Emotion Review, Volume 14, Issue 2, Page 132-160, April 2022. Autonomic nervous system activity is a fundamental component of emotional responding. It is not clear, however, whether positive emotional states are associated with differential ANS reactivity. To address this issue, we conducted a meta-analytic review of 120 articles, measuring ANS activity during 11 elicited positive emotions, namely amusement, attachment love, awe, contentment, craving, excitement, gratitude, joy, nurturant love, pride, and sexual desire. We identified a widely dispersed collection of studies. (...) Univariate results indicated that positive emotions produce no or weak and highly variable increases in ANS reactivity. However, the limitations of work to date – which we discuss – mean that our conclusions should be treated as empirically grounded hypotheses that future research should validate. (shrink)

Based on anthropological fieldwork in Australia and Colombia, this collection of essays uses the workings of the human nervous system to illustrate concepts of culture.

The contributors to Nervous Systems reassess contemporary artists' and critics' engagement with social, political, biological, and other systems as a set of complex and relational parts: an approach commonly known as systems thinking. Demonstrating the continuing relevance of systems aesthetics within contemporary art, the contributors highlight the ways that artists adopt systems thinking to address political, social, and ecological anxieties. They cover a wide range of artists and topics, from the performances of the Argentinian collective the Rosario Group and (...) the grid drawings of Charles Gaines to the video art of Singaporean artist Charles Lim and the mapping of global logistics infrastructures by contemporary artists like Hito Steyerl and Christoph Büchel. Together, the essays offer an expanded understanding of systems aesthetics in ways that affirm its importance beyond technological applications detached from cultural contexts. (shrink)

What is it like to be an octopus, one of those eight-armed, infinitely flexible sea creatures with a nervous system distributed over head, eyes and arms? One interesting approach is to argue that octopuses, because of their distributed nervous systems, are likely to possess disunified consciousness (Carls-Diamante 2017). However, this supposed isomorphism between a “unified” nervous system and “unified” consciousness is problematic, since the term “unity” is taken as a “given” even though it is far from clear (...) what it means. I will argue that explaining the structure of consciousness requires a prior explanation in terms of how it is achieved by the organism through sensorimotor integration. On this account, the structure of an organism’s consciousness is explained partly by what the external world is like, and partly by how the organism’s body, senses and nervous system enable the organism to interact with the external world. (shrink)

The target article discusses various aspects of the relationship between the sympathetic system and pain. To this end, the patients under study are divided into three groups. In the first group, called (RSD), the syndrome can be characterized by a triad of autonomic, motor, and sensory symptoms, which occur in a distally generalized distribution. The pain is typically felt deeply and diffusely, has an orthostatic component, and is suppressed by the ischemia test. Under those circumstances, the pain is likely to (...) respond to sympatholytic interventions. In a second group, called (SMP) syndrome, the principal symptoms are spontaneous pain, which is felt superficially and has no orthostatic component, and allodynia. These symptoms, typically confined to the zone of a lesioned nerve, may also be relieved by sympathetic blocks. Since the characteristics of the pain differ between RSD and SMP, the underlying kind of sympathetic–sensory coupling may also vary between these cases. A very small third group of patients exhibits symptoms of both RSD and SMP. The dependence or independence of pain on sympathetic function reported in most published studies seems to be questionable because the degree of technical success of the block remains uncertain. Therefore, pain should not be reported as sympathetic function independent until the criteria for a complete sympathetic block have been established and satisfied. (shrink)

New possibilities to modify function and direct repair in the central nervous system (CNS) have been established by the merger of gene transfer technology with neural transplantation. Rapid advances in viral‐mediated DNA‐delivery procedures permit the study of novel gene expression in neurons and glial cells. Foreign genes, transferred by a virus vector, can be used to generate new cell lines, identify transplanted cells, and express growth factors or enzymes for neurotransmitter synthesis. In addition to CNS cell types, non‐neural cells (...) are also being studied with transgene technology in the nervous system. Functional effects have been obtained with grafts of genetically modified cells in animal models of several nervous system disorders, and the recent results set the stage for potential application of these techniques to human CNS gene therapy. (shrink)

