You will be shown an abstract from a biomedical research paper. Given this abstract, your task is to extract all unique entities of the following types: ["Outcome", "Participant", "Intervention"].

Please return the output as a JSON object of the format: {"Participant" : ["patients with COPD", ...], "Intervention" : ["Atenolol", ...], "Outcome" : ["blood pressure", ...]}. The keys should be entity types and values should be lists of extracted entities belonging to the corresponding type. If you cannot find entities belonging to a specific type, the value should be [].

Only output the JSON object and do not include any additional text.

Abstract:

Modulation of human motor cortex excitability by single doses of amantadine . Amantadine-sulfate has been used for several decades to treat acute influenza A , Parkinson 's disease ( PD ) , and acute or chronic drug-induced dyskinesia . Several mechanisms of actions detected in vivo/in vitro including N-methyl-D-aspartate ( NMDA ) -receptor antagonism , blockage of potassium channels , dopamine receptor agonism , enhancement of noradrenergic release , and anticholinergic effects have been described . We used transcranial magnetic stimulation ( TMS ) to evaluate the effect of single doses of amantadine on human motor cortex excitability in normal subjects . Using a double-blind , placebo-controlled , crossover study design , motor thresholds , recruitment curves , cortical stimulation-induced silent period ( CSP ) , short intracortical inhibition ( ICI ) , intracortical facilitation ( ICF ) , and late inhibition ( L-ICI ) in 14 healthy subjects were investigated after oral doses of 50 and 100 mg amantadine with single and paired pulse TMS paradigms . Spinal cord excitability was investigated by distal latencies and M-amplitudes of the abductor digiti minimi muscle . After intake of amantadine , a significant dose-dependent decrease of ICF was noticed as well as a significant increase of L-ICI as compared to placebo . The effect on ICF and L-ICI significantly correlated with amantadine serum levels . ICI was slightly increased after amantadine intake , but the effect failed to be significant . Furthermore , amantadine had no significant effects on motor thresholds , MEP recruitment curves , CSP , or peripheral excitability . In conclusion , a low dose of amantadine is sufficient in modulating human motor cortex excitability . The decrease of ICF and increase of L-ICI may reflect glutamatergic modulation or a polysynaptic interaction of glutamatergic and GABA-ergic circuits . Although amantadine has several mechanisms of action , the NMDA-receptor antagonism seems to be the most relevant effect on cortical excitability . As L-ICI can be influenced by this type of drug , it may be an interesting parameter for studies of motor learning and use-dependent plasticity .
{"Intervention": ["Amantadine-sulfate", "placebo-controlled", "transcranial magnetic stimulation ( TMS )", "amantadine", "oral doses of 50 and 100 mg amantadine", "single and paired pulse TMS paradigms"], "Outcome": ["N-methyl-D-aspartate", "M-amplitudes", "peripheral excitability .", "MEP recruitment curves", "CSP", "antagonism", "cortex", "modulating human motor cortex excitability", "Spinal cord excitability", "cortical excitability", "ICI", "L-ICI", "ICF", "Modulation of human motor cortex excitability", "motor thresholds"], "Participant": ["normal", "healthy", "14"]}