The Neural Fate of Consciously Perceived and Missed Events i
n the Attentional Blink
Marois et al.임상상담 전공 이지은
Two stages of attention
Attentional stage
Unconsciousstage
identification, consolidation, & conscious report
Rapid, global,& highly efficient categorization
Attentional blink (AB) paradigm
A
F
G
T
Shapiro et al., 1997
Rapid Serial Visual Presentation(RSVP)
Single-target test
Dual-target test
연구의 목적
-the different neural substrate for the two stage of attention 연구 AB paradigm – 의식적으로 보고한 target 과 보고되지 않은 target 간에 서로 다른 뇌영역 관여할 것
Parietofrontal cortical network –capacity-limited attention-demanding stage
Inferior temporal cortex -visual categorization & representation
- 연구의 가설 1) reported & unreported 시각자극 둘 다 occipitotemporal cortex 에까지 이르는 high-level stage 에 관여될 것
2) reported & unreported 시각자극은 정보처리의 뒷 단계인 parietofrontal network of attention 에서 차이날 것
실험절차1) 행동실험-dual task 실험 :T1 & T2 detection-single task 실험 :T2 detection
2) FMRI 실험-localizer task-dual task
Neural response to T2 processing
행동적 결과
Parahippocampal Place Area
Parahippocampal Place Area 의Timecourse of the hemodynamic response
Hit –o oMiss –o x CR -x x FA -x o
PPA 는 제시되는 자극이 의식되지 못하더라도 반응 -physical representation
Parietofrontal cortex
Frontal cortex 는 자극이 의식될 때만 반응 -explicit perception
Parietal & frontal cortex 의Timecourse of the hemodynamic response
Neural substrates of AB
Attentional stage
Unconsciousstage
Frontal cortex-consciously reported world
Medial temporal cortex-physical visual world
Neural correlates of a perceptual decision in ventral premoto
r cortex
임상상담 전공이지은
Ventral premotor cortex(VPC)
VPC :sensory information 을 action 으로 연결시키는 과정에 관련
1) parietal & prefrontal cortex 로부터 입력 & motor area, subcortical, & spinal cord 로 입력 2) VPC 에 감각 , 운동 neurons 존재 , 복잡한 sensorimotor action 입력 3) VPC 의 inactivation 은 sensorimotor task 에 영향
Ventral PremotorCortex (VPC) 실험조건 :
Base frequency 보다Comparison frequency 가높은지 낮은지 판단
통제조건 :빛나던 button 을 누름
결과 분석 :자극 -f1, f2, f2-f1반응 -hits & errors
과제 및 절차
VPC 의4 neurons 의
반응
Dynamics of VPC population response
Subgroups of VPC neurons
Neuronal &Behavioral response
논의
VPCSensation action
과거와 현재 정보의 통합
dynamic cross-talk
Reward-dependent gain and bias of visual responses
in primate superior colliculus
임상상담 전공이지은
• superior colliculus(SC) :sensory signals 를 가진 정보들이 입력되어 눈과 머리의 움직임을 orienting 하는 sensorimotor mechanisms
• 수많은 경쟁적 자극 중 선택의 문제 : “past experience of reward”
• 연구 목적 :investigate whether the SC is involved in the selection of visual targets by reward
실험 방법• Memory-guided saccade task (one-direction rewarded version) -cue :RF / cue :non RF -reward :RF / reward :non RF
• single-unit recording into SC
• measures -gross visual response -base activity -net visual response =gross-base
Base activity gross visual response
Cue100ms
Gain type
gain
bias type
PrecedingAnticipator
yactivity
Gain & bias type
PrecedingAnticipator
yactivity
Reward-continge
ntIncrease
RFrewarde
d
RFnonrewarded
각 neuron 에서 Net visual response 와 base act
ivity 간의 관계
Distribution in depth of reward-contingent modulation of SC
response
Discussion
• Using asymmetrically rewarded version of the memory-guided saccade task,
Cue 자극이 앞으로 올 보상을 의미할 때 SC neurons 의 visual response 가 증가함
-gain type / bias type
Basal gangliacuadate nucleus(CD)
Substantia nigraPars reticulata(SNr)
Saccadic behavior
Superior colliculus(SC)
Bias type•SNr & SC 의 연결부위 – SC 의 중간층 =SC 의 bias neurons 의 위치 saccadic activity •supplementary eye field (Coe et al., 2002)
Gain type•SC 의 response latency (40-80ms) << SNr & CD response latency (90-200ms) • early portion of SC response
-cortical eye fields
Cortical areas
CD
SNrbias
Gain & bias
gain
500 원
Discussion
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