Low-dimensional chaos maps learning in a model neuropil (olfactory bulb).

Quantification of a chaotic system can be made by calculating the correlation dimension (D2) of the data that the system generates (Packard et al., 1980). The D2 algorithm, however, requires stationarity of the generator, a feature that biological data rarely reflect (Mayer-Kress et al., 1988). So we developed the "point correlation dimension" (PD2), an algorithm that accurately tracks D2 in linked data of different dimensions (Carpeggiani et al., 1991). We now present a mathematical argument that, for stationary data, individual PD2s converge to D2 and we demonstrate that the algorithm rejects contributions made by bursts of noise. Data were obtained from the surface of the olfactory bulb of the conscious rabbit (64 electrodes, 640 Hz each, 1.3 sec epochs) before and after presentation of a novel or habituated odor. D2 could be calculated in only 1 of 10 novel-odor trials, whereas PD2 could be calculated in all. Both algorithms indicated that a novel odor evokes a spatially uniform dimensional increase. The PD2 uniquely exhibited the dimensional decreases that occur during inspiration and the gradients of mean dimension present during the nonstimulated control state. These control gradients remained unchanged without odor experience, but showed spatially specific PD2 increases following odor habituation. It is interpreted that, 1) the PD2 is sensitive, accurate, and appropriate for dimensional assessment of biological data, 2) that during analysis of unfamiliar information a single global process is transiently evoked in the neuropil, and 3) after experience multiple spatially specific processes tonically map the sites of learning.     

Extinction instead of incubation following classical aversive conditioning in dogs.

Two dogs received a single paired classical conditioning trial, with tone CS and 12 mA shock US. Both dogs then showed a conditioned blood pressure increase in response to the nonreinforced CS, which extinguished with additional nonreinforced presentations. The CR showed spontaneous recovery four days later, but reextinguished with additional nonreinforced presentations. The results were interpreted as not supporting Eysenck's theory of "incubation" following one-trial aversive conditioning.     

Ivan Pavlov on communist dogmatism and the autonomy of science in the Soviet Union in the early 1920s. 1923.

On 25 September, 1923, two days before his 74th birthday, Ivan Petrovich Pavlov stood before a class of medical students assembled in the auditorium of his Alma Mater, the Military Medical Academy in Leningrad. Pavlov, the recipient of the Nobel prize in medicine in 1904 for his work in physiology, was about to address his first class of the new academic year, and, as was his custom, he had prepared his first lecture on a general theme. This was an especially significant address, however, for in it Pavlov reviewed the impressions he had gathered during his travels in Western Europe and the United States in the summer of 1923, and he criticised the prevailing ideology of Soviet communism by attacking the ideas of Nikolai Ivanovich Bukharin, then the leading expositor of Bolshevik Marxism. An English translation of the lecture is printed below.     

Marital satisfaction and family stress as predictors of classroom behaviors

The purpose of this research was to examine the relationship between parents' perceptions of marital satisfaction and family stress and their third grade children's classroom behavior. Twenty-one married couples completed questionnaires during home visits. Behavior observations were made from videotapes of children recorded in their classroom during lunch and group academic periods on each of three days. Frequencies of peer interactions, solitary behaviors, and teacher interactions were coded. Regression analyses showed that mothers' level of marital satisfaction (but not fathers') predicted their children's frequency of peer interactions during lunch. Fathers' level of perceived family stress (but not mothers') predicted their children's frequency of peer interactions during lunch. Neither measure for either parent was related to the frequency of peer interactions, solitary behaviors, or teacher interactions observed during the academic sessions. These findings highlight the importance of assessing the potential differential relation of parent variables to children's trans-situational behaviors, and the examination of these variables in relation to different social-environmental contexts in which children participate outside the home.     

Three intensive community-based programs for children and youth with serious emotional disturbance and their families

Systems of care for children with serious emotional disturbance and their families have generally lacked intensive community-based programs. We describe three types of newly established community-based programs in New York State and present a general evaluation plan for determining which programs work for various children and their families. The three community-based programs are Intensive Case Management, Family-Based Treatment, and Family-Centered Intensive Case Management. Process and outcome evaluations are being conducted for each of these programs. These evaluations make use of common intake and termination instruments, based on a minimum data set, standardized assessment instruments, and a common logic model, thus facilitating the comparison of findings across evaluations.     

A tether system for cardiovascular studies with the behaving micropig

A tether system has been developed for continuous monitoring of blood pressure in the micropig. The micropig is a suitable model for blood-pressure research because of the similarity of its cardiovascular system to that of humans and because of its sensitivity to high sodium intake. The system consists of a metal boom, attached via a universal joint to a wall 6 ft above floor level, that extends horizontally to the center of the enclosure. A fluid and electronic swivel affixed to the boom is connected to a flexible, hollow, metal tether that descends to a vest worn by the micropig. The vest contains a pressure transducer to which an indwelling arterial catheter is connected via a stopcock. The transducer cable and an infusion line ascend through the interior of the tether to the swivel. The system remains in equilibrium through a system of pulleys and counterweights. Continuous, 24-h recording shows a diurnal variation characterized by higher heart rate but lower blood pressure during the day than at night. The system has been found to be effective for continuous studies over intervals of a month or more.     

Response-key input via the IBM PC/XT/AT’s parallel printer port

A simple and inexpensive way to connect response keys to the IBM PC/XT/AT’s parallel printer port is presented.     

Shaw’s stored information as a quantitative measure of sequential structure

In this paper, we describe a method to study the sequential structure in interevent times. The technique uses the stored information of an iterative map developed by-Shaw (1984). The stored information is a quantitative measure of the sequential organization or predictability in data. This paper discusses the concept of stored information and provides a FORTRAN routineto compute the stored information of interevent time data. Several synthetic data sets with known sequential structures are examined. Finally, we present some initial results from computing the stored information of experimental interresponse time data.     

GRADER: A computer program that recommends student letter grades

GRADER, a computer program that makes student test and/or course letter grade recommendations to instructors, is described. The program uses an algorithm to combine the content mastery (percentage correct) and peer comparison (“curve”) approaches to set grade cutoffs. In addition to standardizing the procedures with which letter grade cutoffs are made, GRADER may help to reduce instructor grading subjectivity and obviate tendencies toward grade inflation or deflation.