Last class…

1.Historical precursors/contributors2.‘Construction’ of a brain3.Comparative neuroanatomy4.Functional neuroanatomy

Outline for Today

1.Continue with functional neuroanatomy

2.The neuron3.How do neurons communicate?

Neocortex has 4 major lobes

Frontal lobe contains primary motor cortex (motor homunculus)--direct control of body’s muscles mapped onto the cortex

What else does the frontal cortex do?

Case study: Phineas Gage was a railroad construction foreman who was blasting rock near Cavendish, Vermont in 1848 when a thirteen-pound iron rod was shot through his brain.

The famous The famous case of case of Phineas Phineas GageGage

Prefrontal cortex:Executive function-Making judgments,Assessing social situations, monitoring behavior.

PARIETAL LOBE contains primary somatosensory cortex -your feeling of touch from various body areas are mapped onto this region

Einstein’s Einstein’s parietalparietallobes are bigger-lobes are bigger-does that account does that account for his for his intelligence?intelligence?

What else does the

parietal lobe do?

Primary Auditory Cortex is in Temporal Lobe

Fusiform Face RegionWhat else does the temporal lobe do?

Prosopagnosia“face blindness”

Learning, memory, emotionLearning, memory, emotion

What else does the temporal lobe do?

Amnesia; Alzheimer’s diseasePost-traumatic stress disorder

Filled with cerebrospinal fluid (CSF):1. Serves as shock absorber-(between skull and brain, too)2. Mediates between blood and brain in exchange of nutrients/waste

Ventricular System

Sagittal Coronal Horizontal

Normal pressure hydrocephalus (NPH)

When there is a blockage (dam) in the ventricular system (lake):

Basic Subdivisions

• Cerebral cortex (or neocortex); forebrain– 4 lobes: frontal; parietal; temporal; occipital– Hippocampus; amygdala; thalamus– Ventricles

• Brain stem– Midbrain; pons; medulla

• Cerebellum

Arousal, sleep, relay of sensory info

Respiration, heart rate, blood pressure

“Orienting” (processing of sound, vision)

Practice Exam Questions:

1.The French philosopher, Rene Descartes, proposed the radical idea that:

a)All animals have spiritsb)Brains are made of discrete cells called

neuronsc)Humans are no more intelligent than animalsd)Human action can be understood by using

scientific means

2. List two advantages to the very bumpy cerebral cortex we see in some species, like humans.

The soupThe soup

The wiresThe wires

&&

Neural communication involves both electrical and chemical signals.

1. Wires (electrical properties)

2. Soup (chemical properties)

““Wires and Soup”Wires and Soup”

Anatomy of a Neuron

Axon hillock

100-150 billion in human brain

Anatomy of a Neuron

Axon hillock

100-150 billion in human brain

Flow of information

Continuous web?!

Ramon y CajalCamillo Golgi

How do neurons communicate?

““a flash of a flash of lightning”?lightning”?

How do neurons communicate?

““a flash of a flash of lightning”?lightning”?

An electrical “flash” is part of the story

To get this “flash” you need to have someinitial charge.

Neurons at rest are charged.

What keeps them charged?

Electrical Properties of Electrical Properties of NeuronsNeurons

• Resting potential

• Graded potential

• Action potential

How did we learn about theelectrical properties ofneurons?

Squid Giant Axon

Hodgkin & Huxley

Resting potentialResting potential

microelectrodes Ø mV

Extracellular

Intracellular

axon

Resting potentialResting potential

-70microelectrodes mV

Extracellular

Intracellular

axon

Neurons at rest are in a state of dynamic equilibrium.

1. Factors at work to distribute ions equally across the cell membrane

2. Factors at work that prevent the ions from being equal

Given the chance the ions will redistribute.

Resting potentialResting potential

Extracellular

Intracellular

axon

Inside Outside

K+Na+

Cl-

O-

Cl-

Na+

K+

O-

Neuron at rest has this distribution of ions