Electroencephalographic power spectral analysis of growing goat kids ( Capra hircus)

Abstract

Neuronal differentiation and maturation of the brain follow distinctive ontogenetic sequences that are characteristic for each animal specie. The present study was designed to investigate the developmental aspects of the electroencephalogram (EEG) in growing male and female goat kids, using power spectral analysis to assess useful indicators for estimating brain activity in young goats. Moreover, the spectral analysis results could be used as standard for evaluating abnormal brain activity in goats. Seven healthy Saanen kids were selected 2 days after birth. Kids were tested at 15 (T1), 30 (T2), 45 (T3), 60 (T4) and 75 (T5) days of age, respectively. The EEG sessions recorded lasted 20 min and during the session the kids were physically separated from their dams by a wire mesh. Wakefulness and drowsy states in the animals were observed. Visual examination of the EEG revealed an high voltage–low frequency background activity during the wakefulness state. Vertex waves, k-complexes and spindle activity were detected with the high voltage–low frequency background activity during the drowsy state. Spectral analysis of the EEG (q-EEG) was performed in order to assess the quantitative parameters of the background activity in the wakefulness state. q-EEG analysis was performed using Fast Fourier Transform; the spectral bands delta (0.5–4.0 Hz), theta (4.1–8.0 Hz), alpha (8.1–12.0 Hz) and beta (12.1–30.0 Hz) were calculated and expressed as relative power (%). Results were compared for each age stage and each scalp area, using an ANOVA for repeated measures. A significant decrease in the slow theta rhythms and an increase of fast beta rhythms was recorded. The distribution of the four frequency bands was posterior for delta, frontal and central for theta, as well as for beta and most of alpha patterns. These quantitative data may be useful indicators for assessing brain function of young goats and as standard data for evaluating abnormal brain activity in goats.