Effetto dell'intossicazione acuta da alcol sui processi neurali durante le decisioni di impegnarsi in comportamenti a rischio di HIV

participants receive alcohol beverage

High-proof alcohol (e.g., Everclear) will be mixed with orange juice in an approximately 1:3 ratio and split evenly into two drinks. After splitting the orange juice into two cups, a small amount (approx. 6 ml) of high-proof alcohol will be floated on top of the beverage.

Placebo

The final drink will have the same volume of liquid as the alcohol beverage.

Participants will see a picture of one of the individuals selected during the pre-scan PSD procedure. They will also see two choices corresponding to 1) "Sex with this person without a condom NOW" or 2) "Sex with this person with a condom [NOW or delay] . Participants will have 6 seconds to press a button corresponding to their choice. Conditions of interest will vary as follows: choice difficulty- easy (probability of choosing later option <0.33 or >0.67) or hard (probability of choosing alternative option between 0.33 and 0.67); preference- now (probability of choosing later option <0.5) or delay (probability of choosing later option >0.5); sexual risk - high (individual most likely to have an STD) or low (individual least likely to have an STD); and desirability - high (individual you most want to have sex with) or low (individual you least want to have sex with).

This will be used to assess interest in risky sexual activity. It is an 11 question self-report questionnaire with each question scored on a scale of 1-4. Scores on this measure will allow us to consider whether individual differences in the reward value of sexual activity account for differences in performance and neural correlates of the PSD task.

This will be used to assess interest in sexual activity. It is a 14-question self-report questionnaire with each question scored on a scale of 0-8, where higher scores reflect more sexual desire. It typically takes less than 10 minutes to complete. Scores on this measure will allow us to consider whether individual differences in the reward value of sexual activity account for differences in performance and neural correlates of the PSD task.

During scanning, participants will be shown two squares: a "safe" square and a "risk" square. If the participant chooses the "safe" square, they will earn a set amount of money ($0.25); if they choose the "risk" square, they have the possibility of winning up to $5.00 but also the possibility of losing up to $5.00. Across 40 trials, participants will be able to earn between $0 and $35. All events will be shown for 2 seconds with 2, 4, or 6 second jittered intervals between.

Participants will view 60 cards with an image of a clothed person, spread on a table in front of them so they can all be viewed at the same time. Participants will be instructed to select all the pictures of individuals who they would be willing to have casual sex with based on physical appearance if the circumstances were right. From the pictures of individuals who the participant indicated that they would have sex with, participants will be asked to select 1) the individual most and 2) least likely to have a STD, and 2) the individual they most and 4) least want to have sex with.

A 45-question self-report questionnaire that takes approximately 7 minutes to complete. It assesses how much the participant knows about how HIV is transmitted and prevented.

Assesses quantitatively both intravenous drug use and sexual HIV risk behaviors. This includes 11 questions about sharing and cleaning needles, number of sexual partners, condom use, and sex work. Each item is scored on a scale of 0-5 where higher scores indicate more HIV risk. It takes less than 10 minutes to administer. Scores on this measure will allow us to consider whether performance and neural correlates of the PSD task are related to actual HIV risk behaviors in our sample.

Used to collect additional information on HIV risk. This will include such topics as condom attitudes and negotiation, HIV testing and history of exposure, sexual activities, partner risk behaviors, and perceived risk. Information from this survey will allow us to consider whether performance and neural correlates of the PSD task are related to actual HIV risk behaviors in our sample.

This will be used to measure social desirability bias. It is a 40-question self-report questionnaire that measures self-deceptive positivity and impression management. Number of items with extremely high agreement indicates level of desirable responding. We will use this to identify participants who may have inaccurately responded to questions about sexual history and HIV risk due to a desire to represent themselves better, and thus, might potentially bias our results in some way.