Affective Systems are responsible for processing and responding to both aversive and positive motivational situations or contexts, encompassing emotional responses such as fear, anxiety, reward seeking, and mood regulation.

• Threat and Risk Evaluation: Threat and Risk Evaluation is the process of assessing the potential for harm or loss.
  • mania: Mania is a state of abnormally elevated mood, energy, and activity levels, often seen in bipolar disorder. We've categorized lesional mania as a disruption of the brain's normal systems for Threat and Risk Evaluation.
• Reward Responsiveness: Reward Responsiveness is the degree to which an individual is likely to respond to rewards.
  • anhedonia: Anhedonia is the inability to experience pleasure from activities usually found enjoyable, such as eating, exercise, or social interactions.
• Habit: Habit is a routine of behavior that is repeated regularly and tends to occur subconsciously. Relates to compulsive behavior.
  • ocd: Lesional OCD is a form of Obsessive-Compulsive Disorder resulting from brain lesions, characterized by compulsive behaviors and obsessive thoughts.
• Volition: Volition is the cognitive process by which an individual decides on and commits to a particular course of action.
  • abulia: Abulia is a neurological condition characterized by a lack of will or initiative. Individuals with abulia often show diminished motivation and an inability to make decisions or initiate actions. Athymhormia is a neuropsychiatric condition characterized by a loss of drive and motivation, often associated with damage to the basal ganglia, and is considered a synonym for abulia.
  • akinetic mutism: Akinetic mutism is a state of unresponsiveness and lack of movement, often seen in neurological conditions affecting the frontal lobes or basal ganglia.
• Positive Affect: Positive Affect is a relatively long lasting emotional state associated with positive feelings and well-being.
  • depression: Depression is a mood disorder characterized by persistent feelings of sadness, loss of interest, and various physical and cognitive symptoms. We've categorized lesional anxiety as a disruption of the brain's normal positive affective systems.
  • anxiety: Anxiety is a mental health disorder characterized by feelings of worry, anxiety, or fear that are strong enough to interfere with one's daily activities. We've categorized lesional anxiety as a disruption of the brain's normal positive affective systems.
  • apathy: Apathy is a lack of interest, enthusiasm, or concern, often seen in various neurological and psychiatric conditions.
• Impulse Control: Impulse Control is the ability to resist or delay an impulse, drive, or temptation to act.
  • hypersexuality: Hypersexuality is a condition characterized by an increased frequency or intensity of sexual thoughts, urges, or behaviors, often associated with neurological conditions or disorders such as bipolar disorder, frontotemporal dementia, or brain injury.
  • pseudobulbar affect: Pseudobulbar affect (PBA) is a neurological condition characterized by uncontrollable episodes of laughing or crying that are disproportionate to the individual's emotional state. PBA is often associated with neurological conditions such as multiple sclerosis, ALS, stroke, or traumatic brain injury.
  • aggression: Aggression is a behavioral response characterized by hostile or violent behavior towards others, which can be verbal or physical. It may be a symptom of various neurological or psychiatric conditions, often resulting from disruptions in brain regions responsible for impulse control, emotional regulation, and social behavior. Common causes include brain lesions, traumatic brain injury, frontal lobe damage, and certain neurodegenerative diseases.
• Other Inhibitory Systems: Other subdomains related to responses to aversive situations and inhibition of behavior.

  No symptoms available for this subcategory.

• Other Positive Valence Systems: Other subdomains related to responses to positive motivational situations or contexts.

  No symptoms available for this subcategory.

Cognitive Systems are responsible for various cognitive processes.

