Neuroscience Concepts and History Quiz

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Questions and Answers

What is the main function of center/surround detectors in visual processing?

To process depth perception in three dimensions

To enhance color sensitivity in the visual cortex

To identify edges in the visual field (correct)

To regulate the speed of neuronal firing

In the context of synaptic learning through STDP, what happens to the synaptic strength when multiple presynaptic neurons fire together with the postsynaptic neuron?

Synaptic strength increases for those that fire together (correct)

Synaptic strength remains unchanged

Synaptic strength is affected only by the latest presynaptic neuron

Synaptic strength decreases for all presynaptic neurons

Which aspect is suggested to predict psychopathology according to recent findings?

Higher overall brain volume in adolescents

Increased neuron connectivity in the frontal lobe

Reduced thickness of the cortex in specific regions (correct)

Enhanced synaptic plasticity in the temporal lobe

What is the significance of STDP in neural processing?

It transforms weak detectors into fast, tuned detectors within synapses Signup and view all the answers

Which regions are more frequently associated with psychopathology based on the data presented?

Association regions implicated in emotional regulation Signup and view all the answers

What concept does Marr's framework explore regarding the brain?

The three levels of information processing Signup and view all the answers

What does a presynaptic spike do to a postsynaptic neuron?

Influences its voltage Signup and view all the answers

Which statement about Aristotle's view on the brain is accurate?

He argued that the heart was the primary organ for sensation. Signup and view all the answers

What role do synapses play in neuron communication?

They can adjust strength and can be inhibitory or excitatory. Signup and view all the answers

How can learning occur biologically in the brain?

Through the adjustment of synaptic weights and signs. Signup and view all the answers

What is the main function of retinal bipolar cells in the brain?

To build line segment detectors and manage visual signals. Signup and view all the answers

What happens to a neuron when recent excitatory inputs exceed recent inhibitory inputs?

It spikes, sending a signal down its axon. Signup and view all the answers

What does Spike Timing Dependent Plasticity (STDP) do when a presynaptic spike occurs before a postsynaptic spike?

Increases synaptic weight Signup and view all the answers

Which aspect of brain organization does Cajal's work highlight?

The complex network and interconnections of neurons. Signup and view all the answers

In the context of STDP, what does a postsynaptic spike indicate?

Something interesting has happened Signup and view all the answers

What characterizes unsupervised learning in relation to STDP?

Learning structure across inputs without specific targets Signup and view all the answers

What is required alongside unsupervised learning to program the brain for cognitive tasks?

Supervised learning Signup and view all the answers

What is the primary goal of supervised learning in the context of neural activity?

To wire up synapses to achieve a desirable output Signup and view all the answers

What is a characteristic of the orientation map in the visual cortex?

It reflects the organization of visual input Signup and view all the answers

What role does the hippocampus play in memory processing?

It tags events with temporal codes. Signup and view all the answers

What can be inferred about the relationship between STDP and cognitive tasks?

Cognitive tasks need both STDP and supervised learning. Signup and view all the answers

Study Notes

Marr’s Three Levels of Analysis

This level describes the goal and properties of a system
This level outlines the information that is manipulated, the format, and the rules used in the process
This level identifies the physical objects in the world that carry out the process

History of the Brain

The Egyptians recognized mental symptoms as coming from brain injuries in the 17th century BC
Aristotle argued that the heart was the center of sensation in the 4th century BC
- He believed that only some animals have brains, but all have hearts
- He argued that the heart is more centrally located and is affected by emotions
- He also claimed the brain was not sensitive to pain
Santiago Ramón y Cajal (late 1800s):
- The neuron is the basic unit of information processing in the brain
- Neurons communicate with each other through synapses

Neuron Communication

The voltage of a neuron can be influenced by other neurons that synapse to it
A spike is triggered when the voltage rises above a certain threshold
Spikes travel down the axon and influence other neurons
Synapses have weighted strengths, meaning that some presynaptic spikes have a greater influence than others
Synapses can be inhibitory, meaning that presynaptic spikes can suppress postsynaptic spikes
A neuron will spike only when recent excitatory inputs exceed recent inhibitory inputs

Receptive Fields

Retinal bipolar cells have a "center-surround" receptive field
- Light in the center increases the cell’s firing rate
- Light in the surround decreases the cell's firing rate

Building a Line Segment Detector

Receptive fields of neurons are organized to detect specific features, such as line segments

Learning in the Brain

The brain learns from experience by adjusting the weights and signs of synapses
Many learning rules have been proposed, and the answer may differ in different neurons

Spike Timing Dependent Plasticity (STDP)

When a presynaptic spike occurs just before a postsynaptic spike, synaptic strength increases
When a presynaptic spike occurs just after a postsynaptic spike, synaptic strength decreases
This is an example of unsupervised learning
STDP is related to detecting "interesting" patterns in inputs and/or across time
STDP is not related to goals or mistakes

Supervised Learning

Supervised learning involves telling the system what the desired output is for each set of inputs
The goal is to wire up synapses to achieve a desired output
This is done in connectionist models, but it is unclear how the brain does this

Brain Organization

Cortical regions are organized into maps
Orientation map in visual cortex:
- Different parts of the visual cortex respond to different orientations of lines
Retinotopic maps in visual cortex:
- Different parts of the visual cortex respond to different parts of the visual field
Hippocampus, object representation, motion processing, eye movement control, and first cortical region (V1) are all organized into networks
Brain regions work together to process different types of information

Measuring Brain Processes

Brain measurements can be used to study cognition
Brain measurements can go beyond behavior to reveal the underlying neural mechanisms
Measurements can reveal the synaptic strengths and learning mechanisms taking place within the brain

STDP Example

STDP can be used to create an “interesting” pattern from a set of inputs, like detecting when neurons 3, 4, and 5 fire together
This learning can be carried out right in the synapse

Cortical Thickness and Psychopathology

Reduced thickness of cortex is associated with psychopathology, especially in association regions

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Description

Test your knowledge on the key concepts in neuroscience, including Marr’s Three Levels of Analysis, the historical perspectives on the brain, and neuron communication. Explore how various thinkers over time have shaped our understanding of this complex organ and its functions.