PMID-11704255[0] Unilateral lesions of the pedunculopontine nucleus do not alleviate subthalamic nucleus-mediated anticipatory responding in a delayed sensorimotor task in the rat.
- the title says it all ;)
- they describe hemiballismus as "stereotyped repetitive involuntary movements of the cotralateral limbs" (might have to see this to understand it)
- what the rat had to do:
- press lever 1 upon trigger 1 stimuli
- wait 3-4 seconds for the trigger 2 stimuli
- then press lever 2, upon which a pellet of food was given to the rat.
- lesions of the STN in the rat do not induce hyperkinetic movements in overt behaviors, but cause anticipatory motor responses in delayed-reaction tasks, like a nose-poke.
- see figure 7 for the bar-graph of this.
- rats tended to release the lever before the reward or CS for reward was triggered
- still - this might be a cognitive problem, not a lack of anticipation.
- the PPN has remarkable reciprocating connections with the STN, and other basal ganglia nuclei
- PPN lesion increases reaction time during conditioned movements, making the animals bradykinetic or akinetic
- "the animals bearing the combined lesion were severely impaired in conditioned responding to salient stimuli involved in the paradigm and showed side-specific lengthening of reaction and movement times without global motor impairments."
- has anybody looked at activity in the PPN of parkinsonian monkeys? hum.
- compare to [1] - PPN lesions can restore normal activity in SNr & STN. but, if you don't have the STN to restore, then PPN doesn't matter.
____References____
[0] Florio T, Capozzo A, Cellini R, Pizzuti G, Staderini EM, Scarnati E, Unilateral lesions of the pedunculopontine nucleus do not alleviate subthalamic nucleus-mediated anticipatory responding in a delayed sensorimotor task in the rat.Behav Brain Res 126:1-2, 93-103 (2001 Nov 29) |
[1] Breit S, Lessmann L, Unterbrink D, Popa RC, Gasser T, Schulz JB, Lesion of the pedunculopontine nucleus reverses hyperactivity of the subthalamic nucleus and substantia nigra pars reticulata in a 6-hydroxydopamine rat model.Eur J Neurosci 24:8, 2275-82 (2006 Oct) |
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