The biological basis of memory Gavin Norton Room 6MO7

Memory storage Association cortices Unimodal Multimodal

Primary motor cortex a - Frontal lobe Primary somatic sensory cortex b - Temporal lobe Primary visual cortex c - Occipital lobe Primary auditory cortex d – Parietal lobe Primary olfactory cortex

Unimodal somatosensory cortex Touch Pressure Temperature Texture Vibration Proprioception Tactile discrimination Size and shape of objects, direction of movement

Unimodal auditory cortex Sound frequency Sound pitch Sound timing Auditory perception

Unimodal visual cortex Dorsal pathways Motion and depth Form and colour Ventral pathways Visual perception

Multimodal cortices further integrate Somatosensory and visual Motor and Wernickes Visual and auditory Visual and visual Perception of space Somatosensory and visual Visual and visual Advanced visual perception Perception of language Visual and auditory (Wernickes area) Motor and Wernickes Language expression

1. 2. 3. 4. 5. 6. 1. Agnosias, apraxias 4. Receptive aphasia/dysphasia 2. Achromatosia, visual agnosias 5. Expressive aphasia/dysphasia 3. Neglect syndrome 6. Prosopagnosia and loss of recall of specific items

Agnosias, apraxias Agnosia-disorder of higher sensory analysis Apraxia-disorder of higher level (skilled) motor function Tactile agnosias Agraphasthesia Astereognosis - can’t identify shapes drawn on hand - can’t identify objects in hand Apraxias Motor (e.g. dressing) Constructional Visual agnosias Spatial agnosia (optic ataxia) Simultanagnosia - can’t judge distances - can’t compare sizes and shapes

Memory processing Short-term memory (working memory) Long-term memory

Short-term memory (working memory) 1. 2. 3. 4. 1. Spatial working memory 2. Object working memory 3. Verbal working memory 4. Object working memory

Long-term memory Anatomical substrate Explicit (declarative) Implicit (non-declarative) Procedural (motor skills) Basal ganglion Non-associative (habituation and sensitisation) ? Associative (conditioning) Amygdala Temporal lobe Anatomical substrate

Hippocampal formation + dentate gyrus and subiculum

Medial cerebral cortex a = frontal lobe b = temporal lobe c = occipital lobe d = parietal lobe parahippocampus hippocampus Perirhinal and enterorhinal cortices Mamillary body and mamillothamalic tract

Explicit long-term memory Sensory input Unimodal and multimodal cortices Working memory in frontal lobes Parahippocampal cortex Perirhinal and enterorhinal cortices Mamillary body and mamillothalamic tract Hippocampus Dentate Subiculum

Glutamate NMDA AMPA NMDA Mg2+ Ca2+ Increases release Ca2+ Mg2+ Sensitises Less negative

Amnesias and dementias Short-term memory deficits Long-term memory deficits Anterograde amnesia Retrograde amnesia Korsakoff’s syndrome