Organization of the Nervous System II

From Cortical columns notes to the end of section

what is segregation?

information processed within one hemisphere —> specialization

what is integration?

information processed across hemispheres —> coordination

how do the left and right hemispheres differ in segregation and integration?

they have different balances of within vs. between hemisphere communication

Which hemisphere shows more segregation vs. integration?

Left hemisphere → more segregation; Right hemisphere → more integration.

How are hemispheric connectivity patterns related to different abilities?

Greater left-hemisphere segregation → better language performance; greater right-hemisphere integration → better visual-spatial performance.

What are cortical maps?

organized cortical representations of information from the body and environment

how is related information typically or organized in cortical maps?

neighboring or related information is represented by neighboring populations of neurons

what does this organization of neighboring information create?

topographic maps across cortical tissue

What types of information can be represented by cortical maps?

• Body/touch: pressure, temperature, pain, body position

• Visual world: shapes, colors, motion, spatial location

• Sound: pitch, loudness, timing, complex sounds, speech

what is somatotopy?

neighboring parts of the body are represented in an ordered arrangement in the cortex

how does sensitivity affect cortical representations in somatotopy?

more sensitive body regions receive more cortical territory

What is the cortical homunculus?

A map showing how different body parts are represented across the cortex.

Why are some body parts exaggerated in the cortical homunculus?

They receive more cortical territory because they require more detailed sensory or motor processing.

What is the difference between the somatosensory and motor homunculus?

Somatosensory maps body sensation; motor maps control of body movement.

What is retinotopy?

neighboring locations in the visual field are systemically represented in neighboring areas of the visual cortex

how much cortical space is devoted to the center of vision?

the center of vision receives disproportionately more cortical territory

what is tonotopy?

an ordered representation of sound frequencies in the auditory cortex

how are sound frequencies organzied in a tonotopic map?

nearby neurons tend to prefer nearby sound frequencies

How are low and high sound frequencies organized in the auditory system?

Low and high frequencies are represented in different, systematically ordered locations.

How is tonotopic organization related to the cochlea?

Different cochlear locations respond to different frequencies, and this organization is preserved in auditory cortex.

do neural signals usually travel through a simple input —> output pathway?

no, neural processing often involves feedback loops

what happens to information during cortical feedback loops?

information returns to regions that participated in earlier processing

what is the purpose of cortical feedback loops?

they allow processing to be continuously updated

What is an example of a feedback loop during visual processing?

V1 sends feedback to the LGN in the thalamus to influence incoming visual information.

How can feedback help the brain find a visual target?

It enhances information matching the target and suppresses non-matching information.

What is re-entry in neural processing?

Brain regions send information back and influence regions that previously provided input.

Does information only move forward during neural processing?

No. Brain regions can feed information back to earlier regions

what factors can shape processing through re-entry?

context, expectations , attention, and goals

How does re-entry work between two cortical areas?

One area sends information forward, and the receiving area sends feedback to influence the earlier area.

What is an example of re-entry during object recognition?

The orbitofrontal cortex makes a quick prediction and sends feedback to visual cortex to help recognize the object.

how can higher-level processing affect sensory information?

it influences how incoming sensory information is interpreted

what is an example of higher level processing influencing perception?

the brain makes a prediction about what an object is before fully processing it’s sensory details

What are hubs in the brain?

Highly connected regions that link otherwise specialized brain networks.

How do hubs respond to different task demands?

They change their connections to flexibly integrate information based on the current task.

What do frontoparietal hubs do?

They flexibly change which brain networks they communicate with depending on the task.

How do frontoparietal network (FPN) hubs help with new tasks?

They flexibly connect with task-relevant networks, allowing information or learned patterns to transfer between tasks.

in summary, How does behavior emerge from neural activity?

From distributed, interacting neural systems.

in summary, how is the nervous system organized hierarchically?

higher levels can modulate nd influence lower-level circuits

what 2 processes work together during neural processing?

integration & specialization

in summary, what are the 3 major ways the cortex is organized?

layers, columns, and topographic maps

why is neural processing considered recurrent?

loops, re-entry, and hubs allow continuous coordination and updating