Alternative cleavage and polyadenylation (APA) can diversify coding and non‐coding regions, but has particular impact on increasing 3′ UTR diversity. Through the gain or loss of regulatory elements such as RNA binding protein and microRNA sites, APA can influence transcript stability, localization, and translational efficiency. Strikingly, the central nervous systems of invertebrate and vertebrate species express a broad range of transcript isoforms bearing extended 3′ UTRs. The molecular mechanism that permits proximal 3′ end bypass in neurons is mysterious, and (...) only beginning to be elucidated. This landscape of neural 3′ UTR extensions, many reaching unprecedented lengths, may help service the unique post‐transcriptional regulatory needs of neurons. A combination of approaches, including transcriptome‐wide profiling, genetic screening to identify APA factors, biochemical dissection of alternative 3′ end formation, and manipulation of individual neural APA targets, will be necessary to gain fuller perspectives on the mechanism and biology of neural‐specific 3′ UTR lengthening. (shrink)

Test anxiety is a widespread and primarily detrimental emotion in learning and achievement settings. This research aimed to explore the autonomic nervous system response patterns of test-anxious individuals in response to evaluative stress. By presenting a standard interview task, an evaluative scenario was effectively induced. Heart rate variability, a biomarker that can accurately reflect the ANS activity, was used to reflect the physiological responses of 48 high test-anxious subjects and 49 low test-anxious subjects. Results indicate that: both groups show (...) a significantly increased emotional arousal in the evaluative scenario; high test-anxious individuals show a significantly decreased emotional pleasantness in the evaluative scenario, whereas low test-anxious individuals show no significant changes; both groups show a significantly increased low-frequency HRV; high test-anxious individuals show a significantly decreased high-frequency HRV and root mean square of successive heartbeat interval differences, whereas low test-anxious individuals remain stable. These findings suggest that high test-anxious individuals display an increased sympathetic nervous system activity and a decreased parasympathetic nervous system activity in response to evaluative stress, while low-anxious individuals display an increased SNS activity and a stable PNS activity in response to evaluative stress. (shrink)

To foster understanding in the psychopathology of patients with anorexia nervosa at the psychological and physiological level, standardized experimental studies on reliable biomarkers are needed, especially due to the lack of disorder-specific samples. To this end, the autonomic nervous system response to a psychosocial stressor was investigated in n = 19 PAN, age, and gender-matched to n = 19 healthy controls. For this purpose, heart rate and heart rate variability parameters were assessed in a cross-sectional study design under two (...) experimental conditions: rest and stress. In addition, psychological indicators of stress were assessed. An 2 × 2 × 8 ANOVA demonstrated similar HR and HRV patterns between PAN and HC at rest. Under stress, PAN demonstrated a blunted HR [condition*time*group: F = 9.326, p = 0.000, η2 = 0.206] and an attenuated HRV response. Significant effects of stress appraisal and BMI on HRV-reactivity were revealed. SA on SDNN = Condition*time*SA = F = 2.676, p = 0.033, η2 = 0.073. BMI on LF/HF-Ratio = Condition*time*BMI = F = 3.339, p = 0.019, η2 = 0.164. Psychological indices suggested higher levels of chronic and appraised stress in PAN relative to HC. Additional analyses demonstrated that ED-symptoms are highly correlated with the latter constructs, as well as with psychological burden, but not with weight. Further, it was shown that abnormalities in reactivity persisted despite normalized ANS activity. Overall, we suggested that besides weight recovery, improvement in stress appraisal could be beneficial for cardiac health. In this light, a combination of therapy and biofeedback training may improve treatment outcomes and regulate stress reactivity. (shrink)

Paulin and Cahill‐Lane explore the origins of event processing and event prediction in animal evolution. They propose that the evolutionary benefit of being able to predict and thus to quickly react to anticipated events may have triggered the evolution of the earliest nervous systems.

Gooddy, a British neurologist, argues that our sense of time, and relativity in general, is a function of the nervous system. Written for the general reader, the 10 essays discuss atomic, cellular, and glandular "clocks," age, government time vs. personal time, and time disorders (such as being in love). Annotation copyrighted by Book News, Inc., Portland, OR.

