3.1.1 learning & memory I

Sensory memory duration and capacity

<1 second with large capacity acting as a filter

Working memory duration and capacity

~20 seconds with 7 + or - 2 capacity, acting as a workspace to manipulate conscious information.

Long-term memory duration and capacity

Long-lasting sometimes permanent, unlimited capacity.

What is semantic memory?

General facts and knowledge.

What is episodic memory?

Autobiographical memory of personal experiences.

What structures are involved in the medial temporal memory circuit?

Hippocampus, Entorhinal and Perirhinal cortices, and Parahippocampus.

What is the perforant pathway?

Neocortex → Rhinal cortices → Hippocampus → Fornix → Thalamus and Hypothalamus → declarative memory storage in cortex.

Role of Hippocampus?

Convergence point binding experiences/cortical features into coherent memory.

Role of Rhinal cortices?

Stimulus familiarity, object recognition and bridging to neocortical memory network,

Role of Parahippocampus?

Process environmental scenes and spatial-contextual associations.

What is consolidation?

Conversion of memory from labile to stable form.

What is encoding?

Transformation or perception of thought or feeling into memory.

What is Anterograde amnesia?

Inability to form new declarative long-term memories.

What is Retrograde amnesia?

Loss of memories that were formed before injury.

What is temporal grading (Ribot’s law)?

Older memories preserves because they complete cortical consolidation where as recent hippocampal-dependant memories are lost.

Amnesia severity progression (least to most) re: MTL lesions

Hippocampus → Adjacent Entorhinal and Parahippocampal → Rhinal cortices.

Patient H.M. (Henry Molaison) bilateral medial temporal lobe lesion effects?

Severe anterograde amnesia and temporary graded retrograde amnesia.

Patient N.A Left dorsolateral thalamus lesion effects?

Severe anterograde amnesia and graded ~2 years retrograde amnesia.

Mammillary bodies atrophy and dorsomedial thalamus lesion effects?

Anterograde and retrograde amnesia.