COGNITIVE SCIENCE 17 Can You Remember My Name? Part 2 Jaime A. Pineda, Ph.D.
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Transcript of COGNITIVE SCIENCE 17 Can You Remember My Name? Part 2 Jaime A. Pineda, Ph.D.
COGNITIVE SCIENCE 17
Can You Remember My Name?
Part 2 Jaime A. Pineda, Ph.D.
HIPPO CAMPUS
Hippocampus: The Seahorse
Surrounding areas of hippocampus
(Clark, 2006)Perirhinal, Entorhinal and Parahippocampal Cortices
Hippocampus Malfunctions
• Severe anterograde amnesia
• Mild retrograde amnesia
• Problems navigating space
• Seizures
• Early Alzheimer’s Disease
Hippocampus Functions
• Consolidation of STM to LTM
• Spatial and contextual memory
• Episodic memory
• Declarative memory
• Detection of novel stimuli
• Neurogenesis
Spatial Navigation
Time as London taxi driverV
olu
me
of h
ipp
ocam
pu
s Spatial Navigation (cont.)
Age Differences in Maintenance Processes
600
800
1000
1200
1400
Rea
ctio
n T
ime
Memory Load
OlderYounger
Age differences increase with increasing memory set size
(Anders, Fozard & Lillyquist, 1972)
L R L R
Rypma, Prabhakaran, Desmond, & Gabrieli, 2001Psychology and Aging
Parahippocampus Hippocampus
Entorhinal cortex
Unimodal and polymodal association areas (frontal,
temporal, and parietal lobes)
Postrhinalcortex
Perirhinalcortex
DGCA3
SUBCA1
Trace Link
Hippocampal model
DG CA3 CA1
Entorhinal cortex
• Relating hippocampal structure to episodic memory function
• Mode shifting between storage and retrieval through novelty detection
• Population dynamics
• Relates parahippocampal structure to episodic memory function
• Sensory integration• ‘Object’ & ‘Context’ input• Retrieval mechanisms
– free recall
– cued recall
– recognition
Parahippocampal model
Hippocampus
Entorhinal cortex
Unimodal and polymodal association areas (frontal,
temporal, and parietal lobes)
Postrhinalcortex
Perirhinalcortex
Dentate gyrus
CA3
CA1subiculum
Trisynaptic Circuit
Circuit of Hippocampus Proper
Fimbria fornix (to mammillary bodies)
Hippocampus Cells
Pyramidal Cells
Place cells inhippocampusmap out the environment
Place cells respond as a function of external cues
Activity-Dependent Synaptic Plasticity
• Short-term plasticities– Facilitation (paired pulse facilitation):
100-200 ms; increased Ca++ increased p(NT release)
– Post-tetanic potentiation: 5-10 sec– Depression: hundreds of ms – few
minutes; caused by repetitive stimulation causing a decrease in p(NT release).
Activity-Dependent Synaptic Plasticity (cont.)
• Long-term plasticities– Short-term potentiation/depression– Long-term potentiation/depression
LTP is a persistent increase in synaptic efficacy that can be rapidly induced
Bliss and Lomo, 1973
NMDA Receptor• “Detects” simultaneous events
(“AND” gate)
• Gated by combination of voltage and ligand
– Glu + Gly opens channel to Ca ++,
– Magnesium (Mg++) block removed by membrane depolarization
• Mediates learning and memory via LTP (long term potentiation)
– Involved in process of addiction; behavioral sensitization, and drug craving
Learning Induced Changes in Dendrites
Effects of Increased NMDA Receptors