Neuroplasticity in TBI and Schizophrenia

This proposal will examine measures of neuroplasticity (the brain's ability to alter its function or structure in response to changes in the environment or novel experiences) in Veterans with schizophrenia or traumatic brain injury (TBI). Both conditions are associated with impaired cognition (for example, attention, memory, learning), which is in turn associated with poor community functioning and integration. However, the two disorders differ in their origins: schizophrenia is a neurodevelopmental disorder appearing usually in late adolescence while TBI is an acquired disorder as the result of an injury to the head. Understanding of the root causes of complex cognitive impairments associated with these disorders remains limited. Neuroplasticity is a fundamental brain process that underlies cognitive functioning and may give insight into the causes of cognitive dysfunction in TBI and schizophrenia. Neuroplasticity will be measured using electroencephalography (EEG) by placing small electrodes on the scalp that record the brain's electrical activity. Participants will listen to simple auditory tones and view simple visual patterns while their EEG is recorded. Additionally, participants will have measures of cognition and clinical interviews for diagnosis of a disorder as well as any current levels of symptoms.

EEG recording: In this procedure, the participant's brain function will be recorded while listening to auditory tones or viewing simple visual stimuli. Participants will respond with a button press to specific tones or images. Participants will have all tasks clearly described to them and will practice each task prior to beginning the experiments. While performing these tasks, the brain's electrical activity (commonly referred to as "brain waves") will be recording using electroencephalography (EEG). Participant's will wear a cap that contains several electrodes (small, metal discs that are able to pick up electrical activity). A small amount of gel will be applied to the scalp underneath each electrode. These electrodes simply rest on the surface of the scalp and above and below the left eye. It takes approximately 15 minutes to place and prepare the electrodes. The entire recording session will last approximately 90 minutes (including setup). Before having EEG recorded it is important to wash the hair and scalp and not use conditioners or products in the hair as these may interfere with the electrical signal. The gel used is simply washed out of the hair with running water.

During the auditory task, participants will listen to a series of tones while watching a silent movie. Participants do not need to pay attention to the tones. During the visual task, participants will view a series of images on a computer screen that consist of a checkerboard pattern. Periodically, they will be asked to respond with a button press if one of the images is different than the others.

Interviews: There will be interviews conducted by trained staff that ask questions about participants' demographics (age, gender, education). A clinical interview will be given to all participants to determine if participants have either schizophrenia, a history of a traumatic brain injury, or have no psychiatric illness. All participants will be asked questions about how they are feeling. In addition, participants will answer questions about their family and friends and how they have been getting along with people in their lives.

Behavioral testing: Participants will have measures of cognition assessed using various computer-based tasks and pen-and-pencil questionnaires. These tests assess aspects of cognition including memory, attention, language, and motor skills. Participants will also be asked to view a series of pictures of faces and identify the emotion depicted on the face. Finally, participants will be asked to view a series of short videos consisting of a person telling a personal story. Participants will continuously rate how they think that person in the video is feeling (happy, sad, angry, etc.) while telling their story.

Additional Information: It may sometimes be necessary to contact a participant's physician to inquire about their medical history or diagnosis. Permission will be sought from participant's in order for contact to be made with their physician.

Eligibility Criteria:
Inclusion Criteria:

* Veterans with a diagnosis of schizophrenia or a history of mild or moderate traumatic brain injury (TBI)
* Veterans without a psychiatric diagnosis and no history of TBI (healthy control participants) will also be recruited
* No other neurological or medical condition interfering with providing informed consent or valid assessment
* No current depression based on the Structured Clinical Interview for DSM-5 (SCID-I) or depressive symptoms rated moderate or higher

  * a rating of 13 or higher on the Hamilton Depression Rating Scale
* No DSM-V substance use disorder greater than mild severity in the past 3 months
* No form of cognitive remediation in the 6 months prior to testing
* An 8th grade reading level assessed with the Wide Range Achievement Test (WRAT)
* Normal or corrected-to-normal vision and hearing

Exclusion Criteria:

Exclusion criteria for all patient participants include:

* changes in medication dosage or type 3 months prior to testing
* hospitalization for psychiatric health in the 3 months prior to testing
* changes in housing status in the 6 months prior to testing