First-person approaches in neuroscience of consciousness: Brain dynamics correlate with the intention to act

The belief in free will has been frequently challenged since Benjamin Libet published his famous experiment in 1983. Although Libet’s experiment is highly dependent upon subjective reports, no study has been conducted that focused on a first-person or introspective perspective of the task. We took a neurophenomenological approach in an N = 1 study providing reliable and valid measures of the first-person perspective in conjunction with brain dynamics. We found that a larger readiness potential (RP) is attributable to more frequent occurrences of self-initiated movements during negative deflections of the slow cortical potentials (SCP). These negative deflections occur in parallel with an inner impulse reported by an expert meditator which may in turn lead to a voluntary act. We demonstrate in this proof-of-principle approach that the first-person perspective obtained by an expert meditator in conjunction with neural signal analysis can contribute to our understanding of the neural underpinnings of voluntary acts.     

Subject and Experimenter Errors in Behavioral Research with Particular Reference to Motor Behavior

Sources of error stemming from S and E and their interaction were identified, their prevalence in behavioral science research discussed, and means for eliminating or discounting them suggested. The findings reviewed indicated that E may bias his findings by indicating to S the demand characteristics of the experimental situation. S errors include such behavior as trying to be over-helpful, attempting to defeat E’s intentions, and the Hawthorne effect. Errors from E may arise by transmitting subtle cues to S as to the hypothesized outcome of the experiment, E’s various characteristics, situational factors, and intentional errors. The applicability of these errors to mo tor behavior research was discussed.     

Repetitive transcranial magnetic stimulation induced slow wave activity modification: A possible role in disorder of consciousness differential diagnosis?

Slow wave activity (SWA) generation depends on cortico–thalamo-cortical loops that are disrupted in patients with chronic Disorders of Consciousness (DOC), including the Unresponsive Wakefulness Syndrome (UWS) and the Minimally Conscious State (MCS). We hypothesized that the modulation of SWA by means of a repetitive transcranial magnetic stimulation (rTMS) could reveal residual patterns of connectivity, thus supporting the DOC clinical differential diagnosis. We enrolled 10 DOC individuals who underwent a 24 hh polysomnography followed by a real or sham 5 Hz-rTMS over left primary motor area, and a second polysomnographic recording. A preserved sleep-wake cycle, a standard temporal progression of sleep stages, and a SWA perturbation were found in all of the MCS patients and in none of the UWS individuals, only following the real-rTMS. In conclusion, our combined approach may improve the differential diagnosis between MCS patients, who show a partial preservation of cortical plasticity, and UWS individuals, who lack such properties.     

Cognitive control deficits in adolescents born with very low birth weight (≤ 1500 g): Evidence from dichotic listening

The objective of the paper is to explore bottom‐up auditory and top‐down cognitive processing abilities as part of long‐term outcome assessment of preterm birth. Fifty‐five adolescents (age 13–15) born with very low birth weight (VLBW) were compared to 80 matched controls born to term, using three consonant‐vowel dichotic listening (DL) instruction conditions (non‐forced, forced‐right and forced‐left). DL scores were correlated with cortical gray matter thickness derived from T1‐weighted structural MRI volumes using FreeSurfer to examine group differences also in the neural correlates of higher cognitive processes. While showing normal bottom‐up processing, VLBW adolescents displayed impaired top‐down controlled conflict processing related to significant cortical thickness differences in left superior temporal gryus and anterior cingulate cortex. Preterm birth with VLBW induces fundamental changes in brain function and structure posing a risk for long‐term neurocognitive impairments. Deficits emerge in situations of increasing cognitive conflict and can be related to measures of executive functions as well as morphology.     

The advantage of mentally rotating clockwise

The time taken to decide whether a character is shown in its mirror or normal version has been shown to increase approximately linearly with the angular departure from an up-right position. Additionally, in some studies, decisions took longer for clockwise tilted characters than for counterclockwise tilted ones. Other studies do not report the latter effect. We argue that inconsistencies across studies are caused by variance in participants' strategies. The task employed here was specifically designed to bring these strategies and thereby the direction of rotation under experimental control. From the EEG recorded during the rotation period, we extracted an event-related slow potential whose amplitude is sensitive to the amount of mental rotation. In both strategy conditions, the slow potential's amplitude was lower for clockwise than for counterclockwise rotations. We take this as evidence that mental rotation of alphanumeric characters is easier in a clockwise than in a counterclockwise direction.     

Neuroanatomy of childhood disruptive behavior disorders

Our aims were to (1) examine possible neuroanatomical abnormalities associated with the Disruptive Behavior Disorders (DBDs) as a group and (2) assess neuroanatomical anomalies specific to each DBD (i.e., conduct disorder [CD] and oppositional defiant disorder). Cortical thickness analysis and voxel-based morphometry were analyzed in 47 8-year-old boys (22 DBDs with and without CD and/or ODD and 25 healthy controls) from Magnetic Resonance Imaging brain scans. DBD symptoms were assessed using the Dominic-R. In DBD subjects relative to controls, we found (1) a decreased overall mean cortical thickness; (2) thinning of the cingulate, prefrontal and insular cortices; and (3) decreased gray matter density (GMd) in the same brain regions. We also found that scores on the Dominic-R were negatively correlated with GMd in the prefrontal and precuneus/superior temporal regions. There was a subdiagnostic main effect for CD, related to thinning of the middle/medial frontal, and for ODD in the left rectal/orbitofrontal. Findings suggest that thinning and decreased GMd of the insula disorganizes prefrontal circuits, diminishing the inhibitory influence of the prefrontal cortex on anger, aggression, cruelty, and impulsivity, and increasing a person's likelihood of aggressive behavior. These findings have implications for pathophysiologic models of the DBDs, their diagnostic classification system, and for designing more effective intervention programs.