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 into four general classes. (a) Scalp electrodes are used to record brain wave activity (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.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 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

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 transfer influenced by: Excitement Rehearsal Association of old and new data Long-term memory (LTM) Data permanently lost Afferent inputs Retrieval Forget Data selected for transfer Automatic memory Data unretrievable Temporary storage (buffer) in cerebral cortex Short-term memory (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?