PMID- 15665800
OWN - NLM
STAT- MEDLINE
DCOM- 20050428
LR  - 20061115
IS  - 0172-780X (Print)
IS  - 0172-780X (Linking)
VI  - 25
IP  - 6
DP  - 2004 Dec
TI  - Paradoxical firing of thalamic neurons under neuropathic pain state in rats.
PG  - 407-10
AB  - OBJECTIVES: A novel evaluative approach was used to determine single unit 
      activities of non-bursting intralaminar thalamic nuclei under neuropathic pain 
      state following dorsal rhizotomy. SETTINGS AND DESIGN: Extensive dorsal rhizotomy 
      at cervicothoracic level in rats was used as a model of central pain. After 
      rhizotomy, rats were divided into two groups: rats without any signs of 
      self-mutilation, and those presenting self-mutilation. Spontaneous single unit 
      activities of neurons of intralaminar thalamic nuclei were recorded and 
      interspike intervals (ISIs) of non-bursting cells were counted for both groups 
      and compared with that of non-rhizotomized control rats. Chaodynamic methods were 
      applied for the evaluation of the ISIs. RESULTS: In control rats Lyapunov 
      exponents, Shannon entropy and mutual information average values were 
      significantly higher than those of rhizotomized rats without any signs of 
      self-mutilation. Paradoxically, in animals presenting self-mutilation following 
      rhizotomy the evaluated parameters were similar to those of controls. Further, 
      Lyapunov exponents were positive values in all animals indicating chaotic pattern 
      of the neuronal firing. MAIN FINDINGS: 1. Neurons behave in chaotic way in all 
      animals, 2. The most regular firing was found in non-mutilating rhizotomized 
      animals, 3. Patterns of the firing in selfmutilating rats were similar to those 
      in controls. CONCLUSIONS: It is concluded that pain feeling is not executed 
      neither by changes of chaotic dynamics of non-bursting intralaminar thalamic 
      neurons. On the other hand, the paradoxical firing of the neurons under 
      pathological brain matrix might participate in modification pain feeling.
FAU - Vaculin, Simon
AU  - Vaculin S
AD  - Department of Normal, Pathological and Clinical Physiology, Charles University, 
      3rd Faculty of Medicine, Prague, Czech Republic. svaculin@lf3.cuni.cz
FAU - Franek, Miloslav
AU  - Franek M
FAU - Andrey, Ladislav
AU  - Andrey L
FAU - Rokyta, Richard
AU  - Rokyta R
LA  - eng
PT  - Journal Article
PT  - Research Support, Non-U.S. Gov't
PL  - Sweden
TA  - Neuro Endocrinol Lett
JT  - Neuro endocrinology letters
JID - 8008373
SB  - IM
MH  - Action Potentials
MH  - Animals
MH  - Entropy
MH  - Intralaminar Thalamic Nuclei/*physiology
MH  - Male
MH  - Models, Neurological
MH  - Neuralgia/*physiopathology
MH  - Nonlinear Dynamics
MH  - Rats
MH  - Rats, Wistar
MH  - *Rhizotomy
EDAT- 2005/01/25 09:00
MHDA- 2005/04/29 09:00
CRDT- 2005/01/25 09:00
PHST- 2004/11/17 00:00 [received]
PHST- 2004/11/22 00:00 [accepted]
PHST- 2005/01/25 09:00 [pubmed]
PHST- 2005/04/29 09:00 [medline]
PHST- 2005/01/25 09:00 [entrez]
AID - NEL250604A02 [pii]
PST - ppublish
SO  - Neuro Endocrinol Lett. 2004 Dec;25(6):407-10.