Stress refers to the physiological and psychological response to environmental demands, that
involves the activation of the hypothalamic pituitary adrenal (HPA) axis and cortisol release.
On the other hand, anxiety is a persistent feeling of nervousness, fear and heightened arousal
in the absence of immediate threat, as McEwen (2007) said. The amygdala, located inside the
temporal lobe, as part of the limbic system, is a grouped complex of 13 nuclei in the brain,
together receiving inputs from the central nervous system and projecting nearly every part of
it (Swanson and Petrovich, 1988), which supports a variety of functions such as associative
learning, emotional learning, and responsivity, as well as sexual, and social behaviour. A
dominant perspective in neuroscience proposes that the amygdala acts as a primary driver of
stress and anxiety due to its rapid response to threatening stimuli and its influence on
physiological systems. However, this view has been challenged by evidence suggesting that
anxiety arises from distributed neural networks and dynamic interactions between brain
regions, neurochemical systems, and physiological processes. This essay will focus on
evaluating the claim that amygdala is the primary driver of stress and anxiety, by integrating
findings from neuroimaging techniques, as well as evidence from animal models. According
to applied contexts such as anxiety disorders and examination stress, this essay argues that even
though the amygdala plays a crucial role in rapid threat detection, anxiety is better understood
as part of wider, dysregulated systems.
The amygdala is part of the limbic system that receives sensory information from the thalamus
and cortex, giving it emotional meaning and determining whether a stimulus is perceived as
threatening or not, leading to automatic fight or flight responses, which therefore influences
decision-making and behaviour in an individual (LeDoux, 2000). Once it is activated, it
communicates with several brain regions, including the prefrontal cortex, hippocampus,
hypothalamus, and brain stem, in order to coordinate emotional, cognitive and physiological
responses. Therefore, the connections between the amygdala and the prefrontal cortex (PFC)
are very important, as the amygdala processes emotional input before it reaches to the
prefrontal cortex, where it is then interpreted and consciously regulated as Ochsner & Gross
(2005) stated. Usually, the prefrontal cortex can inhibit excessive amygdala activation when a
perceived threat is not truly dangerous. For instance, walking alone at night and suddenly
seeing a dark shape in distance would make the amygdala trigger a fear response and more
alertness, but then when seen from closer, the prefrontal cortex would evaluate the situation
better and realise that this threat was just a parked bike on the side of the road. However, in
, conditions such as anxiety or Post Traumatic Stress Disorder (PTSD), according to Etkin &
Wager (2007), this regulatory pathway is often weakened, resulting in hyperactive amygdala
responses and therefore leading to exaggerated emotional reactions. Similarly, the interaction
between the amygdala and the hippocampus is also important, as the hippocampus helps
individuals distinguish safe and threatening situations, whilst the amygdala strengthens
emotionally significant memories (McEwen, 2007). Particularly in trauma exposure, this is
highly relevant, as emotional memories may become intrusive as seen in individuals with post
traumatic stress disorder. Physiologically, the amygdala is closely linked to the hypothalamic
pituitary adrenal axis and the autonomic nervous system, so when threat is detected, the
hypothalamus is activated, triggering cortisol release and the fight or flight response, that leads
to an increased blood pressure and heart rate (McEwen, 2007). Though, cortisol also feeds back
to affect the amygdala and hippocampus, illustrating that this relationship is bidirectional rather
than linear. Therefore, chronic stress can strengthen amygdala reactivity by impairing
hippocampal and prefrontal functioning, creating a cycle that maintains anxiety.
This broader systems perspective, therefore, challenges the claim that amygdala is the primary
driver of anxiety, especially when applied to real life aspects. For example, in situations such
as exam stress, students often show increased amygdala activity when they expect being
negatively graded, which is associated with higher anxiety and physiological arousal (Phelps
and Le Doux, 2005). This supports the idea that the amygdala contributes to threat processing,
but a deeper analysis shows that this response is mediated by interactions with other structures,
in particular the prefrontal cortex. In addition, neuroimaging evidence from functional
magnetic resonance imaging (fMRI) studies in anxiety disorders, such as Generalised Anxiety
Disorder (GAD) and Post Traumatic Stress Disorder, reveals not only hyperactivity of the
amygdala, but also a reduced functional connection with the medial prefrontal cortex, as Etkin
& Wager, (2007) indicated, which is responsible for emotional regulation. Furthermore, this
suggests that anxiety arises from dysregulated neural networks that are interconnected, rather
than from amygdala activity alone, challenging the concept of a primary driver and indicating
that it is a more complex model instead. Moreover, in everyday situations of perceived danger,
such as in response to a sudden noise, like door slamming, a loud knock, or a telephone ringing
suddenly, the amygdala enables rapid and automatic processing before full awareness is
reached, as evidenced by magnetoencephalography (MEG) studies, indicating very early
activation in the processing of threatening stimuli (Luo et al., 2007). However, the quick
involves the activation of the hypothalamic pituitary adrenal (HPA) axis and cortisol release.
