The Effects of a Single Dose of Wild Blueberries on Mood and Cognition in Healthy Young Adults

The Positive and Negative Affect Schedule - Expanded Form (PANAS-X) is a validated, self-rated measure of affective state, encompassing two general dimensions (positive and negative affect). These will be calculated separately by adding the values of the individual items (21 positive and 25 negative items). Thus, the scales will range from 0 to 84 points for positive affect and from 0 to 100 for negative affect, with a higher score indicating greater positive or negative affect. Positive affect will be considered the primary measure.

The Positive and Negative Affect Schedule - Expanded Form (PANAS-X) is a validated, self-rated measure of affective state, encompassing two general dimensions (positive and negative affect). These will be calculated separately by adding the values of the individual items (21 positive and 25 negative items). Thus, the scales will range from 0 to 84 points for positive affect and from 0 to 100 for negative affect, with a higher score indicating greater positive or negative affect. Positive affect will be considered the primary measure

A negative interpretation bias is defined as a tendency to interpret ambiguous information in a consistently threatening or negative manner, thus serving as an objective indicator of affective state. In this task, participants will be asked to categorize facial expressions of anger, happiness, and surprise as either positive or negative. Interpretation bias will be operationalized as the percent of trials in which surprised faces were rated as negative, out of the total number of surprise trials (48 trials).

A negative interpretation bias is defined as a tendency to interpret ambiguous information in a consistently threatening or negative manner, thus serving as an objective indicator of affective state. In this task, participants will be asked to categorize facial expressions of anger, happiness, and surprise as either positive or negative. Interpretation bias will be operationalized as the percent of trials in which surprised faces were rated as negative, out of the total number of surprise trials (48 trials).

A task-switching test will be used to assess cognitive performance when switching between two predictable tasks requiring simple numerical decisions. The main outcome of interest is the average accuracy of responses to post-switch trials (those immediately following a switch to a new task).

A task-switching test will be used to assess cognitive performance when switching between two predictable tasks requiring simple numerical decisions. The main outcome of interest is the average accuracy of responses to post-switch trials (those immediately following a switch to a new task).

The Rey Auditory Verbal Learning Test (RAVLT) is a standard neuropsychological assessment designed to evaluate verbal memory. The participant hears a list of 15 words and is asked to recall as many words as possible. This procedure is repeated five times. The main outcome of interest is the number of correctly recalled words 20 minutes after the last presentation of the list of words (Trial A7).

The Rey Auditory Verbal Learning Test (RAVLT) is a standard neuropsychological assessment designed to evaluate verbal memory. The participant hears a list of 15 words and is asked to recall as many words as possible. This procedure is repeated five times. The main outcome of interest is the number of correctly recalled words 20 minutes after the last presentation of the list of words (Trial A7).

Serum levels of BDNF will be analyzed using enzyme-linked immunosorbent assay (ELISA).

Serum levels of BDNF will be analyzed using enzyme-linked immunosorbent assay (ELISA).

The following affective states will be examined separately as defined by the PANAS-X subscales: Joviality (Happiness), Self-Assurance, Attentiveness, Fatigue, Serenity. Higher scores will indicate greater intensity of the respective affective state.

The following affective states will be examined separately as defined by the PANAS-X subscales: Joviality (Happiness), Self-Assurance, Attentiveness, Fatigue, Serenity. Higher scores will indicate greater intensity of the respective affective state.

The average reaction time to correctly categorized happy faces in the facial expression task.

The average reaction time to correctly categorized happy faces in the facial expression task.

The average reaction time to correctly categorized angry faces in the facial expression task.

The average reaction time to correctly categorized angry faces in the facial expression task.

Attentional bias to emotional information will be operationalized as the average reaction time to correctly categorized angry faces divided by the average reaction time to correctly categorized happy faces. Thus, a higher value indicates a tendency to attend to and process positive information over negative information.

Attentional bias to emotional information will be operationalized as the average reaction time to correctly categorized angry faces divided by the average reaction time to correctly categorized happy faces. Thus, a higher value indicates a tendency to attend to and process positive information over negative information.

The average accuracy (in %) of responses to the remaining trials of the task-switching test will be measured as a secondary outcome. In this task, participants have to switch between two predictable tasks requiring simple numerical decisions.

