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