABA). In order to investigate the role of cerebral benzodiazepinereceptor binding in SPS, we performed [ 11 C]flumazenil (FMZ) positron emission tomography (PET) in a female patient with SPS compared to nine healthy controls. FMZ is a radioligand to the postsynaptic (...) central benzodiazepine receptor which is co-localized with the GABA-A receptor. In the SPS patient, we found a global reduction of cortical FMZ binding. In addition, distinct local clusters of reduced radiotracer binding were observed. These data provide first in vivo evidence for a reduced postsynaptic GABA-A receptor availability which may reflect the loss of GABAergic neuronal inhibition in SPS. (shrink)
We propose a theoretical model of the cerebral cortex which is based on its cellular components and integrates its different levels of organization: (1) cells have general adaptive and memorization properties; (2) cortical columns are repetitive interneuronal circuits which determine an adaptive processing specific to the cerebral cortex; (3) cortical maps effect selective combinations which are very efficient to learn basic behaviourial adaptations such as invariant recognition of forms, visually-guided hand movements, or execution of structured motor programs; (4) (...) the network between cortical areas has a global architecture which integrates successive learning experiences into coherent functions such as the human language. (shrink)
Using positron emission tomography (PET) and regional cerebral blood ﬂow (rCBF) measurements, we investigated the cerebral correlates of consciousness in a sequence learning task through a novel application of the Process Dissociation Procedure, a behavioral paradigm that makes it possible to separately assess conscious and unconscious contributions to performance. Results show that the metabolic response in the anterior cingulate / mesial prefrontal cortex (ACC / MPFC) is exclusively and speciﬁcally correlated with the explicit component of performance during recollection (...) of a learned sequence. This suggests a signiﬁcant role for the ACC / MPFC in the explicit processing of sequential material. 2003 Elsevier Science B.V. All rights reserved. (shrink)
We describe a possible link between coordinated lateralised group behaviour serving species survival in lower vertebrates and a striking lateralisation phenomenon found in human social behaviour: the universal preference for cradling a young infant on the left side. Our exploration offers a different perspective on the role of cerebral asymmetry for the survival of both the individual and the species.
Discrimination of forms defined solely by color and discrimination of hue are dissociated in cerebral achromatopsia. Both must be based on potentially explicit information derived from differentially color-sensitive photoreceptors, yet only one gives rise to phenomenal experience of color. By analogy, visual information may be used to form explicit representations for action without giving rise to any phenomenal experience other than that of making the action.
Vallortigara & Rogers (V&R) assume that the alignment of escape responses in gregarious species is the central evolutionary organizer of a wide range of cerebral asymmetries. Although it is indeed likely that the benefits of a population asymmetry in social species outweigh its costs, it is hard to see (a) why the population should not oscillate between two subgroups with mirror-image asymmetries, (b) why solitary animals should keep their inherited population asymmetry despite a resulting fitness reduction, and (c) and (...) why so many vertebrate species have comparable cerebral asymmetries. (shrink)
The cerebral distinctness of the linguistic and mathematical faculties does not entail their functional independence. Approaches to language that posit a common foundation for the two make claims about design features, not location, and are thus not affected by the finding that one ability can be spared by a neurological accident that compromises the other.
Converging lines of evidence indicate that schizophrenia is characterized by impairments of synaptic machinery within cerebral cortical circuits. Efforts to localize these alterations in brain tissue from subjects with schizophrenia have frequently been limited to the quantification of structures that are non-selectively identified (e.g. dendritic spines labeled in Golgi preparations, axon boutons labeled with synaptophysin), or to quantification of proteins using methods unable to resolve relevant cellular compartments. Multiple label fluorescence confocal microscopy represents a means to circumvent many of (...) these limitations, by concurrently extracting information regarding the number, morphology, and relative protein content of synaptic structures. An important adaptation required for studies of human disease is coupling this approach to stereologic methods for systematic random sampling of relevant brain regions. In this review article we consider the application of multiple label fluorescence confocal microscopy to the mapping of synaptic alterations in subjects with schizophrenia and describe the application of a novel, readily automated, iterative intensity/morphological segmentation algorithm for the extraction of information regarding synaptic structure number, size, and relative protein level from tissue sections obtained using unbiased stereological principles of sampling. In this context, we provide examples of the examination of pre- and post-synaptic structures within excitatory and inhibitory circuits of the cerebral cortex. (shrink)
Deficits in brain white matter have been a main focus of recent neuroimaging studies on stuttering. However, no prior study has examined brain connectivity on the global level of the cerebral cortex in persons who stutter (PWS). In the current study, we analyzed the results from probabilistic tractography between regions comprising the cortical speech network. An anatomical parcellation scheme was used to define 28 speech production-related ROIs in each hemisphere. We used network-based statistic (NBS) and graph theory to analyze (...) the connectivity patterns obtained from tractography. At the network level, the probabilistic corticocortical connectivity from the PWS group were significantly weaker that from persons with fluent speech (PFS). NBS analysis revealed significant components in the bilateral speech networks with negative correlations with stuttering severity. To facilitate comparison with previous studies, we also performed tract-based spatial statistics (TBSS) and regional fractional anisotropy (FA) averaging. Results from tractography, TBSS and regional FA averaging jointly highlight the importance of several regions in the left peri-Rolandic sensorimotor and premotor areas, most notably the left ventral premotor cortex and middle primary motor cortex, in the neuroanatomical basis of stuttering. (shrink)
Male superiority in mathematical ability (along with female superiority in verbal fluency) may reflect the operation of an X-Y homologous gene (the right-shift-factor) influencing the relative rates of development of the cerebral hemispheres. Alleles at the locus on the Y chromosome will be selected at a later mean age than alleles on the X, and only by females.