This commentary on blumberg et al. addresses complications associated with diagnostic testing for sympathetic dependence of pain that can lead to inappropriate positive and negative conclusions. In addition, it is suggested that their test be conceived as a test of the effect of local vascular pressure and that the two types of sensory disorders presented may differ primarily in the degree of sensitization of central pain pathways. Detailed reports with functionally-oriented testing like that done by BLUMBERG are essential for an (...) understanding the pathophysiological mechanisms. (shrink)

It remains a standing problem how and why the first nervous systems evolved. Molecular and genomic information is now rapidly accumulating but the macroscopic organization and functioning of early nervous systems remains unclear. To explore potential evolutionary options, a coordination centered view is discussed that diverges from a standard input–output view on early nervous systems. The scenario involved, the skin brain thesis, stresses the need to coordinate muscle-based motility at a very early stage. This paper addresses how (...) this scenario with its focus on coordination also deals with sensory aspects. It will be argued that the neural structure required to coordinate extensive sheets of contractile tissue for motility provides the starting point for a new multicellular organized form of sensing. Moving a body by muscle contraction provides the basis for a multicellular organization that is sensitive to external surface structure at the scale of the animal body. Instead of thinking about early nervous systems as being connected to the environment merely through input and output, the implication developed here is that early nervous systems provide the foundation for a highly specific animal sensorimotor organization in which neural activity directly reflects bodily and environmental spatiotemporal structure. While the SBT diverges from the input–output view, it is closely linked to and supported by ongoing work on embodied approaches to intelligence to which it adds a new interpretation of animal embodiment and sensorimotor organization. (shrink)

Context: Neurophenomenology is a relatively new field, with scope for novel and informative approaches to empirical questions about what structural parallels there are between neural activity and phenomenal experience. Problem: The overall aim is to present a method for examining possible correlations of neurodynamic and phenodynamic structures within the structurally-coupled work of Alexander Technique practitioners with their pupils. Method: This paper includes the development of an enkinaesthetic explanatory framework, an overview of the salient aspects of the Alexander Technique, and the (...) presentation of an elicitation interview technique as part of a neurophenomenological method. It will propose a way of testing the hypothesis that if, in the effective practice of Alexander Technique, there is a union between the nervous systems of teacher and pupil, it should be visible neurologically and affective phenomenologically, and thus it should be possible to investigate both its neural and phenomenal signatures. Results: The proposed means of testing the hypothesis is to use the elicitation interview technique alongside neural monitoring during the teaching of the Alexander Technique in four paired sets of subjects. Constructivist content: At the heart of this paper is the claim that all activity is co-activity. I make no assumption of an ontological primacy of mental or physical, or explanatory primacy of any methodology. Implications: This has important ramifications for somatic education and therapies, for establishing frameworks of co-engagement and care in health-care situations, and for understanding empathy. (shrink)

This target article draws together two groups of experimental studies on the control of human movement through peripheral feedback and centrally generated signals of motor commands. First, during natural movement, feedback from muscle, joint, and cutaneous afferents changes; in human subjects these changes have reflex and kinesthetic consequences. Recent psychophysical and microneurographic evidence suggests that joint and even cutaneous afferents may have a proprioceptive role. Second, the role of centrally generated motor commands in the control of normal movements and movements (...) following acute and chronic deafferentation is reviewed. There is increasing evidence that subjects can perceive their motor commands under various conditions, but that this is inadequate for normal movement; deficits in motor performance arise when the reliance on proprioceptive feedback is abolished either experimentally or because of pathology. During natural movement, the CNS appears to have access to functionally useful input from a range of peripheral receptors as well as from internally generated command signals. The unanswered questions that remain suggest a number of avenues for further research. (shrink)

In many evolutionary/functionalist theories, emotions organize the activity of the autonomic nervous system and other physiological systems. Two kinds of patterned activity are discussed: coherence, and specificity. For each kind of patterning, significant methodological obstacles are considered that need to be overcome before empirical studies can adequately test theories and resolve controversies. Finally, links that coherence and specificity have with health and well-being are considered.

The objective of this paper is to present a new theory of synaptic function in the nervous system. The basis for this theory is the experimental demonstration that a nerve impulse assumes five different forms as it advances through the synaptic region, and that five basic mathematical operations have been identified as being involved in the transformation of one form into another form. As a result of these data, the synaptic region is regarded as a functional unit where information (...) coming to it is unpacked, processed, stored, and retrieved for transit to another synaptic region or effector site. The data also suggests that a nerve impulse is a bolus of energy, therefore, without substance; that it contains information coded in its shape or form; that it is precisely described mathematically. Furthermore, the data suggests synaptic regions process these nerve impulses by applying mathematical operations to them; that function in the synaptic region is highly stereotyped (programmed); that chemical substances are associated with the mathematical operations. The basic approach of this theory is to regard a significant portion of the nervous system as an interface between the external universe and man himself. As an interface, the nervous system receives and processes information from both the external universe and man himself in a programmed manner. The interface functions by converting the information it receives into a bolus of energy, the nerve impulse, then processes the bolus by converting it into numbers or functions and applying mathematical operation to it. (shrink)

In many evolutionary/functionalist theories, emotions organize the activity of the autonomic nervous system and other physiological systems. Two kinds of patterned activity are discussed: coherence, and specificity. For each kind of patterning, significant methodological obstacles are considered that need to be overcome before empirical studies can adequately test theories and resolve controversies. Finally, links that coherence and specificity have with health and well-being are considered.

