Barrels XXII meeting report: Barrels blow into the Windy City

The 22nd Annual Barrels Meeting blew into Evanston, near the Windy City, in November 2009 as the meeting was hosted on the Evanston, IL campus of Northwestern University. The longest running satellite meeting to the Society for Neuroscience Meeting annually brings together researchers from around the world focused on the development, function, behavior, and physiology of the rodent whisker-to-barrel system and other associated cortical and subcortical areas. The 2009 edition of the meeting was focused on three central themes: the molecular development and developmental plasticity in barrel cortex, optical analysis of barrel cortex function, and the coding of touch. The main symposia were complemented by short talks, data blitz sessions, and a poster session.     

Barrels XXX meeting report: Barrels in Baltimore

The Barrels meeting annually brings together researchers focused on the rodent whisker to cortical barrel system prior to the Society for Neuroscience meeting. The 2017 meeting focused on the classification of cortical interneurons, the role interneurons have in shaping brain dynamics, and finally on the circuitry underlying oral sensations. The meeting highlighted the latest advancements in this rapidly advancing field.     

Subbarrel Patterns in Somatosensory Cortical Barrels Can Emerge from Local Dynamic Instabilities

Complex spatial patterning, common in the brain as well as in other biological systems, can emerge as a result of dynamic interactions that occur locally within developing structures. In the rodent somatosensory cortex, groups of neurons called “barrels” correspond to individual whiskers on the contralateral face. Barrels themselves often contain subbarrels organized into one of a few characteristic patterns. Here we demonstrate that similar patterns can be simulated by means of local growth-promoting and growth-retarding interactions within the circular domains of single barrels. The model correctly predicts that larger barrels contain more spatially complex subbarrel patterns, suggesting that the development of barrels and of the patterns within them may be understood in terms of some relatively simple dynamic processes. We also simulate the full nonlinear equations to demonstrate the predictive value of our linear analysis. Finally, we show that the pattern formation is robust with respect to the geometry of the barrel by simulating patterns on a realistically shaped barrel domain. This work shows how simple pattern forming mechanisms can explain neural wiring both qualitatively and quantitatively even in complex and irregular domains.     

Barrels XXXII meeting report: whiskers in the windy city

Abstract

The 32nd Annual Barrels meeting was hosted at the Northwestern University Feinberg School of Medicine in Chicago, Illinois on October 17th and 18th, 2019. The annual meeting brings together researchers who utilize the rodent whisker-to-barrel system as a means to understand cortical function and development. This year’s meeting focussed on social behaviours, development and cerebellar functions within the barrel system and beyond.     

Barrels XXVIII take the Windy City by storm

The 28th annual Barrels meeting was held prior to the Society for Neuroscience meeting in October 2015 at the Northwestern University School of Law in Chicago, Illinois. The meeting brought together researchers focused on the rodent sensorimotor system. The meeting focused on modern techniques to decipher cortical circuits, social interactions among rodents, and decision-making. The meeting allowed investigators to share their work via short talks, poster presentations, and a data blitz.     

Barrelettes without Barrels in the American Water Shrew

Water shrews (Sorex palustris) depend heavily on their elaborate whiskers to navigate their environment and locate prey. They have small eyes and ears with correspondingly small optic and auditory nerves. Previous investigations have shown that water shrew neocortex is dominated by large representations of the whiskers in primary and secondary somatosensory cortex (S1 and S2). Flattened sections of juvenile cortex processed for cytochrome oxidase revealed clear borders of the whisker pad representation in S1, but no cortical barrels. We were therefore surprised to discover prominent barrelettes in brainstem of juvenile water shrews in the present investigation. These distinctive modules were found in the principal trigeminal nucleus (PrV), and in two of the three spinal trigeminal subnuclei (interpolaris – SpVi and caudalis – SpVc). Analysis of the shrew''s whisker pad revealed the likely relationship between whiskers and barrelettes. Barrelettes persisted in adult water shrew PrV, but barrels were also absent from adult cortex. Thus in contrast to mice and rats, which have obvious barrels in primary somatosensory cortex and less clear barrelettes in the principal nucleus, water shrews have clear barrelettes in the brainstem and no barrels in the neocortex. These results highlight the diverse ways that similar mechanoreceptors can be represented in the central nervous systems of different species.     

An ocean full of BARRELS: Barrels XXVI meeting report

The 26th annual Barrels meeting was convened on the campus of the University of California San Diego, not far from the shores of the Pacific Ocean. The meeting focused on three main themes: the structure and function of the thalamic reticular nucleus, the neurovasculature system and its role in brain metabolism, and the origins and functions of cortical GABAergic interneurons. In addition to the major themes, there were short talks, a data blitz, and a poster session which highlighted the diversity and quality of the research ongoing in the rodent whisker-to-barrel system.     

