Higher Mental Functions

Higher Mental Functions

The brain exhibits electrical activity, which is associated with higher mental functions.

Brain Wave Patterns and the EEG

An electroencephalogram or EEG records brain activity. The patterns, known as brain waves, are like finger prints and are associated with various activities.

Copyright © 2010 Pearson Education, Inc.

Electroencephalography and brain waves.

Alpha waves—awake but relaxed

Beta waves—awake, alert

Theta waves—common in children

Delta waves—deep sleep

(b) Brain waves shown in EEGs fall intofour general classes.

(a) Scalp electrodes are used to record brain waveactivity (EEG).

1-second interval

Brain Wave Patterns and the EEG

This are expressed as a frequency and is measured in hertz (Hz). 1 Hz corresponds to one peak per second.

EEG’s can be used to study brain activity.

Consciousness

This is defined on a series of graded behavior that includes:– Alertness– Drowsiness– Stupor– Coma

To be conscious the following criteria must be met:– Large areas of the cerebral cortex must be

involved.– Other types of neural activity are included, such as

motor control.– It is interconnected. Information is retrieved and

process from various memories.

Sleep and Sleep Wake Cycles

Sleep and Sleep Wake Cycles

Sleep is defined as a state of partial unconsciousness from which a person can be aroused by stimulation. This distinguishes it from a coma.

Sleep and Sleep Wake Cycles

Two types of sleep are seen during the normal sleep cycle. They are associated with eye motion. They are: – non-rapid eye movement (NREM) – rapid eye movement (REM).

Why Sleep?

Absence of sleep results in depression with some personality changes and difficultly in concentrating. Adults typically require 7 to 8 hours a night. What about you?

Sleep

Can lack of sleep kill you?

Memory

Memory

Although memory is the storage and retrieval of information, there appears to be no one area of the brain which carries out this function

Memory

Memory appears to occur in two phases, short term and long term memory.

Short Term Memory (STM)

STM is also known as working memory. The amount of information that can be stored for any one event is limited.

Short Term Memory (STM)

The amount of information that can be stored for any one event is limited. For example, one can remember a telephone number but would not be able to remember an entire phone book page.What is life like without a short term memory?

Long Term Memory (LTM)

Long term memory is not limited. An entire page of a phone book would be stored here. Information can be forgotten.

Memorization vs Learning

Copyright © 2010 Pearson Education, Inc.

Outside stimuli

General and special sensory receptors

Data transferinfluenced by:

ExcitementRehearsalAssociation ofold and new data

Long-termmemory(LTM)

Data permanentlylost

Afferent inputs

Retrieval

Forget

Forget

Data selectedfor transfer

Automaticmemory

Data unretrievable

Temporary storage(buffer) in cerebral cortex

Short-termmemory (STM)

Information transfer from the STM to the LTM can be affected by the following factors:– Emotional state: increase awareness– Rehearsal or repetition of material (STUDYING!)– Association: relating new with old – Automatic memory: Subconscious memory

Declarative memory involves learning facts or explicit information such as the muscles of the leg.

Non declarative (Procedural) memory involves less conscious learning such as a skill, playing the piano (procedural), riding a bike (motor) or emotional memory. These usually are not forgotten

Memory storage appears to be associated with the area that needs them.

The hippocampus is central in declarative memory while non declarative memory by passes this structure

Molecular Basis of Memory

Studies in animals reveal that learning involves the following changes in the brains:– An increase in neuronal mRNA – The dendrites change shape– Unique extracellular proteins form in the

synapses– Pre synaptic terminals may increase– More neurotransmitter is released

So how does your memory work?