The effects of peripheral deafferentation on spontaneously bursting neurons in the somatosensory cortex of waking cats.
Single neurons (n = 356) were studied in the forelimb representation of awake, quietly resting cats. Thirty-five spontaneously bursting neurons in a sample of 206 cells recorded before forelimb deafferentation were compared to 39 spontaneously bursting neurons in a sample of 127 neurons studied 1-3 weeks after deafferentation. The probability of encountering bursting neurons increased significantly following deafferentation from 17% to 31% of the sample (P < 0.005). The same 5 classes of bursting cells were observed after deafferentation but there were significant changes in the duration of interspike intervals in some classes, in the probability of observing certain classes, and in the proportion of spikes found in bursts. The probability of encountering class III cells, a class thought to consist primarily of non-inactivating pyramidal burst neurons, nearly doubled and the average interspike interval length within the burst increased from 1.9 to 3.0 ms. The burst structure in the other classes did not change but they were found less frequently. These other classes may include inhibitory interneurons which receive less excitatory drive after deafferentation and therefore provide less inhibition to class III cells. The differential behavior of the different classes of bursting cells may be one reason why the overall level of spontaneous activity does not change after deafferentation and it suggests that there are homeostatic mechanisms in primary somatosensory cortex that maintain a certain level of neural activity.
Webster
H H
HH
Département de Physiologie, Université de Montréal, Que, Canada.
Salimi
I
I
Myasnikov
A A
AA
Dykes
R W
RW
D000344:Afferent Pathways / Q000502:physiology*; D000818:Animals; D015415:Biomarkers; D001931:Brain Mapping; D002415:Cats; D003714:Denervation; D004558:Electric Stimulation; D005260:Female; D005552:Forelimb / Q000294:innervation; D005904:Glial Fibrillary Acidic Protein / Q000032:analysis; D008297:Male; D009474:Neurons / Q000502:physiology*; D010525:Peripheral Nerves / Q000502:physiology; D013003:Somatosensory Cortex / Q000502:physiology*; D013238:Stereotaxic Techniques; D013997:Time Factors; D014851:Wakefulness
D015415:Biomarkers; D005904:Glial Fibrillary Acidic Protein