Large Scale Brain Networks

A large scale brain network is a set of connections among various locations (neural bodies) inside the cerebrum. There are two basic kinds of connections in the brain: structural connections and functional connections. How do they differ?

Structural Connections

Functional-Dynamic Connections

There is disagreement over how many major networks function in the brain. The list below indicates 7 networks that many researchers have come to regard as quite important (Sughrue, 2022).

• Sensorimotor Network (SMN)
  
  
• The sensorimotor network is responsible for (1) processing external physical stimuli, (2) feeling internal sensations, (3) evaluating the senses, and (4) producing a motor response
  

• Visual System (VIS)
  
  
• Responsible for sight and visual processing
• Tasks: (1) engage in visual processing, (2) analyzing motion, (3) recognize patterns, textures, and faces, (4) identify the location of objects, buildings, or people in space, (5) determining the function and permanence of objects, (6) aid in problem solving, and (7) reinforce visually learned behaviors
  

• Limbic System (LMBS)
  
  
• The limbic system has developed throughout the course of evolution to regulate core functions in mammals and humans. These processes often take the form of
  
  (1) The response to a stimulus, such as a new smell, sound, or sight
  (2) The level of reaction or motivation, be it self-protection or reward-seeking
  (3) The behavior that ensues
  (4) The emotion associated with that response or behavior
  (5) The memories formed based on the experience, and
  (6) Any learning or takeaways from the experience
  

• Central Executive Network (CEN) [also call Executive Control Network (ECN) or Fronto-Parietal Network (FPN)]
  
  
  
  
  
• Responsible for active tasks and decision making. It is "outward" facing, that is, engaged with the world around the person.
  
• The CEN performs high-level cognitive tasks, and works alongside or in anticorrelation with the other six main brain networks. The CEN engages in:
  
  (1) Active tasks and external thinking involving working memory
  (2) Controlled processing of information
  (3) Integration of information from the other brain networks
  (4) Rule-based problem solving and decision making
  (5) Consideration of multiple, independent stimuli and independent factors
  (6) Organizing behavior based on internal drives, subjective preferences, and choices, and
  (7) Reinforce visually learned behaviors
  

• Default Mode Network (DMN): Sometimes called the "Task-Negative Network"
  
  
• The default mode network (DMN) is the “internal mind” - it is not focused on what is around the individual, but on internal thinking. The kinds of activities of the DMN include

(1) Daydreaming & other forms of "spontaneous thinking"

(2) Considering one's own present mental state; self-referential or "introspective" thinking; one's own internal narrative (internal talk); internally-directed thought

(3) Reflecting on "the autobiographical self" and dealing with autobiographical memories

(4) Episodic memory and future thinking;  decision making about the future, i.e., recalling the past and thinking ahead about what to to do in the future, and

(5) Mentalizing or social cognition, that is, thinking about other people: Reflecting on what others may be thinking about (figuring out their "theory of mind") and trying to "understand, infer, and share the thoughts, feelings, and intentions of other individuals (Crepsi et al., 2016, p. 185)

• Salience Network (SALN)
  
  
• The salience network (SN) is “the moderator.”
  
  
• As your mind’s personal moderator, the salience network constantly monitors the external world and carefully decides how other brain networks react to new information and stimuli.
  
  
• The SN moderates switching between the internal and external processing of the brain’s two main control networks: the default mode network (DMN) and central executive network (CEN), respectively.
  
  
• In healthy brains, these two networks are not active at the same time. To avoid missed information or mixed messages, the SN determines which network is in control at any given moment.

• Dorsal Attention Network (DAN)
  
  
• The DAN is a consistent, bilateral network for the steady holding of attention.
  
  
• The DAN is a "top-down" network of the brain which selects or attends to important visual and spatial information, particularly in detecting novel features of the environment which are important or most salient for the individual.
  

Other networks that have been proposed include

• Ventral Attention Network (VAN)
  
  
• The VAN is a "bottom-up" network of the brain which responds when stimuli in the environment unexpectedly or suddenly appear and require that an individual pay attention.
  

• Auditory Network (AUDN)
  
  
• Discrimination of tone & pitch as well as response to speech & music