Conceptional Neuroscience exam 1

What is Cognitive Neuroscience

Cognitive Neuroscience studies how brain structure and function produce mental processes and behavior

What is Neuroscience

the study of the nervous system and processes

What is cognitive psychology

the study of mental functions

What is the difference between cognitive psychology and neuroscience

Cognitive psych focuses on mental processes, not the brain itself while neuroscience focuses on the nervous system and the brain

What is dualism

Proposed by Rene Descartes - the mind is non-physical and the brain/body is physical. They are separate but interact

What is the major type of evidence that challenged Dualism

brain lesion studies

What is localization

Proposed by Gall, the brain is an organ of the mind and each function is localized in specific regions - the idea of phrenology

What is phrenology

the shape of the skull reflects the size of underlying brain regions, and those regions correspond to specific personality traits and cognitive abilities

What is the aggregate field theory

Proposed by Flourens - the brain works together as a whole and higher cognitive functions are distributed across the brain

What evidence strongly supported localization of language in the brain

Broca and Wernicke brain lesion studies

What is the modern view of the mind vs brain debate

mind is a product of brain activity. They are not separate and this was proven by brain lesion studies. There are networks of specialized regions

Explain Brocas area

when it is damaged there is no speech production but the ability to comprehend speech is intact

What actions would have been the most diffuicult for “Tan” after his stroke

reading out loud

Explain wernickes area

Damage to it causes fluent speech but no ability to comprehend it

Explain Golgi’s belief regarding neurons

His black staining technique caused him to believe that the brain is one continuous network - syncytium

Explain neuron doctrine

proposed by cajal - it states that the nervous system is composed of individual neurons that are the basic structure and functional units of the brain

What direction does electrical transmission flow

Dendrites - soma - axon - terminals

Why was the idea of synapse important

it supported neuron doctrine by showing that neurons are separate cells that communicate across gaps

What is behaviorism and why did it reject studying the mind

behaviorism was a psychological approach that focused only on observable behavior and rejected the study of internal mental processes because they could not be directly measured

Explain how behaviorism led to the cognitive revolution

Behaviorism could not explain processes like memory and language because they require internal representation not just response to stimulus

Cytoarchitectonic maps by Broadmann distinguished different cortical regions by what

their structure at a cellular level

The observation that lesions on the left side of the brain will more likely result in speech problems than lesions on the right side of the brain best supports what

Brain localization

A researcher observes that lesioning Region A impairs syntax but not articulation, while
lesioning Region B impairs articulation but not syntax. What is the strongest conclusion

Syntax and articulation rely on partially separable neural systems

Which finding would most strongly challenge strict localization of function?

Broca’s area activates during both speech production and working memory tasks

Which observation most directly supports the neuron doctrine

Synaptic delay between cells

What are neurons

signal units that send and receive information

What are glial cells

cells that support and insulate neurons

Name the common types of glial cells

Astrocyctes -- blood/brain barrier
Oligodendrocytes - Myelin in CNS
Schwann cells - Myelin in PNS
Microglia - clean up damage

Explain neuron structure

soma - keeps cells alive through metabolic activity
dendrites - receive signals
axons - deliver signals

explain the relationship between pre and post synaptic neurons

Presynaptic - sends
postsynaptic - receives

Explain membrane potential

Membrane potential is the electrical voltage difference between the inside and outside of a neuron, created by unequal distribution of ions across the cell membrane. It exists because the membrane is selectively permeable (mainly to K⁺) and because ion pumps (especially the Na⁺/K⁺ pump) maintain different concentrations of Na⁺ and K⁺ inside vs. outside the cell. At rest, this produces a typical resting membrane potential of about –70 mV, with the inside of the neuron being more negative than the outside. An electrical gradient is created. Voltage gated ion channels react to change in electrical gradient which initiates action portential

Where does axon potential start

the axon hillock due to the triggering due to high density of voltage gates ion channels

What are voltage gated ion channels

proteins in the neuron’s membrane that open or close in response to changes in membrane voltage

What are the two main ions in action potential

NA - outside and K - inside

explain depolarization

a stimulus pushes the membrane to the threshold of -55 mV. Voltage gated Na channels open FAST, membrane potential shoots up to 30 mV

Explain repolarization

Na channels inactivate and voltage gated k channels open slowly. k leaves the cell and membrane potential drops back to -70 mV

Explain hyper polarization

k channels stay open longer than needed. membrane dips down to -80 to -90 mV and the refractory period occurs

What is the refractory period

the time after an action potential when the neuron cannot fire another action potential

