Cortical Processing/Sensation vs Perception

sensation

• The registration of sensory stimuli by neural receptors

• The transmission of that stimulus in the nervous system

• The registraton of that stimulus in the cerebral cortex

perception

• The processing of sensory input by the cerebral cortex

• Typically involves stored information from the cortex, including previous experiences

perceptual constancy

See familiar objects as unchanging, even when aspects of the stimulus change, such as lighting or viewing angle

perceptual set

Tendency to perceive some stimuli but not others and to base expectations on past experience

unimodal

• parietal lobe

• temporal lobe

• frontal lobe

• occipital lobe

parietal lobe

• Most somesthetic sensaton (most sensory input from the body)

• Areas 5 and 7 (superior parietal lobule)

• Involved with processing of body image, body in space, organizing body in space for acton

temporal lobe

• Most auditory sensaton

• Transverse Temporal gyri

• Hippocampus

frontal lobe

Attention

occipital lobe

• Most visual sensation

• Medial is more registration

multimodal association cortex

These areas don’t just process one sense, they combine multiple senses together

• large amount of multimodal processing occurring around the posterior aspect of the lateral fissure

• inferior parietal lobule

• lateral temporal gyri

• lateral occiptal gyri

inferior parietal lobule

• Supramarginal gyrus is a somatosensory associaton area

• Angular is a visual associaton area; also called a reading center and plays a role in arithmetc functions

lateral temporal gyri

Helps with:

• sound meaning

• language comprehension

• object recognition

lateral occipital gyri

• Helps interpret what you are seeing

• Not just “seeing light”—but recognizing objects

neural networks

• Perception is not based on fixed, single neural pathways

• Instead, perception arises from distributed _

• A group of neurons is activated together in response to a stimulus

• Processing occurs through simultaneous network activity

• Involves system processing simultaneously of feedforward and feedback

  connections

• Perception is determined by the dynamic activity of the entire system

  • Not just the initial stimulus or input

synesthesia

defined as a perceptual phenomenon in which stimulation of one sensory pathway automatically activates another linked pathway

• most common is color and number or letter

right hemisphere

• Uniquely specialized for spatial processing

• Visualization

• Intuitive

• Conceptual

• Think about geometry and spatial match like calculus and inference

left hemisphere

• Specifically designed for temporal processing

• This includes sequencing

• Analytical and numerical think about sequential math like countng, algebra, solving equations

• For MOST people, both right (95%) and lefthanded (33%) it is the dominant hemisphere for language

unilateral disregard for neglect

• More commonly seen in Right hemisphere lesions

• Often associated with damage to superior parietal lobule

theory of perceptual processing

• Perception is interactive and dynamic

• Brain constantly interprets, predicts, and adjusts

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How it Works

1. Feedforward processing

• Sensory input travels upward

• Body → spinal cord → brain

➡ “What is coming in?”

2. Feedback processing

• Brain sends signals back down

• It modulates what we pay attention to

➡ “What should I focus on?”

3. Parallel processing

• Multiple systems work at the same time

• Vision, touch, memory, attention all integrate

astereognosis

inability to identify familiar objects by touch

adyselxia

• difficulty with reading, despite normal intelligence

• angular gyrus

agraphesthesia

cant identify numbers or letter traces on back of hands with eyes closed

prosopagnosia

• inability to recognize faces, including your own

• associated with damage to a part of occipitotemporal gyrus known as fusiform gyrus

apraxia

• inability to execute a motor command despite the motor ability to do so; it is a central processing disorder

• a synonym is motor planning disorder

• different types such as dressing and construction associated with damage to right angular gyrus

proprioception

sensation that arises from muscle, tendons, joints, etc. unconsciously

kinesthesia

conscious processing of proprioception input

aphasia

a language disorder caused by brain damage, usually from a stroke, that impairs speaking, understanding, reading, and writing, though intelligence typically remains intact

stereognosis

the ability to perceive and identify 3D objects through touch alone, without visual or auditory input