How Does the Brain Compute?. A nerve cell, or a neuron, consists of many different parts

How Does the Brain Compute?

How Does the Brain Compute?A nerve cell, or a neuron, consists of many A nerve cell, or a neuron, consists of many

different parts.different parts.

Sensory Neuron(Bipolar)

Interneuron Neuron (Unipolar)

Motor Neuron(Multipolar Neuron)

Types of Neurons

Types of NeuronsSensory Neurons – Afferent Neurons

• Carry the message from the sense organs to the CNS

Interneurons • Make up the CNS

Motor Neurons – Efferent Neurons• Carry the message from the CNS to the muscles or glands

How is the Electrical Signal Sent?

2 K+

3 Na+

ATP

Outside

Inside K+

The Resting Potential

K Na

Proteins (A) -

How is the Electrical Signal Sent?

All or none!

Outside

Inside

K Na

NaNaNaNa NaNa NaNaNaNa

KK

KK KK

KK Na

KK

How is Information Transmitted?

If neurons do not touch, how can information get from one neuron to the next neuron?

How is Information Transmitted?

How is Information Transmitted?

Recycling channel

• Neurotransmitters

• Postsynaptic Receptors

• Recycling Channels

1 2

How is Information Transmitted?• Reuptake

• Diffusion

• Enzymatic Degradation

How is Information Transmitted?• Reuptake

• Diffusion

• Enzymatic Degradation

How is Information Transmitted?• Reuptake

• Diffusion

• Enzymatic DegradationEnzyme

How is Information Transmitted?

(The Synapse) Neurotransmitters

Dendrite

Soma

Axon

Terminal

How is Information Transmitted?Neurotoxins!

How is Information Transmitted?

Nerve AgentsTabun (GA)Sarin (GB)Soman (GD)VX

1995 – Tokyo Subway (Sarin)2013 – Syria (Sarin)

2013 – Bihar, India (Organophosphate pesticides)

How is Information Transmitted?

Action Potential Synaptic Terminal

Neurotransmitters

Axon

Cell BodyDendrites

How Fast do Electrical Signals Travel?

100 mile/hr – 160 km/hr

Saltatory ConductionNode of RanvierMyelin

Axon

Increases speed of conduction!

vs

Unmyelinated vs Myelinated Axons