Both predator and prey: emotional arousal in threat and reward

This research examined the psychophysiology of emotional arousal anticipatory to potentially aversive and highly pleasant outcomes. Human brain reactions (event-related potentials) and body reactions (heart rate, skin conductance, the probe startle reflex) were assessed along motivational gradients determined by apparent distance from sites of potential punishment or reward. A predator-prey survival context was simulated using cues that signaled possible money rewards or possible losses; the cues appeared to loom progressively closer to the viewer, until a final step when a rapid key response could ensure reward or avoid a punishing loss. The observed anticipatory response patterns of heightened vigilance and physiological mobilization are consistent with the view that the physiology of emotion is founded on action dispositions that evolved in mammals to facilitate survival by dealing with threats or capturing life-sustaining rewards.     

Finger flexor motor control patterns during active flexion: an in vivo tendon force study

An in vivo tendon force measurement system was used to evaluate index finger flexor motor control patterns during active finger flexion. During open carpal tunnel release surgery (N=12) the flexor digitorum profundus (FDP) and flexor digitorum superficilias (FDS) tendons were instrumented with buckle force transducers and participants performed finger flexion at two different wrist angles (0 degrees or 30 degrees ). During finger flexion, there was concurrent change of metacarpophalangeal (MCP) and proximal interphalangeal (PIP) joint angles, but the FDP and FDS tendon force changes were not concurrent. For the FDS tendon, no consistent changes in force were observed across participants at either wrist angle. For the FDP tendon, there were two force patterns. With the wrist in a neutral posture, the movement was initiated without force from the finger flexors, and further flexion (after the first 0.5s) was carried out with force from the FDP. With the wrist in a flexed posture, the motion was generally both initiated and continued using FDP force. At some wrist postures, finger flexion was initiated by passive forces which were replaced by FDP force to complete the motion.     

Crisis Assessment and Psychiatric Hospitalization of Children and Adolescents in State Custody

We investigated the clinical characteristics and placement decisions among a group of children who were wards of the state and had been evaluated for a crisis assessment. The sample consisted of 383 children and adolescents (ages 2-20 years) who were wards of the Illinois Department of Children and Family Services (DCFS). This study retrospectively reviewed the symptoms, risk factors, functioning and co-morbid variables, and placement or system characteristics of these children using a structured assessment tool, the Childhood Severity of Psychiatric Illness (CSPI). Results indicated that risk behaviors as rated on the CSPI, including suicidality, dangerousness, and runaway tendency, were significant predictors of psychiatric hospitalization. The importance of more widespread usage of standardized assessment tools in evaluating children's mental health needs is discussed.     

Phase Transitions and Critical Fluctuations in Rhythmic Coordination of Ipsilateral Hand and Foot

Four subjects performed rhythmic movements of the ankle and the wrist in time with an auditory metronome, in two modes of coordination, antiphase and in-phase. The forearm was placed in either a prone or a supine position. When movements were prepared in the antiphase mode, spontaneous transitions to the in-phase mode, or to phase wandering were observed as metronome frequency was increased. When prepared in the in-phase mode, transitions between in-phase modes or to phase wandering were occasionally observed. Predicted signature features of nonequilbrium phase transitions were noted, including loss of stability and critical fluctuations. The stability of the movement patterns was determined by spatial (dependent upon the direction of movement) rather than anatomical (dependent on the coupling of specific muscle groups) constraints. The position of the forearm had no consistent bearing upon the variability of the phase relations between the limbs, the frequency of phase transitions, or the time of onset of transitions. These results are discussed with reference to the coordination dynamics (e.g., multistability, loss of stability) of multijoint movements.