### Biological Basis of the Computational Model The provided code is part of a computational model designed to investigate functional connectivity in neural systems, specifically comparing synaptic activity and fMRI signals. Here is a breakdown of the biological concepts represented: #### **1. Objective of the Model:** The goal of the code is to visualize the correlation coefficients between different modules within a large-scale neural network model. By comparing synaptic time-series data with fMRI-derived time-series data, the study aims to examine the functional connectivity (FC) and how well the synaptic activity aligns with what is observed in fMRI data. #### **2. Functional Connectivity:** In neuroscience, functional connectivity refers to the statistical dependencies between different brain regions as they process information. Here, FC is expressed through correlation coefficients computed from both synaptic activity and fMRI time-series data. - **Synaptic Time-Series:** This represents actual synaptic activity within the brain, derived from a simulation using a neurocomputational model known as the Large-Scale Neural Modeling software (LSNM). - **fMRI Time-Series:** Functional Magnetic Resonance Imaging (fMRI) indirectly measures neuronal activity through fluctuations in cerebral blood flow. It offers a macroscopic view of brain activity often used in neuroscientific studies. #### **3. Neural Modules:** The code evaluates connections among several neural modules denoted by abbreviations such as 'V1', 'V4', 'FS', 'D1', 'D2', 'FR', and 'cIT'. These correspond to different brain regions or processing modules in the model. For instance: - **V1 and V4:** Typically refer to primary (V1) and secondary (V4) visual cortex areas, crucial for visual processing. - **FS:** May refer to a module involved in feature selection. - **D1 and D2:** Could represent different layers or populations within a region known for complex processing, possibly in decision-making tasks. - **FR and cIT:** Might reference frontal regions associated with higher cognitive tasks and the inferior temporal cortex, respectively. #### **4. Experimental Conditions:** The model distinguishes between different conditions, labeled as 'DMS' (Delayed Match to Sample) and 'CTL' (Control), for both synaptic ('syn') and fMRI data. This format typically involves cognitive tasks used in studies of working memory or decision-making processes. - **DMS:** Often used in experiments to study the working memory, where subjects must remember a sample stimulus after a delay. - **CTL:** Represents a control condition used for comparison against the experimental DMS condition. #### **5. Data Visualization:** The visualization aspect of the model seeks to provide a clear, comparative insight into how synaptic activities correlate with fMRI data under the specified conditions. This is crucial for understanding which neural connections are active during tasks represented in the model and how these connections are portrayed in fMRI results. ### Summary Overall, the code integrates synaptic and fMRI data to evaluate and visualize network-level functional connectivity across a computational brain model. It contrasts the natural neural activity observed in modeled synaptic data with the macro-scale patterns captured by fMRI, elucidating the underlying neurophysiological mechanisms in tasks, particularly those involving working memory and visual processing.