Thoughts from high-level processes often arise involuntarily and in response to external stimuli. The reflexive imagery task (RIT) has been used to identify the kinds of conscious thoughts and imagery that can arise involuntarily in response to stimuli. In most RITs, subjects are presented with stimuli and instructed to not perform a mental operation in response to the stimuli. For example, subjects are presented with 2 dots after having been instructed to not count any objects. Often, subjects cannot suppress the operation and experience the involuntary imagery (e.g., “two”). RITs have not examined whether such effects arise for insights or syntactic processing. In our “insight” RIT, subjects were presented with 20 word pairs (e.g., wax–flame) and instructed to not think of any associates (e.g., “candle”). Subjects thought (involuntarily) of associates for 68% of the pairs. In our “syntax” RIT, subjects learned to associate nonsense visual symbols with words (e.g., “green” and “sun”). After training, in the read condition, subjects read the strings formed from pairs of these symbols (e.g., “green sun”). In the suppress condition, subjects were instructed to suppress reading. Subjects reported involuntary reading of these strings on 48% of the 20 trials. The mean accuracy rate of the judgments regarding nonsensicality (e.g., green sun) in the suppress condition was high (86%), corroborating that subjects were reading the sentences. Together, the data from our new tasks shed light on the capabilities of the mechanisms that, in everyday life, engender the often “high-level” contents that occupy our conscious minds.

The groundbreaking, viewpoint theory of Merker et al. explains several properties of the conscious field, including why the observer cannot directly apprehend itself. We propose that viewpoint theory might also provide a progressive, constitutive marker of consciousness and shed light on why most of the contents of consciousness are encapsulated.

The function of the conscious field remains mysterious from a scientific point of view. This article reviews theoretical approaches (passive frame theory and ideomotor approaches) that elucidate how the conscious field is intimately related to a special kind of action selection. This form of action selection is peculiar to the skeletal-muscle output system. The notion of encapsulation and how it explains many properties of the conscious field are discussed, including why the conscious field, though in the service of adaptive action, contains contents that are not action-relevant; why the field has a first-person perspective; and why the field is so thorough, in terms of its contents, the contrasts among contents, and the representation of spatial layout. The authors discuss subordinate encapsulation and the hypothesis that the conscious field is what allows for encapsulated conscious contents to influence action selection collectively, yielding what in everyday life is called voluntary behavior.

Acoustic coordinated reset (aCR) therapy for tinnitus aims to desynchronize neuronal populations in the auditory cortex that exhibit pathologically increased coincident firing. The original therapeutic paradigm involves fixed spacing of four low-intensity tones centered around the frequency of a tone matching the tinnitus pitch, fT, but it is unknown whether these tones are optimally spaced for induction of desynchronization. Computational and animal studies suggest that stimulus amplitude, and relatedly, spatial stimulation profiles, of coordinated reset pulses can have a major impact on the degree of desynchronization achievable. In this study, we transform the tone spacing of aCR into a scale that takes into account the frequency selectivity of the auditory system at each therapeutic tone’s center frequency via a measure called the gap index. Higher gap indices are indicative of more loosely spaced aCR tones. The gap index was found to be a significant predictor of symptomatic improvement, with larger gap indices, i.e., more loosely spaced aCR tones, resulting in reduction of tinnitus loudness and annoyance scores in the acute stimulation setting. A notable limitation of this study is the intimate relationship of hearing impairment with the gap index. Particularly, the shape of the audiogram in the vicinity of the tinnitus frequency can have a major impact on tone spacing. However, based on our findings we suggest hypotheses-based experimental protocols that may help to disentangle the impact of hearing loss and tone spacing on clinical outcome, to assess the electrophysiologic correlates of clinical improvement, and to elucidate the effects following chronic rather than acute stimulation.

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In 1959, Neal Miller made the bold claim that the Stimulus–Response, Behaviorist models of that era were describing the way in which stimuli lead to the entry of contents into consciousness (“entry,” for short). Today, researchers have begun to investigate the link between external stimuli and involuntary entry, using paradigms such as the reflexive imagery task (RIT), the focus of our review. The RIT has revealed that stimuli can elicit insuppressible entry of high-level cognitions. Knowledge of the boundary conditions of the RIT effect illuminates the limitations of involuntary processes and the role of consciousness in the regulation of behavior. We review the boundary conditions of this paradigm as well as its systematic effects. Systematic effects are unlikely to be due to experimental demand. While reviewing each effect, we consider its theoretical implications. In addition, throughout our review, we discuss future directions for the study of insuppressible entry using the RIT. Last, we discuss a theoretical development (passive frame theory) that stems from the RIT and illuminates how involuntary entry and encapsulation, though at times disadvantageous for the actor, are essential for adaptive action selection during the course of ontogeny.

Enhanced neuronal synchronization of the subthalamic nucleus (STN) is commonly found in PD patients and corresponds to decreased motor ability. Coordinated reset (CR) was developed to decouple synchronized states causing long lasting desynchronization of neural networks. Vibrotactile CR stimulation (vCR) was developed as non-invasive therapeutic that delivers gentle vibrations to the fingertips. A previous study has shown that vCR can desynchronize abnormal brain rhythms within the sensorimotor cortex of PD patients, corresponding to sustained motor relief after 3 months of daily treatment. To further develop vCR, we created a protocol that has two phases. Study 1, a double blinded randomized sham-controlled study, is designed to address motor and non-motor symptoms, sensorimotor integration, and potential calibration methods. Study 2 examines dosing effects of vCR using a remote study design. In Study 1, we will perform a 7-month double-blind sham-controlled study including 30 PD patients randomly placed into an active vCR or inactive (sham) vCR condition. Patients will receive stimulation for 4 h a day in 2-h blocks for 6 months followed by a 1-month pause in stimulation to assess long lasting effects. Our primary outcome measure is the Movement Disorders Society-Unified Parkinson's Disease Rating Scale (MDS-UPDRS) part III off medication after 6 months of treatment. Secondary measures include a freezing of gait (FOG) questionnaire, objective motor evaluations, sensorimotor electroencephalography (EEG) results, a vibratory temporal discrimination task (VTDT), non-motor symptom evaluations/tests such as sleep, smell, speech, quality of life measurements and Levodopa Equivalent Daily Dose (LEDD). Patients will be evaluated at baseline, 3, 6, and 7 months. In the second, unblinded study phase (Study 2), all patients will be given the option to receive active vCR stimulation at a reduced dose for an additional 6 months remotely. The remote MDS-UPDRS part III off medication will be our primary outcome measure. Secondary measures include sleep, quality of life, objective motor evaluations, FOG and LEDD. Patients will be evaluated in the same time periods as the first study. Results from this study will provide clinical efficacy of vCR and help validate our investigational vibrotactile device for the purpose of obtaining FDA clearance.Clinical Trial Registration:ClinicalTrials.gov, identifier: NCT04877015.

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