The Emerging Science of Interoception: Sensing, Integrating, Interpreting, and Regulating Signals within the Self.

Interoception refers to the representation of the internal states of an organism, and includes the processes by which it senses, interprets, integrates, and regulates signals from within itself. This review presents a unified research framework and attempts to offer definitions for key terms to describe the processes involved in interoception. We elaborate on these definitions through illustrative research findings, and provide brief overviews of central aspects of interoception, including the anatomy and function of neural and non-neural pathways, diseases and disorders, manipulations and interventions, and predictive modeling.

NIH BRAIN Circuits Programs: An Experiment in Supporting Team Neuroscience.

The NIH BRAIN Initiative is aimed at revolutionizing our understanding of the human brain. Here, we present a discussion of support for team research in investigative neuroscience at different stages and on various scales.

The promise of the BRAIN initiative: NIH strategies for understanding neural circuit function.

New neurotechnologies fueled by the BRAIN Initiative now allow investigators to map, monitor and modulate complex neural circuits, enabling the pursuit of research questions previously considered unapproachable. Yet it is the convergence of molecular neuroscience with the new systems neuroscience that promises the greatest future advances. This is particularly true for our understanding of nervous system disorders, some of which have known molecular drivers or pathology but result in unknown perturbations in circuit function.

Tectal etiology for irrepressible saccades: a case study in a Rhesus monkey.

Brain circuits controlling eye movements are widely distributed and complex. The etiology of irrepressible square wave saccades is not fully understood and is likely different for different neuropathologies. In a previous study, spontaneously occurring irrepressible saccades were noted after a cerebrovascular accident that damaged the rostral superior colliculus (SC) and its commissure in a Rhesus monkey.

A flexible user-interface for audiovisual presentation and interactive control in neurobehavioral experiments.

A major problem facing behavioral neuroscientists is a lack of unified, vendor-distributed data acquisition systems that allow stimulus presentation and behavioral monitoring while recording neural activity. Numerous systems perform one of these tasks well independently, but to our knowledge, a useful package with a straightforward user interface does not exist. Here we describe the development of a flexible, script-based user interface that enables customization for real-time stimulus presentation, behavioral monitoring and data acquisition.

Saccade trajectories evoked by sequential and colliding stimulation of the monkey superior colliculus.

Using microstimulation we employed an explicit experimental control of activity in the superior colliculus at two sites within the motor map. We compared saccade metrics and dynamics evoked at each site independently with those caused by sequential presentation and collisions of the two stimulation trains. Essentially, we forced controlled spatio-temporal patterns of activity into the saccade control circuit with various timing relationships from known sites within the collicular motor map, thus revealing the spatio-temporal transformation from superior colliculus to eye movement dynamics under experimentally controlled conditions.

Activity of omnipause neurons during "staircase saccades" elicited by persistent microstimulation of the superior colliculus.

We have recorded the activity of omnipause neurons (OPNs) in the raphe interpositus during so-called staircase saccades produced by prolonged activation of the superior colliculus (SC) by microstimulation. By showing that OPNs cyclically pause during the periodic movements produced by the steady activation function, we reveal the functional relationship of the OPNs within the recurrent brainstem network that produces dynamic, closed-loop, and feedback control of saccades. Despite persistent, steady activation of the SC, the OPNs followed the periodic activity of the brainstem burst generator.

Irrepressible saccades from a tectal lesion in a Rhesus monkey.

We present a case of spontaneously occurring irrepressible saccades in an experimental Rhesus monkey. Though eye jerks are sometimes associated with cerebellar disease, central demyelination or brainstem lesions, there is little consensus on their neurological mechanisms. From neurological and anatomical investigation we report that these irrepressible saccades were caused by a discrete cerebrovascular accident that involved the rostral superior colliculus along with its commissure, and with minor invasion of periaqueductal gray and adjacent mesencephalic reticular formation.

Spectral cancellation of microstimulation artifact for simultaneous neural recording in situ.

A fundamental technical hurdle in systems neurophysiology has been to record the activity of individual neurons in situ while using microstimulation to activate inputs or outputs. Stimulation artifact at the recording electrode has largely limited the usefulness of combined stimulating and recording to using single stimulation pulses (e.g.

Reliable real-time spike discrimination during microstimulation.

A fundamental technical hurdle in systems neurophysiology has been to record the activity of individual neurons in situ while using microstimulation to activate inputs or outputs. Stimulation artifact at the recording electrode has largely limited the usefulness of combined stimulating and recording to using single stimulation pulses or to presenting brief trains of pulses to look for transient responses. We have developed an adaptive filter that in real time allows continuous extracellular isolation of individual neural spikes during sustained experimental microstimulation.

Single-unit recording in the lateral geniculate nucleus of the awake behaving monkey.

In recent years, recording neuronal activity in the awake, behaving primate brain has become established as one of the major tools available to study the neuronal specificity of the initiation and control of various behaviors. Primates have traditionally been used in these studies because of their ability to perform more complex behaviors closely akin to those of humans, a desirable prerequisite since our ultimate aim is to elucidate the neuronal correlates of human behaviors. A wealth of knowledge has accumulated on the sensory and motor systems such as vision, audition, and eye movements.