• Executive Function: Executive Function is a set of cognitive processes that are necessary for the cognitive control of behavior, including working memory, reasoning, task flexibility, problem solving, and attention control.
  • attention deficits: Attention deficits involve difficulty in maintaining focus, being easily distracted, and having trouble organizing tasks, often seen in ADHD and other conditions.
  • executive dysfunction: Executive dysfunction refers to difficulties with cognitive processes such as planning, organizing, problem-solving, and decision-making, often seen in conditions like ADHD and frontal lobe damage.
• Perception: Perception is the organization, identification, and interpretation of sensory information in order to represent and understand the environment.
  • auditory agnosia: Auditory agnosia is the inability to recognize or interpret sounds despite having normal hearing, often due to brain injury.
  • allesthesia: Allesthesia is a condition in which sensations are perceived on the opposite side of the body from where they actually occur, often associated with brain injury. Synchiria is a condition where a stimulus applied to one side of the body is perceived on both sides, often associated with brain lesions.
  • room tilt illusion: The Room Tilt Illusion is a perceptual phenomenon where an individual perceives their surroundings as tilted or rotated. This illusion can be associated with vestibular disorders, brain lesions, or visual-vestibular conflicts.
  • blindsight: Blindsight is a condition where individuals with cortical blindness can respond to visual stimuli without consciously perceiving them.
  • anton syndrome: Anton Syndrome is a rare condition in which a person who is cortically blind due to brain damage is unaware of or denies their blindness, often confabulating visual experiences.
  • size perception: Size perception distortion is a visual distortion where objects appear larger or smaller than their actual size, often due to retinal or neurological conditions. This includes conditions such as micropsia and macropsia.
  • alice in wonderland syndrome: Alice in Wonderland Syndrome (AIWS) is a neurological condition characterized by distortions in perception, including altered perception of size, time, space, and body image. These perceptual distortions can affect vision, touch, and the sense of time, leading to a disorienting and surreal experience. Often accompanies with body image distortion, autoscopy, micropsia, macropsia, teleopsia, pelopsia, palinopsia, temporal distortions, oscillopsia, and metamorphopsia, which are listed as additional terms in our database.
  • body image distortion: Body Image Distortion is a perceptual disturbance where an individual's perception of their own body size, shape, or position is inaccurate, often associated with neurological or psychological conditions.
  • metamorphopsia: Metamorphopsia is a visual distortion where objects appear wavy, curved, or misshapen, typically caused by retinal or neurological issues.
  • neglect: Neglect is a condition where a person is unaware of or ignores one side of their body or environment, often due to brain injury, particularly in the parietal lobe.
  • oscillopsia: Oscillopsia is a visual disturbance where objects appear to oscillate or move back and forth, often caused by vestibular disorders or neurological conditions.
  • palinopsia: Palinopsia is a visual disturbance where an image continues to appear after the stimulus has been removed, often caused by neurological disorders or medication side effects.
  • phonagnosia: Phonagnosia is the inability to recognize familiar voices, typically resulting from brain damage affecting the right hemisphere.
  • prosopagnosia: Prosopagnosia, also known as face blindness, is the inability to recognize familiar faces, caused by damage to the fusiform gyrus in the brain.
  • prosopometamorphopsia: Prosopometamorphopsia is a condition where faces appear distorted, often caused by lesions or other abnormalities in the brain.
  • simultanagnosia: Simultanagnosia is a condition where an individual cannot perceive more than one object at a time, often caused by damage to the parietal lobes.
  • synesthesia: Synesthesia is a condition in which stimulation of one sensory pathway leads to involuntary experiences in a second sensory pathway, such as seeing colors when hearing music.
  • distance perception distortion: Distance perception distortion encompasses visual distortions where objects appear either farther away (teleopsia) or closer (pelopsia) than they actually are. These conditions are often associated with neurological conditions or visual processing disorders.
  • visual agnosia: Visual agnosia is the inability to recognize or identify objects despite having intact vision, typically caused by damage to the visual processing areas of the brain.
  • astereognosia: Astereognosia, also known as astereognosis, is the inability to identify objects by touch alone, without the aid of vision, despite having intact sensory abilities.
• Memory: Memory is the faculty of the brain by which information is encoded, stored, and retrieved when needed.