A new theory for basic function in the nervous system has recently been proposed (Dempsher, J., 1979a, 1979b; 1980, 1981). The major basic themes of the new theory are as follows: (1) There are two fundamental units of structure and function, the fibre or conducting mechanism, and the neurocentre, where nervous system function as we know it takes place. (2) The nerve impulse is regarded as a mathematical event. The mathematics is the result of a prescribed fusion of (...) energy and matter. (3) Nervous system function everywhere in the nervous system is mathematical. In the fibre, the prescribed fusion of energy and matter results in a number. In the neurocentre, the prescribed fusion of energy and matter results in a mathematical function. Basic function in the nervous system everywhere requires a transformation of a nerve impulse in the fibre into a nerve impulse in the neurocentre with opposing properties: The nerve impulse in the fibre is confined to the fibre; cannot sum with another nerve impulse; can travel long distances with constant form and velocity; curvature in space and time are not significant features; and it is regarded as a number. On the other hand, the nerve impulse in the neurocentre is confined to the neurocentre; can sum with other nerve impulses; cannot travel long distances - even in a very short distance, it changes form; curvature in space and time is a very significant feature; and it is regarded as a mathematical function.The approach to determine how one form of the nerve impulse is transformed into the other at the input region is based on two of the differences listed above: (1) The nerve impulse in the fibre cannot sum with another nerve impulse in the fibre, whereas in the neurocentre, several nerve impulses sum to form a larger nerve impulse. (2) The nerve impulse in the fibre is regarded as a number, in the neurocentre, it is regarded as a mathematical function. The commonality of (1) and (2) is that the properties defining the nerve impulse in the fibre are associated with the property ofdiscreteness, whereas, the properties defining the nerve impulse in the neurocentre are associated with the property ofcontinuousness. Thus, the basic theme of unification of function at the input region of the neurocentre is the transformation of a phenomenon with the property of discreteness into a phenomenon with the property of continuousness. The solution to this transformation is approached from two directions:biologic andmathematical. In the biologic approach, the unit element of the nerve impulse in the fibre terminations (as.u. as a wave of energy, a spike in the classical theory) fuses with a. calcium-binding protein causing the release of Ca++. The calcium ions then combine with another protein. Associated with the second reaction is a conformational change in the Ca++-protein complex and the unit element in the neurocentre, bs.u., is emitted. Individual bs.u. then fuse with acetylcholine; summation occurs andwave b is emitted. In the mathematical approach, the nerve impulse as a number, is partitioned into two numbers with a precise rule relating these two numbers. One possibility suggested is that the number can be regarded as the value of a trigonometric function. This value then gives rise to an angle with sides related in a ratio or proportionality fashion — a relationship with the property of continuousness, as contrasted with that of a single number, discreteness. Both biologic and mathematical approaches are united so as to suggest that the mathematical (trigonometric) function arose as the result of a fusion of energy (as.u. as a wave of energy) and the calcium-binding protein as matter; following this reaction, bs.u., with opposing properties, is emitted. (shrink)

Title page Representational theories propose a set of sufficient conditions for a state to be phenomenally conscious. It turns out that insofar as these conditions have been worked out in detail, the autonomic nervous system (ANS) ought to be conscious - but of course it’s not. In this paper, we’ll describe only a tiny portion of the complexities of the ANS, using these to counterexample only a single theory of phenomenal consciousness, namely, Fred Dretske’s. But we think the ANS (...) comparison strategy is a fruitful one in general, and we hope to convince you of this too. (shrink)

Degeneracy is ubiquitous across biological systems where structurally different elements can yield a similar outcome. Degeneracy is of particular interest in neuroscience too. On the one hand, degeneracy confers robustness to the nervous system and facilitates evolvability: Different elements provide a backup plan for the system in response to any perturbation or disturbance. On the other, a difficulty in the treatment of some neurological disorders such as chronic pain is explained in light of different elements all of which contribute (...) to the pathological behavior of the system. Under these circumstances, targeting a specific element is ineffective because other elements can compensate for this modulation. Understanding degeneracy in the physiological context explains its beneficial role in the robustness of neural circuits. Likewise, understanding degeneracy in the pathological context opens new avenues of discovery to find more effective therapies. (shrink)

