Dissociating Components of Anhedonia: A Pilot fMRI Study

To quantify brain activity associated with reward "wanting," the investigators will contrast fMRI activation while participants view information about reward probability and choose to perform the easy or hard task with activity during fixation. The investigators will contrast activation during performance feedback and presentation of reward magnitude with activation during fixation to capture brain activity associated with reward "liking." Parameter estimates (ß) will be generated, which indicated relative strength of covariance between the data and the hemodynamic response function (HRF). The investigators will use a three-dimensional spatial contiguity threshold of 20 voxels and a statistical significance threshold of p ≤ .005 to decrease the likelihood of spurious findings.

The EEfRT is a computerized task in which participants are presented with a series of repeated trials during which they choose between performing a ''hard-task'' or an ''easy-task'' in order to earn varying amounts of monetary rewards.

Cognitive screening instrument. The highest possible score is 30. 18 - 26 = mild cognitive impairment, 10 - 17 = moderate cognitive impairment and less than 10 = severe cognitive impairment.

The scale includes 36 tasks which are grouped into five subscales assessing different cognitive domains, namely: Attention, Initiation/Perseveration (I/P), Construction, Conceptualization and Memory.

Participants must 1) read color words (red, green and blue) aloud, 2) name the ink color of a string of X's presented in rows on a page, and 3) name the ink color of color words (red, green, blue) written in either the same or a different color as the word meaning.

Subjects hear a string a numbers and letters and must repeat them with the numbers first, in order, followed by the letters in alphabetical order.

The task requires a subject to 'connect-the-dots' of 25 consecutive targets on a sheet of paper or computer screen. There are two parts to the test: A, in which the targets are all numbers (1,2,3..) and the test taker needs to connect them in sequential order, and B, in which the subject alternates between numbers and letters (1, A, 2, B, etc.). The test should be finished as quickly as possible within 5 minutes. The poorer the performance the higher the impairment.

A number of stimulus cards are to be match within 20 minutes. Participants must figure out the sorting rule based on feedback from the examiner.

Subjects are asked to name as many words as they can in 60 seconds based on either a letter (F, A, and S) or a category (animals) rule.

Subjects repeat a string of numbers in either the same order (digits forward) or in reverse order (digits backward).

Subjects are asked to learn and remember a 16-item word list.

Subjects are asked to learn and remember the identity and location of 6 simple figures displayed on a page.

18-item self-report questionnaire assessing anticipatory pleasure and consummatory pleasure

The SHAPS measures hedonic capacity. A higher total SHAPS score will indicate a higher level of anhedonia or the inability to experience pleasure.

Subjects are required to respond to a 20-item test using 5-point scale that ranges from very slightly or not at all (1) to extremely (5).

21-item self-report questionnaire assessing symptoms of depression.

Subjects answer 30 yes/no questions assessing symptoms of depression.

This is a 20-item measure of depression severity.

The STAI measures two extremes of anxiety affect, labeled state anxiety (A-State), and trait anxiety (A-Trait). Higher scores suggest higher levels of anxiety.

14-item self-report questionnaire assessing symptoms of apathy over the previous 2-4 weeks

33 queries belonging to nine domains, each corresponding to a clinical manifestation of apathy