Muscarinic agonists as cognitive enhancers

1. A method of decreasing regressive errors while enhancing behavioral flexibility in a human subject in need thereof, comprising:

administering to a subject in need thereof an effective amount of CDD-0102 [5-(3-ethyl-1,2,4-oxadiazol-5-yl)-1,4,5,6-tetrahydropyrimidine] compound or a pharmaceutically acceptable salt or hydrate thereof to selectively activate M 1 muscarinic receptors in the subject without substantially producing M 2 , M 3 , M 4 and/or M 5 muscarinic receptor subtype activity in the subject;

wherein the compound is administered in a daily dosage ranging from about 0.01 mg/kg to about 0.3 mg/kg of body weight;

wherein the subject has autism spectrum disorders (ASD), does not have attention deficit hyperactivity disorder (ADHD) and does not have a cholinergic deficit, but does exhibit regressive errors;

wherein the subject is treated for regressive errors not associated with cholinergic deficits, but where cognitive function or behavioral flexibility is impaired;

wherein the regressive errors have already developed and the subject is protected against worsening of the regressive errors;

and,

decreasing regressive errors by enhancing behavioral flexibility and increasing the ability to initially inhibit a previously relevant strategy and to maintain a new, relevant strategy once selected.

2. The method according to claim 1 , wherein the compound is administered in a dosage unit as a solid formulation; in a dosage unit as a tablet or capsule formulation.

3. The method according to claim 1 , wherein the compound is administered orally or by injection.

4. The method according to claim 1 , wherein the subject is evaluated before, during and/or after administration of the compound to determine efficacy of the treatment.

5. The method according to claim 1 , including obtaining systemic measurements of the levels of the compound at various time points after administration of the compound.