behaviorally relevant information. Attention The suggested mechanism is that gamma waves relate to neural consciousness via the mechanism for conscious attention: Thus the claim is that when all these neuronal clusters oscillate together during these transient periods of synchronized firing, they help bring up memories and associations from the visual percept to other notions. This brings a distributed matrix of cognitive processes together to generate a coherent, concerted cognitive act, such as perception. This has led to theories that gamma waves are associated with solving the binding problem. Gamma waves are observed as neural synchrony from visual cues in both conscious and subliminal stimuli. This research also sheds light on how neural synchrony may explain stochastic resonance in the nervous system. Clinical relevance Mood disorders Altered gamma wave activity is associated with mood disorders such as major depression or bipolar disorder and may be a potential biomarker to differentiate between unipolar and bipolar disorders. For example, human subjects with high depression scores exhibit differential gamma signaling when performing emotional, spatial, or arithmetic tasks. Increased gamma signaling is also observed in brain regions that participate in the default mode network, which is normally suppressed during tasks requiring significant attention. Rodent models of depression-like behaviors also exhibit deficient gamma rhythms. Schizophrenia Decreased gamma-wave activity is observed in schizophrenia. Specifically, the amplitude of gamma oscillations is reduced, as is the synchrony of different brain regions involved in tasks such as visual oddball and Gestalt perception. People with schizophrenia perform worse on these behavioral tasks, which relate to perception and continuous recognition memory. The neurobiological basis of gamma dysfunction in schizophrenia is thought to lie with GABAergic interneurons involved in known brain wave rhythm-generating networks. Antipsychotic treatment, which diminishes some behavioral symptoms of schizophrenia, does not restore gamma synchrony to normal levels. Epilepsy Gamma oscillations are observed in the majority of seizures and may contribute to their onset in epilepsy. Visual stimuli such as large, high-contrast gratings that are known to trigger seizures in photosensitive epilepsy also drive gamma oscillations in visual cortex. During a focal seizure event, maximal gamma rhythm synchrony of interneurons is always observed in the seizure onset zone, and synchrony propagates from the onset zone over the whole epileptogenic zone. Alzheimer's disease Enhanced gamma band power and lagged gamma responses have been observed in patients with Alzheimer's disease (AD). Interestingly, the tg APP-PS1 mouse model of AD exhibits decreased gamma