Neuroscience Lecture Review

Class Overview

• Basic Announcements

  • Professor welcomes students.

  • Reminder about Lab Two scheduled for this week, significant for preparation for the SafeMeds assessment.

  • Test One is scheduled for next Monday during normal lecture time; details available on Nuku.

Transition to New Instructor

• Chris Maimon is not present.

• Dr. David Carmel is now teaching; he is a senior lecturer in the School of Psychology, part of the CBNS program.

• Dr. Carmel’s research focuses on consciousness, the relationship between brain function and awareness, perception, and attention.

• Students are encouraged to engage with Dr. Carmel throughout the week.

Important Demonstrations

• Students handed notes with a cross and a circle for a demonstration regarding the blind spot in human vision.

  • Demonstration Instructions:

  • Close left eye with left hand, hold note with right hand (cross on left, circle on right).

  • Look at the cross and slowly bring the note closer.

  • At a certain distance, the circle should disappear, demonstrating a blind spot in vision.

  • Students instructed to notice that the area where the circle disappears appears as a blank white space, not a gap.

  • The demonstration illustrates brain processing and integration of visual information despite gaps in sensory input.

Explanation of the Blind Spot

• Why the blind spot exists:

  • The optical nerve leaves the eyeball at a specific point where there are no photoreceptors, creating a blind spot.

  • Despite knowing about the blind spot, individuals often do not perceive it due to the brain's capability of filling in visual information.

Neural Activity and Networks

• Focus on how neurons communicate and perform functions.

  • Recap of neuron functionality from previous modules.

  • Discussion of action potentials, synaptic transmission, and networks:

  • Neurons communicate via action potentials and neurotransmitters.

  • On average, each neuron forms about 10,000 synapses with other neurons.

Neural Communication Process

• How neurons fire:

  • Neurons experience spatial summation: integrated inputs can depolarize the neuron and trigger action potentials if it exceeds a certain threshold.

  • Action potentials are an all-or-nothing response, resulting in neurotransmitter release at the synapse.

  • Chemical transmission occurs in the synapse, highlighting the electrochemical nature of brain function.

Real-world Example of Neuronal Function

• Overview of John O’Keefe's discovery of place cells and the relevance of grid cells.

  • Place Cells: specific neurons that fire when an animal is at a particular location.
    - Grid Cells: provide a coordinate system for spatial navigation.

  • Ethical considerations in animal research explained in the context of neuronal studies.

Video Demonstration

• Video showcasing a rat walking, highlighting neuronal firing corresponding to its location within its environment.

  • Visual and auditory feedback demonstrates the function of place and grid cells.

Summary of Synaptic Transmission

• Types of inputs to a postsynaptic cell: excitatory inputs (EPSP) and inhibitory inputs (IPSP).

  • Combined activity can lead to action potentials based on the individual neuron’s excitatory/inhibitory inputs.

Knee Jerk Reflex Example

• Explanation of the patellar reflex as a simple example of neural circuits.

  • Involves a sensory neuron, interneurons, and motor neurons, demonstrating the complexity of even basic reflexes.

• Mechanism of Reflex Reaction:

  • Reflex does not involve the brain directly. Inputs from the stretch of the tendon activate sensory neurons leading to muscle contraction without conscious thought.

Introduction to Neural Computation Theory

• Overview of how neurons can perform logical operations through interconnected networks.

  • Simple models demonstrating logical operations such as AND, OR, and NOT operations in neural circuit modeling.

  • Activation Thresholds for output neurons defined to determine firing conditions based on inputs.

  • Example circuits to illustrate how networks can be designed to perform simple logic tasks.

Future Topics

• Advanced discussions will continue on Wednesday covering further aspects of neural networks and computations in cognitive functions.

• Students encouraged to ask questions regarding today's content before the next lecture.