Integrative Functions of the Cerebrum

Integration

One of the functions of the cerebellum that process sensory information by analyzing and storing it and making decisions for various responses

Integration: Integrative Functions

The integrative functions include cerebral activities such as wakefulness and sleep, learning and memory, and language.

Circadian Rhythm

The body's natural 24-hour internal clock that regulates sleep, hormone release, body temperature, and other vital bodily functions, which is established by the suprachiasmatic nucleus of the hypothalamus

Reticular Activating System

A part of the reticular formation that increases activity throughout the cerebral cortex, directly and through the thalamus, helping the nervous system transition between sleep and wakefulness.

Arousal

A state of physiological and psychological alertness, wakefulness, and reactivity to stimuli that increases activity in the reticular activating system

Arousal: Pathway

The reticular activating system must be stimulated by sensory input, such as pain, touch, or pressure, to alert the cerebral cortex and promote arousal and wakefulness.

Arousal: Exception

Although somatic sensory receptors activates reticular activating system, olfactory nerve cells, even strong odors may fail to cause arousal.

Consciousness

The state of being awake, aware of one's surroundings, and experiencing an inner life of thoughts, feelings, and sensations

Sleep

A naturally recurring state of altered consciousness characterized by reduced physical activity, suspended sensory awareness, and relaxed muscle tone

Sleep Deprivation

A condition where an individual consistently receives insufficient sleep relative to their biological and physiological needs, which impairs attention, learning, and performance

Stages of Sleep

Normal sleep consists of two components: nonrapid eye movement (NREM) sleep and rapid eye movement (REM) sleep

NREM Sleep

Non-rapid eye movement (NREM) is divided into three stages that have characteristics of slowed heart rate, breathing, and brain activity for the transition to REM

NREM Sleep: Stage 1

Transitional phase between wakefulness and sleep, where the person is relaxed with eyes closed and has fleeting thoughts

NREM Sleep: Stage 2

The first stage of true sleep, when a person is easy to awaken, may experience brief dreams, and the eyes may slowly roll from side to side.

NREM Sleep: Stage 3

A period of moderately deep sleep, with heart rate, breathing, and blood pressure reaching their lowest levels, and this stage occurs about 20 minutes after falling asleep.

NREM Sleep: Stage 4

The deepest stage of sleep, when brain activity and body temperature decrease, reflexes remain mostly intact, muscle tone decreases slightly, and the person is very difficult to awaken.

NREM Sleep: Physiological Changes

During NREM sleep, heart rate, respiratory rate, blood pressure, and muscle tone decrease, allowing the body shift positions in bed; dreaming is less common and usually less vivid, emotional, and logical than REM dreams.

REM Sleep

The body goes under a critical, high-activity sleep stage characterized by rapid eye movements, vivid dreaming, increased heart rate, and temporary muscle paralysis

REM Sleep: Physiological Changes

During REM sleep, heart rate, breathing rate, and blood pressure increase, while most skeletal muscles become paralyzed because somatic motor neurons are inhibited, except for the muscles used for breathing and eye movement.

REM Sleep: Neural Activity

Brain imaging studies reveal increased activity in the visual association area and the limbic system (visual imagery and emotions), and decreased activity in the prefrontal cortex (reasoning), contributing to vivid, emotional, and less logical dreams.

Sleep Intervals

NREM and REM sleep alternate in about 90-minute cycles, with each cycle progressing through NREM stages and then REM; there are usually 4–5 cycles, with REM periods getting longer as the night progresses

Sleep Intervals: Age

As a person ages, the average total time spent sleeping decreases, and the percentage of REM sleep declines

NREM Sleep Centers

NREM sleep centers in the hypothalamus and basal forebrain induce NREM sleep

REM Sleep Centers

REM sleep centers in the pons and midbrain induce NREM sleep

Adenosine

A natural brain chemical that builds up during periods of high usage of ATP and creates your biological drive to sleep

Adenosine: Pathway

As adenosine builds up during wakefulness, it binds to inhibitory A1 receptors that suppress cholinergic neurons in the reticular activating system, reducing arousal and promoting sleep.

Stimulants

Caffeine in coffee and theophylline in tea are both naturally occurring stimulants that prevent adenosine from binding to A1 receptors to maintain wakefulness.

Sleep: Benefits

Sleep is widely believed to help the body repair itself, consolidate memories, strengthen immune function, and support brain maturation.