The average accuracy (in %) of responses to the remaining trials of the task-switching test will be measured as a secondary outcome. In this task, participants have to switch between two predictable tasks requiring simple numerical decisions.

The average reaction time of correct responses to post-switch trials of the task-switching test.

The average reaction time of correct responses to post-switch trials of the task-switching test.

The average reaction time of correct responses to remaining trials of the task-switching test.

The average reaction time of correct responses to remaining trials of the task-switching test.

The number of correctly retrieved words on Trial 5 (List A) of the Rey Auditory Verbal Learning Test.

The number of correctly retrieved words on Trial 5 (List A) of the Rey Auditory Verbal Learning Test.

The number of correctly retrieved words from the interference list (List B) of the Rey Auditory Verbal Learning Test.

The number of correctly retrieved words from the interference list (List B) of the Rey Auditory Verbal Learning Test.

The number of correctly recalled words on the Rey Auditory Verbal Learning Test 2 minutes after the final presentation of List A (and following the presentation and recall of List B).

The number of correctly recalled words on the Rey Auditory Verbal Learning Test 2 minutes after the final presentation of List A (and following the presentation and recall of List B).

Proactive interference on the Rey Auditory Verbal Learning Test is defined as the number of correctly recalled words from the interference List B divided by the number of correctly recalled words on Trial 1 of List A (B1/A1). A higher score indicates less proactive interference.

Proactive interference on the Rey Auditory Verbal Learning Test is defined as the number of correctly recalled words from the interference List B divided by the number of correctly recalled words on Trial 1 of List A (B1/A1). A higher score indicates less proactive interference.

Retroactive interference on the Rey Auditory Verbal Learning Test is defined as the number of correctly recalled words on Trial 6 of List A (the free recall trial after the interference List B) divided by the number of correctly recalled words on Trial 5 of List A (A6/A5). A higher score indicates less retroactive interference.

Retroactive interference on the Rey Auditory Verbal Learning Test is defined as the number of correctly recalled words on Trial 6 of List A (the free recall trial after the interference List B) divided by the number of correctly recalled words on Trial 5 of List A (A6/A5). A higher score indicates less retroactive interference.

Retention on the Rey Auditory Verbal Learning Test is defined as the number of correctly recalled words on Trial 7 of List A (the delayed recall trial at 20 minutes) divided by the number of correctly retrieved words on Trial 6 of List A (A7/A6). Thus, a higher score indicates a higher retention rate.

Retention on the Rey Auditory Verbal Learning Test is defined as the number of correctly recalled words on Trial 7 of List A (the delayed recall trial at 20 minutes) divided by the number of correctly retrieved words on Trial 6 of List A (A7/A6). Thus, a higher score indicates a higher retention rate.

The activity of the enzyme MAO-B in serum will be analyzed using a fluorometric assay.

The activity of the enzyme MAO-B in serum will be analyzed using a fluorometric assay.

Serum levels of DHPG will be analyzed using liquid chromatography-mass spectrometry (LS-MS) to indirectly determine monoamine oxidase A (MAO-A) activity.

Serum levels of DHPG will be analyzed using liquid chromatography-mass spectrometry (LS-MS) to indirectly determine monoamine oxidase A (MAO-A) activity.

Serum levels of IL-6 will be analyzed using enzyme-linked immunosorbent assay (ELISA) as an indication of systemic inflammation.

Serum levels of IL-6 will be analyzed using enzyme-linked immunosorbent assay (ELISA) as an indication of systemic inflammation.

Serum levels of CRP will be analyzed using enzyme-linked immunosorbent assay (ELISA) as an indication of systemic inflammation.

Serum levels of CRP will be analyzed using enzyme-linked immunosorbent assay (ELISA) as an indication of systemic inflammation.

In the final task of the Rey Auditory Verbal Learning Test, participants need to recognize the 15 words from List A from a list of 50 words. Recognition memory is defined as the number of correctly recognized words out of the total number of words.

In the final task of the Rey Auditory Verbal Learning Test, participants need to recognize the 15 words from List A from a list of 50 words. Recognition memory is defined as the number of correctly recognized words out of the total number of words.