Cortical gamma oscillations: the functional key is activation, not cognition

Area of Science:

• Neuroscience
• Cognitive Neuroscience
• Systems Neuroscience

Background:

• Cortical gamma oscillations are increasingly studied for their potential role in solving the brain's binding problem.
• Existing research often attributes specific cognitive functions to gamma synchrony.

Purpose of the Study:

• To critically review the basic neuroscience and cognitive aspects of gamma range oscillatory synchrony.
• To propose a "default assumption" that gamma oscillations signal physiological activation and the need for excitation-inhibition balance.

Main Methods:

• Critical review of existing literature on gamma oscillations in neuroscience and cognitive science.
• Examination of specific cases, including "binding by synchrony" experiments.
• Analogy drawn with regional control of cerebral blood flow.

Main Results:

• Gamma oscillations are proposed to be generic neural control operations, not implementing specific functions.
• They correlate with neural activation and cerebral blood flow control.
• Covariation with cognitive activity can be explained by neural activation, not specific cognitive roles.

Conclusions:

• There is no compelling evidence to assign functional roles to gamma oscillatory synchrony beyond infrastructural neural control.
• Gamma oscillations serve as a generic mechanism for regulating cortical tissue activation.
• Their primary function is to enable neural tissue to perform system-level functions through basic control operations.