$re = '/\d+(?:\.\d+)?\s+EXP\s+New\strial\s\([^)]*\):\s+{[^}]+}/';
$str = '483.3731 EXP New trial (rep=0, index=1): {u\'selectPlayer\': 1, u\'neutralStim4\': u\'PSYCHOLOGIST\', u\'neutralStim2\': u\'PONG\', u\'neutralStim\': u\'YEN\', u\'positiveStim\': u\'PEACEFUL\', u\'neutralStim3\': u\'DASH\', u\'positiveStim3\': u\'HAPPY\', u\'positiveStim2\': u\'HONORABLE\', u\'negativeStim\': u\'BETRAYAL\', u\'negativeStim4\': u\'GUNPOINT\', u\'negativeStim3\': u\'JEALOUS\', u\'negativeStim2\': u\'MISTRUST\', u\'positiveStim4\': u\'AWESOME\'}';
preg_match_all($re, $str, $matches, PREG_SET_ORDER, 0);
// Print the entire match result
var_dump($matches);
Please keep in mind that these code samples are automatically generated and are not guaranteed to work. If you find any syntax errors, feel free to submit a bug report. For a full regex reference for PHP, please visit: http://php.net/manual/en/ref.pcre.php