  • amnesia: Amnesia is a loss of memory, which can be partial or complete, and can result from brain injury, illness, or psychological factors. Types of amnesia include retrograde amnesia, which is the loss of pre-existing memories.
• Language: Language is a system of communication that uses symbols to convey information.
  • agraphia: Agraphia is the inability to write, often due to brain injury or neurological disorders.
  • alexia: Alexia, also known as acquired dyslexia, is the inability to read despite previous reading ability, often resulting from brain injury.
  • aphasia: Aphasia is an impairment of language ability, affecting speech, comprehension, reading, or writing, typically due to brain injury. This can include various speech disorders such as cluttering, which involves rapid and disorganized speech affecting clarity and fluency. Aphasia also encompasses general speech deficits, which are impairments in the ability to produce or comprehend spoken language.
  • mutism: Mutism is the inability or refusal to speak, often associated with severe psychological trauma, neurological disorders, or developmental issues.
  • palilalia: Palilalia is a speech disorder characterized by the involuntary repetition of words or phrases, often seen in neurological conditions like Tourette syndrome.
  • stuttering: Stuttering is a speech disorder characterized by frequent disruptions in the flow of speech, such as repetitions, prolongations, or blocks.
• Sense of Self: Sense of Self is a system that represents the individual’s experience of being a separate and distinct entity that is continuous in time and space.
  • anosodiaphoria: Anosodiaphoria is a condition in which a person is aware of their illness but shows indifference or lack of concern about it.
  • anosognosia: Anosognosia is a lack of awareness or denial of a neurological condition or deficit, often seen in stroke or dementia patients.
  • autoscopy: Autoscopy is a phenomenon where an individual experiences seeing their own body from an external perspective, often associated with neurological or psychiatric conditions.
  • autotopagnosia: Autotopagnosia is the inability to localize and name parts of one's own body, typically due to parietal lobe damage.
  • asomatognosia: Asomatognosia is a condition where an individual is unable to recognize parts of their own body, typically due to brain injury.
  • somatoparaphrenia: Somatoparaphrenia is a type of delusion where a person denies ownership of a limb or an entire side of their body, often seen in patients with right hemisphere brain damage.
  • supernumerary limb: Supernumerary phantom limb is a phenomenon where individuals perceive the presence of an extra limb, often following an amputation or brain injury.
• Reality Monitoring: Reality Monitoring is a cognitive system that is responsible for discriminating between internally generated information and information that arises from external sources.
  • capgras: Capgras syndrome is a delusional belief that a familiar person has been replaced by an imposter, often associated with psychiatric or neurological conditions.
  • confabulation: Confabulation is the production of fabricated, distorted, or misinterpreted memories about oneself or the world, without the intention to deceive.
  • delusion: Delusion is a firmly held false belief despite clear evidence to the contrary, commonly seen in psychiatric conditions such as schizophrenia. Often accompanied by paranoia (listed as an additional term in our database).
  • paranoia: Paranoia is an irrational and persistent feeling or belief that one is being persecuted, targeted, harassed, or conspired against, commonly seen in psychiatric conditions such as schizophrenia.
  • psychosis: Psychosis is a severe mental disorder characterized by a disconnection from reality, which can include hallucinations, delusions, and impaired insight.
  • reduplicative paramnesia: Reduplicative paramnesia is a delusional belief that a familiar place has been duplicated or relocated, often seen in brain injury or dementia.
  • visual hallucinations: Visual hallucinations are perceptions of objects or events that are not actually present, often seen in psychiatric and neurological disorders.
  • cotard syndrome: Cotard's delusion is a rare psychiatric condition in which individuals mistakenly believe they are dead, nonexistent, or have lost their bodily functions. This nihilistic belief often accompanies severe depression and other mental health disorders, profoundly distorting the person's perception of reality.
• Emotional Processing: Emotional Processing is the process of recognizing, understanding, and responding to emotions in oneself and others.
  • alexithymia: Alexithymia is the difficulty in identifying and describing emotions in oneself, which can impact social interactions.
• Other: Other Cognitive Systems
  • mathematical impairment: Mathematical impairment refers to the inability to perform mathematical calculations, which can result from brain injury or neurological conditions. This includes conditions such as acalculia and anarithmetia.
  • amusia: Amusia is the inability to perceive or produce music, which can be congenital or acquired.

