Thalamocortical dysrhythmia is a neurological and neuropsychiatric syndrome characterized by magnetoencephalographic (MEG) activity. This study investigates the presence of low-frequency theta (4–8 Hz) rhythmicity and increased coherence between high- and low-frequency oscillations in patients with neurogenic pain, tinnitus, Parkinson's disease, and depression, compared to healthy controls. These findings suggest the presence of a thalamocortical dysrhythmia, which is proposed to be responsible for these conditions. The theta activity results from resonant interactions between the thalamus and cortex, driven by low-threshold calcium spike bursts in thalamic cells. These bursts are linked to thalamic cell hyperpolarization, caused by either excess inhibition or disfacilitation. The emergence of clinical symptoms is attributed to ectopic gamma-band activation, termed the "edge effect," which is observed as increased coherence between low- and high-frequency oscillations, likely due to inhibitory asymmetry in thalamocortical modules at the cortical level. The study used MEG recordings from nine healthy controls and nine patients with neurological or neuropsychiatric disorders. The results showed a shift from normal alpha rhythms to robust theta rhythmicity in patients, along with increased global power and coherence. These findings align with single-unit recordings from the thalamus in patients with similar conditions. The theta activity is associated with persistent low-frequency thalamocortical resonance during wakefulness and wide coherence across recorded channels. The edge effect, involving gamma-band activity, is proposed to generate clinical symptoms, as it leads to increased coherence and positive symptoms in patients. The study discusses the role of thalamocortical dynamics in generating these dysrhythmias, emphasizing the interaction between specific and nonspecific thalamocortical systems. The dysrhythmia is thought to arise from changes in intrinsic ionic conductances in thalamic relay cells, leading to hyperpolarization and low-frequency oscillations. These oscillations can entrain corticothalamic loops, increasing coherence and generating positive symptoms. The dysrhythmia is triggered bottom-up in conditions like tinnitus and Parkinson's disease, while top-down mechanisms may be involved in other conditions. The study also relates these findings to other imaging technologies, suggesting that MEG is well-suited for analyzing thalamocortical dysrhythmia due to its high temporal resolution and spatial accuracy. The results are supported by references to previous studies on the role of thalamocortical activity in brain functions and disorders.Thalamocortical dysrhythmia is a neurological and neuropsychiatric syndrome characterized by magnetoencephalographic (MEG) activity. This study investigates the presence of low-frequency theta (4–8 Hz) rhythmicity and increased coherence between high- and low-frequency oscillations in patients with neurogenic pain, tinnitus, Parkinson's disease, and depression, compared to healthy controls. These findings suggest the presence of a thalamocortical dysrhythmia, which is proposed to be responsible for these conditions. The theta activity results from resonant interactions between the thalamus and cortex, driven by low-threshold calcium spike bursts in thalamic cells. These bursts are linked to thalamic cell hyperpolarization, caused by either excess inhibition or disfacilitation. The emergence of clinical symptoms is attributed to ectopic gamma-band activation, termed the "edge effect," which is observed as increased coherence between low- and high-frequency oscillations, likely due to inhibitory asymmetry in thalamocortical modules at the cortical level. The study used MEG recordings from nine healthy controls and nine patients with neurological or neuropsychiatric disorders. The results showed a shift from normal alpha rhythms to robust theta rhythmicity in patients, along with increased global power and coherence. These findings align with single-unit recordings from the thalamus in patients with similar conditions. The theta activity is associated with persistent low-frequency thalamocortical resonance during wakefulness and wide coherence across recorded channels. The edge effect, involving gamma-band activity, is proposed to generate clinical symptoms, as it leads to increased coherence and positive symptoms in patients. The study discusses the role of thalamocortical dynamics in generating these dysrhythmias, emphasizing the interaction between specific and nonspecific thalamocortical systems. The dysrhythmia is thought to arise from changes in intrinsic ionic conductances in thalamic relay cells, leading to hyperpolarization and low-frequency oscillations. These oscillations can entrain corticothalamic loops, increasing coherence and generating positive symptoms. The dysrhythmia is triggered bottom-up in conditions like tinnitus and Parkinson's disease, while top-down mechanisms may be involved in other conditions. The study also relates these findings to other imaging technologies, suggesting that MEG is well-suited for analyzing thalamocortical dysrhythmia due to its high temporal resolution and spatial accuracy. The results are supported by references to previous studies on the role of thalamocortical activity in brain functions and disorders.