Core Concept of Cannon and Bard
The thalamic theory developed by researchers W. Cannon and P. Bard fundamentally shifted the focus of research into the nature of feelings. The main premise of their concept is that the genesis of emotions is inextricably linked to the functional activity of deep brain structures.
Instead of seeking the source of emotional experiences exclusively in the periphery of the body or the cerebral cortex, the authors proposed that subcortical nodes are the central link in emotional responding. According to this theory, it is there that the mechanisms we subjectively feel as joy, fear, or anger are triggered.
Clinical Evidence
Any physiological concept requires robust confirmation. For the thalamic theory, one of the most important pillars has been medical practice and patient observations.
Clinicians noted that when pathological lesions are localized directly within deep brain structures, patients exhibit pronounced emotional disturbances. These pathologies include:
- Intracerebral tumors compressing subcortical centers.
- Hemorrhages in the thalamic and hypothalamic regions.
The spectrum of resulting disorders proved extremely broad. Depending on the exact location and extent of the damage, patients displayed extreme states ranging from pathologically elevated, uncontrolled irritability to the total suppression of any emotional expression (apathy).
Experimental Data: W.R. Hess's Experiments
The second fundamental base of evidence was gathered by neurophysiologist W.R. Hess through animal experiments. His research allowed for real-time observation of subcortical center activity.
Research Methodology Hess used the method of chronically implanted electrodes in the brains of animals (cats). The electrodes were targeted precisely to structures of the thalamus and hypothalamus. This allowed specific nuclei to be stimulated with an electric current and the reactions of the free, conscious animal to be observed.
Results of Stimulation Deep brain stimulation caused a cascade of diverse behavioral patterns. Depending on the stimulation site, the cats clearly demonstrated the following reactions:
- Feeding (food-seeking, chewing).
- Aggressive (hissing, clawing, attacking).
- Defensive (attempts to escape, hiding).
- Sexual reactions.
Interestingly, all these reactions are closely intertwined in their genesis with the structures of the limbic system, which acts as the supreme regulator of autonomic and emotional functions.
The Phenomenon of "Sham Emotions"
A crucial term introduced by W.R. Hess based on his experiments is "Sham emotions" (sham emotions).
Observing cats during hypothalamic stimulation, the researcher witnessed fierce aggression or panic. However, after shutting off the current, the animal immediately calmed down as if nothing had happened. Hess designated these intense reactions as "sham" because an observer can only evaluate external, motor, and autonomic manifestations. At the same time, it is extremely difficult to reliably judge from the animal's behavior whether a real, deep subjective experience—characteristic of a true emotion—is actually taking place.