Multivariate analysis of the modifications induced by an environmental acoustic cue on rat exploratory behavior.
The aim of the present paper is to study by means of a multivariate analysis the modifications induced by an environmental acoustic cue on the structure of rat exploratory behavior. Adult male Wistar rats were observed during the exploration of a soundproof observation box. Each rat was acoustically stimulated after 150 s from the beginning of the experimental session, lasting 300 s, and recorded through a digital videocamera. A frame by frame analysis was thereafter carried out using a professional video-recording system. Thirteen behavioral patterns were selected: immobility, immobile-sniffing, walking, rearing, climbing, chewing, paw-licking, face-grooming, body-grooming, head-turning, tuning, oriented-sniffing, focusing. Both descriptive and multivariate analyses (cluster, stochastic, adjusted residuals) were carried out. Through descriptive statistical analysis, latencies and per cent distribution of each pattern were studied. A multivariate cluster analysis revealed the presence of three main behavioral clusters, an additional one being identified following acoustic stimulation. Multivariate stochastic analysis showed that all the patterns converged on immobile-sniffing which could represent a key component in behavioral switching processes related to environmental exploration. Moreover, through adjusted residuals, the degree of relationship among different patterns was shown according to statistic Z-distribution. Our data assign new ethological meanings to different behavioral patterns. Notably, head-turning is suggested to be considered as a generic directional search and tuning as a subtle activity of stimulus localization.
Casarrubea
Maurizio
M
Department of Experimental Medicine, Human Physiology Section, Università di Palermo, Italy. m.casarrubea@unipa.it
Sorbera
Filippina
F
Crescimanno
Giuseppe
G
D000161:Acoustic Stimulation / Q000379:methods; D000162:Acoustics; D000818:Animals; D001522:Behavior, Animal; D016000:Cluster Analysis; D003463:Cues; D004777:Environment; D005106:Exploratory Behavior / Q000502:physiology*; D008297:Male; D015999:Multivariate Analysis; D051381:Rats; D017208:Rats, Wistar; D013269:Stochastic Processes; D013997:Time Factors; D014741:Video Recording