Small damage of brain parenchyma reliably triggers spreading depolarization

Transient loss of interhemispheric functional connectivity following unilateral cortical spreading depression in awake rats

“…Our study showed the highly dynamic character of CSD-induced behavioral changes – an early brief period of enhanced grooming during CSD (40–80 sec), late post-CSD behavioral activation (300–420 sec), episodes of atypical behavior such as tremor, freezing and forced circling (100–300 sec). Similar behavioral changes, including grooming during CSD, episodes of freezing, circling and locomotor activation after CSD, have been described in other studies in awake rodents (10,29,30). The only change in spontaneous behavior, observed during CSD traveling over the neocortex in our study, was increased grooming, which is known to be associated with facial pain in rodents (31) and is produced by CGRP administration (32).…”

“…Comparison of spontaneous behavior after sham stimulation (n = 14) and a single unilateral CSD (n = 13) has shown significant enhancement of grooming during CSD (40–80 sec) and remote post-CSD (300–420 sec) behavioral activation (Figure 6). In addition to these changes in general behavior, atypical behavioral patterns were observed following CSD (Figure 6): Behavioral arrest (freezing-like episodes) with or without tremor (100–280 sec) and forced circling to the side contralateral to CSD (140–280 sec) heralded CSD penetration into the striatum, as we reported previously (10). The abnormal behavioral patterns were time-locked with the observed post-CSD hemispheric disconnection (Figure 6).…”

“…The post-CSD drop of hemispheric communication coincides with the occurrence of freezing episodes (10,29,30) and development of mild neurological deficits (contralateral sensory neglect and motor impairment) described after CSD in experimental animals, including models of familial hemiplegic migraine (4,30,33). Impaired perception of sensory stimuli received by the contralateral side of the body is thought to underlie the neurological deficits induced by CSD (4).…”

“…The cortical hyperactivation following CSD may have detrimental effects and carry the risk of producing abnormal excitation (seizures) (10,18,19). Long-range excitatory trans-hemispheric connections may easily transfer the seizure-like activity to the unaffected contralateral cortex, but we found no signs of its abnormal activation.…”

5-HT1A receptor agonism in the basolateral amygdala increases mutual-reward choices in rats

“…The mere presence of the cannulas might lead to inflammatory reactions of the surrounding tissue, which might even be exaggerated by the mechanical and psychological stress of daily injections. Recently it was shown that the insertion of an injection needle through a guide cannula into the BLA was sufficient to trigger the occurrence of an acute spreading depolarization that in turn caused freezing behavior and lasted for 1.5 min after the initial insult 58 . In addition, BLA lesions have been specifically associated with decreased mutual-reward choices in the PCT 14 and do interfere with general reward learning in multiple ways (reviewed in Wassum and Izquierdo 59 ).…”