Arousal/Regulatory Systems are responsible for generating activation of neural systems as appropriate for various contexts, and providing appropriate homeostatic regulation of such systems as energy balance and sleep.

• Sleep: Sleep is a naturally recurring state characterized by reduced or absent consciousness, relatively suspended sensory activity, and inactivity of nearly all voluntary muscles.
  • bruxism: Bruxism is the involuntary grinding or clenching of teeth, often occurring during sleep and associated with stress or anxiety.
  • rem sleep behavior disorder: REM Sleep Behavior Disorder (RBD) is a sleep disorder characterized by the acting out of dreams that occur during the REM (rapid eye movement) sleep stage. This can include talking, yelling, punching, kicking, and other movements. It is often associated with neurological conditions such as Parkinson's disease.
  • hypersomnia: Hypersomnia is excessive daytime sleepiness or prolonged nighttime sleep, which can be a symptom of various sleep disorders.
  • insomnia: Insomnia is a sleep disorder characterized by difficulty falling asleep, staying asleep, or achieving restorative sleep.
  • narcolepsy: Narcolepsy is a sleep disorder characterized by excessive daytime sleepiness and sudden, uncontrollable episodes of falling asleep.
  • parasomnia: Parasomnia is a category of sleep disorders involving abnormal movements, behaviors, or experiences during sleep, including sleepwalking and night terrors.
• Consciousness: Consciousness is the state or quality of awareness, or, of being aware of an external object or something within oneself.
  • loss of consciousness: Loss of consciousness is a state in which a person is unable to respond to stimuli and appears to be asleep or unresponsive. This can occur suddenly and can result from various causes, including head injury, stroke, cardiac arrest, seizures, and severe illness.
  • coma: Coma is a state of prolonged unconsciousness in which a person is unresponsive to their environment and cannot be awakened. This condition can result from various causes, including severe head injury, stroke, brain tumor, drug or alcohol intoxication, or an underlying illness such as diabetes or infection.
• Autonomic and Homeostatic Functions: Homeostasis is the property of a system in which variables are regulated so that internal conditions remain stable and relatively constant.
  • takotsubo: Lesional Takotsubo Cardiomyopathy, also known as stress-induced cardiomyopathy or broken heart syndrome, is a temporary heart condition that is often brought on by stressful situations and extreme emotions. It involves sudden weakening of the heart muscle, leading to abnormal heart muscle movement.
• Epilepsy: Epilepsy is a group of neurological disorders characterized by epileptic seizures.
  • seizures: Seizures are sudden, uncontrolled electrical disturbances in the brain that can cause changes in behavior, movements, feelings, and levels of consciousness.
  • status epilepticus: Status epilepticus is a dangerous condition in which epileptic seizures follow one another without recovery of consciousness between them.
• Other: Other Arousal/Regulatory Systems

  No symptoms available for this subcategory.

Sensory Systems are responsible for processing sensory information from the body and the environment.

• Somatosensory: Somatosensory is the system that is responsible for the processing of sensory information from the body.
  • allodynia: Allodynia is a condition where normal, non-painful stimuli are perceived as painful. It is often associated with hyperesthesia, which is an increased sensitivity to sensory stimuli, such as touch or pain. These conditions represent abnormal sensory processing, where the threshold for pain and sensory perception is lowered.
  • dysesthesia: Dysesthesia is an abnormal and unpleasant sensation, often described as burning, tingling, prickling, numbness, or electric shock-like, usually caused by nerve damage or compression.
  • central pain: Central pain is a neurological condition characterized by chronic pain that results from damage or dysfunction within the central nervous system, including the brain and spinal cord. The pain can vary in intensity and type, including burning, aching, or stabbing sensations.
  • hypoesthesia: Hypoesthesia is a reduced sense of touch or sensation, often resulting from nerve damage or neurological disorders.
• Vestibular: Vestibular is the system that provides the leading contribution to the sense of balance and spatial orientation for the purpose of coordinating movement with balance.
  • vertigo: Vertigo is a sensation of spinning or dizziness, where a person feels as if they or their surroundings are moving when they are not. It is often caused by problems with the inner ear or the brain, including conditions like benign paroxysmal positional vertigo (BPPV), vestibular neuritis, Meniere's disease, or migraines.
• Spatial: Spatial is the system that is responsible for the processing of spatial information.

  No symptoms available for this subcategory.

• Proprioception: Proprioception is the sense of the relative position of one's own parts of the body and strength of effort being employed in movement.

  No symptoms available for this subcategory.

• Visual: Visual is the system that is responsible for the processing of visual information.
  • cortical blindness: Cortical blindness is the loss of vision due to damage to the visual cortex, despite the eyes and optic nerves being intact.
  • color agnosia: Color agnosia is the inability to recognize or identify colors, despite having normal color vision, typically due to brain damage.
  • akinetopsia: Akinetopsia, also known as motion blindness, is a condition where an individual cannot perceive motion, caused by brain damage.
  • visual field defect: A visual field defect is a loss of part of the usual field of vision, often due to damage to the retina, optic nerve, or brain. This includes conditions such as hemianopia and quadrantanopia, which are characterized by the loss of vision in half or a quarter of the visual field, respectively.
• Auditory: Auditory is the system that is responsible for the processing of auditory information.
  • hyperacusis: Hyperacusis is an increased sensitivity to normal environmental sounds, often resulting in discomfort or pain.
  • sound localization impairment: Sound localization impairment is a condition where an individual has difficulty determining the origin of sounds in their environment, often due to damage or dysfunction in the auditory system.
  • tinnitus: Tinnitus is the perception of noise or ringing in the ears when no external sound is present. It can be a symptom of various underlying conditions, such as hearing loss, ear infections, or neurological disorders.
  • auditory hallucinations: Auditory hallucinations are perceptions of sounds or voices that are not actually present, often associated with psychiatric conditions like schizophrenia.
• Olfactory: Olfactory is the system that is responsible for the processing of olfactory information.
  • dysosmia: Dysosmia refers to disorders of smell, including anosmia (complete loss of sense of smell), hyposmia (reduced ability to detect odors), and hyperosmia (increased sensitivity to odors). These conditions can result from various causes such as head trauma, respiratory infections, neurological disorders, or during pregnancy. Anosmia is the most severe form, representing a total loss of smell.
  • olfactory hallucinations: Olfactory hallucinations are the perception of smells that are not present, which can range from pleasant to foul odors. These hallucinations are often caused by neurological disorders, olfactory dysfunction, or brain lesions.
• Gustatory: Gustatory is the system that is responsible for the processing of gustatory information.

