Depletion of particular brain tissue linked to chronic depression, suicide: Study

Context:

In recent research, a common characteristic has been found in the brain structure of people who died by suicide. There was a sharp fall in the density of ‘Astrocytes’, a particular nerve cell throughout the brain.

What are Astrocytes?

• It is a type of supportive nerve cell, looks like the end of a frayed rope.
• Astrocytes are highly heterogeneous neuroglial cells with distinct functional and morphological characteristics in different parts of the brain.
• They are responsible for maintaining a number of complex processes needed for a healthy central nervous system (CNS).
• The density was five times lower in the mediodorsal thalamus and caudate nucleus and half in the prefrontal cortex in the subjects who had died by suicides.
• Astrocytes can strongly modulate most facets of neuronal activity, including neuronal firing, neurotransmitter synthesis, neurotransmitter reuptake, and synaptic transmission.

How does reduction in astrocytes have negative effects?

• With fewer astrocytes, the neurons in this circuit (important for decision making and emotional regulation, functions) may not function as well as they otherwise would.
• Abnormalities in the prefrontal cortex also seem to be connected to impulsivity, which may play a role in suicide in some cases.

Three regions of the brain that are considered to be responsible for emotion regulation were studied— the dorsomedial prefrontal cortex, dorsal caudate nucleus, and mediodorsal thalamus.