UNIT ACTIVITY IN THE HYPOTHALAMUS.
Final technical rept.,
CAMBRIDGE UNIV (ENGLAND)
Pagination or Media Count:
A study of over 800 units in the hypothalamus and other forebrain areas of more than a hundred animals has confirmed and extended earlier observations on the characteristics of hypothalamic unit activity. The majority of recorded hypothalamic neurones had spontaneous rates of firing in the range of 1-10sec, and exhibited a more regular pattern of firing than neurones in the cortex or thalamus. The responses of hypothalamic neurones revealed a marked degree of sensory convergence. Usually two or more sensory stimuli excited the same neurone, but inhibitory interactions between differing sensory modalities were also observed. There was little evidence that neurones having particular patterns of activity or responsiveness were situated exclusively in localised areas. Fast unresponsive neurones were common in the subthalamus but also occurred in the ventral thalamus and hypothalamus. Neurones firing in short rapid bursts were found commonly in the thalamus and occasionally in the hypothalamus. Adjacent neurones frequently showed dissimilar behaviour. Hypoxia, hypercapnia and hypoglycaemia had a predominantly excitatory effect on neurones in the posterior and lateral hypothalamic areas, associated with augmented sympathetico -adrenal activity. Author
- Anatomy and Physiology