Proceedings of the Barrels II Workshop: cortical circuits

The second session of the Barrels II Workshop focused on the function of cortical circuitry in the rodent vibrissa-to-barrel system. The session began with talks by Asaf Keller (University of Maryland), Christopher Moore (MIT), and David Pinto (Brown University). These presentations were followed by shorter talks by Mark Andermann (MIT), Alison Barth (Carnegie-Mellon University), Dirk Feldmeyer (Max Planck Institute), Cathy Garabedian (UCSF), Garrett Stanley (Harvard University), and Simona Temereanca (University of Pittsburgh). Presentations covered several central themes, including the functional organization of cortical circuitry, thalamocortical response transformations, temporal response properties, and the role of vibrissa resonance in high frequency representations. For simplicity, this review is organized by these central themes and does not follow the order of presentations at the meeting.     

Proceedings of the Barrels II Workshop: cortical circuits

The second session of the Barrels II Workshop focused on the function of cortical circuitry in the rodent vibrissa-to-barrel system. The session began with talks by Asaf Keller (University of Maryland), Christopher Moore (MIT), and David Pinto (Brown University). These presentations were followed by shorter talks by Mark Andermann (MIT), Alison Barth (Carnegie-Mellon University), Dirk Feldmeyer (Max Planck Institute), Cathy Garabedian (UCSF), Garrett Stanley (Harvard University), and Simona Temereanca (University of Pittsburgh). Presentations covered several central themes, including the functional organization of cortical circuitry, thalamocortical response transformations, temporal response properties, and the role of vibrissa resonance in high frequency representations. For simplicity, this review is organized by these central themes and does not follow the order of presentations at the meeting.     

Barrels XXIII: Barrels by the shore

The 23rd annual Barrels meeting was held on the University of California, San Diego campus and highlighted the latest advances in the whisker-to-barrel pathway and beyond. The annual meeting brought together investigators from a dozen countries to present their data in posters and short talks. The meeting focused on several themes, first the barrel system was used as a model to study the consequences that result from alterations in the normal pattern(s) of development. A second session focused on what happens to whisker information once it leaves the layer IV barrel. A third session addressed issues of coding within the barrel system and a final session highlighted the latest advances in the engineering of transgenic mouse lines. The meeting highlighted the utility of the barrel system to study cortical circuitry in the normal and pathological state.     

Barrels III: Proceedings of a Satellite Symposium of the 1990 Society for Neuroscience Meeting

On October 27 and 28, 1990, approximately 100 somatosensory neurobiologists met in St. Louis, Missouri to discuss the current state of inquiry into the organization of the somatosensory system, emphasizing those portions of the system devoted to processing of inputs from digitized cutaneous organs, such as the rodent mystacial vibrissae. Given the homeomorphic relationship between the vibrissae and cortical and subcortical barrels, a large number of laboratories now employ this model to ask fundamental questions about central processing of sensory inputs, mechanisms controlling topographic pattern formation, and substrates for injury-induced neuronal reorganization. The focus of the third annual Barrels Symposium (Barrels III) was on behavioral aspects of the whisker sense, cholinergic regulation of cortical modules, and genetic and peripheral determinants of barrel development.     

Barrels IX-proceedings

The properties of a newly developed tonic heat pain model (THPM), which makes use of pulsating contact heat, were investigated in 18 young men. The most important feature of this model is that repetitive heat pulses with an intensity of 1°C above the individual pain threshold are employed. This approach was used to tailor the tonic pain stimulation to the individual pain sensitivity. In the first of two experiments, the effects of pulse frequencies ranging from 5 to 30 pulses per minute (ppm) on ratings of pain intensity and pain unpleasantness (visual analogue scales) were examined. At all frequencies, both ratings increased steadily over the 5-min test period. Frequencies of 15 ppm or more appeared to enhance pain intensity throughout the test period compared to the lower frequencies, but did not appear to alter pain unpleasantness. This suggests that only pain intensity is influenced by slow temporal summation and that a sort of frequency threshold exists for this kind of summation. In the second experiment, the THPM was compared to a well-established form of tonic pain stimulation, the compressor test (CPT); visual analogue scales were again used, and in addition the McGill Pain Questionnaire was employed. The CPT appeared to produce stronger tonic pain than the THPM. However, as is typical with tonic pain, both tonic pain models induced relatively higher values on the affective pain dimension than on the sensory pain dimension. The time course of pain was dynamic in the CPT, with an increase followed by a plateau phase, at least in those subjects who could tolerate the CPT for more than 60 sec. In contrast, as in the first experiment, the pain ratings in the THPM were characterized by a slow and steady increase over time. Moreover, there was absolutely no indication of a dichotomy between “pain-sensitive” and “pain-tolerant” individuals in the THPM, although such a dichotomy was evident in the CPT. This implies that the distinction between pain-sensitive and pain-tolerant individuals can be made only with the CPT, and that this distinction represents individual differences in peripheral vascular reactions to cold rather than in pain perception. In conclusion, the THPM appears to produce a stable and predictable temporal pattern of tonic pain with a predominant affective component, and to be suitable for application in the majority of individuals without causing undue discomfort.     

