Sensory coding
Sensory coding: how neurons represent various characteristics of the environment
Specificity coding is how the brain uses specific neurons to respond to specific stimuli, like one neuron for recognizing a face or a particular object.
The grandmother cell hypothesis is a theory suggesting that individual neurons are highly specialized and respond to very specific stimuli, such as a single neuron firing only when you see your grandmother's face. Just thinking about her could make it fire.
Sparse coding is a way the brain represents information using only a small number of active neurons at a time. Instead of all neurons firing, only a few fire for a specific stimulus, making it efficient and precise.
Population coding: is when the brain represents information using patterns of activity across a large group of neurons. Instead of relying on a single neuron, many neurons work together, with each contributing a part of the overall "message." This allows for more complex and accurate processing of stimuli.
Representation in the brain
Distributed representation in pain processing means that multiple brain regions and neurons work together to interpret and respond to pain. Different neurons encode aspects like the location, intensity, and emotional impact of the pain.
Example:
If you stub your toe:
Somatosensory cortex processes where it hurts.
Anterior cingulate cortex handles emotional distress.
Insula interprets the unpleasantness.
The combined activity across these areas gives you the full experience of pain.
Connections between brain area →
Structural Connectivity: Refers to the physical connections between brain regions, such as axons and synapses, forming the "wiring" of the brain.
Functional Connectivity: Refers to how brain regions communicate and work together, based on patterns of activity, even if they're not directly connected.
Broca's Area:
Location: In the left frontal lobe, typically in the posterior part of the frontal gyrus.
Function: Responsible for speech production and the ability to form grammatically correct sentences.
Damage: Causes Broca's aphasia, where speech is slow and labored but comprehension remains mostly intact.
Wernicke's Area:
Location: In the left temporal lobe, in the posterior part of the superior temporal gyrus.
Function: Responsible for speech comprehension and understanding language.
Damage: Causes Wernicke's aphasia, where speech is fluent but often nonsensical, and understanding of language is impaired.
Ommatidia: The individual, lens-like units of the compound eye, found in insects and some crustaceans, that each collect visual information from a small part of the visual field.
Purkinje Shift: The shift from cone-mediated color vision to rod-mediated vision as light decreases. This shift causes colors to appear differently under dim light, with blue appearing brighter than red.
Rod Monochromats: Individuals who have only rods in their retinas and lack functioning cones, resulting in color blindness and poor vision under bright light, but normal vision in low light.
Visual Evoked Potential (VEP): An electrical response recorded from the brain in response to visual stimuli, used to assess the function of the visual pathway.
Refractive Errors: Problems with the way the eye focuses light, leading to blurry vision, such as nearsightedness (myopia), farsightedness (hyperopia), and astigmatism.
Preferential Looking Technique: A method used in developmental psychology to assess visual preference in infants by measuring how long they look at different stimuli.
Rod-Cone Break: The point during dark adaptation when rod cells begin to take over vision from the cones, leading to a change in visual sensitivity.
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