The year 2009 marked the 100th anniversary of the publication of the famous brain map of Korbinian Brodmann. Although a "classic" guide to microanatomical parcellation of the cerebral cortex, it is – from today's state-of-the-art neuroimaging perspective – problematic to use Brodmann's map as a structural guide to functional units in the cortex. In this article we discuss some of the reasons, especially the problematic compatibility of the "post-mortem world" of microstructural brain maps with the "in vivo world" of (...) neuroimaging. We conclude with some prospects for the future of in vivo structural brain mapping: a new approach which has the enormous potential to make direct correlations between microstructure and function in living human brains: "in vivo Brodmann mapping" with high-field magnetic resonance imaging. (shrink)
K L Kahlbaum published in 1874 the ﬁrst recorded description of catatonia. Akinetic catatonia is now deﬁned as a neuropsychiatric syndrome principally characterised by akinesia, mutism, stupor, and catalepsy. 1 Even if some advances have been made in the recognition of catatonia, in particular by the development of different rating scales, 1 the pathophysiology of this syndrome is not clearly established. A right handed 14 year old girl presented with akinetic catatonia during an episode of depression in the context of (...) a bipolar type I disorder. Her catatonic status was characterised by akinesia with brief episodic spontaneous stereotyped movements, mutism, no spontaneous oral intake, catalepsy, waxy ﬂexibility, and stupor with brief occasional eye contacts. This corresponded to a total score of 19 on the Northoff Catatonia Scale.1 Electroencephalogram performed one day after onset of symptoms showed diffuse theta activity with sporadic diffuse delta activity. Cerebral magnetic resonance imaging was normal. Brain positron emission tomographies (PET) were obtained on a CTI-Siemens HR+ tomograph. A ﬁrst PET (PET1) using (18F(- ﬂuorodeoxyglucose (FDG) was performed on day 2 in a drug free state. Thereafter, intramuscular injection of 2 mg of lorazepam induced rapid clinical remission of the akinetic phase. Oral lorazepam was then given (3.75 mg/day) during ﬁve days. On day 8, a second PET with FDG was performed while the patient was treated by olanzapine (15 mg/day) and presented hyperactivity, logorrhoea, and disinhibition characterised by uncontrolled social interactions and physical contacts. Neuropsychological testing performed some days after remission revealed no apraxia or language disturbances but dysfunction of executive tasks manifested in the revised Wisconsin card sorting, the Tower of London, Stroop, and Trailmaking tests. Voxel based analyses comparing patient’s cerebral glucose metabolism with that of 29 right handed healthy controls (16 women and 13 men, mean age 32) were performed using Statistical Parametric Mapping (SPM99) (Wellcome Department of Cognitive Neurology, London, UK).. (shrink)
Functional imaging techniques, such as positron emission tomography and functional magnetic resonance imaging, present a unique opportunity to examine, in humans, the cerebral representation of space in vivo. Space is ubiquitous and not a unitary phenomenon, and the brain uses visual, vestibular and proprioceptive inputs to produce multiple representations of space subserving spatial cognition, ranging from gaze control to remembering multiple complex large-scale environments. Functional imaging studies have shown the importance of the parietal cortex in perceptual, motor, attention and (...) working memory aspects of body-centred human spatial cognition. Functional imaging has also revealed pathways in humans homologous to those found in monkeys for the separate processing of spatial location and object identity. There are further suggestions of similar differentiation in working memory. The importance of the medial temporal region in the recall of spatial location has been confirmed also and novel virtual reality paradigms are now providing insights into the cerebral representation of spatially-extended large-scale environments. We still have much to learn about the cerebral representation of space in the human brain and functional brain imaging, in concert with patient studies and animal models, will allow us to continue investigating. (shrink)
BACKGROUND: Through their action on the locus coeruleus, ␣ 2-adrenoceptor agonists induce rapidly reversible sedation while partially preserving cognitive brain functions. Our goal in this observational study was to map brain regions whose activity is modified by clonidine infusion so as to better understand its loci of action, especially in relation to sedation. METHODS: Six ASA I–II right-handed volunteers were recruited. Electroencephalogram (EEG) was monitored continuously. After a baseline H215O activation scan, clonidine infusion was started at a rate ranging from (...) 