Diverse and temporally precise kinetic feature selectivity in the VPm thalamic nucleus.
The thalamo-cortical pathway is the crucial sensory gateway into the cerebral cortex. We aimed to determine the nature of the tactile information encoded by neurons in the whisker somatosensory relay nucleus (VPm). We wanted to distinguish whether VPm neurons encode similar stimulus features, acting as a single information channel, or encode diverse features. We recorded responses to whisker deflections that thoroughly explored the space of temporal stimulus variables and identified features to which neurons were selective by reverse correlation. The timescale of the features was typically 1-2 ms, at the limit imposed by our experimental conditions, indicating highly acute feature selectivity. Sensitivity to stimulus kinetics was strikingly diverse. Some neurons (25%) only encoded velocity; others were sensitive to position, acceleration, or more complex features. A minority (19%) encoded two or more features. These results indicate that VPm contains a distributed representation of whisker motion, based on high-resolution kinetic features.
Petersen
Rasmus S
RS
Faculty of Life Sciences, University of Manchester, Manchester M60 1QD, UK. r.petersen@manchester.ac.uk
Brambilla
Marco
M
Bale
Michael R
MR
Alenda
Andrea
A
Panzeri
Stefano
S
Montemurro
Marcelo A
MA
Maravall
Miguel
M
D000200:Action Potentials / Q000502:physiology*; D000818:Animals; D001696:Biomechanical Phenomena; D001931:Brain Mapping; D008954:Models, Biological; D009475:Neurons, Afferent / Q000145:classification / Q000502:physiology*; D010812:Physical Stimulation / Q000379:methods; D051381:Rats; D017208:Rats, Wistar; D013997:Time Factors; D020651:Ventral Thalamic Nuclei / Q000166:cytology / Q000502:physiology*; D014738:Vibrissae / Q000294:innervation*