Frontal Lobes: Functions and Problems

Frontal Lobes: Functions

• Consciousness, awareness of self and environment, are functions of the frontal lobes.
• Frontal lobes enable the initiation of activity in response to the environment.
• The frontal lobes play a crucial role in making judgments about daily activities.
• Emotional response control, expressive language, meaning to words, and word associations are all functions of the frontal lobes.
• Memory for habits and motor activities resides in the frontal lobes.

Frontal Lobes: Observed Problems

• Damage to the frontal lobes can result in loss of simple movement (paralysis).
• Sequencing, the inability to plan multi-step tasks (making coffee), is an observed problem.
• Loss of spontaneity and flexibility in thinking may occur.
• Persistence of a single thought (perseveration) can manifest.
• Inability to focus (attending), mood changes (emotional lability), and changes in personality and social behavior are observed.
• Difficulty with problem-solving and inability to express language (Broca's aphasia) can arise.

Parietal Lobes: Functions

• Location for visual attention and touch perception are functions of the parietal lobes.
• Goal-directed voluntary movements and manipulation of objects rely on the parietal lobes.
• Integration of senses for understanding concepts takes place.

Parietal Lobes: Observed Problems

• Inability to attend to multiple objects, inability to name objects (anomia), and difficulty with writing (agraphia) are observed problems.
• Difficulties with reading (alexia) and drawing can arise.
• Challenges in distinguishing left from right, doing mathematics (dyscalculia) may occur.
• Lack of body/space awareness (apraxia), impaired visual attention, and poor eye-hand coordination are observed.

Occipital Lobes: Functions

• Vision depends on the occipital lobes.

Occipital Lobes: Observed Problems

• Visual field cuts, difficulty locating objects, and difficulty identifying colors (color agnosia) are observed.
• Hallucinations, word blindness an inability to regonize words, and difficulty recognizing drawn objects are problems.
• The inability to recognize movement (movement agnosia) and challenges in reading and writing arise following damage.

Temporal Lobes: Functions

• Hearing ability, memory acquisition, some visual perceptions and categorization of objects depends on temporal lobes function

Temporal Lobes: Observed Problems

• Difficulty recognizing faces (prosopagnosia) and understanding speech (Wernicke's aphasia) can be problems.
• Disturbance with selective attention is observed.
• Difficulty identifying and verbalizing objects, short-term memory loss, and altered sexual behavior occur with temporal lobe dysfunction.
• Inability to categorize objects, persistant talking due to right lobe damage, and increased aggression can be problems.

Brain Stem: Functions

• Breathing, heart rate, swallowing, reflexes to seeing and hearing (startle response) and digestion are the function of the brainstem.
• Controls sweating, blood pressure, and temperature (Autonomic Nervous System.
• Affects alertness, sleep, and balance (Vestibular Function).

Brain Stem: Observed Problems

• Decreased breathing capacity for speech, swallowing problems (dysphagia), and difficulty with environment perception can manifest.
• Problems with balance/movement, dizziness/nausea (vertigo), and sleeping difficulties (insomnia, sleep apnea) can be observed.

Cerebellum: Functions

• Coordination of voluntary movement, balance, and equilibrium.
• Some memory for reflex motor acts.

Cerebellum: Observed Problems

• Loss of coordination, inability to walk or grab objects, tremors, dizziness (vertigo), and slurred speech can be observed.
• Inability to make rapid movements arises due to cerebellum dysfunction.

Additional Info on Brain Function

• Thalamus functions as a "central switching station" for sensory information (except olfactory).
• Hypothalamus controls the autonomic nervous system and maintains homeostasis.
• Limbic System is related to emotional expression, memory, and motivation.
• Amygdala attaches emotional significance to information and mediates defensive and aggressive behavior.
• Hippocampus: Involved in memory and the transfer of information from short-term to long-term.

Neurotransmitters: The Basics

• There are well over 100 different neurotransmitters
• Psychopharmacology focuses on six key neurotransmitter systems.

Key Neurotransmitter Systems

• Serotonin
• Norepinephrine
• Dopamine
• Acetylcholine
• Glutamate
• GABA (γ-aminobutyric acid)

Acetylcholine

• It is involved in voluntary movement, learning, memory, and sleep.
• Too much it is associated with depression.
• Too little in the hippocampus is associated with dementia.

Dopamine

• It is correlated with movement, attention, learning, and reward.
• Too much in one area of the brain while too little in another has been associated with schizophrenia.
• Too little is associated with some forms of depression and muscular rigidity/tremors in Parkinson's disease.

Norepinephrine

• It mediates fight-or-flight response.
• Too much can lead to anxiety and hyperactivity without actual danger.
• Too little is associated with depression.

Serotonin

• It plays a role in mood, anxiety, emotions, appetite, sleep, and impulsive/aggressive behavior.
• Too little is associated with depression.

GABA (Gamma-Amino Butyric Acid)

• It is a major inhibitory neurotransmitter system in the CNS.
• Causes calmness, sleepiness, reduced inhibition and decreased pain sensation.
• Too little is associated with anxiety disorders.

Glutamate

• Major excitatory neurotransmitter in the brain.
• Required for learning and memory.
• Low levels can lead to fatigue and poor brain activity.
• Increased levels can cause death to neurons and contribute to neurodegenerative diseases, depression, OCD, and autism.