Final cog neuro part 2

fingertips/lips have more

cortical neurons that the lower back, higher receptor density

back/limbs

have large receptive fields, low receptor density, fewer cortical neurons

red arrow

excited

yellow

inhibited

Yellow blue cell

excites yellow

Patient DF and the ventral/dorsal pathway

She could not verbally describe the width, nor could she mimic the block's width with her fingers. Her damaged ventral "what" pathway meant she had zero conscious perception of the object's physical form

neurotransmitter for activating muscles is

ACh— bridges the NS and skeletal muscle system

double dissociation

• Patient Group 1: Shows impairment on Task A but performs normally on Task B.

• Patient Group 2: Shows normal performance on Task A but is impaired on Task B.

single dissociaton

Patient 1 has damage to Structure X. When tested, they fail miserably at Task A, but perform flawlessly on Task B

superior colliculus

visual processing , coordinate reflexive saccades— snapping your eyes and head toward a sudden movement

inferior colliculus

auditory processing, every sound picked up travels to auditory nerve

PGN (perigeniculate nucleus)

actively suffocates background noise early on at the level of the thalamus, before the images even reach your conscious visual cortex

The battle between the superior colliculus and frontal eye fields in anti-saccade task

• The Superior Colliculus (SC): Drives the bottom-up, reflexive pro-saccade toward the stimulus.

• The Frontal Eye Fields (FEF): Drives the top-down executive inhibition of the SC reflex and coordinates the anti-saccade away from the stimulus.

Receptive fields in the ventral stream and how their size changes as one goes from poster to anterior

This expansion allows the brain to transition from processing raw pixels and lines to building complex, position-invariant representations of whole objects and faces.

high convergence

adds signals together to maximize sensitivity to dim light but destroys acuity

low convergence

isolates signals to maximize acuity (spatial resolution) but makes the system blind in dim light (low sensitivity)

specificity coding

specialized neuron that responds only to one stimulus

sparce coding

occurs when a particular stimulus is represented by a pattern of firing of only a small group of neurons

center surround antagonism in edge enhancement

an increase in perceived contrast at borders between regions of the visual field 

direct pathway of basal ganglia

facilitate wanted movement, “go” signal, bypasses intermediate structures and plugs straight from the striatum into the GPi

indirect pathway in the basal ganglia

suppress unwanted movements

cones

high acuity, low sensitivity, require bright daylight to activate all

rods

high sensitivity, low acuity, operate in dim environments

supplementary motor area

internal plans, memory-driven motor scripts

premotor area

external plans, sensory driven reactive movements, object directed grasping

CA3 (place cells)

pattern completion, process of retrieving a complete memory, allows the brain to "fill in the blanks"—such as remembering a full experience from a single sensory input

CA1

creates a “compressed” retrieval cue, most studied area (easier to access)

grid cells

involved with pathfinding, form a map of the local environment

declarative memory

episodic knowledge; what did you have for dinner last night?

semantic memory

facts, what a dog is

echoic memory

auditory, smaller capacity but longer duration

iconic memory

massive capacity but short duratioin

ACC

Weighs reward value against the cost/effort of the action.

Function of amygdala

emotional processing, with a specialized focus on threat detection, fear conditioning, and social-emotional evaluation.

broca’s aphasia

deficit of language production (expression)

wernicke’s aphasia

deficit of language comprehension (meaning)

Coding of action rules in frontal cortex (anterior-posterior gradient)

• Posterior (Back): Controls how to physically move (muscles, vectors).

• Middle: Controls when to move based on environmental conditions (sensorimotor mapping).

• Anterior (Front): Controls why you are moving relative to long-term goals and broad behavioral rules.

Anosognosia in sensory neglect

brain doesn’t process the left side of space and has no internal record that the left side ever existed

Anosognosia in Wernicke’s aphasia

language monitoring center is dead, so brain cannot hear that its own speech is word salad

encapuslation

It keeps sensory processing fast, mandatory, and insulated from cognitive biases during critical, split-second moments.

memory consolidaton

transfer of memory control from (hippocampus) to a permanent structural network (cortex).