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Study brain structure, function, and plasticity in relation to behavior and cognition.
The sequence of events in synaptic transmission.
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Neuropsychology is the study of brain-behavior relationships, examining how brain structure and function influence cognition, emotion, and behavior. This field bridges neuroscience and psychology to understand both normal functioning and the effects of brain damage or dysfunction. Clinical neuropsychologists assess and treat individuals with brain injuries, neurological diseases, and developmental disorders.
Central Nervous System (CNS): Brain and spinal cord Peripheral Nervous System (PNS): Nerves outside the CNS
Major Brain Structures:
Cerebral Cortex: The outer layer responsible for higher cognitive functions - Frontal Lobe: Executive functions, planning, decision-making, motor control, personality - Parietal Lobe: Sensory integration, spatial awareness, attention - Temporal Lobe: Auditory processing, language comprehension, memory - Occipital Lobe: Visual processing
Subcortical Structures: - Limbic System: Emotion and memory (hippocampus, amygdala, cingulate gyrus) - Basal Ganglia: Movement initiation and control - Thalamus: Sensory relay station - Hypothalamus: Homeostasis, hormone regulation
Brainstem: Vital functions (breathing, heart rate, sleep-wake cycles) Cerebellum: Motor coordination, balance, motor learning
The Neuron: Fundamental unit of the nervous system - Cell Body (Soma): Contains nucleus and metabolic machinery - Dendrites: Receive signals from other neurons - Axon: Transmits signals to other neurons - Axon Terminals: Release neurotransmitters - Myelin Sheath: Insulation that speeds signal transmission
Action Potential: Electrochemical signal traveling along the axon - Resting potential: -70mV - Depolarization: Sodium influx - Repolarization: Potassium efflux - Refractory period: Brief unresponsive period
Synaptic Transmission: 1. Action potential reaches axon terminal 2. Calcium influx triggers vesicle release 3. Neurotransmitters released into synaptic cleft 4. Binding to postsynaptic receptors 5. Excitatory (EPSP) or inhibitory (IPSP) effects 6. Neurotransmitter removal (reuptake, enzymatic degradation, diffusion)
Major Neurotransmitter Systems: - Glutamate: Primary excitatory neurotransmitter - GABA: Primary inhibitory neurotransmitter - Dopamine: Reward, motivation, motor control - Serotonin: Mood, sleep, appetite - Norepinephrine: Arousal, attention - Acetylcholine: Memory, muscle activation
Neuroplasticity refers to the brain's ability to change and reorganize throughout life.
Types of Plasticity: - Synaptic Plasticity: Changes in synaptic strength (long-term potentiation, long-term depression) - Structural Plasticity: Changes in dendritic spines, axonal sprouting - Neurogenesis: Formation of new neurons (hippocampus, olfactory bulb) - Cortical Reorganization: Remapping of cortical areas after injury
Hebbian Learning: 'Neurons that fire together, wire together' - coincident activity strengthens connections.
Critical Periods: Windows of heightened plasticity during development (e.g., language acquisition, visual development).
Experience-Dependent Plasticity: Brain changes in response to learning and environmental enrichment.
Recovery After Brain Injury: - Diaschisis resolution: Recovery of temporarily dysfunctional connected areas - Compensation: Intact brain regions assume functions of damaged areas - Rehabilitation: Training-induced plasticity to restore function
Lateralization refers to the tendency for certain functions to be predominantly processed by one hemisphere.
Left Hemisphere (typically): - Language production and comprehension - Analytical and sequential processing - Mathematical calculation - Right-hand motor control
Right Hemisphere (typically): - Visuospatial processing - Face recognition - Emotional prosody - Holistic/gestalt processing - Left-hand motor control
Split-Brain Research: Studies of patients with severed corpus callosum (Sperry, Gazzaniga) demonstrated hemispheric specialization and the role of the corpus callosum in interhemispheric communication.
Important Caveats: - Lateralization is relative, not absolute - Both hemispheres work together in most tasks - Individual variation exists (especially in left-handers) - Pop psychology oversimplifies (e.g., 'left-brained' vs. 'right-brained' people)
Clinical neuropsychological assessment evaluates cognitive functions through standardized testing.
Domains Assessed: - Attention: Sustained, selective, divided attention - Memory: Working memory, verbal/visual learning, delayed recall - Language: Naming, fluency, comprehension, repetition - Visuospatial: Construction, perception, spatial reasoning - Executive Functions: Planning, inhibition, cognitive flexibility, problem-solving - Processing Speed: Speed of cognitive operations - Motor Functions: Fine motor speed and dexterity
Common Assessment Instruments: - Wechsler scales (WAIS, WMS) - Trail Making Test - Wisconsin Card Sorting Test - Rey Complex Figure - Boston Naming Test - Stroop Test
Interpretation: Compare performance to normative data, identify patterns of strengths and weaknesses, relate to known brain-behavior relationships.
Traumatic Brain Injury (TBI): - Caused by external force to the head - Severity ranges from mild (concussion) to severe - Common deficits: attention, memory, executive function, emotional regulation
Stroke (Cerebrovascular Accident): - Ischemic (blocked blood vessel) or hemorrhagic (bleeding) - Symptoms depend on location and extent - Common syndromes: aphasia, neglect, hemianopia
Neurodegenerative Diseases: - Alzheimer's Disease: Progressive memory loss, language difficulties, visuospatial impairment - Parkinson's Disease: Motor symptoms (tremor, rigidity, bradykinesia) plus cognitive changes - Huntington's Disease: Movement disorder with psychiatric and cognitive symptoms - Multiple Sclerosis: Demyelinating disease with variable cognitive effects
Epilepsy: Recurrent seizures; cognitive effects depend on seizure type and focus location.
Structural Imaging: - CT (Computed Tomography): X-ray based; detects acute hemorrhage, structural abnormalities - MRI (Magnetic Resonance Imaging): Superior soft tissue contrast; detailed structural views - DTI (Diffusion Tensor Imaging): Visualizes white matter tracts
Functional Imaging: - fMRI (functional MRI): Measures blood oxygenation (BOLD signal) as proxy for neural activity - PET (Positron Emission Tomography): Measures metabolic activity using radioactive tracers - SPECT (Single Photon Emission CT): Blood flow imaging
Electrophysiological Methods: - EEG (Electroencephalography): Records electrical activity from scalp; excellent temporal resolution - MEG (Magnetoencephalography): Records magnetic fields; excellent temporal and spatial resolution - ERP (Event-Related Potentials): Brain responses time-locked to stimuli
Emerging Techniques: Near-infrared spectroscopy (NIRS), transcranial magnetic stimulation (TMS), optogenetics
Typical functional differences between the left and right cerebral hemispheres.
| Left Hemisphere | Right Hemisphere | |
|---|---|---|
| Language | Production and comprehension | Emotional prosody and tone |
| Processing Style | Analytical and sequential | Holistic and gestalt |
| Spatial Ability | Limited | Mental rotation and navigation |
| Motor Control | Right side of body | Left side of body |
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