A telemetric method for measuring and recording head rotations in human infants

A simple and reliable apparatus for recording directional head movements of infants is described. The technique permits unrestricted movement and avoids distress associated with mechanical head harnesses.     

A simple encoding and recording system for small group observation

A simple and inexpensive system for coding and recording interaction patterns in small groups is described. It consists of a keyboard and a standard tape recorder, and it is capable of storing sequential data using up to 36 codes. Its main application is in the study of speaker-target patterns, but it can also be used in encoding up to 12 behavioral codes, or six speakers and 6 codes. The keyboard costs less than $200 and is used with conventional tape recorders and minicomputers available at most research sites.     

A small pulse generator for calibrating EEG recording systems

A battery-powered pulse generator of uncomplicated circuit arrangement has the advantage of being easily constructed and, also, can be positioned in a confined testing area in order to simulate the low-amplitude signals of a S. It may be especially useful for EEG recording systems for small animals. In this way, the complete recording system, including connecting cables, can be calibrated, and its performance readily assessed with respect to frequency response and to susceptibility to noise pickup.     

Adaptation to displacing prisms in human infants.

This research reports a first attempt to study adaptation to laterally displacing prisms in human infants of ages six to ten months. Twenty infants were tested over four days under conditions similar to those used in adult adaptation studies. Evidence was found of vigorous adaptation when infants were exposed to base-right prisms under conditions of active exposure. Detailed consideration is given to the conditions and methods of studying adaptation in infants and implications for adult studies.     

A digital system for recording startle,responses in small animals

An easily constructed, isometric startle-recording system is described. The animal enclosure is attached to a plywood board-which, in ten, is mounted in a “springboard” arrangement. Movement is detected by a phonocartridge mounted beneath the chamber, and a digital record of this movement is obtained through the use of a voltage-to-frequency converter. A brief experiment in which the system was used to assess the rat’s reaction to electric footshock is also presented.     

A system for automatic recording and analysis of motor activity in rats

We describe the design and evaluation of an electronic system for the automatic recording of motor activity in rats. The device continually locates the position of a rat inside a transparent acrylic cube (50 cm/side) with infrared sensors arranged on its walls so as to correspond to the x-, y-, and z-axes. The system is governed by two microcontrollers. The raw data are saved in a text file within a secure digital memory card, and offline analyses are performed with a library of programs that automatically compute several parameters based on the sequence of coordinates and the time of occurrence of each movement. Four analyses can be made at specified time intervals: traveled distance (cm), movement speed (cm/s), time spent in vertical exploration (s), and thigmotaxis (%). In addition, three analyses are made for the total duration of the experiment: time spent at each x–y coordinate pair (min), time spent on vertical exploration at each x–y coordinate pair (s), and frequency distribution of vertical exploration episodes of distinct durations. User profiles of frequently analyzed parameters may be created and saved for future experimental analyses, thus obtaining a full set of analyses for a group of rats in a short time. The performance of the developed system was assessed by recording the spontaneous motor activity of six rats, while their behaviors were simultaneously videotaped for manual analysis by two trained observers. A high and significant correlation was found between the values measured by the electronic system and by the observers.     

An automated eye movement recording system for use with human infants

An infrared corneal reflection eye movement system modified for work with human infants is described. The system generates on-line digital information on eye position at a sampling rate that allows examination of the temporal and spatial characteristics of fixations and eye move-ments. An algorithm for defining fixation and eye movement episodes is described.     

Ethical issues in discharge planning for vulnerable infants and children

Discharge planning for vulnerable infants and children is a collaborative, interdisciplinary, decision-making activity that is grounded in the ethical complexities of clinical practice. Although it is a psychosocial intervention that frequently causes moral distress for professionals and has the potential to inflict harm on children and their families, the process has received little attention from ethicists. An ongoing study of the transition of technology-dependent children from hospital to home suggests that the ethical issues embedded in the discharge-planning process may be concealed by dominant cultural values, institutional policies, clinical standards, historical precedents, and legal regulations.     

A TV monitored system for recording open-field activity in the rat

A system for monitoring and recording the movements of a rodent in an open field is described. A TV camera and a grid generator combine the animal’s position in the field with an overlaid 16 by 16 grid pattern. These are displayed on the TV monitor. The location of the animal is recorded with each sweep of the video raster. The movement of the animal is then plotted by a Rockwell microprocessor that prints out the animal’s location at set intervals.     

The use of an ultrasonic monitor for recording locomotor activity

An ultrasonic activity monitor has been designed that can be used to detect motion in air or within an aquarium. Stability and linearity of response of the monitor have been measured. The system has been used to examine activity rhythms of the marine invertebrate,Octoput ornatus Gould.     

Effects of wrist rest and forearm support on muscle activity

This study examined the effects of wrist rest and forearm support on reducing computer operators' activities using the trapezius, deltoid, biceps brachii, extensor carpi radialis longus, and extensor digitorum. 12 young (M= 25.9 yr., SD= 2.4) men were asked to perform both static and dynamic mouse operations in four conditions, two using a wrist rest and two using a forearm support. Analysis showed that use of the forearm support had a significant effect on reducing the EMG activity in muscles of the trapezius, deltoid, biceps brachii, extensor carpi radialis longus, and extensor digitorum. However, the wrist rest only significantly reduced deltoid and extensor carpi radialis longus activities.     

Dissociation between small and large numerosities in newborn infants

In the first year of life, infants possess two cognitive systems encoding numerical information: one for processing the numerosity of sets of 4 or more items, and the second for tracking up to 3 objects in parallel. While a previous study showed the former system to be already present a few hours after birth, it is unknown whether the latter system is functional at this age. Here, we adapt the auditory‐visual matching paradigm that previously revealed sensitivity to large numerosities to test sensitivity to numerosities spanning the range from 2 to 12. Across studies, newborns discriminated pairs of large numerosities in a 3:1 ratio, even when the smaller numerosity was 3 (3 vs. 9). In contrast, newborn infants failed to discriminate pairs including the numerosity 2, even at the same ratio (2 vs. 6). These findings mirror the dissociation that has been reported with older infants, albeit with a discontinuity situated between numerosities 2 and 3. Two alternative explanations are compatible with our results: either newborn infants have a separate system for processing small sets, and the capacity of this system is limited to 2 objects; or newborn infants possess only one system to represent numerosities, and this system either is not functional or is extremely imprecise when it is applied to small numerosities.     

Effector dynamics of rhythmic wrist activity and its implications for (modeling) bimanual coordination

To examine the role of the effector dynamics of the wrist in the production of rhythmic motor activity, we estimated the phase shifts between the EMG and the task-related output for a rhythmic isometric torque production task and an oscillatory movement, and found a substantial difference (45-52 degrees) between the two. For both tasks, the relation between EMG and task-related output (torque or displacement) was adequately reproduced with a physiologically motivated musculoskeletal model. The model simulations demonstrated the importance of the contribution of passive structures to the overall dynamics and provided an account for the observed phase shifts in the dynamic task. Additional simulations of the musculoskeletal model with added load suggested that particular changes in the phase relation between EMG and movement may follow largely from the intrinsic muscle dynamics, rather than being the result of adaptations in the neural control of joint stiffness. The implications of these results are discussed in relation to (models of) interlimb coordination in rhythmic tasks.