Amygdala

Amygdala is one of two almond-shaped clusters of nuclei located deep and medially within the temporal lobes of the brain’s cerebrum in complex vertebrates, including humans.

The term amygdala was first introduced by Karl Friedrich Burdach in 1822.

In one study, electrical stimulations of the right amygdala induced negative emotions, especially fear and sadness. In contrast, stimulation of the left amygdala was able to induce either pleasant (happiness) or unpleasant (fear, anxiety, sadness) emotions. Other evidence suggests that the left amygdala plays a role in the brain’s reward system.

Glutamatergic neurons in the basolateral amygdala send projections to the nucleus accumbens shell and core. Activation of these projections drive motivational salience. The ability of these projections to drive incentive salience is dependent upon dopamine receptor D1.

Each side holds a specific function in how we perceive and process emotion. The right and left portions of the amygdala have independent memory systems, but work together to store, encode, and interpret emotion.

The amygdala is one of the best-understood brain regions with regard to differences between the sexes. The amygdala is larger in males than females in children aged 7 to 11, adult humans, and adult rats.

There is considerable growth within the first few years of structural development in both male and female amygdalae.

Within this early period, female limbic structures grow at a more rapid pace than the male ones. Amongst female subjects, the amygdala reaches its full growth potential approximately 1.5 years before the peak of male development.

The structural development of the male amygdala occurs over a longer period than in women. Despite the early development of female amygdalae, they reach their growth potential sooner than males, whose amygdalae continue to develop. The larger relative size of the male amygdala may be attributed to this extended developmental period.

Early research on primates provided explanations as to the functions of the amygdala, as well as a basis for further research. As early as 1888, rhesus monkeys with a lesioned temporal cortex (including the amygdala) were observed to have significant social and emotional deficits.

Heinrich Klüver and Paul Bucy later expanded upon this same observation by showing that large lesions to the anterior temporal lobe produced noticeable changes, including overreaction to all objects, hypoemotionality, loss of fear, hypersexuality, and hyperorality, a condition in which inappropriate objects are placed in the mouth.

Some monkeys also displayed an inability to recognize familiar objects and would approach animate and inanimate objects indiscriminately, exhibiting a loss of fear towards the experimenters.

Pridaj komentár

Zadajte svoje údaje, alebo kliknite na ikonu pre prihlásenie:

WordPress.com Logo

Na komentovanie používate váš WordPress.com účet. Odhlásiť sa /  Zmeniť )

Google photo

Na komentovanie používate váš Google účet. Odhlásiť sa /  Zmeniť )

Twitter picture

Na komentovanie používate váš Twitter účet. Odhlásiť sa /  Zmeniť )

Facebook photo

Na komentovanie používate váš Facebook účet. Odhlásiť sa /  Zmeniť )

Connecting to %s

%d blogerom sa páči toto: