Basal-Ganglia & Thalamus
The basal ganglia refers to large clusters of nerve cells located within the cerebrum and upper parts of the brain stem. They are connected with all 3 brain layers.
They help coordinate postures, temporal start & stop as well as smooth sequencing of movements and voluntary emotional activity. Their interaction with the amygdala supports this active component of the behavioral expression of emotion.
The thalamus, coined from the Greek word for “chamber”, is the part of the brain responsible for signal relaying and prioritization. It consists of twin bulb-shaped regions, symmetrical about the brain’s midline.
The thalamus is the final relay station to distill sensory information into a more interpretable form for perceptual data before it is passed on to the cerebral cortex. It receives input from different brain areas, primarily all the senses, except olfaction.
It regulates motor control, modulates arousal mechanisms, maintains alertness, and directs attention to sensory events. The thalamus consists of 3 circuits:
- The specific nucleii are responsible for scanning the cerebral cortex and determining active brain regions, those firing at around 40Hz, then relaying this information to the rest of the thalamus.
- The reticular formation is constantly making intelligent guesses as to what sensory object is generating these activation patterns.
- The intra-laminar circuit compares these pattern guesses with similar patterns in memory.
All these circuits cooperate to produce a coherent framework for the interpretation of incoming sensory data.