A comparative review of rodent prefrontal cortex and working memory

The prefrontal cortex is critical to working memory processes. Current theories of prefrontal function are largely based on primate behavioural and electrophysiological data. As molecular genetic techniques advance in mice, so investigations into the rodent prefrontal cortex should expand, such that rodent models of prefrontal function during working memory may be used to study the synaptic and molecular basis of the phenomenon. This review attempts to summarize aspects of published data that pertain to working memory and suggest directions that will allow a coherent comparison of prefrontal function and interaction in monkey, rat and mouse.     

Barrels VIII: Proceedings of a Satellite Symposium of the 1995 Society for Neuroscience Meeting

A meeting of somatosensory and developmental biologists was held on November 10 and 11, 1995, in San Diego, California, to consider recent findings pertaining to the somatosensory system. The focus of this, the eighth annual Barrels Symposium (Barrels VIII), was on somatosensory circuits and plasticity, and the development of somatosensory primary afferent projections and barrel-like aggregates in the brainstem, thalamus, and cortex     

Barrels X-meeting announcement

Abstract

A cerebrovascular accident, otherwise known as stroke, has the potential to damage multiple areas within the brain affecting descending motor control via a multitude of pathways resulting in a wide variety of movement problems. The cortico-reticulospinal system, one of the largest motor systems, is frequently affected, compromising its output, resulting in postural control deficits. The identification of clinically relevant instruments and scales to document and evaluate recovery in post-stroke patients is vital. However, the availability of such measures and scales which take into consideration the role of postural control as an integral component of functional movement performance are scarce. This paper will critically discuss the importance of integrating current neuroscience and motor control knowledge in order to better understand and describe the clinical presentation of persons post-stroke such that the effectiveness of stroke rehabilitation can be appropriately measured.     

Barrels by the sea: Barrels XX meeting report

The 20th annual Barrels meeting brought together researchers who utilize behavioral, physiological, anatomical, and molecular techniques to understand the structure and function of the barrel system. Barrels XX featured talks on the role inhibition has in shaping cortical responses within the barrel system, the molecular cues that influence the development of the whisker-to-barrel system, and the synaptic plasticity that can shape responses within the system. The meeting highlighted why the whisker-to-barrel system is an ideal model to investigate the development of cortical circuitry and how its functioning can influence behavioral responses.     

Barrels by the sea: Barrels XX meeting report

The 20th annual Barrels meeting brought together researchers who utilize behavioral, physiological, anatomical, and molecular techniques to understand the structure and function of the barrel system. Barrels XX featured talks on the role inhibition has in shaping cortical responses within the barrel system, the molecular cues that influence the development of the whisker-to-barrel system, and the synaptic plasticity that can shape responses within the system. The meeting highlighted why the whisker-to-barrel system is an ideal model to investigate the development of cortical circuitry and how its functioning can influence behavioral responses.     

Functional architecture of auditory cortex

Three complementary approaches demonstrate new types of organization in rodent, feline and primate auditory cortex, as well as differences in processing between auditory and visual cortex. First, connectional work reveals patterns of thalamocortical and corticocortical input unique to the auditory cortex. Second, physiological studies find multiple, interleaved auditory processing modules related to corticocortical connections and embedded in the isofrequency gradient. Third, functional analyses demonstrate independent processing streams for sound localization and identification analogous to the 'what' and 'where' streams in visual cortex, although the modular arrangements are modality-specific. Taken together, these data show that the auditory cortex has common and unique functional substrates.     

Top-down control of motor cortex ensembles by dorsomedial prefrontal cortex

Dorsomedial prefrontal cortex is critical for the temporal control of behavior. Dorsomedial prefrontal cortex might alter neuronal activity in areas such as motor cortex to inhibit temporally inappropriate responses. We tested this hypothesis by recording from neuronal ensembles in rodent dorsomedial prefrontal cortex during a delayed-response task. One-third of dorsomedial prefrontal neurons were significantly modulated during the delay period. The activity of many of these neurons was predictive of premature responding. We then reversibly inactivated dorsomedial prefrontal cortex while recording ensemble activity in motor cortex. Inactivation of dorsomedial prefrontal cortex reduced delay-related firing, but not response-related firing, in motor cortex. Finally, we made simultaneous recordings in dorsomedial prefrontal cortex and motor cortex and found strong delay-related temporal correlations between neurons in the two cortical areas. These data suggest that functional interactions between dorsomedial prefrontal cortex and motor cortex might serve as a top-down control signal that inhibits inappropriate responding.     

Cortical mechanisms in hearing

Current understanding of neural processing in the auditory cortex has been shaped by a variety of experimental approaches in animals and humans. It remains a daunting challenge to reconcile data as diverse as synaptic properties recorded in a rodent brain slice and functional images of auditory cortex in a behaving human. Nevertheless, the gaps are narrowing through a renewed focus on humans and other primates, a continuing interest in evidence for functional pathways, a broader application of modern imaging techniques, a growing awareness of cortical sensitivity to dynamic features of sounds, and an improved understanding of auditory cortical circuitry.