Analysis of ultrasonic vocalizations emitted by intruders during aggressive encounters among rats (Rattus norvegicus)

This investigation was concerned with the identification of the ultrasonic vocalizations produced by intruders during aggressive interactions and the role of these signals in agonistic behavior of rats. In the first experiment, experienced resident males were paired with both devocalized and intact vocalizing naive intruder males. Devocalization of the intruder males resulted in a drastic decrease in 50-kHz vocalizations and the elimination of all 22-kHz vocalizations. This almost total absence of ultrasonic vocalizations was not accompanied by any change in resident aggressive behavior or intruder defensive and submissive behavior. In a second experiment, naive intruders were tested with either deafened or intact resident males. Similarly, preventing residents from hearing intruder ultrasounds had no detectable effect on any aggressive behavior. These experiments are not consistent with the correlative evidence that intruder-produced 22-kHz vocalizations inhibit the aggressive behavior of the resident. The results also show that most of the ultrasonic vocalizations emitted during aggressive encounters are probably produced by the intruder.     

Aokigahara-jukai: suicide and amnesia in Mt. Fuji's Black Forest

Aokigahara-jukai (Jukai), a dense forest at the foot of Mt. Fuji, is well known as the leading suicide site in Japan, with about 30 people committing suicide there every year. This paper describes Jukai and three cases of psychogenic amnesia following attempted suicide there. Amnesia as an alternative to suicide and the significance of death in Jukai are discussed.     

Hypothalamic circuit regulating colonic transit following chronic stress in rats

Although acute stress accelerates colonic transit, the effect of chronic stress on colonic transit remains unclear. In this study, rats received repeated restraint stress (chronic homotypic stress) or various types of stress (chronic heterotypic stress) for 5 and 7 days, respectively. Vehicle saline, oxytocin (OXT), OXT receptor antagonist or corticotropin-releasing factor (CRF) receptor antagonists were administered by intracerebroventricular (ICV) injection prior to restraint stress for 90 min. Immediately after the stress exposure, the entire colon was removed and the geometric center (GC) of Na51CrO4 (a nonabsorbable radioactive marker; 0.5 μCi) distribution was calculated to measure the transit. Gene expression of OXT and CRF in the paraventricular nucleus (PVN) was evaluated by in situ hybridization. Accelerated colonic transit with the acute stressor was no longer observed following chronic homotypic stress. This restored colonic transit was reversed by ICV injection of an OXT antagonist. In contrast, chronic heterotypic stress significantly accelerated colonic transit, which was attenuated by ICV injection of OXT and by a CRF receptor 1 antagonist. OXT mRNA expression in the PVN was significantly increased following chronic homotypic stress, but not chronic heterotypic stress. However, CRF mRNA expression in the PVN was significantly increased following acute and chronic heterotypic stress, but not chronic homotypic stress. These results indicate that central OXT and CRF play a pivotal role in mediating the colonic dysmotility following chronic stress in rats.     

The role of imagery-related properties in picture naming: A newly standardized set of 360 pictures for Japanese

Picture naming was investigated primarily to determine its dependence on certain imagery-related variables, with a secondary aim of developing a new set of Japanese norms for 360 pictures. Pictures refined from the original Nishimoto, Miyawaki, Ueda, Une, and Takahashi (Behavior Research Methods 37:398?C416, 2005) set were used. Naming behaviors were measured using four imagery-related measures (imageability, vividness, image agreement, and image variability) and four conventional measures (naming time, name agreement, familiarity, and age of acquisition), as well as a number of other measures (17 total). A simultaneous multiple regression analysis performed on naming times showed that the most reliable predictor was H, a measure of name diversity; two image-related measures (image agreement and vividness) and age of acquisition also contributed substantially to the prediction of naming times. The accuracy of picture naming (measured as name agreement) was predicted by vividness, age of acquisition, familiarity, and image agreement. This suggests that certain processes involving mental imagery play a role in picture naming. The full set of norms and pictures may be downloaded from http://www.psychonomic.org/archive/ or along with the article from http://www.springerlink.com.     

Asymmetries for the categorization of kanji nouns, adjectives, and verbs presented to the left and right visual fields

Kanji is one form of written Japanese in which the symbolic/analytic characteristics of language are dissociated from systematic phonetic characteristics; as such, it makes possible a more careful test of which aspect of language is responsible for the frequently observed superior left-hemisphere performance. In this study, subjects were asked to categorize tachistoscopically presented kanji as nouns, adjectives, or verbs. The previously reported (Hatta 1977, Neuropsychologia, 15, 685–688) left-visual-field advantage for kanji was found only in the case of nouns. Adjectives and verbs were processed more rapidly and correctly in the right visual field.     

A low-cost universal feeder

Construction of a universal feeder for a cost of less than $200 is described. The feeder consists of two plywood panels, the first of which is circular and has grooves cut around its margin to hold reinforcers. This circular panel is secured to the second, rectangular panel so that it is free to rotate. A brush fixed onto the axle of a stepper motor above the circular panel sweeps the reinforcers away from the circular panel. Another stepper motor rotates the circular panel after each delivery to prepare the next reinforcer for delivery.     

Automated Measurement of Mouse Freezing Behavior and its Use for Quantitative Trait Locus Analysis of Contextual Fear Conditioning in (BALB/cJ × C57BL/6J)F2 Mice

The most commonly measured mouse behavior in fear conditioning tests is freezing. A technical limitation, particularly for genetic studies, is the method of direct observation used for quantifying this response, with the potential for bias or inconsistencies. We report the use of a computerized method based on latency between photobeam interruption measures as a reliable scoring criterion in mice. The different computer measures obtained during contextual fear conditioning tests showed high correlations with hand-scored freezing; r values ranged from 0.87 to 0.94. Previously reported strain differences between C57BL/6J and DBA/2J in context-dependent fear conditioning were also detected by the computer-based system. In addition, the use of computer-scored freezing of 199 (BALB/cJ×C57BL/6J)F₂ mice enabled us to detect a suggestive gender-dependent chromosomal locus for contextual fear conditioning on distal chromosome 8 by QTL analysis. Automation of freeze scoring would significantly increase efficiency and reliability of this learning and memory test.     

The latent four-zone structure in classroom seating space

The purpose of this study was to extract a latent space structure of classrooms from students seating preferences, and to determine whether classroom division on the basis of latent space structure is useful in predicting actual seating behaviors. The actual seating positions of 151 female junior college students were observed in classrooms once a week for one semester; then students were asked to estimate their seating preference among 49 seating positions in an imaginary classroom. Students did have different preferences for seating positions. A factor analysis suggested that classroom seating space should be divided into four zones: rear, front, center, and sides. A multiple discriminant analysis suggested that the seating positions that students actually took reflected a four-zone structure. Classroom division based on the four-zone structure proved useful in understanding students' seating behaviors.     

A group-centered object relations approach to group psychotherapy with severely disturbed patients

This paper discusses how the application of object relations theory to clinical intervention has extended the application of psychoanalytic group psychotherapy to more severely disturbed patients. The author suggests how to structure the group based on individual and group needs. Clinical issues are presented, including the group as a container, communication peculiarities, and psychotic response to separation, sexuality, and interpretation.