Early Brain Mapping: Phrenology

Early Brain Mapping: Phrenology

• By studying the lumps on a person’s skull, early scientists thought that they could map out the brain.

• Not accurate • But did lead to the

idea of localization of brain functions.

Older/Lower Level Brain Structures

Primitive Parts of Brain• Like the oldest part of a tree is in the center

that is then surrounded by newer growth, the older parts of the brain that we share with other animals, are found at the central lower region of the brain.

The Brainstem

Hindbrain Structures

• Brainstem– medulla– reticular formation– pons

• Cerebellum

Medulla

• Breathing• Heart rate• Digestion• Other vital reflexes

–swallowing–coughing–vomiting–sneezing

Pons

• Helps coordinate movements on left and right sides of the body

• Sends motor info to Cerebellum– e.g., postural reflexes

which help you maintain balance while standing or moving

Thalamus• Sensory control center in

brain• Sends sensory info to parts of

the brain that can understand it

• Receives replies back from higher brain areas and sends them to lower level structures

• Like the Post Office taking incoming messages and delivering them

_______

Reticular Formation/Activating System

• Network of neurons in the brainstem (and thalamus)

• Sleep and arousal• Attention – filters

incoming sensory info

Cerebellum• Word actually means “little

brain”• Place where procedural

memories are kept. – e.g. how to ride a bike,

swim• Coordinated, rapid voluntary

movements– e.g., playing the piano,

kicking, throwing, etc.• Damage to cerebellum

– jerky, exaggerated movements

– difficulty walking– loss of balance

Midbrain Structures

Middle Region involved in visual & auditory

processing.

Early warning system gets you ready for flight

or fight

Forebrain Structures

• Thalamus• Limbic

System• Cortex

The Limbic System

• Emotional Center:– Hypothalamus– Amygdala– Hippocampus

Parts Of The Limbic System

Hippocampus• Helps us form new

memories.

• What happens when this is damaged? – Remember the video of

Clive Wearing & EP?

Parts of the Limbic SystemAmygdala• Fear:

• Aggression:

Amygdala and Emotion

• Helps us identify emotion from facial expressions

Amygdala damage makes this task difficult

(click on picture to advance photos)

Parts of the Limbic SystemHypothalamus• Link between the

Nervous System & Endocrine System.

• Provides us with pleasurable feelings for doing the things that keep our species alive.

Hypothalamus• Involved in the 5 F’s

– 1. Food/Thirst, – 2. Flight, – 3. Fight, – 4. Furnace (Temperature) – 5. Fornication

– sexual behavior– hunger, thirst– sleep– water and salt balance– body temperature regulation– circadian rhythms– role in hormone secretion

Hypothalamus – Pleasure Center of the Brain

• Rat with an electrode implanted in a reward center of its hypothalamus, See some actual footage of this.

• Rat readily crosses an electrified grid, accepting the painful shocks, to press a lever that sends electrical impulses to its "pleasure centers."

• How often did the rat press the lever in an hour?• 7,000 times!!! It finally collapsed from exhaustion (Olds

1958)

Hypothalamus and HormonesThe Feedback Loop

• Feedback Loop lets brain know when to start & stop secreting hormones

• Hypothalamus tells pituitary gland to send messages to other glands to release their hormones.

• Once hormones are released, hypothalamus registers this and sends message to pituitary gland to send continue or stop message out to glands.

DAILY

DOUBLE

What are the 5 F’s that the Hypothalamus influences?

1. Food/Thirst2. Flight3. Fight4. Furnace – Body temperature5. Fornication