On the other hand, anxiety is a persistent feeling of nervousness, fear and heightened arousal
in the absence of immediate threat, as McEwen (2007) said. The amygdala, located inside the
temporal lobe, as part of the limbic system, is a grouped complex of 13 nuclei in the brain,
together receiving inputs from the central nervous system and projecting nearly every part of
it (Swanson and Petrovich, 1988), which supports a variety of functions such as associative
learning, emotional learning, and responsivity, as well as sexual, and social behaviour. A
dominant perspective in neuroscience proposes that the amygdala acts as a primary driver of
stress and anxiety due to its rapid response to threatening stimuli and its influence on
physiological systems. However, this view has been challenged by evidence suggesting that
anxiety arises from distributed neural networks and dynamic interactions between brain
regions, neurochemical systems, and physiological processes. This essay will focus on
evaluating the claim that amygdala is the primary driver of stress and anxiety, by integrating
findings from neuroimaging techniques, as well as evidence from animal models. According
to applied contexts such as anxiety disorders and examination stress, this essay argues that even
though the amygdala plays a crucial role in rapid threat detection, anxiety is better understood
as part of wider, dysregulated systems.
The amygdala is part of the limbic system that receives sensory information from the thalamus
and cortex, giving it emotional meaning and determining whether a stimulus is perceived as
threatening or not, leading to automatic fight or flight responses, which therefore influences
decision-making and behaviour in an individual (LeDoux, 2000). Once it is activated, it
communicates with several brain regions, including the prefrontal cortex, hippocampus,
hypothalamus, and brain stem, in order to coordinate emotional, cognitive and physiological
responses. Therefore, the connections between the amygdala and the prefrontal cortex (PFC)
are very important, as the amygdala processes emotional input before it reaches to the
prefrontal cortex, where it is then interpreted and consciously regulated as Ochsner & Gross
(2005) stated. Usually, the prefrontal cortex can inhibit excessive amygdala activation when a
perceived threat is not truly dangerous. For instance, walking alone at night and suddenly
seeing a dark shape in distance would make the amygdala trigger a fear response and more
alertness, but then when seen from closer, the prefrontal cortex would evaluate the situation
better and realise that this threat was just a parked bike on the side of the road. However, in
, conditions such as anxiety or Post Traumatic Stress Disorder (PTSD), according to Etkin &
Wager (2007), this regulatory pathway is often weakened, resulting in hyperactive amygdala
responses and therefore leading to exaggerated emotional reactions. Similarly, the interaction
between the amygdala and the hippocampus is also important, as the hippocampus helps
individuals distinguish safe and threatening situations, whilst the amygdala strengthens
emotionally significant memories (McEwen, 2007). Particularly in trauma exposure, this is
highly relevant, as emotional memories may become intrusive as seen in individuals with post
traumatic stress disorder. Physiologically, the amygdala is closely linked to the hypothalamic
pituitary adrenal axis and the autonomic nervous system, so when threat is detected, the
hypothalamus is activated, triggering cortisol release and the fight or flight response, that leads
to an increased blood pressure and heart rate (McEwen, 2007). Though, cortisol also feeds back
to affect the amygdala and hippocampus, illustrating that this relationship is bidirectional rather
than linear. Therefore, chronic stress can strengthen amygdala reactivity by impairing
hippocampal and prefrontal functioning, creating a cycle that maintains anxiety.
This broader systems perspective, therefore, challenges the claim that amygdala is the primary
driver of anxiety, especially when applied to real life aspects. For example, in situations such
as exam stress, students often show increased amygdala activity when they expect being
negatively graded, which is associated with higher anxiety and physiological arousal (Phelps
and Le Doux, 2005). This supports the idea that the amygdala contributes to threat processing,
but a deeper analysis shows that this response is mediated by interactions with other structures,
in particular the prefrontal cortex. In addition, neuroimaging evidence from functional
magnetic resonance imaging (fMRI) studies in anxiety disorders, such as Generalised Anxiety
Disorder (GAD) and Post Traumatic Stress Disorder, reveals not only hyperactivity of the
amygdala, but also a reduced functional connection with the medial prefrontal cortex, as Etkin
& Wager, (2007) indicated, which is responsible for emotional regulation. Furthermore, this
suggests that anxiety arises from dysregulated neural networks that are interconnected, rather
than from amygdala activity alone, challenging the concept of a primary driver and indicating
that it is a more complex model instead. Moreover, in everyday situations of perceived danger,
such as in response to a sudden noise, like door slamming, a loud knock, or a telephone ringing
suddenly, the amygdala enables rapid and automatic processing before full awareness is
reached, as evidenced by magnetoencephalography (MEG) studies, indicating very early
activation in the processing of threatening stimuli (Luo et al., 2007). However, the quick