Central nervous system (CNS)Abbreviations: CNS=central nervous system; PNS=peripheral nervous system; MS=multiple sclerosis; MBP=myelin basic protein; MHC=major histocompatibility complex; EAE=experimental allergic encephalomyelitis; O‐2A=oligodendrocyte‐type 2 astrocyte; GC=galactocerebroside; GFAP=glial fibrillary acidic protein; FGF=fibroblast growth factor; IGF1=insulin‐like growth factor. regeneration is a subject of great interest, particularly in diseases causing a dramatic loss of neurons. However, some CNS diseases do not affect neurons but damage other cells, such as the myelin‐forming cells — called oligodendrocytes — which are also crucial to the (...) harmonious function of the nervous system. Diseases in which oligodendrocytes and myelin are attacked can cause devastating neurological dysfunction which is sometimes followed by recovery and myelin repair or remyelination. The question of the regeneration potential of oligodendrocytes in experimental and human demyelinating diseases such as multiple sclerosis has been debated for a long time. Present evidence suggests that oligodendrocyte precursor cells persist in the adult CNS and that oligodendrocyte regeneration can occur but may be limited by ongoing disease processes. Here we will briefly review recent advances which have broadened our understanding of the cellular and molecular events of CNS remyelination. (shrink)

Philosophers of mind, both in the conceptual analysis tradition and in the empirical informed school, have been implicitly neglecting the potential conceptual role of the Peripheral Nervous System (PNS) in understanding sensory and perceptual states. Instead, the philosophical as well as the neuroscientific literature has been assuming that it is the Central Nervous System (CNS) alone, and more exactly the brain, that should prima facie be taken as conceptually and empirically crucial for a philosophical analysis of such states (...) This is the first monograph that focuses on the PNS and its constitutive role in sensory states, including pain, mechanoception, proprioception, tactile perception, and so forth. -/- The author argues that the brain-centeredness of current philosophy of mind is a prejudice, and proposes a series of original ways in which classic puzzles in the philosophy of mind can be solved once the hypothesis that PNS is a constitutive element of mental states is taken seriously. The author calls this “the Peripheral Mind Hypothesis”, and employs it in a vast range of issues, such as functionalism, physicalism, mental content, embodiment, as well as some issues in neuroethics. -/- Making equal use of conceptual analysis, empirical data from neuroscience, first-person phenomenological data, and philosophical speculation, this work offers a fresh look at, and novel solutions to many philosophical problems. (shrink)

Fezf1 and Fezf2 are highly conserved transcription factors that were first identified by their specific expression in the anterior neuroepithelium of Xenopus and zebrafish embryos. These proteins share an N‐terminal domain with homology to the canonical engrailed repressor motif and a C‐terminal DNA binding domain containing six C2H2 zinc‐finger repeats. Over a decade of study indicates that the Fez proteins play critical roles during nervous system development in species as diverse as fruit flies and mice. Herein we discuss recent (...) progress in understanding the functions of Fezf1 and Fezf2 in neurogenesis and cell fate specification during mammalian nervous system development. Going forward we believe that efforts should focus on understanding how expression of these factors is precisely regulated, and on identifying target DNA sequences and interacting partners. Such knowledge may reveal the mechanisms by which Fezf1 and Fezf2 accomplish both independent and redundant functions across diverse tissue and cell types. (shrink)

BackgroundResearch on interpersonal synchrony has mostly focused on a single modality, and hence little is known about the connections between different types of social attunement. In this study, the relationship between sympathetic nervous system synchrony, movement synchrony, and the amount of speech were studied in couple therapy.MethodsData comprised 12 couple therapy cases. Synchrony in electrodermal activity, head and body movement, and the amount of speech and simultaneous speech during the sessions were analyzed in 12 sessions at the start of (...) couple therapy and eight sessions at the end of therapy. Synchrony was calculated from cross-correlations using time lags and compared to segment-shuffled pseudo synchrony. The associations between the synchrony modalities and speech were analyzed using complex modeling.FindingsCouple therapy participants’ synchrony mostly occurred in-phase. Anti-phase synchrony was more common in movement than in sympathetic nervous system activity. Synchrony in sympathetic nervous system activity only correlated with movement synchrony between the client-therapist dyads. Movement synchrony and the amount of speech correlated negatively between spouses and co-therapists, meaning that the more time the dyad members talked during the session, the less bodily synchrony they exhibited.ConclusionThe different roles and relationships in couple therapy were associated with the extent to which synchrony modalities were linked with each other. In the relationship between clients and therapists, synchrony in arousal levels and movement “walked hand in hand”, whereas in the other relationships they were not linked. Generally, more talk time by the therapy participants was associated with anti-phase movement synchrony. If, as suggested, emotions prepare us for motor action, an important finding of this study is that sympathetic nervous system activity can also synchronize with that of others independently of motor action. (shrink)