How does the action potential return to rest

K channels close and Na/K pump restores ion distribution

explain ion distribution for the inside

K - high
Na - low
Cl - low
ca - very low

explain ion distribution for outside

k - low
Na - high
cl - high
ca - high

What are ion channels

proteins that allow ion to move down

Explain the channels

leak channel - always open
voltage gated - opens with voltage change
ligand gated - opens when neurotransmitter binds
mechanical gated - opens with pressure

What are gates

moving parts of the channels

Explain the gates

Na channels have activation gates - open quickly and inactivation gate that closes slowly
K channels open slowly during depolarization

explain the pump

move ions against gradient using ATP. 3 Na out and 2 K in this maintains resting potential

Dendrites

receive signals

Soma

integrates signals

Axon

conducts action potential long distances

myelin sheath

insulates actions and speeds up conduction

Nodes of ranvier

Gaps where action potential jumps - saltatory

Axon terminals

release neurotransmitters

Explain how neurons transmit information

Neurotransmitters bind to dendrite receptors which create graded potentials which are small and local changes. If enough occur the threshold is at axon hillock. the action potential fires and travels down the axon. when it reaches the terminal it opens the voltage gated ca channel and triggers neurotransmitter release. those neurotransmitters cross the synapse

Explain NA channels in the phases

Resting - closed
Threshold - opening
Depolarization - open
peak - inactivating
repolarization - inactivated
hyper polarization - closed
rest - closed

Explain K channels in the phases

Resting - leak open
threshold - closed
depolarization - closed
peak - opening
repolarization - open
hyper polarization - slowly closing
rest - closed

What is the all or none principle

action potentials are the same size and the strength of stimulus = frequency

Explain myelination

it speeds conduction and without it action potential loses power

Explain synaptic transmission

electrical signal becomes chemical. presynaptic neuron releases neurotransmitters and it crosses the synaptic cleft and binds to postsynaptic receptors

Front

Rostral

Back

Caudal

Top

Dorsal

Bottom

Ventral

Cut top to bottom

Sagittal

Horizontal cut

Axial

Vertical cut

Coronal

Brainstem

medulla - breathing
pons - eye movement
midbrain - sensory and motor processing

cerebellum

balance and smooth movement

Diencephalon

Thalamus - sensory gateway and LGN and MGN
Hypothalamus- hormones and homeostasis

Limbic system

Emotion

Basal ganglia

movement regulation

Cerebral cortex

Gray matter - cell body
White matter - axions and glia

Four lobes

Frontal - movement and cognitive control
Parietal - somatosensory and spatial
temporal - auditory/movement/language
occipital - vision

What is concentration gradient

number of ions found on opposite sides of the cell membrane

The prefrontal cortex is located where

the most anterior portion of the frontal lobe

What does the prefrontal cortex do

executive function

Axon transmission is

electrical

Neuronal transmission is

chemical

What is the primary visual cortex also known as

the Striate Cortex

Why does increasing extracellular potassium reduce the resting membrane potential magnitude

It reduces the concentration gradient for k efflux

What are mental representations

symbols that we have in our mind that are dynamic

Why is reaction time important

how much processing is required

What is serial processing

processing one by one and this leads to a linear increase in reaction time

What is parallel processing

brain processes multiple pieces at once

What is task inference

the brain cannot turn off some processes

Explain double dissociation

a method used to show that two cognitive functions rely on different brain systems typically used in lesion studies

How is pharmacology used

injection of a drug causes different behavior or cognitive outcomes

What is agonist

mimics neurotransmitters

What is antagonist

blocks neurotransmitters

What are the limits of pharmacology

because it affects the whole body and it is hard to pinpoint effects

What is the only invasive brain stimulation

deep brain stimulation when electrodes are planted in the brain

What are the non invasive brain stimulation methods

TMS, tDCS, tACS

explain TMS

magnetic pulses stimulate cortex and disrupt functions - both inhabitation in excitation

explain tDCS

weak electrical currents - escitibilty

explain tACS

alternating currents that target brain oscillations

What are the limits of non-invasive brain stimulation

Cannot reach deep structures, low spatial precision, and the results are inconsistent

Explain MRI

uses magnetic fields to visualize anatomy. hydrogen protons align in the magnetic field and radio pulses disturb the alignment. the scanner measures energy released when proton realign

What is DTI

measures the white matter tracts by tracking water movement. gray matter is random diffusion and white matter is directional

What is anisotropy

axons are covered by fatty myelin, myelin hinders water from moving through sides of axon

Explain fMRI

it does not measure brain activity instead it measures oxygen levels of blood. when an area is active the brain sends a surge of fresh oxygenated blood to the area and that it is the most active

What is BOLD and its relationship

blood oxygen level dependent - ratio between oxygenated and deoxygenated hemoglobin. if it is high it indicated that the brain region is active