Okazawa et al. (2021) Cell
REPRESENTATIONAL GEOMETRY OF PERCEPTUAL DECISIONS IN THE MONKEY PARIETAL CORTEX.
Okazawa G, Hatch CE, Mancoo A, Machens CK, Kiani R.
Past study considered that average firing rate of neural activity in the parietal cortex represents evidence for perceptual decisions. We found that this is not the case in face categorization tasks and revealed that evidence is instead encoded along a non-linear task-dependent manifold in neural state space.
Okazawa, Sha, & Kiani (2021) J Neurosci
LINEAR INTEGRATION OF SENSORY EVIDENCE OVER SPACE AND TIME UNDERLIES FACE CATEGORIZATION.
Okazawa G, Sha L, Kiani R.
In simple perceptual tasks such as dot direction discrimination, the brain accumulates sensory evidence for decisions. How about more complex decisions such as face categorization? We found that face categorization could be explained as linear accumulation of evidence over space (facial features) and time.
Okazawa et al. (2018) Nat Comm
PSYCHOPHYSICAL REVERSE CORRELATION REFLECTS BOTH SENSORY AND DECISION-MAKING PROCESSES
Okazawa G, Sha L, Purcell BA, Kiani R
Psychophysical reverse correlation has been extensively used to reveal sensory filters or properties of decision-making process. Through modeling and psychophysics, we show that many parameters in both sensory and decision-making processes affect psychophysical kernel and thus we should be very careful when interpreting its results. A model-based approach is recommended.
Okazawa, Tajima, Komatsu (2015) PNAS
IMAGE STATISTICS UNDERLYING NATURAL TEXTURE SELECTIVITY OF NEURONS IN MACAQUE V4
Okazawa G, Tajima S, Komatsu H
A mid-level visual area, V4, responds to complex visual stimuli, but it was not clear what neurons were responding to. We show single V4 neurons respond to naturalistic textures and these responses could be explained as selectivity for higher-order image statistics.
FULL PUBLICATION LIST
Image statistics underlying natural texture selectivity of neurons in macaque V4. (2015)
Okazawa G, Tajima S, Komatsu H Proceedings of the National Academy of Sciences, USA 112 (4) E351-E360 [pdf]
Effects of luminance contrast on the color selectivity of neurons in the macaque area v4 and inferior temporal cortex. (2014)
Namima T, Yasuda M, Banno T, Okazawa G, Komatsu H J Neuroscience 34(45):14934-47 [pdf]
Image Statistics for Golden Appearance of a Painting by a Japanese Edo-era Artist Jakuchu Ito. (2013)
Okazawa G, Komatsu H in Lecture Notes in Computer Science, Computational Color Imaging (Ed. Tominaga S et. al) 7786:68-79, Springer
‘Yellow’ or ‘Gold’?: Neural Processing of Gloss Information [review]. (2013)
Komatsu H, Nishio A, Okazawa G, Goda N in Lecture Notes in Computer Science, Computational Color Imaging (Ed. Tominaga S et. al) 7786:1-12, Springer
Short-Term Memory of the Amplitude of Body Rotation in Orienting Behavior of African Clawed Frog (Xenopus laevis). (2013)
Okazawa G, Funahashi S ISRN Zoology 2013(ID734040):1-9