Anatomy and Functions of the Thalamus and Limbic System

Thalamus

Central relay station for sensory information.

Epithalamus

Connects limbic system to other brain parts.

Subthalamus

Involved in motor control and regulation.

Pineal Gland

Regulates sleep-wake cycles via melatonin.

Habenular Nuclei

Involved in emotional and reward processing.

Stria Medullaris

Connects habenular nuclei to limbic structures.

Third Ventricle

Cavity containing cerebrospinal fluid in the brain.

Relay Nuclei

Transmit sensory and motor information to cortex.

Association Nuclei

Integrate sensory information and memory processing.

Non-specific Nuclei

Regulate consciousness, arousal, and attention.

Anterior Nuclear Group

Involved in attention and memory acquisition.

Medial Group

Affects emotional responses and foresight.

Lateral Group

Processes sensory information and visual attention.

Pulvinar Nucleus

Relay station for visual information processing.

Ventral Anterior Nucleus (VA)

Receives input from basal ganglia for movement.

Ventral Lateral Nucleus (VL)

Relay motor feedback from cerebellum to cortex.

Ventral Posterior Nucleus (VP)

Processes somatosensory information from the body.

Ventral Posterolateral Nucleus (VPL)

Secondary neuron for DCML and STT pathways.

Ventral Posteromedial Nucleus (VPM)

Processes facial sensory information from trigeminal nerve.

Medial Geniculate Body

Relays auditory information to auditory cortex.

Lateral Geniculate Body

Relays visual information to visual cortex.

Intralaminar Nuclei

Maintain consciousness and alertness levels.

Centro-median Nucleus

Involved in pain pathways and cognitive processes.

Basal Ganglia Connections

Integrate motor control and cognitive functions.

Motor Pathways

Transmit signals for voluntary muscle movements.

Reticular nucleus

Controls thalamic function profoundly.

Pineal gland

Produces melatonin; located between superior colliculi.

Subthalamus

Regulates movement and motor control.

Subthalamic nuclei

Inhibited by Globus Pallidus externus.

Globus Pallidus internus

Activated by STN; inhibits thalamus.

Thalamic lesions

Cause sensory loss and motor impairments.

Thalamic pain syndrome

Severe chronic pain from thalamic lesions.

Cognitive impairments

Include aphasia and hemineglect.

Epithalamic lesions

Lead to sleep and emotional dysfunction.

Hypothalamic lesions

Result in endocrine and thermoregulation issues.

Thalamic infarcts

Lead to various clinical syndromes.

Dejerine-Roussy Syndrome

Chronic pain opposite lesion; sensory disturbances.

Thalamic Hand Syndrome

Abnormal hand posture; wrist flexion, thumb extension.

Thalamic Aphasia

Language deficits from dominant hemisphere infarction.

Thalamic Neglect

Lack of awareness opposite lesion side.

Thalamic Amnesia

Memory deficits due to anterior thalamus infarction.

Thalamic Hemiparesis

Weakness on one side; sensory loss present.

Thalamic Oculomotor Syndrome

Abnormal eye movements from paramedian thalamus infarction.

Limbic system

Integrates sensory info with emotional responses.

Cingulate gyrus

Links behavior outcomes to motivation and learning.

Fornix

Major output tract of hippocampus; connects limbic structures.

Parahippocampal gyrus

Crucial for memory encoding and retrieval.

Memory processing

Involves encoding, retrieval, and spatial memory.

Emotional nervous system

Regulates responses to emotional stimuli.

Motivation

Influences learning and behavioral outcomes.

Motor control

Regulated by thalamic and subthalamic structures.

Sensory disturbances

Numbness, tingling, or burning sensations.

Infarction

Tissue death due to loss of blood supply.

Hippocampus

Encodes short-term memories into long-term memories.

Declarative Memory

Type of memory for facts and events.

Anterograde Amnesia

Inability to form new memories post-damage.

Amygdala

Integrative control center for emotions and behavior.

Fight or Flight

Physiological response to perceived threats.

Flat Affect

Emotional unresponsiveness due to amygdala damage.

Septal Nucleus

Involved in reward, pleasure, and emotional regulation.

Orbito-Medial Prefrontal Cortex

Key area for decision-making and impulse control.

Hypothalamus

Regulates emotional responses and endocrine functions.

Papez Circuit

Pathway linking emotion and memory processing.

Episodic Memory

Memory of events with emotional significance.

Fornix

Outflow tract connecting hippocampus to other areas.

Mammillary Bodies

Involved in emotional responses and memory processing.

Anterior Nucleus of Thalamus

Regulates attention and episodic emotional memory.

Cingulate Gyrus

Connects brain hemispheres and processes emotions.

Amygdala Pathways

Links emotional responses to autonomic and endocrine systems.

Hippocampal Formation

Includes structures crucial for memory formation.

Cingulum Bundle

Connects cingulate gyrus with limbic system regions.

Autonomic Nervous System (ANS)

Regulates involuntary bodily functions like heart rate.

Endocrine Function

Controls hormone release affecting various body functions.

Homeostasis

Maintains internal balance of bodily systems.

Circadian Rhythms

Biological processes that follow a 24-hour cycle.

Emotional Regulation

Managing emotional responses to stimuli.

Social Conduct

Behavioral norms guiding interactions with others.

Hypothalamus

Regulates vital functions like appetite and temperature.

Lateral Hypothalamus

Loss of appetite and weight loss (aphagia).

Ventromedial Hypothalamus

Causes hyperphagia and obesity when damaged.

Anterior Hypothalamus

Controls heat loss; lesions cause hyperthermia.

Posterior Hypothalamus

Regulates heat conservation; lesions cause hypothermia.

Supraoptic Nuclei

Produces ADH; lesions lead to diabetes insipidus.

Paraventricular Nuclei

Regulates water balance and secretes oxytocin.

Mammillary Bodies

Involved in memory processing; lesions cause memory loss.

Suprachiasmatic Nucleus

Regulates circadian rhythms and sleep-wake cycles.

Diabetes Insipidus

Excessive urination due to ADH loss.

Hyperphagia

Excessive eating due to VMH lesions.

Aphagia

Loss of appetite due to lateral hypothalamus damage.

Hyperthermia

Inability to cool down from anterior hypothalamus lesions.

Hypothermia

Inability to warm up from posterior hypothalamus lesions.

Circadian Rhythms

Biological processes regulated by the suprachiasmatic nucleus.

Limbic System

Emotional nervous system managing responses and memory.

Olfactory Cortex

Processes smell; part of the limbic system.

Hippocampus

Involved in memory regulation and spatial navigation.

Amygdala

Processes emotions like fear and stress responses.

Autonomic Nervous System

Regulates stress response via hypothalamic connections.

Anterior Thalamic Nucleus

Receives input from mammillary bodies for memory.

Parasympathetic Nervous System

Controls heat dissipation via anterior hypothalamus.

Sympathetic Nervous System

Controls heat conservation via posterior hypothalamus.