6 to 10 g ⅐ kgϪ1 ⅐ h Ϫ1. A sequence of 11 similar scans was then performed at 8 min intervals. Plasma clonidine concentration was measured. Using statistical parametric mapping, we sought linear correlations between normalized regional cerebral blood flow (rCBF), an indicator of regional brain activity, and plasma clonidine concentration or spindle EEG activity. RESULTS: Clonidine induced clinical sedation and EEG patterns (spindles) comparable to early stage nonrapid eye movement sleep. A significant negative linear correlation between clonidine concentration and rCBF or spindle activity was observed in the thalamus, prefrontal, orbital and parietal association cortex, posterior cingulate cortex, and precuneus. CONCLUSIONS: The EEG patterns and decreases in rCBF of specific brain regions observed during clonidine-induced sedation are similar to those of early stage nonrapid eye movement sleep. Patterns of deactivated brain regions are also comparable to those observed during general anesthesia or vegetative state, reinforcing the hypothesis that alterations in the activity of a common network occur during these modified conscious states. (shrink)
A broad range of evidence regarding the functional organization of the vertebrate brain – spanning from comparative neurology to experimental psychology and neurophysiology to clinical data – is reviewed for its bearing on conceptions of the neural organization of consciousness. A novel principle relating target selection, action selection, and motivation to one another, as a means to optimize integration for action in real time, is introduced. With its help, the principal macrosystems of the vertebrate brain can be seen to form (...) a centralized functional design in which an upper brain stem system organized for conscious function performs a penultimate step in action control. This upper brain stem system retained a key role throughout the evolutionary process by which an expanding forebrain – culminating in the cerebral cortex of mammals – came to serve as a medium for the elaboration of conscious contents. This highly conserved upper brainstem system, which extends from the roof of the midbrain to the basal diencephalon, integrates the massively parallel and distributed information capacity of the cerebral hemispheres into the limited-capacity, sequential mode of operation required for coherent behavior. It maintains special connective relations with cortical territories implicated in attentional and conscious functions, but is not rendered nonfunctional in the absence of cortical input. This helps explain the purposive, goal-directed behavior exhibited by mammals after experimental decortication, as well as the evidence that children born without a cortex are conscious. Taken together these circumstances suggest that brainstem mechanisms are integral to the constitution of the conscious state, and that an adequate account of neural mechanisms of conscious function cannot be confined to the thalamocortical complex alone. (Published Online May 1 2007) Key Words: action selection; anencephaly; central decision making; consciousness; control architectures; hydranencephaly; macrosystems; motivation; target selection; zona incerta. (shrink)
Despite tremendous advances in neuroscience, the topic “brain, sex and gender” remains a matter of misleading interpretations, that go well beyond the bounds of science. In the 19th century, the difference in brain sizes was a major argument to explain the hierarchy between men and women, and was supposed to reflect innate differences in mental capacity. Nowadays, our understanding of the human brain has progressed dramatically with the demonstration of cerebral plasticity. The new brain imaging techniques have revealed the (...) role of the environment in continually re-shaping our brain all along our lifetimes as it goes through new experiences and acquires new knowledge. However, the idea that biology is a major determining factor for cognition and behavioral gender differentiation, is still very much alive. The media are far from being the only guilty party. Some scientific circles actively promote the idea of an innate origin of a gender difference in mental capacities. Experimental data from brain imaging, cognitive tests or genetics are often distorted to serve deterministic ideas. Such abuse of “scientific discourses” have to be counteracted by effective communication of clear and unbiased information to the citizens. This paper presents a critical analysis of selected examples which emphasize sex differences in three fields e.g. skills in language and mathematics, testosterone and financial risk-taking behavior, moral cognition. To shed light on the data and the methods used in some papers, we can now—with today’s knowledge on cerebral plasticity—challenge even more strongly, many false interpretations. Our goal here is double: we want to provide evidence against archaic beliefs about the biological determinism of sex differences but also promote a positive image of scientific research. (shrink)
Merker's approach allows the formulation of an evolutionary view of consciousness that abandons a dependence on structural homology – in this case, the presence of a cerebral cortex – in favor of functional concordance. In contrast to Merker, though, I maintain that the emergence of complex, dynamic interactions, such as those which occur between thalamus and cortex, was central to the appearance of consciousness. (Published Online May 1 2007).