Term
Amygdala
- Overview
- Associated Functions
- Associated Cognitive Disorders
- Implications of Damage |
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Definition
Overview
The amygdala is a complex structure adjacent to the hippocampus. The amygdala is involved in processing emotions, and fear-learning. It links areas of the cortex that process "higher" cognitive information with hypothalamic and brainstem systems that control "lower" metabolic responses (e.g. touch, pain sensitivity, and respiration). This allows the amygdala to coordinate phsyiologial responses based on cognitive information, such as the fight-or-flight response.
The amygdala has three functionally distinct parts
1. The medial group of subnuclei has many connections with the olfactory bulb and olfactory cortex.
2. The basolateral group has extensive connections with the cerebral cortex, particularly the orbital and medial prefrontal cortex.
3. The central and anterior group of nuclei has many connections with the brainstem, hypothalamus, and sensory structure.
Associated Functions
- fear processing
- emotion processing
- learning
- fight-or-flight response
- reward-processing
Associated Cognitive Disorders
- Many studies have linked autism with amygdala dysfunction. The lack of empathy often shown by autistic individuals has been associated with the amygdala (Blair, 2008).
- Neural activity in the amygdala has also been strongly linked to depression (Northoff, 2007) and bipolar disorder (Phillips and Viesta, 2007).
- There is very strong evidence linking amygdala response to PTSD.
Implications of Damage
- aggression
- irritability
- loss of control of emotion
- disruption of short-term memory
- deficits in recognizing emotions (particularly fear) |
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Term
Basal Ganglia
- Overview
- Associated Functions
- Associated Cognitive Disorders
- Implications of Damage
- Substructures |
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Definition
Overview
The Basal ganglia comprise a group of structures that regulate the initiation of movements, balance, eye movements, and posture. They are strongly connected to other motor areas in the brain and link the thalamus with the motor cortex. The basal ganglia are also involved in cognitive and emotional behaviors and play an important role in reward and reinforcement, addictive behaviors and habit formation.
Associated Functions
- Movement regulation
- Skill-learning
- Habit formations
- Reward systems
Associated Cognitive Disorders
- Particularly associated with movement disorders such as Parkinson's and Huntington's disease.
- In terms of cognitive disorders, basal ganglia abnormalities have been found in individuals with schizophrenia, and may explain habit learning deficits associated with the disorder (Keri, 2008).
- The basal ganglia may also contribute to the neuropathology of depression, particularly in relation to the limbic system (Stathis et al., 2007)
Implications of Damage
- Tremors
- Involuntary Muscle Movements
- Abnormal Increase in Muscle Tone
- Difficulty Initiating Movement
- Abnormal Pressure
Substructures
- Caudate Nucleus
-Globus Pallidus
- Nucleus Accumbens
- Putamen
- Substantia Nigra
- Subthalamic Nucleus |
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Term
The Brainstem
- Overview
- Associated Functions
- Associated Cognitive Disorders
- Implications of Damage
- Substructures
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Definition
Overview
The brainstem consists of a group of structures that lie deep within the brain, including the pons, medulla oblongata, and midbrain. It plays an important role in maintaining homeostasis by controlling autonomic functions such as breathing, heart rate, and blood pressure. While the brainstem can organize motor movements such as reflexes, it coordinates with the motor cortex and associated areas to contribute to fine movements of limbs and the face.
Associated Functions
- Maintaining homeostasis by controlling autonomic functions (blood pressure, breathing, digestion, heart rate, perspiration, and temperature)
- Alertness
- Sleep
- Balance
- Startle Response
Associated Cognitive Disorders
- A number of studies have found brain stem abnormalities in individuals with autism (Rodier, 2003)
Substructures
- Midbrain
- Pons
- Medulla Oblongata |
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Term
Broca's Area
- Overview
- Associated Functions
- Associated Cognitive Disorders
- Implications of Damage |
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Definition
Overview
Broca's Area is a functionally defined structure in the left frontal lobe of about 97% of humans (including a large majority of left-handers). Broca's Area is involved mainly in the production of spoken and written language and also in language processing and comprehension . It takes is name from the French scientist whose work with language-impaired patients lef him to conclude that we speak with our left-brain.
