Posted by desolationrower on March 17, 2009, at 2:45:51
In reply to Re: ADD meds/motivation/concentration, posted by garnet71 on March 17, 2009, at 0:01:24
hm, well ok. i do think different meds can be helpful. methylphenidate is the reuptake inhibitor, btw. AMP is the catecholemine releaser (also blocks uptake). Two things to know about catecholamine activity though is that there is both phasic, and tonic. for dopamine there is low level amount that interacts with d2 autoreceptors. the locus correuleous has tonic and phasic firing (mostly NA neurons) and generally tonic levles, the high is more energy/awake vs sleep. phasic bursts are what give attention to things as important. I forget the exact relevance of DA activity, there have been various mathematical signal processing models, i do'nt think theres really a consensus. One thing i've seen is that overactivity in the striatum of DA phasically can cause impulsiveness, but also that underactivity prevents proper maintnence of long-term goal, and then allows for increased distractability. otoh inattention, inhibition and social anxiety have sometimes shown the opposite, so there isn't a clear role for DA worked out yet i don't think. Ok, the second thing to know is that there isa lot of interaction in these systems, and location or even timing can have big effects. so moderate levels of NA in the frontal cortex agonize the postynaptic alpha2 adrenoceptors, and increase focus. less NA, no focus, but too much NA, alpha1 and beta adrenoceptors are ativated, and you get distracted, and pfc inhibition fails and pfc loses control->this is happening when you stress out and can't think straight. SO then pfc attentional networks are important for control of lower regions, as NA & DA in the pfc affect da release in the limbic regions. frontal NA is also important for maintaining DA in lower levels in the 'response' portion to stress, once NA drops in cortex it cascades into feeling of hopelessness & 'give up'.