Sleep Deprivation: Dangers

Studies have shown that sleep deprivation impairs attention, memory, performance, and immunity— may even cause mood swings, hallucinations, and even death.

Coma

A deep, prolonged state of unconsciousness where a person cannot be awakened and fails to respond normally to light, sound, or pain

Coma: Causes

Causes of coma include head injuries, damages to the reticular activating system, brain infections, alcohol intoxication, and drug overdoses.

Coma: Persistent Vegetative State

A serious medical condition where a person in coma for a few weeks appears awake and breathes on their own, but shows no signs of awareness, thought, or interaction with the world

Coma: Persistent Vegetative State: Recall

Recall that those in a persistent vegetative state still have an active brain waveform activity, as such, they are not brain dead

Learning

The ability to acquire new information or skills through instruction or experience

Learning: Associative Learning

Associative learning involves the organism to make connections between events that occur together (e.g., classical conditioning in Ivan Pavlov's dog experiment)

Learning: Non-associative Learning

Non-associative learning involves repeated exposure to a single stimulus, which causes a change in behavior

Learning: Non-associative Learning: Habituation

A type of non-associative learning in which a repeated exposure to an irrelevant stimulus causes a decreased behavioral response

Learning: Non-associative Learning: Sensitization

A type of non-associative learning in which a repeated exposure to a harmful stimulus causes an increased behavioral response

Memory

The process by which information acquired through learning is stored and retrieved.

Memory: Declarative (Explicit) Memory

The conscious recall of facts, events, and personal experiences that can be intentionally remembered and verbalized, and is stored in the association areas of the cerebral cortex.

Memory: Procedural (Implicit) Memory

The unconscious memory that guides the motor and cognitive skills without requiring conscious awareness, and is stored in the corpus striatum, cerebellum, and premotor area.

Short-term Memory

A temporary stage of memory that holds information for 15 to 30 seconds, but that memory can be remembered longer by actively engaging with it.

Long-term Memory

A continuous stage of memory that stores information, images, ideas, and experiences for periods ranging from days to years.

Short-Term Memory: Electrical and Chemical Activity

Short-term memory appears to depend mainly on temporary electrical and chemical activity in the brain rather than permanent structural changes at synapses.

Short-Term Memory: Long-Term Memory Difference

Conditions that disrupt brain electrical activity can impair short-term memories without disrupting previously established long-term memories, such as anesthesia, coma, and electroconvulsive therapy (ECT)

Short-Term Memory: Existing Synapses

Short-term memory may involve a temporary increase in activity at preexisting synapses rather than the formation of new synaptic structures, especially reverberating circuits

Memory Consolidation

The process of transforming short-term memories into long-term memories, with the hippocampus temporarily storing new declarative memories before transferring them to the cerebral cortex for permanent storage.

Plasticity

The brain's ability to reorganize, change, and adapt its structure and neural connections throughout life, involving individual neurons and its the strengths of synaptic connections

Long-­term Potentiation

A phenomenon in which there is an increase in the strength of signal transmission between two neurons that happens after repeated, high-frequency stimulation

Language

A communication system that involves using words and systematic rules to transmit information from one individual to another.

Language: Language Areas

The cerebral cortex contains two language areas— Wernicke’s area and Broca’s area, which are usually present only in the left cerebral hemisphere

Language: Language Areas: Wernicke’s Area

An association area in the temporal lobe interprets the meaning of spoken and written words from the primary visual and auditory areas and turns those words into thoughts.

Language: Language Areas: Broca’s Area

A motor area in the frontal lobe translates thoughts into speech from Wernicke’s area and the primary motor cortex to innervate the muscles necessary to say what you want to say

Language: Pathway: Step 1

If the word is written, the primary visual cortex sends information to Wernicke’s area; if it is spoken, the primary auditory cortex sends the information to Wernicke’s area so its meaning can be understood.

Language: Pathway: Step 2

Once Wernicke’s area receives this information, it translates the written or spoken word into the appropriate thought.

Language: Pathway: Step 3

Wernicke’s area sends information about the word to Broca’s area, which creates the motor pattern needed to activate the muscles used to speak the word.

Language: Pathway: Step 4

The motor pattern travels from Broca’s area to the primary motor cortex, which activates the speech muscles, causing them to contract and produce the spoken word.