To controlforceaccurately under a wide range of behavioral conditions, the central nervous system would either require a detailed, continuously updated representation of the state of each muscle (and the load against which each is acting) or else force feedback with sufficient gain to cope with variations in the properties of the muscles and loads. The evidence for force feedback with adequate gain or for an appropriate central representation is not sufficient to conclude that force is the major controlled variable (...) in normal limb movements.Morton's hypothesis, thatlengthis controlled by a follow-up servo, has a number of difficulties related to the delays, gains, variability, and specificity in feedback pathways comprising potential servo loops. However, experimental evidence is consistent with these pathways providing servo assistance for some movements produced by coactivation of α- and static γ-motoneurons. Dynamic γ-motoneurons may provide an additional input for adaptive control of different types of movements.The idea that feedback is used to compensate for changes in musclestiffnesshas received experimental support under static postural conditions. However, reflexes tend to increase rather than decrease the range of variation in muscle stiffness during some cyclic movements. Theoretical problems associated with the regulation of stiffness are also discussed. The possibilities of separate control systems forvelocityorviscosityare considered, but the evidence is either negative or lacking. I conclude that different physical variables can be controlled depending on the type of limb movement required. The concept of stiffness regulation is also useful under some conditions, but should probably be extended to the regulation of the visco-elastic properties (i.e., the mechanical impedance) of a muscle or joint. (shrink)

Nervous systems are formidably complex networks of nonlinear interacting components that self organise and continually adapt to enable flexible behaviour. Robust and reliable function is therefore non-trivial to achieve and requires a number of dynamic mechanisms and design principles that are the subject of current research in neuroscience. A striking feature of these principles is that they resemble engineering solutions, albeit at a greater level of complexity and layered organisation than any artificial system. I will draw on these observations (...) to argue that biological robustness in the nervous system remains a deep scientific puzzle, but not one that demands radically new concepts. (shrink)

The article considers patterns of reactivity in organ systems mediated by the autonomic nervous system as they relate to central neural circuits activated by affectively arousing cues. The relationship of these data to the concept of discrete emotion and their relevance for the autonomic feedback hypothesis are discussed. Research both with animal and human participants is considered and implications drawn for new directions in emotion science. It is suggested that the proposed brain-based view has a greater potential for scientific (...) advance than the traditional model that emphasizes specific states of mind as mediators or reflectors of visceral action. (shrink)

There is increasing evidence that carbohydrate antigens act as cell recognition molecules in the highly organized structure of the nervous system. These carbohydrate antigens may be expressed as glycolipids, glycoproteins or proteoglycans, and in some cases all three forms of these glycoconjugates, expressing identical carbohydrate epitopes, can be detected in a specific brain region. This article summarizes recent studies concerning the expression of glycoconjugates during development of the vertebrate central nervous system. These findings are discussed in association with (...) current models of glycoconjugate function. (shrink)

The specification of specific and often unique fates to individual cells as a function of their position within a developing organism is a fundamental process during the development of multicellular organisms. The development of the Drosophila embryonic central nervous system serves as an excellent model system in which to clarify the developmental mechanisms that link pattern formation to cell-type specification. The Drosophila embryonic central nervous system develops from a set of neural stem cells termed neuroblasts. Neuroblasts arise from (...) the ectoderm in an invariant pattern, and each neuroblast acquires a unique fate based on its position within this pattern. Two groups of genes recently have been demonstrated to govern the individual fate specification of neuroblasts. One group, the segment polarity genes, enables neuroblasts that develop in different anteroposterior positions to acquire different fates. The second group, referred to as the columnar genes, ensures that neuroblasts that develop in different dorsoventral domains assume different fates. When integrated, the activities of the segment polarity and columnar genes create a Cartesian coordinate system that bestows unique fates to individual neuroblasts as a function of their position of formation within the ectoderm. BioEssays 1999;21:922–931. © 1999 John Wiley & Sons, Inc. (shrink)