  No symptoms available for this subcategory.

Motor Systems are primarily responsible for the control and execution of motor behaviors, and their refinement during learning and development.

• Gross Motor: Gross Motor is the movement of the large muscles of the body.
  • ataxia: Ataxia is a lack of muscle coordination during voluntary movements, which can affect speech, eye movements, and the ability to swallow.
  • ballismus: Ballismus is a movement disorder characterized by violent, flinging movements of the limbs, often caused by damage to the subthalamic nucleus.
  • bradykinesia: Bradykinesia is the slowness of movement and is a common symptom of Parkinson's disease.
  • chorea: Chorea is a movement disorder characterized by brief, irregular, and involuntary movements, often seen in conditions like Huntington's disease.
  • dysphagia: Dysphagia is a condition characterized by difficulty or discomfort in swallowing, which can result from neurological disorders, structural abnormalities, or other medical conditions.
  • dysdiadochokinesia: Dysdiadochokinesia is the inability to perform rapid, alternating movements, typically resulting from cerebellar dysfunction.
  • paralysis: Hemiparesis and hemiplegia refer to the weakness or paralysis of one side of the body, often resulting from stroke or brain injury. Hemiparesis describes partial paralysis or weakness, while hemiplegia describes complete paralysis.
  • parkinsonian gait: Parkinsonian gait is a distinctive walking pattern characterized by small, shuffling steps and a stooped posture, commonly seen in Parkinson's disease.
  • stereotypy: Stereotypy refers to repetitive, fixed patterns of physical movements or speech, often seen in neurological or developmental disorders.
  • tics: Tics are sudden, repetitive, non-rhythmic motor movements or vocalizations, commonly seen in Tourette syndrome and other neurological conditions.
  • cervical dystonia: Cervical dystonia, also known as spasmodic torticollis, is a neurological movement disorder characterized by involuntary muscle contractions in the neck that cause abnormal movements and postures of the head and neck. Symptoms can include neck pain and tremors.
  • dystonia: Dystonia is a neurological movement disorder characterized by involuntary muscle contractions that cause repetitive or twisting movements and abnormal postures. It can affect one part of the body (focal dystonia), multiple parts (segmental dystonia), or the entire body (generalized dystonia). Symptoms can vary in severity and may be painful.
  • holmes tremor: Holmes Tremor is a rare neurological disorder characterized by a combination of resting, postural, and intention tremors. It typically results from lesions in the brainstem, thalamus, or midbrain, often following a stroke, traumatic brain injury, or multiple sclerosis.
• Fine Motor: Fine Motor is the movement of small muscles, such as those in the fingers and hands.
  • alien limb: Alien limb syndrome is a condition where a person experiences a limb acting seemingly on its own, without conscious control. This often involves the hand but can include other limbs as well.
  • apraxia: Apraxia is the inability to perform purposeful movements or use objects correctly despite having the desire and physical capability to do so.
  • athetosis: Athetosis is characterized by slow, involuntary, writhing movements, usually of the hands and feet, often resulting from basal ganglia damage.
  • asterixis: Asterixis is a motor disorder characterized by sudden, brief, and involuntary jerking movements, often of the hands, that can occur in various neurological and metabolic conditions. It is commonly seen in conditions such as liver disease and encephalopathy.
  • dysarthria: Dysarthria is a motor speech disorder resulting from neurological injury, leading to poor articulation and speech difficulties.
• Oculomotor: Oculomotor is the control of eye movements.

  No symptoms available for this subcategory.