Simultaneous multisite recordings of neural ensemble responses in the motor cortex of behaving rats to peripheral noxious heat and chemical stimuli.
Behav Brain Res
; 223(1): 192-202, 2011 Sep 30.
Article
en En
| MEDLINE
| ID: mdl-21549760
ABSTRACT
Chronic motor cortex (MCx) stimulation (MCS) is an effective approach for patients with chronic, intractable neuropathic pain. However, the underlying neural mechanisms are less known. Combining an in vivo simultaneous multisite recording technique with a video-based behavioral tracker, simultaneous neuronal ensemble activities of the MCx and behavioral responses to noxious heat stimuli applied to bilateral hindpaw pads under naïve and inflammatory pain state were studied in freely behaving rats receiving prior implantation of microwire multielectrode array (2 × 4). Totally, 81 active units were sorted and separated from 40 microwire electrodes pre-implanted in the MCx of 5 rats. Under naïve state, 41% (33/81) units were responsive to contralateral, while 27% (22/81) were responsive to ipsilateral heat stimuli. However, the proportion of heat-responsive units under inflammatory pain state induced by subcutaneous bee venom (BV) injection was significantly increased when compared with saline control (BV vs. saline 60% vs. 48% for contralateral and 51% vs. 37% for ipsilateral, P < 0.05, n = 81 units) as a consequence of recruitment of some previously heat non-responsive to heat sensitive units. Moreover, under the BV-inflamed condition, the discharge rate of the MCx neurons was significantly increased. The time course of increased spontaneous neuronal ensemble activities (n = 81) was in parallel with that of pain-related behaviors following BV injection. It is concluded that there are pain-related neurons in the MCx that can be functionally changed by peripheral inflammatory pain condition.
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MEDLINE
Asunto principal:
Dolor
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Conducta Animal
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Electrofisiología
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Calor
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Corteza Motora
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Neuronas
Idioma:
En
Revista:
Behav Brain Res
Año:
2011
Tipo del documento:
Article