“According to the classic cognitivist or modular view, the brain implements encapsulated mechanisms for cognizing (perceiving, planning, evaluating, decision-making, etc.).

Each module is believed to be responsible for computing an independent cognitive function, largely unaffected by the working of other modules and disconnected from bodily and environmental processes.

This conception still fuels experimental cognitive research, not least because of its suitability for isolated study designs.

However, it has now come under growing criticism as being inadequate for the distributed functioning of the central nervous system, multitasking at every level and highly dependent on contextual variables.

Therefore, the modular model is increasingly replaced by thinking in overarching functional systems and highly flexible brain connectivity patterns, where the same cortical or subcortical area may be co-opted into different functions depending on which of its interconnected networks is activated.

This also corresponds to the complexity of experience itself: all terms for special functions, such as seeing, hearing, thinking, feeling, wishing, and so on, single out components of consciousness, whereas factually subjective states of experience always remain holistic.

Thus, all perceptions are not only embedded in a bodily background experience, but are also connected with feelings, memories, and linguistic concepts.

There is no “pure” pain, no “plain” seeing or hearing. (…)

Granted, partial functions of consciousness can to a certain extent be assigned to certain specialized regions, damage to which then also results in the failure of the function.

Figure 4.7 Reciprocity of process and structure: learning as transformation of experience or behavior into organic dispositions

“Rather, the illness originates in a specific perception of the situation, that is, in an individual act of meaning-ascription that is not, as an intentional relation to the environment, reducible to neuronal processes. 

Depression results from a perceived loss of meaning and social resonance, not from a lack of serotonin.

Moreover, it is not the objective features of the situation, but their subjective evaluation as insurmountable, which is decisive for the depressive reaction.

As a result, biographically acquired dispositions such as lack of self-worth or self-efficacy become highly influential factors in pathogenesis. (…)

Initially, this corresponds to the organism’s functional short-term reaction of fear and readiness (“fight-or-flight response”).

However, under the conditions of a perceived impasse and feelings of helplessness, it leads to massive dysfunctions of the organismic functional cycles. 

The activation of the corticotropin-releasing hormone– adrenocorticotropic hormone–cortisol and sympathicus system

as well as the disturbed serotonin-transmitter regulation in the limbic system places the organism in a permanent state of stress,

corresponding to the aforementioned experience of bodily depletion and constriction.

The self-perception of this altered organismic state, as a negative feedback loop, intensifies the physiological symptoms of stress.

As a result, the initially functional organismic reaction is decoupled from its integration in superordinate feedback cycles and eludes the person’s control.

Negative horizontal feedback loops connecting to the social environment then influence the further course as described earlier.

The desynchronization of biological rhythms (hormonal, sleep cycles, etc.) and the desynchronization from the social environment mutually reinforce each other.

Social desynchronization may also be a decisive cause for the incidence of depression on the macro-level.

The typical triggering situations are mostly characterized by a disruption or at least a serious endangerment of relations and bonds:

a loss of relevant others (bereavement, divorce, or marital crisis) or of important social roles (loss of a job, moving to another city),

furthermore experiences of backlog or defeat, poverty, social exclusion, or isolation resulting in a desynchronization from others.

Such situations, under the condition of an individual vulnerability, are perceived as threatening and unsolvable by the patients: they do not feel equal to the pace of changes or are unable to cope with losses.