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The fundamental function of this part of the ear is to gather sound energy and deliver it to the eardrum. Resonances of the external ear selectively boost sound pressure with frequency in the range 2–5 kHz. [2] The pinna as a result of its asymmetrical structure is able to provide further cues about the elevation from which the sound originated.
It considers the brain a dynamical system and uses differential equations to describe how neural activity evolves over time. In particular, it aims to relate dynamic patterns of brain activity to cognitive functions such as perception and memory. In very abstract form, neural oscillations can be analyzed analytically.
The brain consumes large amounts of energy but does not have a reservoir of stored energy substrates. Since higher processes in the brain occur almost constantly, cerebral blood flow is essential for the maintenance of neurons , astrocytes , and other cells of the brain.
Neuronal activity at the microscopic level has a stochastic character, with atomic collisions and agitation, that may be termed "noise." [4] While it isn't clear on what theoretical basis neuronal responses involved in perceptual processes can be segregated into a "neuronal noise" versus a "signal" component, and how such a proposed dichotomy could be corroborated empirically, a number of ...
The brain utilizes subtle differences in loudness, tone and timing between the two ears to allow us to localize sound sources. [10] Localization can be described in terms of three-dimensional position: the azimuth or horizontal angle, the zenith or vertical angle, and the distance (for static sounds) or velocity (for moving sounds). [ 11 ]
An fMRI device works by detecting changes in neural blood flow that is associated with brain activity. fMRI devices use a strong, static magnetic field to align nuclei of atoms within the brain. An additional magnetic field, often called the gradient field, is then applied to elevate the nuclei to a higher energy state. [5]
PET image of the human brain showing energy consumption. The brain consumes up to 20% of the energy used by the human body, more than any other organ. [131] In humans, blood glucose is the primary source of energy for most cells and is critical for normal function in a number of tissues, including the brain. [132]
Sound energy causes changes in the shape of these cells, which serves to amplify sound vibrations in a frequency specific manner. Lightly resting atop the longest cilia of the inner hair cells is the tectorial membrane , which moves back and forth with each cycle of sound, tilting the cilia, which is what elicits the hair cells' electrical ...