1. Comparison of functional activity at different brain areas related to different cognitive domains e.g. Memory, visuospatial abilities, executive functions, attention, concentration, language, orientation in schizophrenia to healthy subjects.
2. Correlation with resting functional activity at brain areas with clinical deterioration in cognitive functions.

Schizophrenia represents a multifaceted clinical challenge. Patients' outcome is still highly heterogeneous and poor. Cognitive impairment, a central feature of the illness is present in over 80% of patients with schizophrenia, is a main functional disability. Currently available antipsychotics have only limited effects on cognition and side effects may even aggravate some deficits. So far, pharmacological options for cognitive deficits in schizophrenia are unsatisfactory due to either limited efficacy or tolerability concerns. Understanding the quality, quantity of brain changes could cover patterns of potential therapeutic relevance, guiding treatments. Understanding the pathophysiology of impaired cognition in schizophrenia and developing effective treatment for cognitive symptoms are major unmet challenges for contemporary biomedical research. Briefly, deficits in speed of processing have been correlated with a reduced temporal lobe volume and increased ventricular size. Attention impairments were correlated with structural alterations within the frontal and temporal lobes and with widespread reduced volume of subcortical regions . Decreased working memory was correlated with reduced frontal and temporal lobe volumes and cortical thickness while language and memory deficits were correlated with hippocampal volume loss. Impaired visuspatial and memory correlated with hippocampal volume loss. Deficits in reasoning and problem solving, including higher-order executive functions, were also associated with a reduced the dorsolateral prefrontal cortex volume. Among different neuroimaging modalities, functional magnetic resonance imaging (fMRI) predominates in system-level connectomic studies. Particularly, the task-free version-known as resting fMRI-is better tolerated by clinical populations, and circumvents the need for stringent subject compliance. Today, fMRI features are being rigorously examined to identify potential biomarkers for diagnosis and prognosis of different brain disorders

Inclusion Criteria:

• Diagnosis according to Diagnostic and statistical manual of mental of mental disorders -5 (DSM-5) and confirmed by the Structured Clinical Interview for DSM-5 (SCID -I)

Exclusion Criteria:

• History of head injury.
• History of intellectual disability or neurological diseases e.g. cerebrovascular stroke, dementia Parkinsonism, etc.
• History of alcohol and/or substance abuse in the previous six months.
• Inability to provide informed consent.

twenty subjects will be chosen from psychiatric inpatient unit from assiut university hospitals diagnosed with schizophrenia and 20 subjects as control to be investigated for affection of brain activity in case of schizophrenia