Associated Functions
- Language productions (both speech and sign)
- Comprehension of complex syntax
Associated Cognitive Disorders
- Language impairments in autism may be related to abnormalities in Broca's area (Bauman and Kemper 2005).
Implications of Damage
- Broca's aphasia (inability to express language) which includes halting speech
- Repetitive speech (perseveration)
- Disordered syntax and grammar and disordered structure of individual words |
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Term
Cerebellum
- Overview
- Associated Functions
- Associated Cognitive Disorders
- Implications of Damage |
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Definition
Overview
The cerebellum monitors and regulates motor behavior, particularly autonomic movements. Some recent studies have associated the cerebellum with cognitive functions, such as learning and attention. Although the cerebellum accounts for roughly 10% of total brain weight, it contains more neurons than the rest of the brain combined. The cerebellum is also one of the few mammalian brain structures where adult neurogenisis (the development of new neurons) has been confirmed.
Associated Functions
- Coordinate of voluntary
- Motor-learning
- Balance
- Reflex Memory
- Posture
- Timing
- Sequence Learning
Associated Cognitive Disorders
- Individuals with autism sometimes walk with a clumsy gait, a phenomenon that has been linked to the cerebellum.
- Schizophrenia and dyslexia have also been associated with cerebellar dysfunction.
Implications of Damage
- Loss of fine coordination
- Tremor
- Inability to walk
- Dizziness (Vertigo)
- Slurred speech |
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Term
Cingulate Gyrus
- Overview
- Associated Functions
- Associated Cognitive Disorders
- Implications of Damage
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Definition
Overview
An important part of the limbic system, the cingulate gyrus helps regulate emotions and pain. The cingulate gyrus is thought to directly drive the body's conscious response to unpleasant experiences. In addition, it is involved in fear and the prediction (and avoidance) of negative consequences and can help orient the body away from negative stimulus. Learning to avoid negative consequences is an important feature of memory.
Associated Functions
- Pain processing
- Emotion
- Memory
- Self-Regulation
Associated Cognitive Disorders
Because of its role in emotion-processing, the cingulate gyrus has been associated with numerous disorders including autism, bipolar disorder, depression, obsessive-compulsive disorder, post-traumatic stress disorder and schizophrenia (Yucel and colleagues, 2003)
Implications of Damage
- Inappropriate Emotions
- Lack of fear
- Impaired nocioception (sensation of pain)
- Learning Impairments |
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Term
Corpus Callosum
- Overview
- Associated Functions
- Associated Cognitive Disorders
- Implications of Damage
- Substructures
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Definition
Overview
The corpus callosum consists of a large bundle of fibers connecting the right and left hemispheres of the brain. Each hemisphere controls movement in the opposite (contralateral) side of the body and can also specialize in performing specific cognitive and perceptual functions. The corpus callosum allows information to move between hemispheres and is therefore an important integrative structure.
Associated Functions
Connects right and left hemispheres and allows information to pass between them.
Associated Cognitive Disorders
Reductions in corpus callosum volume have been associated with schizophrenia and the onset of psychotic episodes. Abnormalities in corpus callosum morphology have also been observed in Alzheimer's patients, children with ADHD as well as in a large number of non-cognitive disorders.
Implications of Damage
- Coma or vegetative state
- Mutism
- Memory Impairment
- Split-Brain syndrome results in a number of subtle cognitive, movement, and perceptual difficulties
Substructures
- Splenium
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Term
Dentate Gyrus
- Overview
- Associated Functions
- Associated Cognitive Disorders
- Implications of Damage |
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Definition
Overview
The hippocampal formation has three regions, which are highly interconnected: the dentate gyrus, CA3, and CA1. It is one of the very few regions in the brain where adults neurogenesis has been confirmed. The dentate gyrus may play an important role in translating complex neural codes from cortical areas into simpler code that can be used by hippocampus to form new memories.
Associated Functions
- Memory formation
- Possible role in memory recall
Associated Cognitive Disorders
Sahay and colleagues (2007) speculate that neurogenesis in the dentate gyrus may mediate some of the behavioral effects of antidepressants. The dentate gyrus has also attracted attention in relation to Alzheimer's disease because of its resistance to the formation of plaques, tangles, and neuronal death (Ohm, 2007).
Implications of Damage
- Memory Impairments |
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