Major Topics Flashcards
(62 cards)
Primary Somatosensory Cortex
The primary somatosensory cortex (S1) is the part of the brain responsible for processing touch, temperature, pain, and body position (proprioception).
Found in the postcentral gyrus of the parietal lobe (right behind the central sulcus).
Retinogeniculostriate Pathway
The Retinogeniculostriate Pathway is the main visual pathway responsible for conscious vision, allowing us to see details, colors, and recognize objects.
👁 Retina → 👁🗨 Optic Nerve → 🔄 Optic Chiasm → 🎯 Lateral Geniculate Nucleus (LGN) in the Thalamus → 🧠 Primary Visual Cortex (V1) in the Occipital Lobe
Function:
✔ Processes sharp, detailed, and color vision
✔ Helps recognize shapes, faces, and objects
✔ Sends visual information to other brain areas for interpretation and action
Tecto-Pulvinar System
The Tecto-Pulvinar System is a secondary visual pathway that processes motion, spatial awareness, and reflexive eye movements, even without conscious vision.
Pathway Flow:
👁 Retina → 🏹 Superior Colliculus (Midbrain) → 🔄 Pulvinar Nucleus (Thalamus) → 🧠 Other Visual Areas (Extrastriate Cortex)
Function:
✔ Detects motion and sudden visual changes
✔ Controls eye and head movements to track objects
✔ Helps navigate surroundings, even without conscious vision (blindsight)
Scotoma
A scotoma is a blind spot or partial loss of vision in a specific area of the visual field due to damage in the visual system.
Cortical Blindness
Cortical blindness is complete or partial loss of vision caused by damage to the primary visual cortex (V1) in the occipital lobe, despite healthy eyes and optic nerves.
Causes:
-Stroke affecting the occipital lobe
-Traumatic brain injury (TBI)
-Hypoxia (lack of oxygen to the brain)
-Infections or tumors
Blindsight
Blindsight is the ability to respond to visual stimuli without consciously perceiving them, usually due to damage in the primary visual cortex (V1).
Cause:
-Damage to V1 in the occipital lobe (e.g., stroke, brain injury)
-The Tecto-Pulvinar System (secondary visual pathway) remains intact, allowing unconscious visual processing.
Key Features:
-Patients cannot consciously see objects but can still detect movement, light, or location
-Can avoid obstacles or guess object positions better than chance
-Involves the superior colliculus and extrastriate visual areas
Rods and Cones
Rods and cones are light-sensitive photoreceptor cells in the retina that help us see.
Rods 🌙
-Sensitive to low light (night vision)
-Detect black, white, and shades of gray
-More numerous (≈120 million per eye)
Cones 🌞
-Work in bright light (day vision)
-Detect color (red, green, blue types)
-Provide sharp, detailed vision
V1 Cortex Organization
Retinotopic Mapping 🗺️
-The layout of V1 mirrors the visual field like a map.
Ocular Dominance Columns 👀
-Neurons are grouped based on input from the left or right eye.
Orientation Columns 📐
-Cells respond to specific edge orientations
Color Blobs🎨
-Specialized areas process color information.
Key Functions:
Processes basic visual features (edges, colors, motion).
Sends information to higher visual areas (V2, V3, etc.) for complex processing.
Visual Receptor Field Hierarchy
Photoreceptors - Spots- Location
Ganglion Cells - Center-Surround- Location
LGN cells - Center-Surround-Location
V1 cortex - bars - Location/ Orientation Movement Edges
Visual Cortex beyond V1 - complex features
Inferotemporal Cortex - complex stimuli/ensemble coding
Serial vs. Parallel Processing
Serial and parallel processing describe different ways the brain processes visual information.
Serial Processing 🛠️:
- Early visual processing in the V1 cortex, where simple features (edges, orientations) are processed one after another.
-Ensures focused, step-by-step analysis of specific visual details.
Parallel Processing ⚡
-Ventral and Dorsal at the same time
-Different visual features (color, motion, shape) are processed in parallel and then integrated.
Akinetopsia
Akinetopsia is the inability to perceive motion despite having normal vision for stationary objects. People see disjointed snapshots of motion.
Damage to the MT/V5 region
Achromatopsia
Achromatopsia is a rare condition in which a person cannot perceive color, seeing the world only in shades of gray.
Damage to the V4 area in the brain (part of the visual cortex).
Flash-Lag Illusion
The flash-lag illusion is a visual phenomenon where a stationary flash of light appears to be behind a moving object, even though both stimuli occur at the same time.
The brain processes motion and stationary stimuli differently. The motion of the object is integrated over time, while the flash is processed as a discrete event.
Motion processing requires more time, which results in the flash appearing behind the moving object.
Letter Color Synesthesia
A form of synesthesia where individuals perceive letters or numbers as being inherently associated with specific colors. For example, the letter “A” might appear red, “B” could be blue, and so on. This experience is automatic and consistent for each person.
Face Pareidolia
the tendency to see faces in random objects or patterns.
Prosopagnosia
A neurological disorder where individuals have difficulty recognizing faces, despite having normal vision and intelligence.
Damage to the fusiform face area (FFA) in the brain, which is involved in face recognition.
Super-Recognizers
Individuals with an exceptional ability to recognize faces. They have extraordinary face memory, enabling them to identify and remember faces more accurately and consistently than the average person.
The ability is often innate and may be linked to differences in the fusiform face area (FFA) of the brain, which is involved in facial processing.
Fusiform Face Area
A specialized region in the temporal lobe of the brain that is primarily involved in face recognition. It helps us process and distinguish individual faces from one another.
Located in the fusiform gyrus, which is part of the ventral temporal cortex.
Capgras Disorder
A delusional disorder in which a person believes that someone close to them, such as a spouse or family member, has been replaced by an imposter or a look-alike.
Damage to the fusiform face area (FFA) and emotional response.
Apperceptive Agnosia
A type of visual agnosia where individuals have difficulty perceiving the structure of objects.
Associate Agnosia
A visual perception disorder in which a person can perceive objects (i.e., they can see the object and describe its features) but cannot recognize or assign meaning to them.
Visual Object Agnosia
A condition where an individual has difficulty recognizing objects despite having normal vision and the ability to describe their features.
Pure Alexia
A type of reading disorder where an individual has difficulty reading despite having normal vision and the ability to write. This condition occurs due to damage in the brain areas responsible for word recognition and reading processing.
Primary Progressive Aphasia
A neurodegenerative disorder that affects language abilities over time. It is characterized by a gradual loss of the ability to speak, understand language, read, or write, while other cognitive functions (like memory and reasoning) remain relatively intact in the early stages.
